Remove mixed_signals support, minor cleanups (#135)

With minor cleanups:
- remove cfg-schema.yaml, it will be auto-generated in the contrib repo
(and was stale)
- rename otlp* to otelarrow*
- replace OTLP-Arrow with OTel-Arrow

Part of #43 
Fixes #33

collector/exporter/otelarrowexporter/README.md

@@ -219,18 +219,3 @@ exporters:
       zstd:
         level: 1       # 1 is the "fastest" compression level
 ```
-
-### Experimental Configuration
-
-The exporter uses the signal-specific Arrow stream methods (i.e.,
-`ArrowTraces`, `ArrowLogs`, and `ArrowMetrics`) by default.  There is
-an option to use the generic `ArrowStream` method instead.
-
-- `enable_mixed_signals` (default: false): Use `ArrowStream` instead of per-signal stream methods.
-
-This option has the potential to enable the future exporter to cross
-signals, meaning to allow traces, metrics and logs to refer to the
-same shared-data items across a single stream.  Presently, there is no
-cross-signal compression benefit, this option simply causes one method
-name instead of three method names to be used by the exporter
-instances of different signal types.

collector/exporter/otelarrowexporter/config.go

@@ -38,19 +38,9 @@ type Config struct {
 // ArrowSettings includes whether Arrow is enabled and the number of
 // concurrent Arrow streams.
 type ArrowSettings struct {
-	// Disabled prevents registering the OTel Arrow service.
-	Disabled bool `mapstructure:"disabled"`
-
 	// NumStreams determines the number of OTel Arrow streams.
 	NumStreams int `mapstructure:"num_streams"`
 
-	// DisableDowngrade prevents this exporter from fallback back to
-	// standard OTLP.
-	DisableDowngrade bool `mapstructure:"disable_downgrade"`
-
-	// EnableMixedSignals allows the use of multi-signal streams.
-	EnableMixedSignals bool `mapstructure:"enable_mixed_signals"`
-
 	// MaxStreamLifetime should be set to less than the value of
 	// grpc: keepalive: max_connection_age_grace plus the timeout.
 	MaxStreamLifetime time.Duration `mapstructure:"max_stream_lifetime"`
@@ -69,6 +59,13 @@ type ArrowSettings struct {
 	// set to "zstd" to turn on Arrow-Zstd compression.
 	// Note that `Zstd` applies to gRPC, not Arrow compression.
 	PayloadCompression configcompression.CompressionType `mapstructure:"payload_compression"`
+
+	// Disabled prevents registering the OTel Arrow service.
+	Disabled bool `mapstructure:"disabled"`
+
+	// DisableDowngrade prevents this exporter from fallback back to
+	// standard OTLP.
+	DisableDowngrade bool `mapstructure:"disable_downgrade"`
 }
 
 var _ component.Config = (*Config)(nil)

collector/exporter/otelarrowexporter/config_test.go

@@ -83,7 +83,6 @@ func TestUnmarshalConfig(t *testing.T) {
 			},
 			Arrow: ArrowSettings{
 				NumStreams:         2,
-				EnableMixedSignals: true,
 				MaxStreamLifetime:  2 * time.Hour,
 				PayloadCompression: configcompression.Zstd,
 				Zstd:               zstd.DefaultEncoderConfig(),

collector/exporter/otelarrowexporter/factory.go

@@ -92,9 +92,6 @@ var (
 )
 
 func createArrowTracesStream(cfg *Config, conn *grpc.ClientConn) arrow.StreamClientFunc {
-	if cfg.Arrow.EnableMixedSignals {
-		return arrow.MakeAnyStreamClient(arrowStreamMethod, arrowpb.NewArrowStreamServiceClient(conn).ArrowStream)
-	}
 	return arrow.MakeAnyStreamClient(arrowTracesMethod, arrowpb.NewArrowTracesServiceClient(conn).ArrowTraces)
 }
 
@@ -114,9 +111,6 @@ func createTracesExporter(
 }
 
 func createArrowMetricsStream(cfg *Config, conn *grpc.ClientConn) arrow.StreamClientFunc {
-	if cfg.Arrow.EnableMixedSignals {
-		return arrow.MakeAnyStreamClient(arrowStreamMethod, arrowpb.NewArrowStreamServiceClient(conn).ArrowStream)
