From 851049b1973fe24bdee005ef6c4f2b79b2b18179 Mon Sep 17 00:00:00 2001
From: Brett McBride <brett@deakin.edu.au>
Date: Mon, 13 Jun 2022 10:29:02 +1000
Subject: [PATCH 01/14] adding events per spec, "SDK implementations MUST allow
 end users to change the library's default error handling behavior for
 relevant errors"

---
 composer.json                                 |  1 +
 examples/EventsExample.php                    | 68 ++++++++++++++
 src/Contrib/Jaeger/JaegerTransport.php        |  7 +-
 src/Contrib/OtlpGrpc/Exporter.php             |  8 +-
 src/SDK/Common/Event/Dispatcher.php           | 39 ++++++++
 src/SDK/Common/Event/Event/DebugEvent.php     | 20 ++++
 src/SDK/Common/Event/Event/ErrorEvent.php     | 33 +++++++
 src/SDK/Common/Event/Event/WarningEvent.php   |  9 ++
 src/SDK/Common/Event/EventType.php            | 16 ++++
 .../Event/Handler/DebugEventHandler.php       | 18 ++++
 .../Event/Handler/ErrorEventHandler.php       | 18 ++++
 .../Event/Handler/WarningEventHandler.php     | 18 ++++
 src/SDK/Common/Event/SimpleDispatcher.php     | 62 +++++++++++++
 .../Common/Event/SimpleListenerProvider.php   | 47 ++++++++++
 src/SDK/Common/Event/StoppableEventTrait.php  | 20 ++++
 .../Trace/Behavior/HttpSpanExporterTrait.php  |  6 ++
 .../SpanProcessor/SimpleSpanProcessor.php     |  5 +-
 src/SDK/Trace/TracerProviderFactory.php       |  8 +-
 .../Unit/SDK/Common/Event/DispatcherTest.php  | 47 ++++++++++
 .../SDK/Common/Event/SimpleDispatcherTest.php | 93 +++++++++++++++++++
 .../Event/SimpleListenerProviderTest.php      | 83 +++++++++++++++++
 .../Common/Event/StoppableEventTraitTest.php  | 33 +++++++
 .../SpanProcessor/MultiSpanProcessorTest.php  |  2 +-
 .../SDK/Trace/TracerProviderFactoryTest.php   | 18 ++--
 24 files changed, 662 insertions(+), 17 deletions(-)
 create mode 100644 examples/EventsExample.php
 create mode 100644 src/SDK/Common/Event/Dispatcher.php
 create mode 100644 src/SDK/Common/Event/Event/DebugEvent.php
 create mode 100644 src/SDK/Common/Event/Event/ErrorEvent.php
 create mode 100644 src/SDK/Common/Event/Event/WarningEvent.php
 create mode 100644 src/SDK/Common/Event/EventType.php
 create mode 100644 src/SDK/Common/Event/Handler/DebugEventHandler.php
 create mode 100644 src/SDK/Common/Event/Handler/ErrorEventHandler.php
 create mode 100644 src/SDK/Common/Event/Handler/WarningEventHandler.php
 create mode 100644 src/SDK/Common/Event/SimpleDispatcher.php
 create mode 100644 src/SDK/Common/Event/SimpleListenerProvider.php
 create mode 100644 src/SDK/Common/Event/StoppableEventTrait.php
 create mode 100644 tests/Unit/SDK/Common/Event/DispatcherTest.php
 create mode 100644 tests/Unit/SDK/Common/Event/SimpleDispatcherTest.php
 create mode 100644 tests/Unit/SDK/Common/Event/SimpleListenerProviderTest.php
 create mode 100644 tests/Unit/SDK/Common/Event/StoppableEventTraitTest.php

diff --git a/composer.json b/composer.json
index 21376c4e8..3f50bf034 100644
--- a/composer.json
+++ b/composer.json
@@ -15,6 +15,7 @@
         "php-http/async-client-implementation": "^1.0",
         "php-http/discovery": "^1.14",
         "promphp/prometheus_client_php": "^2.2.1",
+        "psr/event-dispatcher": "^1",
         "psr/http-factory-implementation": "^1.0",
         "psr/log": "^1.1|^2.0|^3.0",
         "symfony/polyfill-mbstring": "^1.23"
diff --git a/examples/EventsExample.php b/examples/EventsExample.php
new file mode 100644
index 000000000..9ff316f37
--- /dev/null
+++ b/examples/EventsExample.php
@@ -0,0 +1,68 @@
+<?php
+
+declare(strict_types=1);
+require __DIR__ . '/../vendor/autoload.php';
+
+use Monolog\Formatter\JsonFormatter;
+use Monolog\Handler\StreamHandler;
+use Monolog\Logger;
+use OpenTelemetry\Contrib\Zipkin\Exporter as ZipkinExporter;
+use OpenTelemetry\SDK\Common\Event\Dispatcher;
+use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
+use OpenTelemetry\SDK\Common\Event\EventType;
+use OpenTelemetry\SDK\Common\Event\SimpleDispatcher;
+use OpenTelemetry\SDK\Common\Event\SimpleListenerProvider;
+use OpenTelemetry\SDK\Common\Log\LoggerHolder;
+use OpenTelemetry\SDK\Trace\SpanProcessor\SimpleSpanProcessor;
+use OpenTelemetry\SDK\Trace\TracerProvider;
+use Psr\Log\LogLevel;
+
+/**
+ * This example shows how you can hook in to OpenTelemetry's events, such as when an error or warning is emitted by
+ * the library. OpenTelemetry will always attempt to log and continue on error, and may provide no-op implementations
+ * of classes if it was unable to create them as requested.
+ * The default event handlers will use a PSR-3 logger to log events - verbosity and output format can be controlled
+ * through the usual PSR-3 log levels and formatters (if available).
+ * If you wish to do something different with events, you may provide an alternative PSR-14 implementation, but be
+ * aware that you will need to register handlers for all events that you are interested in.
+ */
+
+//logger used by default event handlers
+LoggerHolder::set(
+    new Logger('otel-php', [(new StreamHandler(STDOUT, LogLevel::DEBUG))->setFormatter(new JsonFormatter())])
+);
+
+/**
+ * Register event listeners - this only works for SimpleEventDispatcher. For other PSR-14 implementations, you will
+/* need to register all events that you are interested in, @see {SDK\Event\EventTypes}
+ */
+$listenerProvider = new SimpleListenerProvider();
+$listenerProvider->listen(EventType::ERROR, function (ErrorEvent $event) {
+    echo 'Custom handling of an error event: ' . $event->getError()->getMessage() . PHP_EOL;
+}, -10); //runs before built-in handler
+$listenerProvider->listen(EventType::ERROR, function (ErrorEvent $event) {
+    echo 'Another custom handling of an error event: ' . $event->getMessage() . PHP_EOL;
+    echo json_encode($event->getError()->getTrace()) . PHP_EOL;
+    echo 'Stopping event propagation...' . PHP_EOL;
+    $event->stopPropagation();
+}, 5); //runs after build-in handler
+$listenerProvider->listen(EventType::ERROR, function (ErrorEvent $event) {
+    echo 'This will not be executed, because a high priority handler stopped event propagation.' . PHP_EOL;
+}, 10);
+
+Dispatcher::setInstance(new SimpleDispatcher($listenerProvider));
+
+//or, provide your own PSR-14 event dispatcher. This must be done before getting a tracer:
+//$listenerProvider = new \Any\Psr14\ListenerProvider();
+//$listenerProvider->listen(EventType::ERROR, function(ErrorEvent $event){...});
+//DispatcherHolder::setInstance(\Any\Psr14\EventDispatcherInterface($listenerProvider));
+
+$tracerProvider =  new TracerProvider(
+    new SimpleSpanProcessor(
+        ZipkinExporter::fromConnectionString('http://invalid-host:9999', 'zipkin-exporter')
+    )
+);
+$tracer = $tracerProvider->getTracer();
+
+$span = $tracer->spanBuilder('root')->startSpan();
+$span->end();
diff --git a/src/Contrib/Jaeger/JaegerTransport.php b/src/Contrib/Jaeger/JaegerTransport.php
index 786d20ae3..3ec31f5f7 100644
--- a/src/Contrib/Jaeger/JaegerTransport.php
+++ b/src/Contrib/Jaeger/JaegerTransport.php
@@ -8,14 +8,13 @@
 use Jaeger\Thrift\Batch;
 use Jaeger\Thrift\Process;
 use Jaeger\Thrift\Span;
-use OpenTelemetry\SDK\Behavior\LogsMessagesTrait;
+use OpenTelemetry\SDK\Common\Event\Dispatcher;
+use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
 use Thrift\Exception\TTransportException;
 use Thrift\Protocol\TCompactProtocol;
 
 final class JaegerTransport implements TransportInterface
 {
-    use LogsMessagesTrait;
-
     // DEFAULT_BUFFER_SIZE indicates the default maximum buffer size, or the size threshold
     // at which the buffer will be flushed to the agent.
     const DEFAULT_BUFFER_SIZE = 1;
@@ -93,7 +92,7 @@ public function flush($force = false): int
             // reset the process tag
             $this->process = null;
         } catch (TTransportException $e) {
-            self::logError('jaeger: transport failure: ' . $e->getMessage());
+            Dispatcher::getInstance()->dispatch(new ErrorEvent('jaeger transport failure', $e));
 
             return 0;
         }
diff --git a/src/Contrib/OtlpGrpc/Exporter.php b/src/Contrib/OtlpGrpc/Exporter.php
index 6687d2ae2..ac24c482c 100644
--- a/src/Contrib/OtlpGrpc/Exporter.php
+++ b/src/Contrib/OtlpGrpc/Exporter.php
@@ -4,6 +4,7 @@
 
 namespace OpenTelemetry\Contrib\OtlpGrpc;
 
+use Exception;
 use grpc;
 use Grpc\ChannelCredentials;
 use OpenTelemetry\Contrib\Otlp\ExporterTrait;
@@ -12,6 +13,9 @@
 use Opentelemetry\Proto\Collector\Trace\V1\TraceServiceClient;
 use OpenTelemetry\SDK\Common\Environment\KnownValues as Values;
 use OpenTelemetry\SDK\Common\Environment\Variables as Env;
+use OpenTelemetry\SDK\Common\Event\Dispatcher;
+use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
+use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
 use OpenTelemetry\SDK\Trace\Behavior\SpanExporterTrait;
 use OpenTelemetry\SDK\Trace\SpanExporterInterface;
 
@@ -140,12 +144,12 @@ protected function doExport(iterable $spans): int
             \Grpc\STATUS_DATA_LOSS,
             \Grpc\STATUS_UNAUTHENTICATED,
         ], true)) {
-            self::logWarning('Retryable error exporting grpc span', ['error' => $error]);
+            Dispatcher::getInstance()->dispatch(new WarningEvent('Retryable error exporting grpc span', new Exception($error['error'], $error['code'])));
 
             return self::STATUS_FAILED_RETRYABLE;
         }
 
-        self::logError('Error exporting grpc span', ['error' => $error]);
+        Dispatcher::getInstance()->dispatch(new ErrorEvent('Error exporting grpc span', new Exception($error['error'])));
 
         return self::STATUS_FAILED_NOT_RETRYABLE;
     }
diff --git a/src/SDK/Common/Event/Dispatcher.php b/src/SDK/Common/Event/Dispatcher.php
new file mode 100644
index 000000000..816fb5b84
--- /dev/null
+++ b/src/SDK/Common/Event/Dispatcher.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\SDK\Common\Event;
+
+use OpenTelemetry\SDK\Common\Event\Handler\DebugEventHandler;
+use OpenTelemetry\SDK\Common\Event\Handler\ErrorEventHandler;
+use OpenTelemetry\SDK\Common\Event\Handler\WarningEventHandler;
+use Psr\EventDispatcher\EventDispatcherInterface;
+
+class Dispatcher
+{
+    private static ?EventDispatcherInterface $instance = null;
+
+    public static function getInstance(): EventDispatcherInterface
+    {
+        if (self::$instance === null) {
+            $dispatcher = new SimpleDispatcher(new SimpleListenerProvider());
+            $dispatcher->listen(EventType::ERROR, new ErrorEventHandler());
+            $dispatcher->listen(EventType::WARNING, new WarningEventHandler());
+            $dispatcher->listen(EventType::DEBUG, new DebugEventHandler());
+
+            self::$instance = $dispatcher;
+        }
+
+        return self::$instance;
+    }
+
+    public static function setInstance(EventDispatcherInterface $dispatcher): void
+    {
+        self::$instance = $dispatcher;
+    }
+
+    public static function unset(): void
+    {
+        self::$instance = null;
+    }
+}
diff --git a/src/SDK/Common/Event/Event/DebugEvent.php b/src/SDK/Common/Event/Event/DebugEvent.php
new file mode 100644
index 000000000..d90923577
--- /dev/null
+++ b/src/SDK/Common/Event/Event/DebugEvent.php
@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\SDK\Common\Event\Event;
+
+class DebugEvent
+{
+    private string $message;
+
+    public function __construct(string $message)
+    {
+        $this->message = $message;
+    }
+
+    public function getMessage(): string
+    {
+        return $this->message;
+    }
+}
diff --git a/src/SDK/Common/Event/Event/ErrorEvent.php b/src/SDK/Common/Event/Event/ErrorEvent.php
new file mode 100644
index 000000000..9392c992e
--- /dev/null
+++ b/src/SDK/Common/Event/Event/ErrorEvent.php
@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\SDK\Common\Event\Event;
+
+use OpenTelemetry\SDK\Common\Event\StoppableEventTrait;
+use Psr\EventDispatcher\StoppableEventInterface;
+use Throwable;
+
+class ErrorEvent implements StoppableEventInterface
+{
+    use StoppableEventTrait;
+
+    private string $message;
+    private Throwable $error;
+
+    public function __construct(string $message, Throwable $error)
+    {
+        $this->message = $message;
+        $this->error = $error;
+    }
+
+    public function getError(): Throwable
+    {
+        return $this->error;
+    }
+
+    public function getMessage(): string
+    {
+        return $this->message;
+    }
+}
diff --git a/src/SDK/Common/Event/Event/WarningEvent.php b/src/SDK/Common/Event/Event/WarningEvent.php
new file mode 100644
index 000000000..30b0e6e16
--- /dev/null
+++ b/src/SDK/Common/Event/Event/WarningEvent.php
@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\SDK\Common\Event\Event;
+
+class WarningEvent extends ErrorEvent
+{
+}
diff --git a/src/SDK/Common/Event/EventType.php b/src/SDK/Common/Event/EventType.php
new file mode 100644
index 000000000..ee6f291a5
--- /dev/null
+++ b/src/SDK/Common/Event/EventType.php
@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\SDK\Common\Event;
+
+use OpenTelemetry\SDK\Common\Event\Event\DebugEvent;
+use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
+use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
+
+class EventType
+{
+    public const ERROR = ErrorEvent::class;
+    public const WARNING = WarningEvent::class;
+    public const DEBUG = DebugEvent::class;
+}
diff --git a/src/SDK/Common/Event/Handler/DebugEventHandler.php b/src/SDK/Common/Event/Handler/DebugEventHandler.php
new file mode 100644
index 000000000..d1952b622
--- /dev/null
+++ b/src/SDK/Common/Event/Handler/DebugEventHandler.php
@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\SDK\Common\Event\Handler;
+
+use OpenTelemetry\SDK\Behavior\LogsMessagesTrait;
+use OpenTelemetry\SDK\Common\Event\Event\DebugEvent;
+
+class DebugEventHandler
+{
+    use LogsMessagesTrait;
+
+    public function __invoke(DebugEvent $event): void
+    {
+        self::logDebug($event->getMessage());
+    }
+}
diff --git a/src/SDK/Common/Event/Handler/ErrorEventHandler.php b/src/SDK/Common/Event/Handler/ErrorEventHandler.php
new file mode 100644
index 000000000..46453d404
--- /dev/null
+++ b/src/SDK/Common/Event/Handler/ErrorEventHandler.php
@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\SDK\Common\Event\Handler;
+
+use OpenTelemetry\SDK\Behavior\LogsMessagesTrait;
+use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
+
+class ErrorEventHandler
+{
+    use LogsMessagesTrait;
+
+    public function __invoke(ErrorEvent $event): void
+    {
+        self::logError($event->getError()->getMessage(), ['error' => $event->getError()]);
+    }
+}
diff --git a/src/SDK/Common/Event/Handler/WarningEventHandler.php b/src/SDK/Common/Event/Handler/WarningEventHandler.php
new file mode 100644
index 000000000..97fc518fe
--- /dev/null
+++ b/src/SDK/Common/Event/Handler/WarningEventHandler.php
@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\SDK\Common\Event\Handler;
+
+use OpenTelemetry\SDK\Behavior\LogsMessagesTrait;
+use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
+
+class WarningEventHandler
+{
+    use LogsMessagesTrait;
+
+    public function __invoke(WarningEvent $event): void
+    {
+        self::logWarning($event->getMessage(), ['error' => $event->getError()]);
+    }
+}
diff --git a/src/SDK/Common/Event/SimpleDispatcher.php b/src/SDK/Common/Event/SimpleDispatcher.php
new file mode 100644
index 000000000..27ea91e8b
--- /dev/null
+++ b/src/SDK/Common/Event/SimpleDispatcher.php
@@ -0,0 +1,62 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\SDK\Common\Event;
+
+use Psr\EventDispatcher\EventDispatcherInterface;
+use Psr\EventDispatcher\ListenerProviderInterface;
+use Psr\EventDispatcher\StoppableEventInterface;
+
+class SimpleDispatcher implements EventDispatcherInterface
+{
+    private ListenerProviderInterface $listenerProvider;
+
+    public function __construct(ListenerProviderInterface $listenerProvider)
+    {
+        $this->listenerProvider = $listenerProvider;
+    }
+
+    public function getListenerProvider(): ListenerProviderInterface
+    {
+        return $this->listenerProvider;
+    }
+
+    public function listen(string $event, callable $listener, int $priority = 0): void
+    {
+        if (is_a($this->listenerProvider, SimpleListenerProvider::class)) {
+            $this->listenerProvider->listen($event, $listener, $priority);
+        }
+        /* there is no standard interface to register listeners, nor access a listener provider. Using a different listener provider
+           requires also setting up all required listeners for that provider */
+    }
+
+    public function dispatch(object $event): object
+    {
+        $listeners = $this->listenerProvider->getListenersForEvent($event);
+
+        $event instanceof StoppableEventInterface
+            ? $this->dispatchStoppableEvent($listeners, $event)
+            : $this->dispatchEvent($listeners, $event);
+
+        return $event;
+    }
+
+    private function dispatchStoppableEvent(iterable $listeners, StoppableEventInterface $event): void
+    {
+        foreach ($listeners as $listener) {
+            if ($event->isPropagationStopped()) {
+                break;
+            }
+
+            $listener($event);
+        }
+    }
+
+    private function dispatchEvent(iterable $listeners, object $event): void
+    {
+        foreach ($listeners as $listener) {
+            $listener($event);
+        }
+    }
+}
diff --git a/src/SDK/Common/Event/SimpleListenerProvider.php b/src/SDK/Common/Event/SimpleListenerProvider.php
new file mode 100644
index 000000000..0d2499cc4
--- /dev/null
+++ b/src/SDK/Common/Event/SimpleListenerProvider.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\SDK\Common\Event;
+
+use Psr\EventDispatcher\ListenerProviderInterface;
+
+class SimpleListenerProvider implements ListenerProviderInterface
+{
+    /** @var array<string, array<int, array<callable>>> */
+    private array $listeners = [];
+
+    /**
+     * @psalm-suppress ArgumentTypeCoercion
+     */
+    public function getListenersForEvent(object $event): iterable
+    {
+        foreach ($this->listeners as $key => $priority) {
+            if (is_a($event, $key)) {
+                foreach ($priority as $listeners) {
+                    foreach ($listeners as $listener) {
+                        yield $listener;
+                    }
+                }
+            }
+        }
+        /*        $eventListeners = $this->listeners[get_class($event)] ?? [[]];
+                foreach ($eventListeners as $listeners) {
+                    foreach ($listeners as $listener) {
+                        yield $listener;
+                    }
+                }*/
+    }
+
+    public function listen(string $event, callable $listener, int $priority = 0): void
+    {
+        /*if (!array_key_exists($event, $this->listeners)) {
+            $this->listeners[$event] = [];
+        }
+        if (!array_key_exists($priority, $this->listeners[$event])) {
+            $this->listeners[$event][$priority] = [];
+        }*/
+        $this->listeners[$event][$priority][] = $listener;
+        ksort($this->listeners[$event]);
+    }
+}
diff --git a/src/SDK/Common/Event/StoppableEventTrait.php b/src/SDK/Common/Event/StoppableEventTrait.php
new file mode 100644
index 000000000..8ebada6df
--- /dev/null
+++ b/src/SDK/Common/Event/StoppableEventTrait.php
@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\SDK\Common\Event;
+
+trait StoppableEventTrait
+{
+    private bool $stopped = false;
+
+    public function isPropagationStopped(): bool
+    {
+        return $this->stopped;
+    }
+
+    public function stopPropagation(): void
+    {
+        $this->stopped = true;
+    }
+}
diff --git a/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php b/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php
index 4fcda9f3e..97d1bddaa 100644
--- a/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php
+++ b/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php
@@ -6,6 +6,8 @@
 
