Argo Events Documentation

This guide demonstrates how to set up a complete event-driven pipeline: an EventBus, a Webhook EventSource, and a Sensor that triggers an Argo Workflow upon receiving an HTTP POST request.

1. Deploy Argo Events components

Apply the following manifests to set up the infrastructure:

# Set up the eventbus
kubectl -n argo-events apply -f https://raw.githubusercontent.com/argoproj/argo-events/stable/examples/eventbus/native.yaml

# Create the webhook event source
kubectl -n argo-events apply -f https://raw.githubusercontent.com/argoproj/argo-events/stable/examples/event-sources/webhook.yaml

# Create the webhook sensor
kubectl -n argo-events apply -f https://raw.githubusercontent.com/argoproj/argo-events/stable/examples/sensors/webhook.yaml

2. Expose the EventSource

To send requests to the event-source pod, use port-forwarding (or configure an Ingress/OpenShift Route):

kubectl -n argo-events port-forward <event-source-pod-name> 12000:12000

3. Trigger the Workflow

Send an HTTP POST request using curl or Postman:

curl -d '{"message":"this is my first webhook"}' -H "Content-Type: application/json" -X POST http://localhost:12000/example

4. Verify the Result

Check that a workflow was created and inspect its logs:

# Check for the workflow
kubectl -n argo-events get wf

# Check the workflow logs
argo logs -n argo-events @latest

Note: The workflow logs will contain the event context and the event data. The data field is base64 encoded.

To use NSQ as an event source, you must deploy the NSQ components (nsqlookupd, nsqd, and nsqadmin) to your Kubernetes cluster. The following manifest provides the necessary Services and Workloads (StatefulSet/Deployments) to run NSQ locally.

Note: The nsqd configuration in this example assumes it is communicating with nsqlookupd.argo-events.svc:4160 and broadcasting via nsqd.argo-events.svc.

apiVersion: v1
kind: Service
metadata:
  name: nsqlookupd
  labels:
    app: nsq
spec:
  ports:
    - port: 4160
      targetPort: 4160
      name: tcp
    - port: 4161
      targetPort: 4161
      name: http
  clusterIP: None
  selector:
    app: nsq
    component: nsqlookupd
---
apiVersion: v1
kind: Service
metadata:
  name: nsqd
  labels:
    app: nsq
spec:
  ports:
    - port: 4150
      targetPort: 4150
      name: tcp
    - port: 4151
      targetPort: 4151
      name: http
  clusterIP: None
  selector:
    app: nsq
    component: nsqd
---
apiVersion: v1
kind: Service
metadata:
  name: nsqadmin
  labels:
    app: nsq
spec:
  ports:
    - port: 4170
      targetPort: 4170
      name: tcp
    - port: 4171
      targetPort: 4171
      name: http
  selector:
    app: nsq
    component: nsqadmin
---
apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
  name: nsqlookupd
spec:
  serviceName: "nsqlookupd"
  replicas: 1
  updateStrategy:
    type: RollingUpdate
  template:
    metadata:
      labels:
        app: nsq
        component: nsqlookupd
    spec:
      containers:
        - name: nsqlookupd
          image: nsqio/nsq:v1.1.0
          imagePullPolicy: Always
          resources:
            requests:
              cpu: 30m
              memory: 64Mi
          ports:
            - containerPort: 4160
              name: tcp
            - containerPort: 4161
              name: http
          livenessProbe:
            httpGet:
              path: /ping
              port: http
            initialDelaySeconds: 5
          readinessProbe:
            httpGet:
              path: /ping
              port: http
            initialDelaySeconds: 2
          command:
            - /nsqlookupd
      terminationGracePeriodSeconds: 5
---
apiVersion: apps/v1beta1
kind: Deployment
metadata:
  name: nsqd
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nsq
      component: nsqd
  template:
    metadata:
      labels:
        app: nsq
        component: nsqd
    spec:
      containers:
        - name: nsqd
          image: nsqio/nsq:v1.1.0
          imagePullPolicy: Always
          resources:
            requests:
              cpu: 30m
              memory: 64Mi
          ports:
            - containerPort: 4150
              name: tcp
            - containerPort: 4151
              name: http
          livenessProbe:
            httpGet:
              path: /ping
              port: http
            initialDelaySeconds: 5
          readinessProbe:
            httpGet:
              path: /ping
              port: http
            initialDelaySeconds: 2
          volumeMounts:
            - name: datadir
              mountPath: /data
          command:
            - /nsqd
            - -data-path
            - /data
            - -lookupd-tcp-address
            - nsqlookupd.argo-events.svc:4160
            - -broadcast-address
            - nsqd.argo-events.svc
          env:
            - name: HOSTNAME
              valueFrom:
                fieldRef:
                  fieldPath: metadata.name
      terminationGracePeriodSeconds: 5
      volumes:
        - name: datadir
          emptyDir: {}
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: nsqadmin
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: nsq
        component: nsqadmin
    spec:
      containers:
        - name: nsqadmin
          image: nsqio/nsq:v1.1.0
          imagePullPolicy: Always
          resources:
            requests:
              cpu: 30m
              memory: 64Mi
          ports:
            - containerPort: 4170
              name: tcp
            - containerPort: 4171
              name: http
          livenessProbe:
            httpGet:
              path: /ping
              port: http
            initialDelaySeconds: 10
          readinessProbe:
            httpGet:
              path: /ping
              port: http
            initialDelaySeconds: 5
          command:
            - /nsqadmin
            - -lookupd-http-address
            - nsqlookupd.argo-events.svc:4161
      terminationGracePeriodSeconds: 5