-	}
 	return arrow.MakeAnyStreamClient(arrowMetricsMethod, arrowpb.NewArrowMetricsServiceClient(conn).ArrowMetrics)
 }
 
@@ -136,9 +130,6 @@ func createMetricsExporter(
 }
 
 func createArrowLogsStream(cfg *Config, conn *grpc.ClientConn) arrow.StreamClientFunc {
-	if cfg.Arrow.EnableMixedSignals {
-		return arrow.MakeAnyStreamClient(arrowStreamMethod, arrowpb.NewArrowStreamServiceClient(conn).ArrowStream)
-	}
 	return arrow.MakeAnyStreamClient(arrowLogsMethod, arrowpb.NewArrowLogsServiceClient(conn).ArrowLogs)
 }
 

collector/exporter/otelarrowexporter/internal/arrow/exporter.go

@@ -76,8 +76,7 @@ type Exporter struct {
 	netReporter netstats.Interface
 }
 
-// AnyStreamClient is the interface supported by all Arrow streams,
-// mixed signals or not.
+// AnyStreamClient is the interface supported by all Arrow streams.
 type AnyStreamClient interface {
 	Send(*arrowpb.BatchArrowRecords) error
 	Recv() (*arrowpb.BatchStatus, error)
@@ -89,10 +88,10 @@ type AnyStreamClient interface {
 // handler isn't able to see the correct uncompressed size.
 type StreamClientFunc func(context.Context, ...grpc.CallOption) (AnyStreamClient, string, error)
 
-// MakeAnyStreamClient accepts any Arrow-like stream (mixed signal or
-// not) and turns it into an AnyStreamClient.  The method name is
-// carried through because once constructed, gRPC clients will not
-// reveal their service and method names.
+// MakeAnyStreamClient accepts any Arrow-like stream and turns it into
+// an AnyStreamClient.  The method name is carried through because
+// once constructed, gRPC clients will not reveal their service and
+// method names.
 func MakeAnyStreamClient[T AnyStreamClient](method string, clientFunc func(ctx context.Context, opts ...grpc.CallOption) (T, error)) StreamClientFunc {
 	return func(ctx context.Context, opts ...grpc.CallOption) (AnyStreamClient, string, error) {
 		client, err := clientFunc(ctx, opts...)
@@ -142,7 +141,7 @@ func (e *Exporter) Start(ctx context.Context) error {
 
 // runStreamController starts the initial set of streams, then waits for streams to
 // terminate one at a time and restarts them.  If streams come back with a nil
-// client (meaning that OTLP+Arrow was not supported by the endpoint), it will
+// client (meaning that OTel-Arrow was not supported by the endpoint), it will
 // not be restarted.
 func (e *Exporter) runStreamController(bgctx context.Context) {
 	defer e.cancel()

collector/exporter/otelarrowexporter/internal/arrow/stream.go

@@ -54,7 +54,7 @@ type Stream struct {
 
 	// client uses the exporter's grpc.ClientConn.  this is
 	// initially nil only set when ArrowStream() calls meaning the
-	// endpoint recognizes OTLP+Arrow.
+	// endpoint recognizes OTel-Arrow.
 	client arrowpb.ArrowStreamService_ArrowStreamClient
 
 	// method the gRPC method name, used for additional instrumentation.
@@ -432,7 +432,7 @@ func (s *Stream) processBatchStatus(ss *arrowpb.BatchStatus) error {
 		ch <- nil
 		return nil
 	}
-	// See ../../otlp.go's `shouldRetry()` method, the retry
+	// See ../../otelarrow.go's `shouldRetry()` method, the retry
 	// behavior described here is achieved there by setting these
 	// recognized codes.
 	var err error

collector/exporter/otelarrowexporter/otlp.go → collector/exporter/otelarrowexporter/otelarrow.go

@@ -54,9 +54,9 @@ type baseExporter struct {
 	// Default user-agent header.
 	userAgent string
 
-	// OTLP+Arrow optional state
+	// OTel-Arrow optional state
 	arrow *arrow.Exporter
-	// streamClientFunc is the stream constructor, depends on EnableMixedTelemetry.
+	// streamClientFunc is the stream constructor
 	streamClientFactory streamClientFactory
 }