 use InvalidArgumentException;
 use JsonException;
+use OpenTelemetry\SDK\Common\Event\Dispatcher;
+use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
 use OpenTelemetry\SDK\Trace\SpanExporterInterface;
 use Psr\Http\Client\ClientExceptionInterface;
 use Psr\Http\Client\ClientInterface;
@@ -46,10 +48,14 @@ protected function doExport(iterable $spans): int
         try {
             $response = $this->dispatchSpans($spans);
         } catch (ClientExceptionInterface $e) {
+            Dispatcher::getInstance()->dispatch(new ErrorEvent('Error exporting span', $e));
+
             return $e instanceof RequestExceptionInterface
                 ? SpanExporterInterface::STATUS_FAILED_NOT_RETRYABLE
                 : SpanExporterInterface::STATUS_FAILED_RETRYABLE;
         } catch (Throwable $e) {
+            Dispatcher::getInstance()->dispatch(new ErrorEvent('Error exporting span', $e));
+
             return SpanExporterInterface::STATUS_FAILED_NOT_RETRYABLE;
         }
 
diff --git a/src/SDK/Trace/SpanProcessor/SimpleSpanProcessor.php b/src/SDK/Trace/SpanProcessor/SimpleSpanProcessor.php
index 106a1beeb..3542ed979 100644
--- a/src/SDK/Trace/SpanProcessor/SimpleSpanProcessor.php
+++ b/src/SDK/Trace/SpanProcessor/SimpleSpanProcessor.php
@@ -6,6 +6,8 @@
 
 use OpenTelemetry\Context\Context;
 use OpenTelemetry\SDK\Behavior\LogsMessagesTrait;
+use OpenTelemetry\SDK\Common\Event\Dispatcher;
+use OpenTelemetry\SDK\Common\Event\Event\DebugEvent;
 use OpenTelemetry\SDK\Trace\ReadableSpanInterface;
 use OpenTelemetry\SDK\Trace\ReadWriteSpanInterface;
 use OpenTelemetry\SDK\Trace\SpanExporterInterface;
@@ -54,7 +56,8 @@ public function shutdown(): bool
         }
 
         $this->running = false;
-        self::logDebug('Shutting down span processor');
+        Dispatcher::getInstance()->dispatch(new DebugEvent('Shutting down span processor'));
+        //self::logDebug('Shutting down span processor');
 
         if (null !== $this->exporter) {
             return $this->forceFlush() && $this->exporter->shutdown();
diff --git a/src/SDK/Trace/TracerProviderFactory.php b/src/SDK/Trace/TracerProviderFactory.php
index f27410eaa..ae5ee5fab 100644
--- a/src/SDK/Trace/TracerProviderFactory.php
+++ b/src/SDK/Trace/TracerProviderFactory.php
@@ -6,6 +6,8 @@
 
 use OpenTelemetry\API\Trace as API;
 use OpenTelemetry\SDK\Behavior\LogsMessagesTrait;
+use OpenTelemetry\SDK\Common\Event\Dispatcher;
+use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
 
 final class TracerProviderFactory
 {
@@ -31,21 +33,21 @@ public function create(): API\TracerProviderInterface
         try {
             $exporter = $this->exporterFactory->fromEnvironment();
         } catch (\Throwable $t) {
-            self::logWarning('Unable to create exporter', ['error' => $t]);
+            Dispatcher::getInstance()->dispatch(new WarningEvent('Unable to create exporter', $t));
             $exporter = null;
         }
 
         try {
             $sampler = $this->samplerFactory->fromEnvironment();
         } catch (\Throwable $t) {
-            self::logWarning('Unable to create sampler', ['error' => $t]);
+            Dispatcher::getInstance()->dispatch(new WarningEvent('Unable to create sampler', $t));
             $sampler = null;
         }
 
         try {
             $spanProcessor = $this->spanProcessorFactory->fromEnvironment($exporter);
         } catch (\Throwable $t) {
-            self::logWarning('Unable to create span processor', ['error' => $t]);
+            Dispatcher::getInstance()->dispatch(new WarningEvent('Unable to create span processor', $t));
             $spanProcessor = null;
         }
 
diff --git a/tests/Unit/SDK/Common/Event/DispatcherTest.php b/tests/Unit/SDK/Common/Event/DispatcherTest.php
new file mode 100644
index 000000000..9271e67a4
--- /dev/null
+++ b/tests/Unit/SDK/Common/Event/DispatcherTest.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Tests\Unit\SDK\Common\Event;
+
+use OpenTelemetry\SDK\Common\Event\Dispatcher;
+use OpenTelemetry\SDK\Common\Event\Event\DebugEvent;
+use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
+use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
+use OpenTelemetry\SDK\Common\Event\SimpleDispatcher;
+use OpenTelemetry\SDK\Common\Event\SimpleListenerProvider;
+use PHPUnit\Framework\TestCase;
+use Psr\EventDispatcher\EventDispatcherInterface;
+
+/**
+ * @covers \OpenTelemetry\SDK\Common\Event\Dispatcher
+ */
+class DispatcherTest extends TestCase
+{
+    public function setUp(): void
+    {
+        Dispatcher::unset();
+    }
+
+    public function tearDown(): void
+    {
+        Dispatcher::unset();
+    }
+
+    public function test_configures_self(): void
+    {
+        $dispatcher = Dispatcher::getInstance();
+        $this->assertInstanceOf(SimpleDispatcher::class, $dispatcher);
+        $this->assertInstanceOf(SimpleListenerProvider::class, $dispatcher->getListenerProvider());
+        $this->assertGreaterThan(0, count([...$dispatcher->getListenerProvider()->getListenersForEvent($this->createMock(ErrorEvent::class))]));
+        $this->assertGreaterThan(0, count([...$dispatcher->getListenerProvider()->getListenersForEvent($this->createMock(WarningEvent::class))]));
+        $this->assertGreaterThan(0, count([...$dispatcher->getListenerProvider()->getListenersForEvent($this->createMock(DebugEvent::class))]));
+    }
+
+    public function test_set_instance(): void
+    {
+        $mock = $this->createMock(EventDispatcherInterface::class);
+        Dispatcher::setInstance($mock);
+        $this->assertSame($mock, Dispatcher::getInstance());
+    }
+}
diff --git a/tests/Unit/SDK/Common/Event/SimpleDispatcherTest.php b/tests/Unit/SDK/Common/Event/SimpleDispatcherTest.php
new file mode 100644
index 000000000..4066d84fd
--- /dev/null
+++ b/tests/Unit/SDK/Common/Event/SimpleDispatcherTest.php
@@ -0,0 +1,93 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Tests\Unit\SDK\Common\Event;
+
+use OpenTelemetry\SDK\Common\Event\SimpleDispatcher;
+use OpenTelemetry\SDK\Common\Event\SimpleListenerProvider;
+use PHPUnit\Framework\TestCase;
+use Psr\EventDispatcher\ListenerProviderInterface;
+use Psr\EventDispatcher\StoppableEventInterface;
+use stdClass;
+
+/**
+ * @covers \OpenTelemetry\SDK\Common\Event\SimpleDispatcher
+ */
+class SimpleDispatcherTest extends TestCase
+{
+    private ListenerProviderInterface $listenerProvider;
+
+    public function setUp(): void
+    {
+        $this->listenerProvider = $this->createMock(ListenerProviderInterface::class);
+    }
+
+    public function test_get_listener_provider(): void
+    {
+        $dispatcher = new SimpleDispatcher($this->listenerProvider);
+        $this->assertSame($this->listenerProvider, $dispatcher->getListenerProvider());
+    }
+
+    public function test_proxies_listen_for_simple_listener_provider(): void
+    {
+        $provider = $this->createMock(SimpleListenerProvider::class);
+        $callable = function () {
+        };
+        $eventName = 'my.event';
+        $priority = 99;
+        $dispatcher = new SimpleDispatcher($provider);
+        $provider
+            ->expects($this->once())
+            ->method('listen')
+            ->with(
+                $this->equalTo($eventName),
+                $this->equalTo($callable),
+                $this->equalTo($priority)
+            );
+        $dispatcher->listen($eventName, $callable, $priority);
+    }
+
+    /**
+     * @doesNotPerformAssertions
+     */
+    public function test_skips_other_listener_providers(): void
+    {
+        $provider = $this->createMock(ListenerProviderInterface::class);
+        $dispatcher = new SimpleDispatcher($provider);
+        $dispatcher->listen('my.event', function () {
+        });
+    }
+
+    /**
+     * @psalm-suppress UndefinedInterfaceMethod
+     */
+    public function test_dispatch_event(): void
+    {
+        $event = new stdClass();
+        $handler = function ($receivedEvent) use ($event) {
+            $this->assertSame($event, $receivedEvent);
+        };
+        $this->listenerProvider->expects($this->once())->method('getListenersForEvent')->willReturn([$handler]); //@phpstan-ignore-line
+        $dispatcher = new SimpleDispatcher($this->listenerProvider);
+        $dispatcher->dispatch($event);
+    }
+
+    /**
+     * @psalm-suppress UndefinedInterfaceMethod
+     */
+    public function test_dispatch_stoppable_event(): void
+    {
+        $event = $this->createMock(StoppableEventInterface::class);
+        $event->method('isPropagationStopped')->willReturnOnConsecutiveCalls(false, true);
+        $handlerOne = function (StoppableEventInterface $event) {
+            $this->assertTrue(true, 'handler called');
+        };
+        $handlerTwo = function (StoppableEventInterface $event) {
+            $this->fail('method should not have been called');
+        };
+        $this->listenerProvider->method('getListenersForEvent')->willReturn([$handlerOne, $handlerTwo]); //@phpstan-ignore-line
+        $dispatcher = new SimpleDispatcher($this->listenerProvider);
+        $dispatcher->dispatch($event);
+    }
+}
diff --git a/tests/Unit/SDK/Common/Event/SimpleListenerProviderTest.php b/tests/Unit/SDK/Common/Event/SimpleListenerProviderTest.php
new file mode 100644
index 000000000..79c86f2ba
--- /dev/null
+++ b/tests/Unit/SDK/Common/Event/SimpleListenerProviderTest.php
@@ -0,0 +1,83 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Tests\Unit\SDK\Common\Event;
+
+use OpenTelemetry\SDK\Common\Event\SimpleListenerProvider;
+use PHPUnit\Framework\TestCase;
+use stdClass;
+
+/**
+ * @covers \OpenTelemetry\SDK\Common\Event\SimpleListenerProvider
+ */
+class SimpleListenerProviderTest extends TestCase
+{
+    private SimpleListenerProvider $provider;
+
+    public function setUp(): void
+    {
+        $this->provider = new SimpleListenerProvider();
+    }
+
+    public function test_add_listeners(): void
+    {
+        $event = new stdClass();
+        $listenerFunction = function () {
+        };
+        $this->provider->listen(get_class($event), $listenerFunction);
+        $listeners = [...$this->provider->getListenersForEvent($event)];
+        $this->assertCount(1, $listeners);
+        $this->assertSame($listenerFunction, $listeners[0]);
+    }
+
+    public function test_can_add_multiple_listeners_with_same_priority(): void
+    {
+        $event = new stdClass();
+        $listenerOne = function ($event) {
+        };
+        $listenerTwo = function ($event) {
+        };
+        $this->provider->listen(get_class($event), $listenerOne);
+        $this->provider->listen(get_class($event), $listenerTwo);
+        $listeners = [...$this->provider->getListenersForEvent($event)];
+        $this->assertCount(2, $listeners);
+        $this->assertSame($listenerOne, $listeners[0]);
+        $this->assertSame($listenerTwo, $listeners[1]);
+    }
+
+    public function test_listener_priority(): void
+    {
+        $event = new stdClass();
+        $listenerOne = function () {
+        };
+        $listenerTwo = function () {
+        };
+        $listenerThree = function () {
+        };
+        $listenerFour = function () {
+        };
+        $this->provider->listen(get_class($event), $listenerOne, 1);
+        $this->provider->listen(get_class($event), $listenerTwo, -1);
+        $this->provider->listen(get_class($event), $listenerThree, 0);
+        $this->provider->listen(get_class($event), $listenerFour, 1);
+        $listeners = [...$this->provider->getListenersForEvent($event)];
+        $this->assertCount(4, $listeners);
+        $this->assertSame($listenerTwo, $listeners[0]);
+        $this->assertSame($listenerThree, $listeners[1]);
+        $this->assertSame($listenerOne, $listeners[2]);
+        $this->assertSame($listenerFour, $listeners[3]);
+    }
+
+    public function test_get_listener_for_subclass(): void
+    {
+        $event = new stdClass();
+        $subclass = $this->createMock(stdClass::class);
+        $listener = function () {
+        };
+        $this->provider->listen(stdClass::class, $listener);
+        $listeners = [...$this->provider->getListenersForEvent($subclass)];
+        $this->assertCount(1, $listeners);
+        $this->assertSame($listener, $listeners[0]);
+    }
+}
diff --git a/tests/Unit/SDK/Common/Event/StoppableEventTraitTest.php b/tests/Unit/SDK/Common/Event/StoppableEventTraitTest.php
new file mode 100644
index 000000000..f623c0548
--- /dev/null
+++ b/tests/Unit/SDK/Common/Event/StoppableEventTraitTest.php
@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Tests\Unit\SDK\Common\Event;
+
+use OpenTelemetry\SDK\Common\Event\StoppableEventTrait;
+use PHPUnit\Framework\TestCase;
+use Psr\EventDispatcher\StoppableEventInterface;
+
+/**
+ * @covers \OpenTelemetry\SDK\Common\Event\StoppableEventTrait
+ */
+class StoppableEventTraitTest extends TestCase
+{
+    /**
+     * @psalm-suppress UndefinedInterfaceMethod
+     */
+    public function test_stop_event(): void
+    {
+        $event = $this->getEvent();
+        $this->assertFalse($event->isPropagationStopped());
+        $event->stopPropagation(); //@phpstan-ignore-line
+        $this->assertTrue($event->isPropagationStopped());
+    }
+
+    public function getEvent(): StoppableEventInterface
+    {
+        return new class() implements StoppableEventInterface {
+            use StoppableEventTrait;
+        };
+    }
+}
diff --git a/tests/Unit/SDK/Trace/SpanProcessor/MultiSpanProcessorTest.php b/tests/Unit/SDK/Trace/SpanProcessor/MultiSpanProcessorTest.php
index 25e9c78c5..a22b7f07b 100644
--- a/tests/Unit/SDK/Trace/SpanProcessor/MultiSpanProcessorTest.php
+++ b/tests/Unit/SDK/Trace/SpanProcessor/MultiSpanProcessorTest.php
@@ -4,12 +4,12 @@
 
 namespace OpenTelemetry\Tests\Unit\SDK\Trace\SpanProcessor;
 
-use Monolog\Test\TestCase;
 use OpenTelemetry\SDK\Trace\ReadableSpanInterface;
 use OpenTelemetry\SDK\Trace\ReadWriteSpanInterface;
 use OpenTelemetry\SDK\Trace\SpanProcessor\MultiSpanProcessor;
 use OpenTelemetry\SDK\Trace\SpanProcessorInterface;
 use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @covers OpenTelemetry\SDK\Trace\SpanProcessor\MultiSpanProcessor
diff --git a/tests/Unit/SDK/Trace/TracerProviderFactoryTest.php b/tests/Unit/SDK/Trace/TracerProviderFactoryTest.php
index 67ca69a20..29c2b04b8 100644
--- a/tests/Unit/SDK/Trace/TracerProviderFactoryTest.php
+++ b/tests/Unit/SDK/Trace/TracerProviderFactoryTest.php
@@ -4,25 +4,27 @@
 
 namespace OpenTelemetry\Tests\Unit\SDK\Trace;
 
