Emitter¶

Emitter event-source subscribes to a channel and helps sensor trigger the workloads.

Event Structure¶

The structure of an event dispatched by the event-source over the eventbus looks like following,

    {
        "context": {
          "type": "type_of_event_source",
          "specversion": "cloud_events_version",
          "source": "name_of_the_event_source",
          "id": "unique_event_id",
          "time": "event_time",
          "datacontenttype": "type_of_data",
          "subject": "name_of_the_configuration_within_event_source"
        },
        "data": {
          "topic": "name_of_the_topic",
          "body": "message_payload"
        }
    }

Specification¶

Emitter event-source specification is available here.

Setup¶

Deploy the emitter in your local K8s cluster.

---
apiVersion: v1
kind: Service
metadata:
  name: broker
  labels:
    app: broker
spec:
  clusterIP: None
  ports:
    - port: 4000
      targetPort: 4000
  selector:
    app: broker
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: broker
spec:
  replicas: 1
  selector:
    matchLabels:
      app: broker
  template:
    metadata:
      labels:
        app: broker
    spec:
      containers:
        - env:
            - name: EMITTER_LICENSE
              value: "zT83oDV0DWY5_JysbSTPTDr8KB0AAAAAAAAAAAAAAAI" # This is a test license, DO NOT USE IN PRODUCTION!
            - name: EMITTER_CLUSTER_SEED
              value: "broker"
            - name: EMITTER_CLUSTER_ADVERTISE
              value: "private:4000"
          name: broker
          image: emitter/server:latest
          ports:
            - containerPort: 8080
            - containerPort: 443
            - containerPort: 4000
          volumeMounts:
            - name: broker-volume
              mountPath: /data
      volumes:
        - name: broker-volume
          hostPath:
            path: /emitter #directory on host

Create the event-source by running the following command.

kubectl apply -n argo-events -f https://raw.githubusercontent.com/argoproj/argo-events/stable/examples/event-sources/emitter.yaml

Inspect the event-source pod logs to make sure it was able to subscribe to the topic specified in the event source to consume messages.

Create the sensor by running the following command.

kubectl apply -n argo-events -f https://raw.githubusercontent.com/argoproj/argo-events/stable/examples/sensors/emitter.yaml

Send a message on emitter channel using one of the clients https://emitter.io/develop/golang/.
Once a message is published, an argo workflow will be triggered. Run argo list to find the workflow.

Troubleshoot¶

Please read the FAQ.