docs: added kafka trigger (argoproj#567)

* fix: tests

docs/triggers/kafka-trigger.md

@@ -0,0 +1,71 @@
+# Kafka Trigger
+
+Kafka trigger allows sensor to publish events on Kafka topic. This trigger helps source the events from outside world into your messaging queues.
+
+## Specification
+The Kafka trigger specification is available [here](https://github.com/argoproj/argo-events/blob/master/api/sensor.md#kafkatrigger).
+
+## Walkthrough
+
+1. Consider a scenario where you are expecting a file drop onto a Minio bucket and want to place that event
+   on a Kafka topic.
+
+1. Set up the Minio Event Source and Gateway [here](https://argoproj.github.io/argo-events/setup/minio/). 
+   Do not create the Minio sensor, we are going to create it in next step.
+
+1. Lets create the sensor,
+
+        apiVersion: argoproj.io/v1alpha1
+        kind: Sensor
+        metadata:
+          name: minio-sensor
+          labels:
+            sensors.argoproj.io/sensor-controller-instanceid: argo-events
+        spec:
+          template:
+            spec:
+              containers:
+                - name: sensor
+                  image: argoproj/sensor:v0.13.0
+                  imagePullPolicy: Always
+              serviceAccountName: argo-events-sa
+          dependencies:
+            - name: test-dep
+              gatewayName: minio-gateway
+              eventName: example
+          subscription:
+            http:
+              port: 9300
+          triggers:
+            - template:
+                name: kafka-trigger
+                kafka:
+                  # Kafka URL
+                  url: kafka.argo-events.svc:9092
+                  # Name of the topic
+                  topic: minio-events
+                  # partition id
+                  partition: 0
+                  payload:
+                    - src:
+                        dependencyName: test-dep
+                        dataKey: notification.0.s3.object.key
+                      dest: fileName
+                    - src:
+                        dependencyName: test-dep
+                        dataKey: notification.0.s3.bucket.name
+                      dest: bucket
+
+1. The Kafka message needs a body. In order to construct message based on the event data, sensor offers 
+   `payload` field as a part of the Kafka trigger.
+
+   The `payload` contains the list of `src` which refers to the source event and `dest` which refers to destination key within result request payload.
+
+   The `payload` declared above will generate a message body like below,
+
+        {
+            "fileName": "hello.txt" // name/key of the object
+            "bucket": "input" // name of the bucket
+        }
+
+1. Drop a file called `hello.txt` onto the bucket `input` and you will receive the message on Kafka topic

mkdocs.yml

@@ -60,6 +60,7 @@ nav:
       - 'triggers/aws-lambda.md'
       - 'triggers/http-trigger.md'
       - 'triggers/nats-trigger.md'
+      - 'triggers/kafka-trigger.md'
   - 'developer_guide.md'
   - 'controllers.md'
   - 'FAQ.md'

sensors/triggers/http/http_test.go

@@ -121,7 +121,7 @@ func TestHTTPTrigger_ApplyResourceParameters(t *testing.T) {
 	updatedTrigger, ok := resource.(*v1alpha1.HTTPTrigger)
 	assert.Nil(t, err)
 	assert.Equal(t, true, ok)
-	assert.Equal(t, "http://another-fake.com", updatedTrigger.URL)
+	assert.Equal(t, "http://fake.com:12000", updatedTrigger.URL)
 	assert.Equal(t, http.MethodGet, updatedTrigger.Method)
 }