+use OpenTelemetry\SDK\Common\Event\Dispatcher;
+use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
 use OpenTelemetry\SDK\Common\Log\LoggerHolder;
 use OpenTelemetry\SDK\Trace\ExporterFactory;
 use OpenTelemetry\SDK\Trace\SamplerFactory;
 use OpenTelemetry\SDK\Trace\SpanProcessorFactory;
 use OpenTelemetry\SDK\Trace\TracerProviderFactory;
 use PHPUnit\Framework\TestCase;
-use Psr\Log\LoggerInterface;
+use Psr\EventDispatcher\EventDispatcherInterface;
 
 /**
  * @coversDefaultClass \OpenTelemetry\SDK\Trace\TracerProviderFactory
  */
 class TracerProviderFactoryTest extends TestCase
 {
-    private $logger;
+    private $dispatcher;
 
     public function setUp(): void
     {
-        $this->logger = $this->createMock(LoggerInterface::class);
-        LoggerHolder::set($this->logger);
+        $this->dispatcher = $this->createMock(EventDispatcherInterface::class);
+        Dispatcher::setInstance($this->dispatcher);
     }
 
     public function tearDown(): void
@@ -51,7 +53,7 @@ public function test_factory_creates_tracer(): void
     /**
      * @covers ::create
      */
-    public function test_factory_logs_warnings_and_continues(): void
+    public function test_factory_emits_warnings_and_continues(): void
     {
         $exporterFactory = $this->createMock(ExporterFactory::class);
         $samplerFactory = $this->createMock(SamplerFactory::class);
@@ -66,7 +68,11 @@ public function test_factory_logs_warnings_and_continues(): void
         $spanProcessorFactory->expects($this->once())
             ->method('fromEnvironment')
             ->willThrowException(new \InvalidArgumentException('foo'));
-        $this->logger->expects($this->atLeast(3))->method('log');
+        $this->dispatcher->expects($this->atLeast(3))->method('dispatch')->with($this->callback(function ($event) {
+            $this->assertInstanceOf(WarningEvent::class, $event);
+
+            return true;
+        }));
 
         $factory = new TracerProviderFactory('test', $exporterFactory, $samplerFactory, $spanProcessorFactory);
         $factory->create();

From 195eabbbd48f6060396a994c24775bf8a542bc3f Mon Sep 17 00:00:00 2001
From: Brett McBride <brett@deakin.edu.au>
Date: Mon, 13 Jun 2022 12:12:40 +1000
Subject: [PATCH 02/14] static analysis fixes

---
 src/SDK/Common/Event/Event/DebugEvent.php     |  9 +++++-
 src/SDK/Common/Event/Event/ErrorEvent.php     |  4 +--
 src/SDK/Common/Event/Event/WarningEvent.php   | 31 ++++++++++++++++++-
 .../SDK/Common/Event/Event/DebugEventTest.php | 23 ++++++++++++++
 .../SDK/Common/Event/Event/ErrorEventTest.php | 23 ++++++++++++++
 .../Common/Event/Handler/DebugHandlerTest.php | 27 ++++++++++++++++
 .../Common/Event/Handler/ErrorHandlerTest.php | 28 +++++++++++++++++
 .../Event/Handler/LogBasedHandlerTest.php     | 27 ++++++++++++++++
 .../Event/Handler/WarningHandlerTest.php      | 28 +++++++++++++++++
 tests/Unit/SDK/Trace/SpanTest.php             |  1 +
 10 files changed, 197 insertions(+), 4 deletions(-)
 create mode 100644 tests/Unit/SDK/Common/Event/Event/DebugEventTest.php
 create mode 100644 tests/Unit/SDK/Common/Event/Event/ErrorEventTest.php
 create mode 100644 tests/Unit/SDK/Common/Event/Handler/DebugHandlerTest.php
 create mode 100644 tests/Unit/SDK/Common/Event/Handler/ErrorHandlerTest.php
 create mode 100644 tests/Unit/SDK/Common/Event/Handler/LogBasedHandlerTest.php
 create mode 100644 tests/Unit/SDK/Common/Event/Handler/WarningHandlerTest.php

diff --git a/src/SDK/Common/Event/Event/DebugEvent.php b/src/SDK/Common/Event/Event/DebugEvent.php
index d90923577..360fb6fae 100644
--- a/src/SDK/Common/Event/Event/DebugEvent.php
+++ b/src/SDK/Common/Event/Event/DebugEvent.php
@@ -7,14 +7,21 @@
 class DebugEvent
 {
     private string $message;
+    private array $extra;
 
-    public function __construct(string $message)
+    public function __construct(string $message, array $extra = [])
     {
         $this->message = $message;
+        $this->extra = $extra;
     }
 
     public function getMessage(): string
     {
         return $this->message;
     }
+
+    public function getExtra(): array
+    {
+        return $this->extra;
+    }
 }
diff --git a/src/SDK/Common/Event/Event/ErrorEvent.php b/src/SDK/Common/Event/Event/ErrorEvent.php
index 9392c992e..ab59acb20 100644
--- a/src/SDK/Common/Event/Event/ErrorEvent.php
+++ b/src/SDK/Common/Event/Event/ErrorEvent.php
@@ -12,8 +12,8 @@ class ErrorEvent implements StoppableEventInterface
 {
     use StoppableEventTrait;
 
-    private string $message;
-    private Throwable $error;
+    protected string $message;
+    protected Throwable $error;
 
     public function __construct(string $message, Throwable $error)
     {
diff --git a/src/SDK/Common/Event/Event/WarningEvent.php b/src/SDK/Common/Event/Event/WarningEvent.php
index 30b0e6e16..0503d7819 100644
--- a/src/SDK/Common/Event/Event/WarningEvent.php
+++ b/src/SDK/Common/Event/Event/WarningEvent.php
@@ -4,6 +4,35 @@
 
 namespace OpenTelemetry\SDK\Common\Event\Event;
 
-class WarningEvent extends ErrorEvent
+use OpenTelemetry\SDK\Common\Event\StoppableEventTrait;
+use Psr\EventDispatcher\StoppableEventInterface;
+use Throwable;
+
+class WarningEvent implements StoppableEventInterface
 {
+    use StoppableEventTrait;
+
+    protected string $message;
+    protected ?Throwable $error = null;
+
+    public function __construct(string $message, ?Throwable $error)
+    {
+        $this->message = $message;
+        $this->error = $error;
+    }
+
+    public function getError(): ?Throwable
+    {
+        return $this->error;
+    }
+
+    public function hasError(): bool
+    {
+        return $this->error !== null;
+    }
+
+    public function getMessage(): string
+    {
+        return $this->message;
+    }
 }
diff --git a/tests/Unit/SDK/Common/Event/Event/DebugEventTest.php b/tests/Unit/SDK/Common/Event/Event/DebugEventTest.php
new file mode 100644
index 000000000..1cb0986c1
--- /dev/null
+++ b/tests/Unit/SDK/Common/Event/Event/DebugEventTest.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Tests\Unit\SDK\Common\Event\Event;
+
+use OpenTelemetry\SDK\Common\Event\Event\DebugEvent;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @covers \OpenTelemetry\SDK\Common\Event\Event\DebugEvent
+ */
+class DebugEventTest extends TestCase
+{
+    public function test_debug_event(): void
+    {
+        $message = 'foo';
+        $extra = ['bar' => 'baz'];
+        $event = new DebugEvent($message, $extra);
+        $this->assertSame($message, $event->getMessage());
+        $this->assertSame($extra, $event->getExtra());
+    }
+}
diff --git a/tests/Unit/SDK/Common/Event/Event/ErrorEventTest.php b/tests/Unit/SDK/Common/Event/Event/ErrorEventTest.php
new file mode 100644
index 000000000..5fcddf776
--- /dev/null
+++ b/tests/Unit/SDK/Common/Event/Event/ErrorEventTest.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Tests\Unit\SDK\Common\Event\Event;
+
+use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @covers \OpenTelemetry\SDK\Common\Event\Event\ErrorEvent
+ */
+class ErrorEventTest extends TestCase
+{
+    public function test_error_event(): void
+    {
+        $message = 'foo';
+        $exception = new \Exception();
+        $event = new ErrorEvent($message, $exception);
+        $this->assertSame($message, $event->getMessage());
+        $this->assertSame($exception, $event->getError());
+    }
+}
diff --git a/tests/Unit/SDK/Common/Event/Handler/DebugHandlerTest.php b/tests/Unit/SDK/Common/Event/Handler/DebugHandlerTest.php
new file mode 100644
index 000000000..ad9eb2ec1
--- /dev/null
+++ b/tests/Unit/SDK/Common/Event/Handler/DebugHandlerTest.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Tests\Unit\SDK\Common\Event\Handler;
+
+use OpenTelemetry\SDK\Common\Event\Event\DebugEvent;
+use OpenTelemetry\SDK\Common\Event\Handler\DebugEventHandler;
+use Psr\Log\LogLevel;
+
+/**
+ * @covers \OpenTelemetry\SDK\Common\Event\Handler\DebugEventHandler
+ */
+class DebugHandlerTest extends LogBasedHandlerTest
+{
+    /**
+     * @psalm-suppress UndefinedInterfaceMethod
+     */
+    public function test_logs_event(): void
+    {
+        $event = new DebugEvent('foo');
+        $handler = new DebugEventHandler();
+        // @phpstan-ignore-next-line
+        $this->logger->expects($this->once())->method('log')->with($this->equalTo(LogLevel::DEBUG));
+        $handler($event);
+    }
+}
diff --git a/tests/Unit/SDK/Common/Event/Handler/ErrorHandlerTest.php b/tests/Unit/SDK/Common/Event/Handler/ErrorHandlerTest.php
new file mode 100644
index 000000000..8b5698bb8
--- /dev/null
+++ b/tests/Unit/SDK/Common/Event/Handler/ErrorHandlerTest.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Tests\Unit\SDK\Common\Event\Handler;
+
+use Exception;
+use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
+use OpenTelemetry\SDK\Common\Event\Handler\ErrorEventHandler;
+use Psr\Log\LogLevel;
+
+/**
+ * @covers \OpenTelemetry\SDK\Common\Event\Handler\ErrorEventHandler
+ */
+class ErrorHandlerTest extends LogBasedHandlerTest
+{
+    /**
+     * @psalm-suppress UndefinedInterfaceMethod
+     */
+    public function test_logs_event(): void
+    {
+        $event = new ErrorEvent('foo', new Exception());
+        $handler = new ErrorEventHandler();
+        // @phpstan-ignore-next-line
+        $this->logger->expects($this->once())->method('log')->with($this->equalTo(LogLevel::ERROR));
+        $handler($event);
+    }
+}
diff --git a/tests/Unit/SDK/Common/Event/Handler/LogBasedHandlerTest.php b/tests/Unit/SDK/Common/Event/Handler/LogBasedHandlerTest.php
new file mode 100644
index 000000000..fada9155b
--- /dev/null
+++ b/tests/Unit/SDK/Common/Event/Handler/LogBasedHandlerTest.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Tests\Unit\SDK\Common\Event\Handler;
+
+use OpenTelemetry\SDK\Common\Log\LoggerHolder;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+use Psr\Log\LoggerInterface;
+
+abstract class LogBasedHandlerTest extends TestCase
+{
+    // @var MockObject&LoggerInterface $logger
+    protected LoggerInterface $logger;
+
+    public function setUp(): void
+    {
+        $this->logger = $this->createMock(LoggerInterface::class);
+        LoggerHolder::set($this->logger);
+    }
+
+    public function tearDown(): void
+    {
+        LoggerHolder::unset();
+    }
+}
diff --git a/tests/Unit/SDK/Common/Event/Handler/WarningHandlerTest.php b/tests/Unit/SDK/Common/Event/Handler/WarningHandlerTest.php
new file mode 100644
index 000000000..b38aaf328
--- /dev/null
+++ b/tests/Unit/SDK/Common/Event/Handler/WarningHandlerTest.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Tests\Unit\SDK\Common\Event\Handler;
+
+use Exception;
+use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
+use OpenTelemetry\SDK\Common\Event\Handler\WarningEventHandler;
+use Psr\Log\LogLevel;
+
+/**
+ * @covers \OpenTelemetry\SDK\Common\Event\Handler\WarningEventHandler
+ */
+class WarningHandlerTest extends LogBasedHandlerTest
+{
+    /**
+     * @psalm-suppress UndefinedInterfaceMethod
+     */
+    public function test_logs_event(): void
+    {
+        $event = new WarningEvent('foo', new Exception());
+        $handler = new WarningEventHandler();
+        // @phpstan-ignore-next-line
+        $this->logger->expects($this->once())->method('log')->with($this->equalTo(LogLevel::WARNING));
+        $handler($event);
+    }
+}
diff --git a/tests/Unit/SDK/Trace/SpanTest.php b/tests/Unit/SDK/Trace/SpanTest.php
index 1d551086f..cef953d4a 100644
--- a/tests/Unit/SDK/Trace/SpanTest.php
+++ b/tests/Unit/SDK/Trace/SpanTest.php
@@ -41,6 +41,7 @@
 
 /**
  * @covers OpenTelemetry\SDK\Trace\Span
+ * @coversDefaultClass \OpenTelemetry\SDK\Trace\Span
  */
 class SpanTest extends MockeryTestCase
 {

From 2093b2c20cd117fa78922614fcff1b77a2d7d648 Mon Sep 17 00:00:00 2001
From: Brett McBride <brett@deakin.edu.au>
Date: Mon, 13 Jun 2022 12:18:24 +1000
Subject: [PATCH 03/14] remove commented-out code

---
 src/SDK/Common/Event/SimpleListenerProvider.php | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/src/SDK/Common/Event/SimpleListenerProvider.php b/src/SDK/Common/Event/SimpleListenerProvider.php
index 0d2499cc4..86fb99abc 100644
--- a/src/SDK/Common/Event/SimpleListenerProvider.php
+++ b/src/SDK/Common/Event/SimpleListenerProvider.php
@@ -25,22 +25,10 @@ public function getListenersForEvent(object $event): iterable
                 }
             }
         }
-        /*        $eventListeners = $this->listeners[get_class($event)] ?? [[]];
-                foreach ($eventListeners as $listeners) {
-                    foreach ($listeners as $listener) {
-                        yield $listener;
-                    }
-                }*/
     }
 
     public function listen(string $event, callable $listener, int $priority = 0): void
     {
-        /*if (!array_key_exists($event, $this->listeners)) {
-            $this->listeners[$event] = [];
-        }
-        if (!array_key_exists($priority, $this->listeners[$event])) {
-            $this->listeners[$event][$priority] = [];
-        }*/
         $this->listeners[$event][$priority][] = $listener;
         ksort($this->listeners[$event]);
     }

From 85dd9ef7bc63a75013ecd11c4c2c2ea24be87f89 Mon Sep 17 00:00:00 2001
From: Brett McBride <brett@deakin.edu.au>
Date: Mon, 13 Jun 2022 14:02:57 +1000
Subject: [PATCH 04/14] self-review, adding tests and tidying

---
 src/SDK/Common/Event/Event/WarningEvent.php   |  2 +-
 .../Trace/Behavior/HttpSpanExporterTrait.php  |  4 +-
 .../Common/Event/Event/WarningEventTest.php   | 31 +++++++
 .../Behavior/HttpSpanExporterTraitTest.php    | 83 +++++++++++++++++++
 4 files changed, 117 insertions(+), 3 deletions(-)
 create mode 100644 tests/Unit/SDK/Common/Event/Event/WarningEventTest.php
 create mode 100644 tests/Unit/SDK/Trace/Behavior/HttpSpanExporterTraitTest.php

diff --git a/src/SDK/Common/Event/Event/WarningEvent.php b/src/SDK/Common/Event/Event/WarningEvent.php
index 0503d7819..94761d2e2 100644
--- a/src/SDK/Common/Event/Event/WarningEvent.php
+++ b/src/SDK/Common/Event/Event/WarningEvent.php
@@ -15,7 +15,7 @@ class WarningEvent implements StoppableEventInterface
     protected string $message;
     protected ?Throwable $error = null;
 
-    public function __construct(string $message, ?Throwable $error)
+    public function __construct(string $message, ?Throwable $error = null)
     {
         $this->message = $message;
         $this->error = $error;
diff --git a/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php b/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php
index 97d1bddaa..2566f21d5 100644
--- a/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php
+++ b/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php
@@ -4,6 +4,7 @@
 
 namespace OpenTelemetry\SDK\Trace\Behavior;
 
+use Exception;
 use InvalidArgumentException;
 use JsonException;
 use OpenTelemetry\SDK\Common\Event\Dispatcher;
@@ -19,8 +20,6 @@
 use Psr\Http\Message\StreamInterface;
 use Throwable;
 
-//use Throwable;
-
 /**
  * @phan-file-suppress PhanTypeInvalidThrowsIsInterface
  */
@@ -60,6 +59,7 @@ protected function doExport(iterable $spans): int
         }
 
         if ($response->getStatusCode() >= 400) {
+            Dispatcher::getInstance()->dispatch(new ErrorEvent('40x error exporting span', new Exception('', $response->getStatusCode())));
             return $response->getStatusCode() < 500
                 ? SpanExporterInterface::STATUS_FAILED_NOT_RETRYABLE
                 : SpanExporterInterface::STATUS_FAILED_RETRYABLE;
diff --git a/tests/Unit/SDK/Common/Event/Event/WarningEventTest.php b/tests/Unit/SDK/Common/Event/Event/WarningEventTest.php
new file mode 100644
index 000000000..560a30d4e
--- /dev/null
+++ b/tests/Unit/SDK/Common/Event/Event/WarningEventTest.php
@@ -0,0 +1,31 @@
+<?php
+
+namespace OpenTelemetry\Tests\Unit\SDK\Common\Event\Event;
+
+use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @covers \OpenTelemetry\SDK\Common\Event\Event\WarningEvent
+ */
+class WarningEventTest extends TestCase
+{
+    public function test_warning_event_with_throwable(): void
+    {
+        $message = 'foo';
+        $exception = new \Exception();
+        $event = new WarningEvent($message, $exception);
+        $this->assertSame($message, $event->getMessage());
+        $this->assertSame($exception, $event->getError());
+        $this->assertTrue($event->hasError());
+    }
+
+    public function test_warning_event_without_throwable(): void
+    {
+        $message = 'foo';
+        $event = new WarningEvent($message);
+        $this->assertSame($message, $event->getMessage());
+        $this->assertFalse($event->hasError());
+        $this->assertNull($event->getError());
+    }
+}
diff --git a/tests/Unit/SDK/Trace/Behavior/HttpSpanExporterTraitTest.php b/tests/Unit/SDK/Trace/Behavior/HttpSpanExporterTraitTest.php
new file mode 100644
index 000000000..7bebbeb15
--- /dev/null
+++ b/tests/Unit/SDK/Trace/Behavior/HttpSpanExporterTraitTest.php
@@ -0,0 +1,83 @@
+<?php
+
+namespace OpenTelemetry\Tests\Unit\SDK\Trace\Behavior;
+
+use GuzzleHttp\Exception\ClientException;
+use OpenTelemetry\API\Trace\SpanInterface;
+use OpenTelemetry\SDK\Common\Event\Dispatcher;
+use OpenTelemetry\SDK\Trace\Behavior\HttpSpanExporterTrait;
+use OpenTelemetry\SDK\Trace\SpanExporterInterface;
+use PHPUnit\Framework\TestCase;
+use Psr\EventDispatcher\EventDispatcherInterface;
+use Psr\Http\Client\ClientInterface;
+use Psr\Http\Message\RequestInterface;
+use Throwable;
+
+/**
+ * @covers \OpenTelemetry\SDK\Trace\Behavior\HttpSpanExporterTrait
+ */
+class HttpSpanExporterTraitTest extends TestCase
+{
+    private SpanExporterInterface $exporter;
+    private ClientInterface $client;
+    private EventDispatcherInterface $dispatcher;
+
+    public function setUp(): void
+    {
+        $this->dispatcher = $this->createMock(EventDispatcherInterface::class);
+        $request = $this->createMock(RequestInterface::class);
+        $this->client = $this->createMock(ClientInterface::class);
+        $this->exporter = $this->createExporter();
+        $this->exporter->setRequest($request);
+        $this->exporter->setClient($this->client);
+        Dispatcher::setInstance($this->dispatcher);
+    }
+
+    public function tearDown(): void
+    {
+        Dispatcher::unset();
+    }
+
+    public function test_export_with_client_exception_generates_error_event(): void
+    {
+        $this->client->expects($this->once())->method('sendRequest')->willThrowException($this->createMock(ClientException::class));
+        $this->dispatcher->expects($this->once())->method('dispatch');
+        $this->exporter->export([$this->createMock(SpanInterface::class)]);
+    }
+
+    public function test_export_with_throwable_generates_error_event(): void
+    {
+        $this->client->expects($this->once())->method('sendRequest')->willThrowException($this->createMock(Throwable::class));
+        $this->dispatcher->expects($this->once())->method('dispatch');
+        $this->exporter->export([$this->createMock(SpanInterface::class)]);
+    }
+
+    private function createExporter(): SpanExporterInterface
+    {
+        return new class extends TestCase implements SpanExporterInterface {
+            use HttpSpanExporterTrait;
+            private RequestInterface $request;
+            public function setRequest(RequestInterface $request): void
+            {
+                $this->request = $request;
+            }
+            public function setClient(ClientInterface $client): void
+            {
+                $this->client = $client;
+            }
+
+            public function serializeTrace(iterable $spans): string
+            {
+                return '';
+            }
+            public static function fromConnectionString(string $endpointUrl, string $name, string $args)
+            {
+                return new \stdClass();
+            }
+            public function marshallRequest(iterable $spans): RequestInterface
+            {
+                return $this->request;
+            }
+        };
+    }
+}

From bba3ac0b6673fbb817a13ace1a40a7537c715da2 Mon Sep 17 00:00:00 2001
From: Brett McBride <brett@deakin.edu.au>
Date: Mon, 13 Jun 2022 14:18:09 +1000
Subject: [PATCH 05/14] making analysis happy

---
 .../Trace/Behavior/HttpSpanExporterTrait.php  |  1 +
 .../Common/Event/Event/WarningEventTest.php   |  2 ++
 .../Behavior/HttpSpanExporterTraitTest.php    | 32 ++++++++++++-------
 3 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php b/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php
index 2566f21d5..bb78d0636 100644
--- a/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php
+++ b/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php
@@ -60,6 +60,7 @@ protected function doExport(iterable $spans): int
 
         if ($response->getStatusCode() >= 400) {
             Dispatcher::getInstance()->dispatch(new ErrorEvent('40x error exporting span', new Exception('', $response->getStatusCode())));
+
             return $response->getStatusCode() < 500
                 ? SpanExporterInterface::STATUS_FAILED_NOT_RETRYABLE
                 : SpanExporterInterface::STATUS_FAILED_RETRYABLE;
diff --git a/tests/Unit/SDK/Common/Event/Event/WarningEventTest.php b/tests/Unit/SDK/Common/Event/Event/WarningEventTest.php
index 560a30d4e..c45c02644 100644
--- a/tests/Unit/SDK/Common/Event/Event/WarningEventTest.php
+++ b/tests/Unit/SDK/Common/Event/Event/WarningEventTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace OpenTelemetry\Tests\Unit\SDK\Common\Event\Event;
 
 use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
diff --git a/tests/Unit/SDK/Trace/Behavior/HttpSpanExporterTraitTest.php b/tests/Unit/SDK/Trace/Behavior/HttpSpanExporterTraitTest.php
index 7bebbeb15..be3757225 100644
--- a/tests/Unit/SDK/Trace/Behavior/HttpSpanExporterTraitTest.php
+++ b/tests/Unit/SDK/Trace/Behavior/HttpSpanExporterTraitTest.php
@@ -1,11 +1,13 @@
 <?php
 
+declare(strict_types=1);
+
 namespace OpenTelemetry\Tests\Unit\SDK\Trace\Behavior;
 
 use GuzzleHttp\Exception\ClientException;
-use OpenTelemetry\API\Trace\SpanInterface;
 use OpenTelemetry\SDK\Common\Event\Dispatcher;
 use OpenTelemetry\SDK\Trace\Behavior\HttpSpanExporterTrait;
+use OpenTelemetry\SDK\Trace\SpanDataInterface;
 use OpenTelemetry\SDK\Trace\SpanExporterInterface;
 use PHPUnit\Framework\TestCase;
 use Psr\EventDispatcher\EventDispatcherInterface;
@@ -22,14 +24,17 @@ class HttpSpanExporterTraitTest extends TestCase
     private ClientInterface $client;
     private EventDispatcherInterface $dispatcher;
 
+    /**
+     * @psalm-suppress UndefinedInterfaceMethod
+     */
     public function setUp(): void
     {
         $this->dispatcher = $this->createMock(EventDispatcherInterface::class);
         $request = $this->createMock(RequestInterface::class);
         $this->client = $this->createMock(ClientInterface::class);
         $this->exporter = $this->createExporter();
-        $this->exporter->setRequest($request);
-        $this->exporter->setClient($this->client);
+        $this->exporter->setRequest($request); //@phpstan-ignore-line
+        $this->exporter->setClient($this->client); //@phpstan-ignore-line
         Dispatcher::setInstance($this->dispatcher);
     }
 
@@ -38,23 +43,29 @@ public function tearDown(): void
         Dispatcher::unset();
     }
 
+    /**
+     * @psalm-suppress UndefinedInterfaceMethod
+     */
     public function test_export_with_client_exception_generates_error_event(): void
     {
-        $this->client->expects($this->once())->method('sendRequest')->willThrowException($this->createMock(ClientException::class));
-        $this->dispatcher->expects($this->once())->method('dispatch');
-        $this->exporter->export([$this->createMock(SpanInterface::class)]);
+        $this->client->expects($this->once())->method('sendRequest')->willThrowException($this->createMock(ClientException::class)); //@phpstan-ignore-line
+        $this->dispatcher->expects($this->once())->method('dispatch'); //@phpstan-ignore-line
+        $this->exporter->export([$this->createMock(SpanDataInterface::class)]);
     }
 
+    /**
+     * @psalm-suppress UndefinedInterfaceMethod
+     */
     public function test_export_with_throwable_generates_error_event(): void
     {
-        $this->client->expects($this->once())->method('sendRequest')->willThrowException($this->createMock(Throwable::class));
-        $this->dispatcher->expects($this->once())->method('dispatch');
-        $this->exporter->export([$this->createMock(SpanInterface::class)]);
+        $this->client->expects($this->once())->method('sendRequest')->willThrowException($this->createMock(Throwable::class)); //@phpstan-ignore-line
+        $this->dispatcher->expects($this->once())->method('dispatch'); //@phpstan-ignore-line
+        $this->exporter->export([$this->createMock(SpanDataInterface::class)]);
     }
 
     private function createExporter(): SpanExporterInterface
     {
-        return new class extends TestCase implements SpanExporterInterface {
+        return new class() implements SpanExporterInterface {
             use HttpSpanExporterTrait;
             private RequestInterface $request;
             public function setRequest(RequestInterface $request): void
@@ -65,7 +76,6 @@ public function setClient(ClientInterface $client): void
             {
                 $this->client = $client;
             }
-
             public function serializeTrace(iterable $spans): string
             {
                 return '';

From 265bdc2cdfbfb6d5d8b52f7e5c7f2a2e3a8d3e16 Mon Sep 17 00:00:00 2001
From: Brett McBride <brett@deakin.edu.au>
Date: Mon, 13 Jun 2022 14:38:25 +1000
Subject: [PATCH 06/14] adding tests for SpanLimits

---
 tests/Unit/SDK/Trace/SpanLimitsTest.php | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 tests/Unit/SDK/Trace/SpanLimitsTest.php

diff --git a/tests/Unit/SDK/Trace/SpanLimitsTest.php b/tests/Unit/SDK/Trace/SpanLimitsTest.php
new file mode 100644
index 000000000..adcf93a33
--- /dev/null
+++ b/tests/Unit/SDK/Trace/SpanLimitsTest.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Tests\Unit\SDK\Trace;
+
+use OpenTelemetry\SDK\Trace\SpanLimits;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @covers \OpenTelemetry\SDK\Trace\SpanLimits
+ */
+class SpanLimitsTest extends TestCase
+{
+    public function test_span_limits(): void
+    {
+        $spanLimits = new SpanLimits(1, 2, 3, 4, 5, 6);
+        $this->assertSame(1, $spanLimits->getAttributeLimits()->getAttributeCountLimit());
+        $this->assertSame(2, $spanLimits->getAttributeLimits()->getAttributeValueLengthLimit());
+        $this->assertSame(3, $spanLimits->getEventCountLimit());
+        $this->assertSame(4, $spanLimits->getLinkCountLimit());
+        $this->assertSame(5, $spanLimits->getAttributePerEventCountLimit());
+        $this->assertSame(6, $spanLimits->getAttributePerLinkCountLimit());
+    }
+}

From f650b8de17518262cf2ff4605b7b114fda6bb2e6 Mon Sep 17 00:00:00 2001
From: Brett McBride <brett@deakin.edu.au>
Date: Mon, 13 Jun 2022 14:54:00 +1000
Subject: [PATCH 07/14] tidy

---
 src/SDK/Common/Event/Handler/DebugEventHandler.php  | 2 +-
 src/SDK/Trace/SpanProcessor/SimpleSpanProcessor.php | 1 -
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/SDK/Common/Event/Handler/DebugEventHandler.php b/src/SDK/Common/Event/Handler/DebugEventHandler.php
index d1952b622..1a63d6ec5 100644
--- a/src/SDK/Common/Event/Handler/DebugEventHandler.php
+++ b/src/SDK/Common/Event/Handler/DebugEventHandler.php
@@ -13,6 +13,6 @@ class DebugEventHandler
 
     public function __invoke(DebugEvent $event): void
     {
-        self::logDebug($event->getMessage());
+        self::logDebug($event->getMessage(), $event->getExtra());
     }
 }
diff --git a/src/SDK/Trace/SpanProcessor/SimpleSpanProcessor.php b/src/SDK/Trace/SpanProcessor/SimpleSpanProcessor.php
index 3542ed979..36cf5a22e 100644
--- a/src/SDK/Trace/SpanProcessor/SimpleSpanProcessor.php
+++ b/src/SDK/Trace/SpanProcessor/SimpleSpanProcessor.php
@@ -57,7 +57,6 @@ public function shutdown(): bool
 
         $this->running = false;
         Dispatcher::getInstance()->dispatch(new DebugEvent('Shutting down span processor'));
-        //self::logDebug('Shutting down span processor');
 
         if (null !== $this->exporter) {
             return $this->forceFlush() && $this->exporter->shutdown();

From 336f48129f2ef351b9d77735afa9779a6ab5f702 Mon Sep 17 00:00:00 2001
From: Brett McBride <brett@deakin.edu.au>
Date: Mon, 13 Jun 2022 21:27:32 +1000
Subject: [PATCH 08/14] reorder assertions

---
 tests/Unit/SDK/Common/Event/Event/WarningEventTest.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/Unit/SDK/Common/Event/Event/WarningEventTest.php b/tests/Unit/SDK/Common/Event/Event/WarningEventTest.php
index c45c02644..6a85da9ae 100644
--- a/tests/Unit/SDK/Common/Event/Event/WarningEventTest.php
+++ b/tests/Unit/SDK/Common/Event/Event/WarningEventTest.php
@@ -18,8 +18,8 @@ public function test_warning_event_with_throwable(): void
         $exception = new \Exception();
         $event = new WarningEvent($message, $exception);
         $this->assertSame($message, $event->getMessage());
-        $this->assertSame($exception, $event->getError());
         $this->assertTrue($event->hasError());
+        $this->assertSame($exception, $event->getError());
     }
 
     public function test_warning_event_without_throwable(): void

From 026f4c8bfaf4f0218bfd86a47af2d144cf94bb32 Mon Sep 17 00:00:00 2001
From: Brett McBride <brett@deakin.edu.au>
Date: Tue, 14 Jun 2022 10:18:19 +1000
Subject: [PATCH 09/14] error -> exception

---
 examples/EventsExample.php                           |  4 ++--
 src/SDK/Common/Event/Event/ErrorEvent.php            |  8 ++++----
 src/SDK/Common/Event/Event/WarningEvent.php          | 12 ++++++------
 src/SDK/Common/Event/Handler/ErrorEventHandler.php   |  2 +-
 src/SDK/Common/Event/Handler/WarningEventHandler.php |  2 +-
 tests/Unit/SDK/Common/Event/Event/ErrorEventTest.php |  2 +-
 .../Unit/SDK/Common/Event/Event/WarningEventTest.php |  4 ++--
 7 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/examples/EventsExample.php b/examples/EventsExample.php
index 9ff316f37..d1c46c47a 100644
--- a/examples/EventsExample.php
+++ b/examples/EventsExample.php
@@ -38,11 +38,11 @@
  */
 $listenerProvider = new SimpleListenerProvider();
 $listenerProvider->listen(EventType::ERROR, function (ErrorEvent $event) {
-    echo 'Custom handling of an error event: ' . $event->getError()->getMessage() . PHP_EOL;
+    echo 'Custom handling of an error event: ' . $event->getException()->getMessage() . PHP_EOL;
 }, -10); //runs before built-in handler
 $listenerProvider->listen(EventType::ERROR, function (ErrorEvent $event) {
     echo 'Another custom handling of an error event: ' . $event->getMessage() . PHP_EOL;
-    echo json_encode($event->getError()->getTrace()) . PHP_EOL;
+    echo json_encode($event->getException()->getTrace()) . PHP_EOL;
     echo 'Stopping event propagation...' . PHP_EOL;
     $event->stopPropagation();
 }, 5); //runs after build-in handler
diff --git a/src/SDK/Common/Event/Event/ErrorEvent.php b/src/SDK/Common/Event/Event/ErrorEvent.php
index ab59acb20..726c0e241 100644
--- a/src/SDK/Common/Event/Event/ErrorEvent.php
+++ b/src/SDK/Common/Event/Event/ErrorEvent.php
@@ -13,17 +13,17 @@ class ErrorEvent implements StoppableEventInterface
     use StoppableEventTrait;
 
     protected string $message;
-    protected Throwable $error;
+    protected Throwable $exception;
 
     public function __construct(string $message, Throwable $error)
     {
         $this->message = $message;
-        $this->error = $error;
+        $this->exception = $error;
     }
 
-    public function getError(): Throwable
+    public function getException(): Throwable
     {
-        return $this->error;
+        return $this->exception;
     }
 
     public function getMessage(): string
diff --git a/src/SDK/Common/Event/Event/WarningEvent.php b/src/SDK/Common/Event/Event/WarningEvent.php
index 94761d2e2..cbbcee2a7 100644
--- a/src/SDK/Common/Event/Event/WarningEvent.php
+++ b/src/SDK/Common/Event/Event/WarningEvent.php
@@ -13,22 +13,22 @@ class WarningEvent implements StoppableEventInterface
     use StoppableEventTrait;
 
     protected string $message;
-    protected ?Throwable $error = null;
+    protected ?Throwable $exception = null;
 
-    public function __construct(string $message, ?Throwable $error = null)
+    public function __construct(string $message, ?Throwable $exception = null)
     {
         $this->message = $message;
-        $this->error = $error;
+        $this->exception = $exception;
     }
 
-    public function getError(): ?Throwable
+    public function getException(): ?Throwable
     {
-        return $this->error;
+        return $this->exception;
     }
 
     public function hasError(): bool
     {
-        return $this->error !== null;
+        return $this->exception !== null;
     }
 
     public function getMessage(): string
diff --git a/src/SDK/Common/Event/Handler/ErrorEventHandler.php b/src/SDK/Common/Event/Handler/ErrorEventHandler.php
index 46453d404..77b879f42 100644
--- a/src/SDK/Common/Event/Handler/ErrorEventHandler.php
+++ b/src/SDK/Common/Event/Handler/ErrorEventHandler.php
@@ -13,6 +13,6 @@ class ErrorEventHandler
 
     public function __invoke(ErrorEvent $event): void
     {
-        self::logError($event->getError()->getMessage(), ['error' => $event->getError()]);
+        self::logError($event->getMessage(), ['exception' => $event->getException()]);
     }
 }
diff --git a/src/SDK/Common/Event/Handler/WarningEventHandler.php b/src/SDK/Common/Event/Handler/WarningEventHandler.php
index 97fc518fe..07c073262 100644
--- a/src/SDK/Common/Event/Handler/WarningEventHandler.php
+++ b/src/SDK/Common/Event/Handler/WarningEventHandler.php
@@ -13,6 +13,6 @@ class WarningEventHandler
 
     public function __invoke(WarningEvent $event): void
     {
-        self::logWarning($event->getMessage(), ['error' => $event->getError()]);
+        self::logWarning($event->getMessage(), ['exception' => $event->getException()]);
     }
 }
diff --git a/tests/Unit/SDK/Common/Event/Event/ErrorEventTest.php b/tests/Unit/SDK/Common/Event/Event/ErrorEventTest.php
index 5fcddf776..3b39b1cbe 100644
--- a/tests/Unit/SDK/Common/Event/Event/ErrorEventTest.php
+++ b/tests/Unit/SDK/Common/Event/Event/ErrorEventTest.php
@@ -18,6 +18,6 @@ public function test_error_event(): void
         $exception = new \Exception();
         $event = new ErrorEvent($message, $exception);
         $this->assertSame($message, $event->getMessage());
-        $this->assertSame($exception, $event->getError());
+        $this->assertSame($exception, $event->getException());
     }
 }
diff --git a/tests/Unit/SDK/Common/Event/Event/WarningEventTest.php b/tests/Unit/SDK/Common/Event/Event/WarningEventTest.php
index 6a85da9ae..1aa876ccb 100644
--- a/tests/Unit/SDK/Common/Event/Event/WarningEventTest.php
+++ b/tests/Unit/SDK/Common/Event/Event/WarningEventTest.php
@@ -19,7 +19,7 @@ public function test_warning_event_with_throwable(): void
         $event = new WarningEvent($message, $exception);
         $this->assertSame($message, $event->getMessage());
         $this->assertTrue($event->hasError());
-        $this->assertSame($exception, $event->getError());
+        $this->assertSame($exception, $event->getException());
     }
 
     public function test_warning_event_without_throwable(): void
@@ -28,6 +28,6 @@ public function test_warning_event_without_throwable(): void
         $event = new WarningEvent($message);
         $this->assertSame($message, $event->getMessage());
         $this->assertFalse($event->hasError());
-        $this->assertNull($event->getError());
+        $this->assertNull($event->getException());
     }
 }

From 0a91c30d780dc2b6baa998e0b1f6cdf792740836 Mon Sep 17 00:00:00 2001
From: Brett McBride <brett@deakin.edu.au>
Date: Wed, 15 Jun 2022 09:45:28 +1000
Subject: [PATCH 10/14] moving event emitting logic into a trait

---
 src/Contrib/Jaeger/HttpSender.php                 |  3 ---
 src/Contrib/Jaeger/JaegerTransport.php            |  6 ++++--
 src/Contrib/Otlp/ExporterTrait.php                |  2 --
 src/Contrib/OtlpGrpc/Exporter.php                 | 10 ++++++----
 src/SDK/Behavior/EmitsEventsTrait.php             | 15 +++++++++++++++
 src/SDK/Trace/Behavior/HttpSpanExporterTrait.php  |  9 +++++----
 .../Trace/SpanProcessor/SimpleSpanProcessor.php   |  7 +++----
 src/SDK/Trace/TracerProviderFactory.php           | 11 +++++------
 8 files changed, 38 insertions(+), 25 deletions(-)
 create mode 100644 src/SDK/Behavior/EmitsEventsTrait.php

diff --git a/src/Contrib/Jaeger/HttpSender.php b/src/Contrib/Jaeger/HttpSender.php
index 60d8e5bb3..87426d5d6 100644
--- a/src/Contrib/Jaeger/HttpSender.php
+++ b/src/Contrib/Jaeger/HttpSender.php
@@ -9,7 +9,6 @@
 use OpenTelemetry\Contrib\Jaeger\BatchAdapter\BatchAdapterFactoryInterface;
 use OpenTelemetry\Contrib\Jaeger\BatchAdapter\BatchAdapterInterface;
 use OpenTelemetry\Contrib\Jaeger\TagFactory\TagFactory;
-use OpenTelemetry\SDK\Behavior\LogsMessagesTrait;
 use OpenTelemetry\SDK\Resource\ResourceInfo;
 use OpenTelemetry\SemConv\ResourceAttributes;
 use Psr\Http\Client\ClientInterface;
@@ -20,8 +19,6 @@
 
 class HttpSender
 {
-    use LogsMessagesTrait;
-
     private string $serviceName;
 
     private TProtocol $protocol;
diff --git a/src/Contrib/Jaeger/JaegerTransport.php b/src/Contrib/Jaeger/JaegerTransport.php
index 3ec31f5f7..a33ca9bc8 100644
--- a/src/Contrib/Jaeger/JaegerTransport.php
+++ b/src/Contrib/Jaeger/JaegerTransport.php
@@ -8,13 +8,15 @@
 use Jaeger\Thrift\Batch;
 use Jaeger\Thrift\Process;
 use Jaeger\Thrift\Span;
-use OpenTelemetry\SDK\Common\Event\Dispatcher;
+use OpenTelemetry\SDK\Behavior\EmitsEventsTrait;
 use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
 use Thrift\Exception\TTransportException;
 use Thrift\Protocol\TCompactProtocol;
 
 final class JaegerTransport implements TransportInterface
 {
+    use EmitsEventsTrait;
+
     // DEFAULT_BUFFER_SIZE indicates the default maximum buffer size, or the size threshold
     // at which the buffer will be flushed to the agent.
     const DEFAULT_BUFFER_SIZE = 1;
@@ -92,7 +94,7 @@ public function flush($force = false): int
             // reset the process tag
             $this->process = null;
         } catch (TTransportException $e) {
-            Dispatcher::getInstance()->dispatch(new ErrorEvent('jaeger transport failure', $e));
+            self::emit(new ErrorEvent('jaeger transport failure', $e));
 
             return 0;
         }
diff --git a/src/Contrib/Otlp/ExporterTrait.php b/src/Contrib/Otlp/ExporterTrait.php
index 4f279f852..26d477bd5 100644
--- a/src/Contrib/Otlp/ExporterTrait.php
+++ b/src/Contrib/Otlp/ExporterTrait.php
@@ -4,13 +4,11 @@
 
 namespace OpenTelemetry\Contrib\Otlp;
 
-use OpenTelemetry\SDK\Behavior\LogsMessagesTrait;
 use OpenTelemetry\SDK\Common\Environment\EnvironmentVariablesTrait;
 use OpenTelemetry\SDK\Trace\Behavior\UsesSpanConverterTrait;
 
 trait ExporterTrait
 {
     use EnvironmentVariablesTrait;
-    use LogsMessagesTrait;
     use UsesSpanConverterTrait;
 }
diff --git a/src/Contrib/OtlpGrpc/Exporter.php b/src/Contrib/OtlpGrpc/Exporter.php
index ac24c482c..fc0d4e596 100644
--- a/src/Contrib/OtlpGrpc/Exporter.php
+++ b/src/Contrib/OtlpGrpc/Exporter.php
@@ -11,9 +11,10 @@
 use OpenTelemetry\Contrib\Otlp\SpanConverter;
 use Opentelemetry\Proto\Collector\Trace\V1\ExportTraceServiceRequest;
 use Opentelemetry\Proto\Collector\Trace\V1\TraceServiceClient;
+use OpenTelemetry\SDK\Behavior\EmitsEventsTrait;
 use OpenTelemetry\SDK\Common\Environment\KnownValues as Values;
 use OpenTelemetry\SDK\Common\Environment\Variables as Env;
-use OpenTelemetry\SDK\Common\Event\Dispatcher;
+use OpenTelemetry\SDK\Common\Event\Event\DebugEvent;
 use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
 use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
 use OpenTelemetry\SDK\Trace\Behavior\SpanExporterTrait;
@@ -21,6 +22,7 @@
 
 class Exporter implements SpanExporterInterface
 {
+    use EmitsEventsTrait;
     use ExporterTrait;
     use SpanExporterTrait;
 
@@ -123,7 +125,7 @@ protected function doExport(iterable $spans): int
         [$response, $status] = $this->client->Export($request)->wait();
 
         if ($status->code === \Grpc\STATUS_OK) {
-            self::logDebug('Exported span(s)', ['spans' => $resourceSpans]);
+            self::emit(new DebugEvent('Exported span(s)', ['spans' => $resourceSpans]));
 
             return self::STATUS_SUCCESS;
         }
@@ -144,12 +146,12 @@ protected function doExport(iterable $spans): int
             \Grpc\STATUS_DATA_LOSS,
             \Grpc\STATUS_UNAUTHENTICATED,
         ], true)) {
-            Dispatcher::getInstance()->dispatch(new WarningEvent('Retryable error exporting grpc span', new Exception($error['error'], $error['code'])));
+            self::emit(new WarningEvent('Retryable error exporting grpc span', new Exception($error['error'], $error['code'])));
 
             return self::STATUS_FAILED_RETRYABLE;
         }
 
-        Dispatcher::getInstance()->dispatch(new ErrorEvent('Error exporting grpc span', new Exception($error['error'])));
+        self::emit(new ErrorEvent('Error exporting grpc span', new Exception($error['error'])));
 
         return self::STATUS_FAILED_NOT_RETRYABLE;
     }
diff --git a/src/SDK/Behavior/EmitsEventsTrait.php b/src/SDK/Behavior/EmitsEventsTrait.php
new file mode 100644
index 000000000..92c087066
--- /dev/null
+++ b/src/SDK/Behavior/EmitsEventsTrait.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\SDK\Behavior;
+
+use OpenTelemetry\SDK\Common\Event\Dispatcher;
+
+trait EmitsEventsTrait
+{
+    protected static function emit(object $event): void
+    {
+        Dispatcher::getInstance()->dispatch($event);
+    }
+}
diff --git a/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php b/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php
index bb78d0636..3f05f4018 100644
--- a/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php
+++ b/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php
@@ -7,7 +7,7 @@
 use Exception;
 use InvalidArgumentException;
 use JsonException;
-use OpenTelemetry\SDK\Common\Event\Dispatcher;
+use OpenTelemetry\SDK\Behavior\EmitsEventsTrait;
 use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
 use OpenTelemetry\SDK\Trace\SpanExporterInterface;
 use Psr\Http\Client\ClientExceptionInterface;
@@ -25,6 +25,7 @@
  */
 trait HttpSpanExporterTrait
 {
+    use EmitsEventsTrait;
     use SpanExporterTrait;
 
     protected string $endpointUrl;
@@ -47,19 +48,19 @@ protected function doExport(iterable $spans): int
         try {
             $response = $this->dispatchSpans($spans);
         } catch (ClientExceptionInterface $e) {
-            Dispatcher::getInstance()->dispatch(new ErrorEvent('Error exporting span', $e));
+            self::emit(new ErrorEvent('Error exporting span', $e));
 
             return $e instanceof RequestExceptionInterface
                 ? SpanExporterInterface::STATUS_FAILED_NOT_RETRYABLE
                 : SpanExporterInterface::STATUS_FAILED_RETRYABLE;
         } catch (Throwable $e) {
-            Dispatcher::getInstance()->dispatch(new ErrorEvent('Error exporting span', $e));
+            self::emit(new ErrorEvent('Error exporting span', $e));
 
             return SpanExporterInterface::STATUS_FAILED_NOT_RETRYABLE;
         }
 
         if ($response->getStatusCode() >= 400) {
-            Dispatcher::getInstance()->dispatch(new ErrorEvent('40x error exporting span', new Exception('', $response->getStatusCode())));
+            self::emit(new ErrorEvent('40x error exporting span', new Exception('', $response->getStatusCode())));
 
             return $response->getStatusCode() < 500
                 ? SpanExporterInterface::STATUS_FAILED_NOT_RETRYABLE
diff --git a/src/SDK/Trace/SpanProcessor/SimpleSpanProcessor.php b/src/SDK/Trace/SpanProcessor/SimpleSpanProcessor.php
index 36cf5a22e..8cf09ac47 100644
--- a/src/SDK/Trace/SpanProcessor/SimpleSpanProcessor.php
+++ b/src/SDK/Trace/SpanProcessor/SimpleSpanProcessor.php
@@ -5,8 +5,7 @@
 namespace OpenTelemetry\SDK\Trace\SpanProcessor;
 
 use OpenTelemetry\Context\Context;
-use OpenTelemetry\SDK\Behavior\LogsMessagesTrait;
-use OpenTelemetry\SDK\Common\Event\Dispatcher;
+use OpenTelemetry\SDK\Behavior\EmitsEventsTrait;
 use OpenTelemetry\SDK\Common\Event\Event\DebugEvent;
 use OpenTelemetry\SDK\Trace\ReadableSpanInterface;
 use OpenTelemetry\SDK\Trace\ReadWriteSpanInterface;
@@ -15,7 +14,7 @@
 
 class SimpleSpanProcessor implements SpanProcessorInterface
 {
-    use LogsMessagesTrait;
+    use EmitsEventsTrait;
 
     private ?SpanExporterInterface $exporter;
     private bool $running = true;
@@ -56,7 +55,7 @@ public function shutdown(): bool
         }
 
         $this->running = false;
-        Dispatcher::getInstance()->dispatch(new DebugEvent('Shutting down span processor'));
+        self::emit(new DebugEvent('Shutting down span processor'));
 
         if (null !== $this->exporter) {
             return $this->forceFlush() && $this->exporter->shutdown();
diff --git a/src/SDK/Trace/TracerProviderFactory.php b/src/SDK/Trace/TracerProviderFactory.php
index ae5ee5fab..3433ae82d 100644
--- a/src/SDK/Trace/TracerProviderFactory.php
+++ b/src/SDK/Trace/TracerProviderFactory.php
@@ -5,13 +5,12 @@
 namespace OpenTelemetry\SDK\Trace;
 
 use OpenTelemetry\API\Trace as API;
-use OpenTelemetry\SDK\Behavior\LogsMessagesTrait;
-use OpenTelemetry\SDK\Common\Event\Dispatcher;
+use OpenTelemetry\SDK\Behavior\EmitsEventsTrait;
 use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
 
 final class TracerProviderFactory
 {
-    use LogsMessagesTrait;
+    use EmitsEventsTrait;
 
     private ExporterFactory $exporterFactory;
     private SamplerFactory $samplerFactory;
@@ -33,21 +32,21 @@ public function create(): API\TracerProviderInterface
         try {
             $exporter = $this->exporterFactory->fromEnvironment();
         } catch (\Throwable $t) {
-            Dispatcher::getInstance()->dispatch(new WarningEvent('Unable to create exporter', $t));
+            self::emit(new WarningEvent('Unable to create exporter', $t));
             $exporter = null;
         }
 
         try {
             $sampler = $this->samplerFactory->fromEnvironment();
         } catch (\Throwable $t) {
-            Dispatcher::getInstance()->dispatch(new WarningEvent('Unable to create sampler', $t));
+            self::emit(new WarningEvent('Unable to create sampler', $t));
             $sampler = null;
         }
 
         try {
             $spanProcessor = $this->spanProcessorFactory->fromEnvironment($exporter);
         } catch (\Throwable $t) {
-            Dispatcher::getInstance()->dispatch(new WarningEvent('Unable to create span processor', $t));
+            self::emit(new WarningEvent('Unable to create span processor', $t));
             $spanProcessor = null;
         }
 

From 87fca9fd5c226da6c287ed8854f111547fc2ff1d Mon Sep 17 00:00:00 2001
From: Brett McBride <brett@deakin.edu.au>
Date: Wed, 22 Jun 2022 15:48:24 +1000
Subject: [PATCH 11/14] moving events into API namespace otel spec says that
 _all_ otel libraries (including API) should be able to expose troubleshooting
 telemetry, so enable that by moving events (and logging) into API

---
 depfile.yaml                                  |  8 ++-
 examples/EventsExample.php                    | 18 ++---
 examples/SettingUpLogging.php                 |  2 +-
 .../Behavior/EmitsEventsTrait.php             |  4 +-
 .../Behavior/LogsMessagesTrait.php            |  5 +-
 src/{SDK => API}/Common/Event/Dispatcher.php  |  8 +--
 .../Common/Event/Event/DebugEvent.php         |  2 +-
 .../Common/Event/Event/ErrorEvent.php         |  4 +-
 .../Common/Event/Event/WarningEvent.php       |  4 +-
 src/API/Common/Event/EventType.php            | 16 +++++
 .../Event/Handler/DebugEventHandler.php       |  6 +-
 .../Event/Handler/ErrorEventHandler.php       |  6 +-
 .../Event/Handler/WarningEventHandler.php     |  6 +-
 .../Common/Event/SimpleDispatcher.php         |  2 +-
 .../Common/Event/SimpleListenerProvider.php   |  2 +-
 .../Common/Event/StoppableEventTrait.php      |  2 +-
 src/{SDK => API}/Common/Log/LoggerHolder.php  |  2 +-
 src/API/composer.json                         |  4 +-
 src/Contrib/Jaeger/JaegerTransport.php        |  4 +-
 src/Contrib/OtlpGrpc/Exporter.php             |  8 +--
 .../Compatibility/BC/GlobalLoggerHolder.php   |  2 +-
 .../Dev/Compatibility/BC/LoggerHolder.php     | 65 +++++++++++++++++++
 src/SDK/Common/Dev/Compatibility/_load.php    |  1 +
 src/SDK/Common/Event/EventType.php            | 16 -----
 .../Trace/Behavior/HttpSpanExporterTrait.php  |  4 +-
 .../SpanProcessor/SimpleSpanProcessor.php     |  4 +-
 src/SDK/Trace/TracerProviderFactory.php       |  4 +-
 src/SDK/composer.json                         |  1 -
 .../Behavior/LogsMessagesTraitTest.php        |  8 +--
 .../Common/Event/DispatcherTest.php           | 16 ++---
 .../Common/Event/Event/DebugEventTest.php     |  6 +-
 .../Common/Event/Event/ErrorEventTest.php     |  7 +-
 .../Common/Event/Event/WarningEventTest.php   |  8 +--
 .../Common/Event/Handler/DebugHandlerTest.php |  9 ++-
 .../Common/Event/Handler/ErrorHandlerTest.php |  8 +--
 .../Event/Handler/LogBasedHandlerTest.php     |  5 +-
 .../Event/Handler/WarningHandlerTest.php      |  9 ++-
 .../Common/Event/SimpleDispatcherTest.php     | 11 ++--
 .../Event/SimpleListenerProviderTest.php      |  9 ++-
 .../Common/Event/StoppableEventTraitTest.php  |  7 +-
 .../Unit/SDK/Common/Log/LoggerHolderTest.php  |  4 +-
 .../Behavior/HttpSpanExporterTraitTest.php    |  2 +-
 .../SDK/Trace/TracerProviderFactoryTest.php   |  6 +-
 43 files changed, 195 insertions(+), 130 deletions(-)
 rename src/{SDK => API}/Behavior/EmitsEventsTrait.php (68%)
 rename src/{SDK => API}/Behavior/LogsMessagesTrait.php (88%)
 rename src/{SDK => API}/Common/Event/Dispatcher.php (79%)
 rename src/{SDK => API}/Common/Event/Event/DebugEvent.php (89%)
 rename src/{SDK => API}/Common/Event/Event/ErrorEvent.php (84%)
 rename src/{SDK => API}/Common/Event/Event/WarningEvent.php (87%)
 create mode 100644 src/API/Common/Event/EventType.php
 rename src/{SDK => API}/Common/Event/Handler/DebugEventHandler.php (59%)
 rename src/{SDK => API}/Common/Event/Handler/ErrorEventHandler.php (61%)
 rename src/{SDK => API}/Common/Event/Handler/WarningEventHandler.php (61%)
 rename src/{SDK => API}/Common/Event/SimpleDispatcher.php (97%)
 rename src/{SDK => API}/Common/Event/SimpleListenerProvider.php (95%)
 rename src/{SDK => API}/Common/Event/StoppableEventTrait.php (86%)
 rename src/{SDK => API}/Common/Log/LoggerHolder.php (96%)
 create mode 100644 src/SDK/Common/Dev/Compatibility/BC/LoggerHolder.php
 delete mode 100644 src/SDK/Common/Event/EventType.php
 rename tests/Unit/{SDK => API}/Behavior/LogsMessagesTraitTest.php (89%)
 rename tests/Unit/{SDK => API}/Common/Event/DispatcherTest.php (74%)
 rename tests/Unit/{SDK => API}/Common/Event/Event/DebugEventTest.php (69%)
 rename tests/Unit/{SDK => API}/Common/Event/Event/ErrorEventTest.php (61%)
 rename tests/Unit/{SDK => API}/Common/Event/Event/WarningEventTest.php (73%)
 rename tests/Unit/{SDK => API}/Common/Event/Handler/DebugHandlerTest.php (61%)
 rename tests/Unit/{SDK => API}/Common/Event/Handler/ErrorHandlerTest.php (68%)
 rename tests/Unit/{SDK => API}/Common/Event/Handler/LogBasedHandlerTest.php (75%)
 rename tests/Unit/{SDK => API}/Common/Event/Handler/WarningHandlerTest.php (62%)
 rename tests/Unit/{SDK => API}/Common/Event/SimpleDispatcherTest.php (88%)
 rename tests/Unit/{SDK => API}/Common/Event/SimpleListenerProviderTest.php (89%)
 rename tests/Unit/{SDK => API}/Common/Event/StoppableEventTraitTest.php (75%)

diff --git a/depfile.yaml b/depfile.yaml
index 95f55995a..acccb0298 100644
--- a/depfile.yaml
+++ b/depfile.yaml
@@ -39,6 +39,10 @@ layers:
         collectors:
             - type: className
               regex: ^Grpc\\
+    -   name: PsrEventDispatcher
+        collectors:
+            - type: className
+              regex: ^Psr\\EventDispatcher\\
     -   name: PsrLog
         collectors:
             - type: className
@@ -82,13 +86,15 @@ ruleset:
     SemConv: ~
     API:
         - Context
+        - PsrEventDispatcher
+        - PsrLog
         - SemConv
     SDK:
         - API
         - Context
         - SemConv
-        - PsrLog
         - PsrHttp
+        - PsrLog
         - Http
         - NyholmDsn
         - Composer
diff --git a/examples/EventsExample.php b/examples/EventsExample.php
index d1c46c47a..afb9dc6f8 100644
--- a/examples/EventsExample.php
+++ b/examples/EventsExample.php
@@ -6,13 +6,13 @@
 use Monolog\Formatter\JsonFormatter;
 use Monolog\Handler\StreamHandler;
 use Monolog\Logger;
+use OpenTelemetry\API\Common\Event\Dispatcher;
+use OpenTelemetry\API\Common\Event\Event\ErrorEvent;
+use OpenTelemetry\API\Common\Event\EventType;
+use OpenTelemetry\API\Common\Event\SimpleDispatcher;
+use OpenTelemetry\API\Common\Event\SimpleListenerProvider;
+use OpenTelemetry\API\Common\Log\LoggerHolder;
 use OpenTelemetry\Contrib\Zipkin\Exporter as ZipkinExporter;
-use OpenTelemetry\SDK\Common\Event\Dispatcher;
-use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
-use OpenTelemetry\SDK\Common\Event\EventType;
-use OpenTelemetry\SDK\Common\Event\SimpleDispatcher;
-use OpenTelemetry\SDK\Common\Event\SimpleListenerProvider;
-use OpenTelemetry\SDK\Common\Log\LoggerHolder;
 use OpenTelemetry\SDK\Trace\SpanProcessor\SimpleSpanProcessor;
 use OpenTelemetry\SDK\Trace\TracerProvider;
 use Psr\Log\LogLevel;
@@ -42,12 +42,12 @@
 }, -10); //runs before built-in handler
 $listenerProvider->listen(EventType::ERROR, function (ErrorEvent $event) {
     echo 'Another custom handling of an error event: ' . $event->getMessage() . PHP_EOL;
-    echo json_encode($event->getException()->getTrace()) . PHP_EOL;
+    echo 'Trace: ' . json_encode($event->getException()->getTrace()) . PHP_EOL;
     echo 'Stopping event propagation...' . PHP_EOL;
     $event->stopPropagation();
-}, 5); //runs after build-in handler
+}, 5); //runs after built-in handler
 $listenerProvider->listen(EventType::ERROR, function (ErrorEvent $event) {
-    echo 'This will not be executed, because a high priority handler stopped event propagation.' . PHP_EOL;
+    echo 'This will not be executed, because a higher priority handler stopped event propagation.' . PHP_EOL;
 }, 10);
 
 Dispatcher::setInstance(new SimpleDispatcher($listenerProvider));
diff --git a/examples/SettingUpLogging.php b/examples/SettingUpLogging.php
index 2c7e3d984..0046a2975 100644
--- a/examples/SettingUpLogging.php
+++ b/examples/SettingUpLogging.php
@@ -5,8 +5,8 @@
 
 use Monolog\Handler\StreamHandler;
 use Monolog\Logger;
+use OpenTelemetry\API\Common\Log\LoggerHolder;
 use OpenTelemetry\Contrib\OtlpGrpc\Exporter as OtlpGrpcExporter;
-use OpenTelemetry\SDK\Common\Log\LoggerHolder;
 use OpenTelemetry\SDK\Trace\SpanProcessor\SimpleSpanProcessor;
 use OpenTelemetry\SDK\Trace\TracerProvider;
 use Psr\Log\LogLevel;
diff --git a/src/SDK/Behavior/EmitsEventsTrait.php b/src/API/Behavior/EmitsEventsTrait.php
similarity index 68%
rename from src/SDK/Behavior/EmitsEventsTrait.php
rename to src/API/Behavior/EmitsEventsTrait.php
index 92c087066..36be9f012 100644
--- a/src/SDK/Behavior/EmitsEventsTrait.php
+++ b/src/API/Behavior/EmitsEventsTrait.php
@@ -2,9 +2,9 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\SDK\Behavior;
+namespace OpenTelemetry\API\Behavior;
 
-use OpenTelemetry\SDK\Common\Event\Dispatcher;
+use OpenTelemetry\API\Common\Event\Dispatcher;
 
 trait EmitsEventsTrait
 {
diff --git a/src/SDK/Behavior/LogsMessagesTrait.php b/src/API/Behavior/LogsMessagesTrait.php
similarity index 88%
rename from src/SDK/Behavior/LogsMessagesTrait.php
rename to src/API/Behavior/LogsMessagesTrait.php
index 23b3fb7d2..244cf5201 100644
--- a/src/SDK/Behavior/LogsMessagesTrait.php
+++ b/src/API/Behavior/LogsMessagesTrait.php
@@ -2,16 +2,15 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\SDK\Behavior;
+namespace OpenTelemetry\API\Behavior;
 
-use OpenTelemetry\SDK\Common\Log\LoggerHolder;
+use OpenTelemetry\API\Common\Log\LoggerHolder;
 use Psr\Log\LogLevel;
 
 trait LogsMessagesTrait
 {
     private static function doLog(string $level, string $message, array $context): void
     {
-        $context['source'] = get_called_class();
         LoggerHolder::get()->log($level, $message, $context);
     }
 
diff --git a/src/SDK/Common/Event/Dispatcher.php b/src/API/Common/Event/Dispatcher.php
similarity index 79%
rename from src/SDK/Common/Event/Dispatcher.php
rename to src/API/Common/Event/Dispatcher.php
index 816fb5b84..a07374850 100644
--- a/src/SDK/Common/Event/Dispatcher.php
+++ b/src/API/Common/Event/Dispatcher.php
@@ -2,11 +2,11 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\SDK\Common\Event;
+namespace OpenTelemetry\API\Common\Event;
 
-use OpenTelemetry\SDK\Common\Event\Handler\DebugEventHandler;
-use OpenTelemetry\SDK\Common\Event\Handler\ErrorEventHandler;
-use OpenTelemetry\SDK\Common\Event\Handler\WarningEventHandler;
+use OpenTelemetry\API\Common\Event\Handler\DebugEventHandler;
+use OpenTelemetry\API\Common\Event\Handler\ErrorEventHandler;
+use OpenTelemetry\API\Common\Event\Handler\WarningEventHandler;
 use Psr\EventDispatcher\EventDispatcherInterface;
 
 class Dispatcher
diff --git a/src/SDK/Common/Event/Event/DebugEvent.php b/src/API/Common/Event/Event/DebugEvent.php
similarity index 89%
rename from src/SDK/Common/Event/Event/DebugEvent.php
rename to src/API/Common/Event/Event/DebugEvent.php
index 360fb6fae..b2433dbe7 100644
--- a/src/SDK/Common/Event/Event/DebugEvent.php
+++ b/src/API/Common/Event/Event/DebugEvent.php
@@ -2,7 +2,7 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\SDK\Common\Event\Event;
+namespace OpenTelemetry\API\Common\Event\Event;
 
 class DebugEvent
 {
diff --git a/src/SDK/Common/Event/Event/ErrorEvent.php b/src/API/Common/Event/Event/ErrorEvent.php
similarity index 84%
rename from src/SDK/Common/Event/Event/ErrorEvent.php
rename to src/API/Common/Event/Event/ErrorEvent.php
index 726c0e241..8d8fd6901 100644
--- a/src/SDK/Common/Event/Event/ErrorEvent.php
+++ b/src/API/Common/Event/Event/ErrorEvent.php
@@ -2,9 +2,9 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\SDK\Common\Event\Event;
+namespace OpenTelemetry\API\Common\Event\Event;
 
-use OpenTelemetry\SDK\Common\Event\StoppableEventTrait;
+use OpenTelemetry\API\Common\Event\StoppableEventTrait;
 use Psr\EventDispatcher\StoppableEventInterface;
 use Throwable;
 
diff --git a/src/SDK/Common/Event/Event/WarningEvent.php b/src/API/Common/Event/Event/WarningEvent.php
similarity index 87%
rename from src/SDK/Common/Event/Event/WarningEvent.php
rename to src/API/Common/Event/Event/WarningEvent.php
index cbbcee2a7..95437187f 100644
--- a/src/SDK/Common/Event/Event/WarningEvent.php
+++ b/src/API/Common/Event/Event/WarningEvent.php
@@ -2,9 +2,9 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\SDK\Common\Event\Event;
+namespace OpenTelemetry\API\Common\Event\Event;
 
-use OpenTelemetry\SDK\Common\Event\StoppableEventTrait;
+use OpenTelemetry\API\Common\Event\StoppableEventTrait;
 use Psr\EventDispatcher\StoppableEventInterface;
 use Throwable;
 
diff --git a/src/API/Common/Event/EventType.php b/src/API/Common/Event/EventType.php
new file mode 100644
index 000000000..bc0abda2f
--- /dev/null
+++ b/src/API/Common/Event/EventType.php
@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\API\Common\Event;
+
+use OpenTelemetry\API\Common\Event\Event\DebugEvent;
+use OpenTelemetry\API\Common\Event\Event\ErrorEvent;
+use OpenTelemetry\API\Common\Event\Event\WarningEvent;
+
+class EventType
+{
+    public const ERROR = ErrorEvent::class;
+    public const WARNING = WarningEvent::class;
+    public const DEBUG = DebugEvent::class;
+}
diff --git a/src/SDK/Common/Event/Handler/DebugEventHandler.php b/src/API/Common/Event/Handler/DebugEventHandler.php
similarity index 59%
rename from src/SDK/Common/Event/Handler/DebugEventHandler.php
rename to src/API/Common/Event/Handler/DebugEventHandler.php
index 1a63d6ec5..c3279bcd8 100644
--- a/src/SDK/Common/Event/Handler/DebugEventHandler.php
+++ b/src/API/Common/Event/Handler/DebugEventHandler.php
@@ -2,10 +2,10 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\SDK\Common\Event\Handler;
+namespace OpenTelemetry\API\Common\Event\Handler;
 
-use OpenTelemetry\SDK\Behavior\LogsMessagesTrait;
-use OpenTelemetry\SDK\Common\Event\Event\DebugEvent;
+use OpenTelemetry\API\Behavior\LogsMessagesTrait;
+use OpenTelemetry\API\Common\Event\Event\DebugEvent;
 
 class DebugEventHandler
 {
diff --git a/src/SDK/Common/Event/Handler/ErrorEventHandler.php b/src/API/Common/Event/Handler/ErrorEventHandler.php
similarity index 61%
rename from src/SDK/Common/Event/Handler/ErrorEventHandler.php
rename to src/API/Common/Event/Handler/ErrorEventHandler.php
index 77b879f42..6cd00b2cb 100644
--- a/src/SDK/Common/Event/Handler/ErrorEventHandler.php
+++ b/src/API/Common/Event/Handler/ErrorEventHandler.php
@@ -2,10 +2,10 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\SDK\Common\Event\Handler;
+namespace OpenTelemetry\API\Common\Event\Handler;
 
-use OpenTelemetry\SDK\Behavior\LogsMessagesTrait;
-use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
+use OpenTelemetry\API\Behavior\LogsMessagesTrait;
+use OpenTelemetry\API\Common\Event\Event\ErrorEvent;
 
 class ErrorEventHandler
 {
diff --git a/src/SDK/Common/Event/Handler/WarningEventHandler.php b/src/API/Common/Event/Handler/WarningEventHandler.php
similarity index 61%
rename from src/SDK/Common/Event/Handler/WarningEventHandler.php
rename to src/API/Common/Event/Handler/WarningEventHandler.php
index 07c073262..ce552ecf6 100644
--- a/src/SDK/Common/Event/Handler/WarningEventHandler.php
+++ b/src/API/Common/Event/Handler/WarningEventHandler.php
@@ -2,10 +2,10 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\SDK\Common\Event\Handler;
+namespace OpenTelemetry\API\Common\Event\Handler;
 
-use OpenTelemetry\SDK\Behavior\LogsMessagesTrait;
-use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
+use OpenTelemetry\API\Behavior\LogsMessagesTrait;
+use OpenTelemetry\API\Common\Event\Event\WarningEvent;
 
 class WarningEventHandler
 {
diff --git a/src/SDK/Common/Event/SimpleDispatcher.php b/src/API/Common/Event/SimpleDispatcher.php
similarity index 97%
rename from src/SDK/Common/Event/SimpleDispatcher.php
rename to src/API/Common/Event/SimpleDispatcher.php
index 27ea91e8b..93cd066e9 100644
--- a/src/SDK/Common/Event/SimpleDispatcher.php
+++ b/src/API/Common/Event/SimpleDispatcher.php
@@ -2,7 +2,7 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\SDK\Common\Event;
+namespace OpenTelemetry\API\Common\Event;
 
 use Psr\EventDispatcher\EventDispatcherInterface;
 use Psr\EventDispatcher\ListenerProviderInterface;
diff --git a/src/SDK/Common/Event/SimpleListenerProvider.php b/src/API/Common/Event/SimpleListenerProvider.php
similarity index 95%
rename from src/SDK/Common/Event/SimpleListenerProvider.php
rename to src/API/Common/Event/SimpleListenerProvider.php
index 86fb99abc..7f82f0030 100644
--- a/src/SDK/Common/Event/SimpleListenerProvider.php
+++ b/src/API/Common/Event/SimpleListenerProvider.php
@@ -2,7 +2,7 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\SDK\Common\Event;
+namespace OpenTelemetry\API\Common\Event;
 
 use Psr\EventDispatcher\ListenerProviderInterface;
 
diff --git a/src/SDK/Common/Event/StoppableEventTrait.php b/src/API/Common/Event/StoppableEventTrait.php
similarity index 86%
rename from src/SDK/Common/Event/StoppableEventTrait.php
rename to src/API/Common/Event/StoppableEventTrait.php
index 8ebada6df..881397dd3 100644
--- a/src/SDK/Common/Event/StoppableEventTrait.php
+++ b/src/API/Common/Event/StoppableEventTrait.php
@@ -2,7 +2,7 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\SDK\Common\Event;
+namespace OpenTelemetry\API\Common\Event;
 
 trait StoppableEventTrait
 {
diff --git a/src/SDK/Common/Log/LoggerHolder.php b/src/API/Common/Log/LoggerHolder.php
similarity index 96%
rename from src/SDK/Common/Log/LoggerHolder.php
rename to src/API/Common/Log/LoggerHolder.php
index 1a91451e1..c39214b04 100644
--- a/src/SDK/Common/Log/LoggerHolder.php
+++ b/src/API/Common/Log/LoggerHolder.php
@@ -2,7 +2,7 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\SDK\Common\Log;
+namespace OpenTelemetry\API\Common\Log;
 
 use Psr\Log\LoggerInterface;
 use Psr\Log\NullLogger;
diff --git a/src/API/composer.json b/src/API/composer.json
index 2f32e8d9f..979c7abfc 100644
--- a/src/API/composer.json
+++ b/src/API/composer.json
@@ -13,7 +13,9 @@
     "require": {
         "php": "^7.4 || ^8.0",
         "open-telemetry/context": "self.version",
-        "open-telemetry/sem-conv": "self.version"
+        "open-telemetry/sem-conv": "self.version",
+        "psr/event-dispatcher": "^1",
+        "psr/log": "^1.1|^2.0|^3.0"
     },
     "autoload": {
         "psr-4": {
diff --git a/src/Contrib/Jaeger/JaegerTransport.php b/src/Contrib/Jaeger/JaegerTransport.php
index a33ca9bc8..431fd82ed 100644
--- a/src/Contrib/Jaeger/JaegerTransport.php
+++ b/src/Contrib/Jaeger/JaegerTransport.php
@@ -8,8 +8,8 @@
 use Jaeger\Thrift\Batch;
 use Jaeger\Thrift\Process;
 use Jaeger\Thrift\Span;
-use OpenTelemetry\SDK\Behavior\EmitsEventsTrait;
-use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
+use OpenTelemetry\API\Behavior\EmitsEventsTrait;
+use OpenTelemetry\API\Common\Event\Event\ErrorEvent;
 use Thrift\Exception\TTransportException;
 use Thrift\Protocol\TCompactProtocol;
 
diff --git a/src/Contrib/OtlpGrpc/Exporter.php b/src/Contrib/OtlpGrpc/Exporter.php
index fc0d4e596..3a1c72625 100644
--- a/src/Contrib/OtlpGrpc/Exporter.php
+++ b/src/Contrib/OtlpGrpc/Exporter.php
@@ -7,16 +7,16 @@
 use Exception;
 use grpc;
 use Grpc\ChannelCredentials;
+use OpenTelemetry\API\Behavior\EmitsEventsTrait;
+use OpenTelemetry\API\Common\Event\Event\DebugEvent;
+use OpenTelemetry\API\Common\Event\Event\ErrorEvent;
+use OpenTelemetry\API\Common\Event\Event\WarningEvent;
 use OpenTelemetry\Contrib\Otlp\ExporterTrait;
 use OpenTelemetry\Contrib\Otlp\SpanConverter;
 use Opentelemetry\Proto\Collector\Trace\V1\ExportTraceServiceRequest;
 use Opentelemetry\Proto\Collector\Trace\V1\TraceServiceClient;
-use OpenTelemetry\SDK\Behavior\EmitsEventsTrait;
 use OpenTelemetry\SDK\Common\Environment\KnownValues as Values;
 use OpenTelemetry\SDK\Common\Environment\Variables as Env;
-use OpenTelemetry\SDK\Common\Event\Event\DebugEvent;
-use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
-use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
 use OpenTelemetry\SDK\Trace\Behavior\SpanExporterTrait;
 use OpenTelemetry\SDK\Trace\SpanExporterInterface;
 
diff --git a/src/SDK/Common/Dev/Compatibility/BC/GlobalLoggerHolder.php b/src/SDK/Common/Dev/Compatibility/BC/GlobalLoggerHolder.php
index 2edf1c2ed..3189f87a8 100644
--- a/src/SDK/Common/Dev/Compatibility/BC/GlobalLoggerHolder.php
+++ b/src/SDK/Common/Dev/Compatibility/BC/GlobalLoggerHolder.php
@@ -4,8 +4,8 @@
 
 namespace OpenTelemetry\SDK\Common\Dev\Compatibility\BC;
 
+use OpenTelemetry\API\Common\Log\LoggerHolder as Moved;
 use OpenTelemetry\SDK\Common\Dev\Compatibility\Util;
-use OpenTelemetry\SDK\Common\Log\LoggerHolder as Moved;
 use Psr\Log\LoggerInterface;
 
 /**
diff --git a/src/SDK/Common/Dev/Compatibility/BC/LoggerHolder.php b/src/SDK/Common/Dev/Compatibility/BC/LoggerHolder.php
new file mode 100644
index 000000000..492394787
--- /dev/null
+++ b/src/SDK/Common/Dev/Compatibility/BC/LoggerHolder.php
@@ -0,0 +1,65 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\SDK\Common\Dev\Compatibility\BC;
+
+use OpenTelemetry\API\Common\Log\LoggerHolder as Moved;
+use OpenTelemetry\SDK\Common\Dev\Compatibility\Util;
+use Psr\Log\LoggerInterface;
+
+/**
+ * @codeCoverageIgnoreStart
+ */
+const OpenTelemetry_SDK_LoggerHolder = 'OpenTelemetry\SDK\LoggerHolder';
+
+class LoggerHolder
+{
+    public static function get(): LoggerInterface
+    {
+        self::triggerClassDeprecationNotice();
+
+        return Moved::get();
+    }
+
+    public static function set(LoggerInterface $logger): void
+    {
+        self::triggerClassDeprecationNotice();
+
+        Moved::set($logger);
+    }
+
+    public static function isSet(): bool
+    {
+        self::triggerClassDeprecationNotice();
+
+        return Moved::isSet();
+    }
+
+    public static function unset(): void
+    {
+        self::triggerClassDeprecationNotice();
+
+        Moved::unset();
+    }
+
+    public static function disable(): void
+    {
+        self::triggerClassDeprecationNotice();
+
+        Moved::disable();
+    }
+
+    private static function triggerClassDeprecationNotice(): void
+    {
+        Util::triggerClassDeprecationNotice(
+            OpenTelemetry_SDK_LoggerHolder,
+            Moved::class
+        );
+    }
+}
+
+class_alias(LoggerHolder::class, OpenTelemetry_SDK_LoggerHolder);
+/**
+ * @codeCoverageIgnoreEnd
+ */
diff --git a/src/SDK/Common/Dev/Compatibility/_load.php b/src/SDK/Common/Dev/Compatibility/_load.php
index d2773d97a..a17a64d7b 100644
--- a/src/SDK/Common/Dev/Compatibility/_load.php
+++ b/src/SDK/Common/Dev/Compatibility/_load.php
@@ -10,5 +10,6 @@
 require_once __DIR__ . '/BC/AbstractClock.php';
 require_once __DIR__ . '/BC/SystemClock.php';
 require_once __DIR__ . '/BC/GlobalLoggerHolder.php';
+require_once __DIR__ . '/BC/LoggerHolder.php';
 require_once __DIR__ . '/BC/InstrumentationLibraryInterface.php';
 require_once __DIR__ . '/BC/InstrumentationLibrary.php';
diff --git a/src/SDK/Common/Event/EventType.php b/src/SDK/Common/Event/EventType.php
deleted file mode 100644
index ee6f291a5..000000000
--- a/src/SDK/Common/Event/EventType.php
+++ /dev/null
@@ -1,16 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace OpenTelemetry\SDK\Common\Event;
-
-use OpenTelemetry\SDK\Common\Event\Event\DebugEvent;
-use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
-use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
-
-class EventType
-{
-    public const ERROR = ErrorEvent::class;
-    public const WARNING = WarningEvent::class;
-    public const DEBUG = DebugEvent::class;
-}
diff --git a/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php b/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php
index 3f05f4018..426e11f10 100644
--- a/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php
+++ b/src/SDK/Trace/Behavior/HttpSpanExporterTrait.php
@@ -7,8 +7,8 @@
 use Exception;
 use InvalidArgumentException;
 use JsonException;
-use OpenTelemetry\SDK\Behavior\EmitsEventsTrait;
-use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
+use OpenTelemetry\API\Behavior\EmitsEventsTrait;
+use OpenTelemetry\API\Common\Event\Event\ErrorEvent;
 use OpenTelemetry\SDK\Trace\SpanExporterInterface;
 use Psr\Http\Client\ClientExceptionInterface;
 use Psr\Http\Client\ClientInterface;
diff --git a/src/SDK/Trace/SpanProcessor/SimpleSpanProcessor.php b/src/SDK/Trace/SpanProcessor/SimpleSpanProcessor.php
index 8cf09ac47..63b7884aa 100644
--- a/src/SDK/Trace/SpanProcessor/SimpleSpanProcessor.php
+++ b/src/SDK/Trace/SpanProcessor/SimpleSpanProcessor.php
@@ -4,9 +4,9 @@
 
 namespace OpenTelemetry\SDK\Trace\SpanProcessor;
 
+use OpenTelemetry\API\Behavior\EmitsEventsTrait;
+use OpenTelemetry\API\Common\Event\Event\DebugEvent;
 use OpenTelemetry\Context\Context;
-use OpenTelemetry\SDK\Behavior\EmitsEventsTrait;
-use OpenTelemetry\SDK\Common\Event\Event\DebugEvent;
 use OpenTelemetry\SDK\Trace\ReadableSpanInterface;
 use OpenTelemetry\SDK\Trace\ReadWriteSpanInterface;
 use OpenTelemetry\SDK\Trace\SpanExporterInterface;
diff --git a/src/SDK/Trace/TracerProviderFactory.php b/src/SDK/Trace/TracerProviderFactory.php
index 3433ae82d..095bb0ef3 100644
--- a/src/SDK/Trace/TracerProviderFactory.php
+++ b/src/SDK/Trace/TracerProviderFactory.php
@@ -4,9 +4,9 @@
 
 namespace OpenTelemetry\SDK\Trace;
 
+use OpenTelemetry\API\Behavior\EmitsEventsTrait;
+use OpenTelemetry\API\Common\Event\Event\WarningEvent;
 use OpenTelemetry\API\Trace as API;
-use OpenTelemetry\SDK\Behavior\EmitsEventsTrait;
-use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
 
 final class TracerProviderFactory
 {
diff --git a/src/SDK/composer.json b/src/SDK/composer.json
index 4cdf06418..3582ac2b8 100644
--- a/src/SDK/composer.json
+++ b/src/SDK/composer.json
@@ -20,7 +20,6 @@
         "php-http/async-client-implementation": "^1.0",
         "php-http/discovery": "^1.14",
         "psr/http-factory-implementation": "^1.0",
-        "psr/log": "^1.1|^2.0|^3.0",
         "symfony/polyfill-mbstring": "^1.23"
     },
     "autoload": {
diff --git a/tests/Unit/SDK/Behavior/LogsMessagesTraitTest.php b/tests/Unit/API/Behavior/LogsMessagesTraitTest.php
similarity index 89%
rename from tests/Unit/SDK/Behavior/LogsMessagesTraitTest.php
rename to tests/Unit/API/Behavior/LogsMessagesTraitTest.php
index 2d55b844c..8753e70d8 100644
--- a/tests/Unit/SDK/Behavior/LogsMessagesTraitTest.php
+++ b/tests/Unit/API/Behavior/LogsMessagesTraitTest.php
@@ -2,17 +2,17 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\Tests\Unit\SDK\Behavior;
+namespace OpenTelemetry\Tests\Unit\API\Behavior;
 
-use OpenTelemetry\SDK\Behavior\LogsMessagesTrait;
-use OpenTelemetry\SDK\Common\Log\LoggerHolder;
+use OpenTelemetry\API\Behavior\LogsMessagesTrait;
+use OpenTelemetry\API\Common\Log\LoggerHolder;
 use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 use Psr\Log\LoggerInterface;
 use Psr\Log\LogLevel;
 
 /**
- * @covers \OpenTelemetry\SDK\Behavior\LogsMessagesTrait
+ * @covers \OpenTelemetry\API\Behavior\LogsMessagesTrait
  */
 class LogsMessagesTraitTest extends TestCase
 {
diff --git a/tests/Unit/SDK/Common/Event/DispatcherTest.php b/tests/Unit/API/Common/Event/DispatcherTest.php
similarity index 74%
rename from tests/Unit/SDK/Common/Event/DispatcherTest.php
rename to tests/Unit/API/Common/Event/DispatcherTest.php
index 9271e67a4..135ae719b 100644
--- a/tests/Unit/SDK/Common/Event/DispatcherTest.php
+++ b/tests/Unit/API/Common/Event/DispatcherTest.php
@@ -2,19 +2,19 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\Tests\Unit\SDK\Common\Event;
+namespace OpenTelemetry\Tests\Unit\API\Common\Event;
 
-use OpenTelemetry\SDK\Common\Event\Dispatcher;
-use OpenTelemetry\SDK\Common\Event\Event\DebugEvent;
-use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
-use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
-use OpenTelemetry\SDK\Common\Event\SimpleDispatcher;
-use OpenTelemetry\SDK\Common\Event\SimpleListenerProvider;
+use OpenTelemetry\API\Common\Event\Dispatcher;
+use OpenTelemetry\API\Common\Event\Event\DebugEvent;
+use OpenTelemetry\API\Common\Event\Event\ErrorEvent;
+use OpenTelemetry\API\Common\Event\Event\WarningEvent;
+use OpenTelemetry\API\Common\Event\SimpleDispatcher;
+use OpenTelemetry\API\Common\Event\SimpleListenerProvider;
 use PHPUnit\Framework\TestCase;
 use Psr\EventDispatcher\EventDispatcherInterface;
 
 /**
- * @covers \OpenTelemetry\SDK\Common\Event\Dispatcher
+ * @covers \OpenTelemetry\API\Common\Event\Dispatcher
  */
 class DispatcherTest extends TestCase
 {
diff --git a/tests/Unit/SDK/Common/Event/Event/DebugEventTest.php b/tests/Unit/API/Common/Event/Event/DebugEventTest.php
similarity index 69%
rename from tests/Unit/SDK/Common/Event/Event/DebugEventTest.php
rename to tests/Unit/API/Common/Event/Event/DebugEventTest.php
index 1cb0986c1..9c28543c9 100644
--- a/tests/Unit/SDK/Common/Event/Event/DebugEventTest.php
+++ b/tests/Unit/API/Common/Event/Event/DebugEventTest.php
@@ -2,13 +2,13 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\Tests\Unit\SDK\Common\Event\Event;
+namespace OpenTelemetry\Tests\Unit\API\Common\Event\Event;
 
-use OpenTelemetry\SDK\Common\Event\Event\DebugEvent;
+use OpenTelemetry\API\Common\Event\Event\DebugEvent;
 use PHPUnit\Framework\TestCase;
 
 /**
- * @covers \OpenTelemetry\SDK\Common\Event\Event\DebugEvent
+ * @covers \OpenTelemetry\API\Common\Event\Event\DebugEvent
  */
 class DebugEventTest extends TestCase
 {
diff --git a/tests/Unit/SDK/Common/Event/Event/ErrorEventTest.php b/tests/Unit/API/Common/Event/Event/ErrorEventTest.php
similarity index 61%
rename from tests/Unit/SDK/Common/Event/Event/ErrorEventTest.php
rename to tests/Unit/API/Common/Event/Event/ErrorEventTest.php
index 3b39b1cbe..5c2693711 100644
--- a/tests/Unit/SDK/Common/Event/Event/ErrorEventTest.php
+++ b/tests/Unit/API/Common/Event/Event/ErrorEventTest.php
@@ -2,13 +2,12 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\Tests\Unit\SDK\Common\Event\Event;
+namespace OpenTelemetry\Tests\Unit\API\Common\Event\Event;
 
-use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
 use PHPUnit\Framework\TestCase;
 
 /**
- * @covers \OpenTelemetry\SDK\Common\Event\Event\ErrorEvent
+ * @covers \OpenTelemetry\API\Common\Event\Event\ErrorEvent
  */
 class ErrorEventTest extends TestCase
 {
@@ -16,7 +15,7 @@ public function test_error_event(): void
     {
         $message = 'foo';
         $exception = new \Exception();
-        $event = new ErrorEvent($message, $exception);
+        $event = new \OpenTelemetry\API\Common\Event\Event\ErrorEvent($message, $exception);
         $this->assertSame($message, $event->getMessage());
         $this->assertSame($exception, $event->getException());
     }
diff --git a/tests/Unit/SDK/Common/Event/Event/WarningEventTest.php b/tests/Unit/API/Common/Event/Event/WarningEventTest.php
similarity index 73%
rename from tests/Unit/SDK/Common/Event/Event/WarningEventTest.php
rename to tests/Unit/API/Common/Event/Event/WarningEventTest.php
index 1aa876ccb..30cf392d5 100644
--- a/tests/Unit/SDK/Common/Event/Event/WarningEventTest.php
+++ b/tests/Unit/API/Common/Event/Event/WarningEventTest.php
@@ -2,13 +2,13 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\Tests\Unit\SDK\Common\Event\Event;
+namespace OpenTelemetry\Tests\Unit\API\Common\Event\Event;
 
-use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
+use OpenTelemetry\API\Common\Event\Event\WarningEvent;
 use PHPUnit\Framework\TestCase;
 
 /**
- * @covers \OpenTelemetry\SDK\Common\Event\Event\WarningEvent
+ * @covers \OpenTelemetry\API\Common\Event\Event\WarningEvent
  */
 class WarningEventTest extends TestCase
 {
@@ -16,7 +16,7 @@ public function test_warning_event_with_throwable(): void
     {
         $message = 'foo';
         $exception = new \Exception();
-        $event = new WarningEvent($message, $exception);
+        $event = new \OpenTelemetry\API\Common\Event\Event\WarningEvent($message, $exception);
         $this->assertSame($message, $event->getMessage());
         $this->assertTrue($event->hasError());
         $this->assertSame($exception, $event->getException());
diff --git a/tests/Unit/SDK/Common/Event/Handler/DebugHandlerTest.php b/tests/Unit/API/Common/Event/Handler/DebugHandlerTest.php
similarity index 61%
rename from tests/Unit/SDK/Common/Event/Handler/DebugHandlerTest.php
rename to tests/Unit/API/Common/Event/Handler/DebugHandlerTest.php
index ad9eb2ec1..a31eaf214 100644
--- a/tests/Unit/SDK/Common/Event/Handler/DebugHandlerTest.php
+++ b/tests/Unit/API/Common/Event/Handler/DebugHandlerTest.php
@@ -2,14 +2,13 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\Tests\Unit\SDK\Common\Event\Handler;
+namespace OpenTelemetry\Tests\Unit\API\Common\Event\Handler;
 
-use OpenTelemetry\SDK\Common\Event\Event\DebugEvent;
-use OpenTelemetry\SDK\Common\Event\Handler\DebugEventHandler;
+use OpenTelemetry\API\Common\Event\Event\DebugEvent;
 use Psr\Log\LogLevel;
 
 /**
- * @covers \OpenTelemetry\SDK\Common\Event\Handler\DebugEventHandler
+ * @covers \OpenTelemetry\API\Common\Event\Handler\DebugEventHandler
  */
 class DebugHandlerTest extends LogBasedHandlerTest
 {
@@ -19,7 +18,7 @@ class DebugHandlerTest extends LogBasedHandlerTest
     public function test_logs_event(): void
     {
         $event = new DebugEvent('foo');
-        $handler = new DebugEventHandler();
+        $handler = new \OpenTelemetry\API\Common\Event\Handler\DebugEventHandler();
         // @phpstan-ignore-next-line
         $this->logger->expects($this->once())->method('log')->with($this->equalTo(LogLevel::DEBUG));
         $handler($event);
diff --git a/tests/Unit/SDK/Common/Event/Handler/ErrorHandlerTest.php b/tests/Unit/API/Common/Event/Handler/ErrorHandlerTest.php
similarity index 68%
rename from tests/Unit/SDK/Common/Event/Handler/ErrorHandlerTest.php
rename to tests/Unit/API/Common/Event/Handler/ErrorHandlerTest.php
index 8b5698bb8..fd23ceaac 100644
--- a/tests/Unit/SDK/Common/Event/Handler/ErrorHandlerTest.php
+++ b/tests/Unit/API/Common/Event/Handler/ErrorHandlerTest.php
@@ -2,15 +2,15 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\Tests\Unit\SDK\Common\Event\Handler;
+namespace OpenTelemetry\Tests\Unit\API\Common\Event\Handler;
 
 use Exception;
-use OpenTelemetry\SDK\Common\Event\Event\ErrorEvent;
-use OpenTelemetry\SDK\Common\Event\Handler\ErrorEventHandler;
+use OpenTelemetry\API\Common\Event\Event\ErrorEvent;
+use OpenTelemetry\API\Common\Event\Handler\ErrorEventHandler;
 use Psr\Log\LogLevel;
 
 /**
- * @covers \OpenTelemetry\SDK\Common\Event\Handler\ErrorEventHandler
+ * @covers \OpenTelemetry\API\Common\Event\Handler\ErrorEventHandler
  */
 class ErrorHandlerTest extends LogBasedHandlerTest
 {
diff --git a/tests/Unit/SDK/Common/Event/Handler/LogBasedHandlerTest.php b/tests/Unit/API/Common/Event/Handler/LogBasedHandlerTest.php
similarity index 75%
rename from tests/Unit/SDK/Common/Event/Handler/LogBasedHandlerTest.php
rename to tests/Unit/API/Common/Event/Handler/LogBasedHandlerTest.php
index fada9155b..7cb3dd0d6 100644
--- a/tests/Unit/SDK/Common/Event/Handler/LogBasedHandlerTest.php
+++ b/tests/Unit/API/Common/Event/Handler/LogBasedHandlerTest.php
@@ -2,10 +2,9 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\Tests\Unit\SDK\Common\Event\Handler;
+namespace OpenTelemetry\Tests\Unit\API\Common\Event\Handler;
 
-use OpenTelemetry\SDK\Common\Log\LoggerHolder;
-use PHPUnit\Framework\MockObject\MockObject;
+use OpenTelemetry\API\Common\Log\LoggerHolder;
 use PHPUnit\Framework\TestCase;
 use Psr\Log\LoggerInterface;
 
diff --git a/tests/Unit/SDK/Common/Event/Handler/WarningHandlerTest.php b/tests/Unit/API/Common/Event/Handler/WarningHandlerTest.php
similarity index 62%
rename from tests/Unit/SDK/Common/Event/Handler/WarningHandlerTest.php
rename to tests/Unit/API/Common/Event/Handler/WarningHandlerTest.php
index b38aaf328..0fa39b71b 100644
--- a/tests/Unit/SDK/Common/Event/Handler/WarningHandlerTest.php
+++ b/tests/Unit/API/Common/Event/Handler/WarningHandlerTest.php
@@ -2,15 +2,14 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\Tests\Unit\SDK\Common\Event\Handler;
+namespace OpenTelemetry\Tests\Unit\API\Common\Event\Handler;
 
 use Exception;
-use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
-use OpenTelemetry\SDK\Common\Event\Handler\WarningEventHandler;
+use OpenTelemetry\API\Common\Event\Event\WarningEvent;
 use Psr\Log\LogLevel;
 
 /**
- * @covers \OpenTelemetry\SDK\Common\Event\Handler\WarningEventHandler
+ * @covers \OpenTelemetry\API\Common\Event\Handler\WarningEventHandler
  */
 class WarningHandlerTest extends LogBasedHandlerTest
 {
@@ -20,7 +19,7 @@ class WarningHandlerTest extends LogBasedHandlerTest
     public function test_logs_event(): void
     {
         $event = new WarningEvent('foo', new Exception());
-        $handler = new WarningEventHandler();
+        $handler = new \OpenTelemetry\API\Common\Event\Handler\WarningEventHandler();
         // @phpstan-ignore-next-line
         $this->logger->expects($this->once())->method('log')->with($this->equalTo(LogLevel::WARNING));
         $handler($event);
diff --git a/tests/Unit/SDK/Common/Event/SimpleDispatcherTest.php b/tests/Unit/API/Common/Event/SimpleDispatcherTest.php
similarity index 88%
rename from tests/Unit/SDK/Common/Event/SimpleDispatcherTest.php
rename to tests/Unit/API/Common/Event/SimpleDispatcherTest.php
index 4066d84fd..4e1927bd4 100644
--- a/tests/Unit/SDK/Common/Event/SimpleDispatcherTest.php
+++ b/tests/Unit/API/Common/Event/SimpleDispatcherTest.php
@@ -2,17 +2,16 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\Tests\Unit\SDK\Common\Event;
+namespace OpenTelemetry\Tests\Unit\API\Common\Event;
 
-use OpenTelemetry\SDK\Common\Event\SimpleDispatcher;
-use OpenTelemetry\SDK\Common\Event\SimpleListenerProvider;
+use OpenTelemetry\API\Common\Event\SimpleDispatcher;
 use PHPUnit\Framework\TestCase;
 use Psr\EventDispatcher\ListenerProviderInterface;
 use Psr\EventDispatcher\StoppableEventInterface;
 use stdClass;
 
 /**
- * @covers \OpenTelemetry\SDK\Common\Event\SimpleDispatcher
+ * @covers \OpenTelemetry\API\Common\Event\SimpleDispatcher
  */
 class SimpleDispatcherTest extends TestCase
 {
@@ -31,7 +30,7 @@ public function test_get_listener_provider(): void
 
     public function test_proxies_listen_for_simple_listener_provider(): void
     {
-        $provider = $this->createMock(SimpleListenerProvider::class);
+        $provider = $this->createMock(\OpenTelemetry\API\Common\Event\SimpleListenerProvider::class);
         $callable = function () {
         };
         $eventName = 'my.event';
@@ -69,7 +68,7 @@ public function test_dispatch_event(): void
             $this->assertSame($event, $receivedEvent);
         };
         $this->listenerProvider->expects($this->once())->method('getListenersForEvent')->willReturn([$handler]); //@phpstan-ignore-line
-        $dispatcher = new SimpleDispatcher($this->listenerProvider);
+        $dispatcher = new \OpenTelemetry\API\Common\Event\SimpleDispatcher($this->listenerProvider);
         $dispatcher->dispatch($event);
     }
 
diff --git a/tests/Unit/SDK/Common/Event/SimpleListenerProviderTest.php b/tests/Unit/API/Common/Event/SimpleListenerProviderTest.php
similarity index 89%
rename from tests/Unit/SDK/Common/Event/SimpleListenerProviderTest.php
rename to tests/Unit/API/Common/Event/SimpleListenerProviderTest.php
index 79c86f2ba..f51557a5e 100644
--- a/tests/Unit/SDK/Common/Event/SimpleListenerProviderTest.php
+++ b/tests/Unit/API/Common/Event/SimpleListenerProviderTest.php
@@ -2,22 +2,21 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\Tests\Unit\SDK\Common\Event;
+namespace OpenTelemetry\Tests\Unit\API\Common\Event;
 
-use OpenTelemetry\SDK\Common\Event\SimpleListenerProvider;
 use PHPUnit\Framework\TestCase;
 use stdClass;
 
 /**
- * @covers \OpenTelemetry\SDK\Common\Event\SimpleListenerProvider
+ * @covers \OpenTelemetry\API\Common\Event\SimpleListenerProvider
  */
 class SimpleListenerProviderTest extends TestCase
 {
-    private SimpleListenerProvider $provider;
+    private \OpenTelemetry\API\Common\Event\SimpleListenerProvider $provider;
 
     public function setUp(): void
     {
-        $this->provider = new SimpleListenerProvider();
+        $this->provider = new \OpenTelemetry\API\Common\Event\SimpleListenerProvider();
     }
 
     public function test_add_listeners(): void
diff --git a/tests/Unit/SDK/Common/Event/StoppableEventTraitTest.php b/tests/Unit/API/Common/Event/StoppableEventTraitTest.php
similarity index 75%
rename from tests/Unit/SDK/Common/Event/StoppableEventTraitTest.php
rename to tests/Unit/API/Common/Event/StoppableEventTraitTest.php
index f623c0548..d08f95101 100644
--- a/tests/Unit/SDK/Common/Event/StoppableEventTraitTest.php
+++ b/tests/Unit/API/Common/Event/StoppableEventTraitTest.php
@@ -2,14 +2,13 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\Tests\Unit\SDK\Common\Event;
+namespace OpenTelemetry\Tests\Unit\API\Common\Event;
 
-use OpenTelemetry\SDK\Common\Event\StoppableEventTrait;
 use PHPUnit\Framework\TestCase;
 use Psr\EventDispatcher\StoppableEventInterface;
 
 /**
- * @covers \OpenTelemetry\SDK\Common\Event\StoppableEventTrait
+ * @covers \OpenTelemetry\API\Common\Event\StoppableEventTrait
  */
 class StoppableEventTraitTest extends TestCase
 {
@@ -27,7 +26,7 @@ public function test_stop_event(): void
     public function getEvent(): StoppableEventInterface
     {
         return new class() implements StoppableEventInterface {
-            use StoppableEventTrait;
+            use \OpenTelemetry\API\Common\Event\StoppableEventTrait;
         };
     }
 }
diff --git a/tests/Unit/SDK/Common/Log/LoggerHolderTest.php b/tests/Unit/SDK/Common/Log/LoggerHolderTest.php
index d19801818..26c78886b 100644
--- a/tests/Unit/SDK/Common/Log/LoggerHolderTest.php
+++ b/tests/Unit/SDK/Common/Log/LoggerHolderTest.php
@@ -4,13 +4,13 @@
 
 namespace OpenTelemetry\Tests\Unit\SDK\Common\Log;
 
-use OpenTelemetry\SDK\Common\Log\LoggerHolder;
+use OpenTelemetry\API\Common\Log\LoggerHolder;
 use PHPUnit\Framework\TestCase;
 use Psr\Log\LoggerInterface;
 use Psr\Log\NullLogger;
 
 /**
- * @covers \OpenTelemetry\SDK\Common\Log\LoggerHolder
+ * @covers \OpenTelemetry\API\Common\Log\LoggerHolder
  */
 class LoggerHolderTest extends TestCase
 {
diff --git a/tests/Unit/SDK/Trace/Behavior/HttpSpanExporterTraitTest.php b/tests/Unit/SDK/Trace/Behavior/HttpSpanExporterTraitTest.php
index be3757225..ee92c4c55 100644
--- a/tests/Unit/SDK/Trace/Behavior/HttpSpanExporterTraitTest.php
+++ b/tests/Unit/SDK/Trace/Behavior/HttpSpanExporterTraitTest.php
@@ -5,7 +5,7 @@
 namespace OpenTelemetry\Tests\Unit\SDK\Trace\Behavior;
 
 use GuzzleHttp\Exception\ClientException;
-use OpenTelemetry\SDK\Common\Event\Dispatcher;
+use OpenTelemetry\API\Common\Event\Dispatcher;
 use OpenTelemetry\SDK\Trace\Behavior\HttpSpanExporterTrait;
 use OpenTelemetry\SDK\Trace\SpanDataInterface;
 use OpenTelemetry\SDK\Trace\SpanExporterInterface;
diff --git a/tests/Unit/SDK/Trace/TracerProviderFactoryTest.php b/tests/Unit/SDK/Trace/TracerProviderFactoryTest.php
index 29c2b04b8..002b9063a 100644
--- a/tests/Unit/SDK/Trace/TracerProviderFactoryTest.php
+++ b/tests/Unit/SDK/Trace/TracerProviderFactoryTest.php
@@ -4,9 +4,9 @@
 
 namespace OpenTelemetry\Tests\Unit\SDK\Trace;
 
-use OpenTelemetry\SDK\Common\Event\Dispatcher;
-use OpenTelemetry\SDK\Common\Event\Event\WarningEvent;
-use OpenTelemetry\SDK\Common\Log\LoggerHolder;
+use OpenTelemetry\API\Common\Event\Dispatcher;
+use OpenTelemetry\API\Common\Event\Event\WarningEvent;
+use OpenTelemetry\API\Common\Log\LoggerHolder;
 use OpenTelemetry\SDK\Trace\ExporterFactory;
 use OpenTelemetry\SDK\Trace\SamplerFactory;
 use OpenTelemetry\SDK\Trace\SpanProcessorFactory;

From 122cc83bd34101fdfe186827712b63d181f83bfb Mon Sep 17 00:00:00 2001
From: Brett McBride <brett@deakin.edu.au>
Date: Wed, 22 Jun 2022 20:00:28 +1000
Subject: [PATCH 12/14] benchmark test for events

---
 tests/Benchmark/EventBench.php | 78 ++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 tests/Benchmark/EventBench.php

diff --git a/tests/Benchmark/EventBench.php b/tests/Benchmark/EventBench.php
new file mode 100644
index 000000000..389ced05c
--- /dev/null
+++ b/tests/Benchmark/EventBench.php
@@ -0,0 +1,78 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Tests\Benchmark;
+
+use OpenTelemetry\API\Common\Event\SimpleDispatcher;
+use OpenTelemetry\API\Common\Event\SimpleListenerProvider;
+use stdClass;
+
+class EventBench
+{
+    private SimpleDispatcher $dispatcher;
+    private SimpleListenerProvider $listenerProvider;
+    private $function;
+    private object $event;
+
+    public function __construct()
+    {
+        $this->listenerProvider = new SimpleListenerProvider();
+        $this->dispatcher = new SimpleDispatcher($this->listenerProvider);
+        $this->function = function(){};
+        $this->event = new stdClass();
+    }
+
+    public function addEventsToListener(): void
+    {
+        for ($i=0; $i<10; $i++) {
+            $this->listenerProvider->listen('event_'.$i, $this->function);
+        }
+        $this->listenerProvider->listen(get_class($this->event), $this->function);
+    }
+
+    /**
+     * @ParamProviders("provideListenerCounts")
+     * @Revs(1000)
+     * @Iterations(10)
+     * @OutputTimeUnit("microseconds")
+     */
+    public function benchAddListeners(array $params): void
+    {
+        for ($i=0; $i<$params[0]; $i++) {
+            $this->listenerProvider->listen('event_'.$i, $this->function);
+        }
+    }
+
+    /**
+     * @ParamProviders("provideListenerCounts")
+     * @Revs(1000)
+     * @Iterations(10)
+     * @OutputTimeUnit("microseconds")
+     */
+    public function benchAddListenersForSameEvent(array $params): void
+    {
+        for ($i=0; $i<$params[0]; $i++) {
+            $this->listenerProvider->listen('event', $this->function);
+        }
+    }
+
+    /**
+     * @BeforeMethods("addEventsToListener")
+     * @Revs(1000)
+     * @Iterations(10)
+     * @OutputTimeUnit("microseconds")
+     */
+    public function benchDispatchEvent(): void
+    {
+        $this->dispatcher->dispatch($this->event);
+    }
+
+    public function provideListenerCounts(): \Generator
+    {
+        yield [1];
+        yield [4];
+        yield [16];
+        yield [256];
+    }
+}
\ No newline at end of file

From 43fb0702a888b12ab9bf1be8befbe6170396c72e Mon Sep 17 00:00:00 2001
From: Brett McBride <brett@deakin.edu.au>
Date: Wed, 22 Jun 2022 20:02:42 +1000
Subject: [PATCH 13/14] fix name

---
 tests/Benchmark/EventBench.php | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/tests/Benchmark/EventBench.php b/tests/Benchmark/EventBench.php
index 389ced05c..367cbcc02 100644
--- a/tests/Benchmark/EventBench.php
+++ b/tests/Benchmark/EventBench.php
@@ -4,6 +4,7 @@
 
 namespace OpenTelemetry\Tests\Benchmark;
 
+use Generator;
 use OpenTelemetry\API\Common\Event\SimpleDispatcher;
 use OpenTelemetry\API\Common\Event\SimpleListenerProvider;
 use stdClass;
@@ -12,23 +13,23 @@ class EventBench
 {
     private SimpleDispatcher $dispatcher;
     private SimpleListenerProvider $listenerProvider;
-    private $function;
+    private $listener;
     private object $event;
 
     public function __construct()
     {
         $this->listenerProvider = new SimpleListenerProvider();
         $this->dispatcher = new SimpleDispatcher($this->listenerProvider);
-        $this->function = function(){};
+        $this->listener = function(){};
         $this->event = new stdClass();
     }
 
     public function addEventsToListener(): void
     {
         for ($i=0; $i<10; $i++) {
-            $this->listenerProvider->listen('event_'.$i, $this->function);
+            $this->listenerProvider->listen('event_'.$i, $this->listener);
         }
-        $this->listenerProvider->listen(get_class($this->event), $this->function);
+        $this->listenerProvider->listen(get_class($this->event), $this->listener);
     }
 
     /**
@@ -40,7 +41,7 @@ public function addEventsToListener(): void
     public function benchAddListeners(array $params): void
     {
         for ($i=0; $i<$params[0]; $i++) {
-            $this->listenerProvider->listen('event_'.$i, $this->function);
+            $this->listenerProvider->listen('event_'.$i, $this->listener);
         }
     }
 
@@ -53,7 +54,7 @@ public function benchAddListeners(array $params): void
     public function benchAddListenersForSameEvent(array $params): void
     {
         for ($i=0; $i<$params[0]; $i++) {
-            $this->listenerProvider->listen('event', $this->function);
+            $this->listenerProvider->listen('event', $this->listener);
         }
     }
 
@@ -68,7 +69,7 @@ public function benchDispatchEvent(): void
         $this->dispatcher->dispatch($this->event);
     }
 
-    public function provideListenerCounts(): \Generator
+    public function provideListenerCounts(): Generator
     {
         yield [1];
         yield [4];

From 9099ff753d7677d28df736c089fb5d978c8fbda2 Mon Sep 17 00:00:00 2001
From: Brett McBride <brett@deakin.edu.au>
Date: Wed, 22 Jun 2022 20:12:12 +1000
Subject: [PATCH 14/14] linting

---
 tests/Benchmark/EventBench.php | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/tests/Benchmark/EventBench.php b/tests/Benchmark/EventBench.php
index 367cbcc02..ecc9b92c7 100644
--- a/tests/Benchmark/EventBench.php
+++ b/tests/Benchmark/EventBench.php
@@ -20,14 +20,15 @@ public function __construct()
     {
         $this->listenerProvider = new SimpleListenerProvider();
         $this->dispatcher = new SimpleDispatcher($this->listenerProvider);
-        $this->listener = function(){};
+        $this->listener = function () {
+        };
         $this->event = new stdClass();
     }
 
     public function addEventsToListener(): void
     {
         for ($i=0; $i<10; $i++) {
-            $this->listenerProvider->listen('event_'.$i, $this->listener);
+            $this->listenerProvider->listen('event_' . $i, $this->listener);
         }
         $this->listenerProvider->listen(get_class($this->event), $this->listener);
     }
@@ -41,7 +42,7 @@ public function addEventsToListener(): void
     public function benchAddListeners(array $params): void
     {
         for ($i=0; $i<$params[0]; $i++) {
-            $this->listenerProvider->listen('event_'.$i, $this->listener);
+            $this->listenerProvider->listen('event_' . $i, $this->listener);
         }
     }
 
@@ -76,4 +77,4 @@ public function provideListenerCounts(): Generator
         yield [16];
         yield [256];
     }
-}
\ No newline at end of file
+}