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EventSource Configuration

EventSources connect to external systems and normalize events for the EventBus.

Pub/Sub EventSource

Connect to Google Cloud Pub/Sub:

apiVersion: argoproj.io/v1alpha1
kind: EventSource
metadata:
  name: gar-image-push
  namespace: argo-events
spec:
  pubsub:
    image-pushed:
      projectID: example-gcp-project
      topicProjectID: example-gcp-project
      topic: gar-image-notifications
      credentialSecret:
        name: gcp-pubsub-credentials
        key: service-account.json
      jsonBody: true
      deleteSubscriptionOnFinish: false

Key settings:

Setting Value Purpose
jsonBody true Parse Pub/Sub messages as JSON
deleteSubscriptionOnFinish false Keep subscription across pod restarts
credentialSecret secret reference GCP service account with pubsub.subscriber role

Silent Failures

Without jsonBody: true, events arrive but fail to parse. No errors appear in logs. The EventSource marks messages as delivered, then discards them.

GitHub Webhook EventSource

Connect to GitHub repositories via webhooks with GitHub App authentication:

apiVersion: argoproj.io/v1alpha1
kind: EventSource
metadata:
  name: github
  namespace: argo-events
spec:
  service:
    ports:
      - name: push
        port: 12000
        targetPort: 12000
  github:
    github:
      repositories:
        - owner: my-org
          names:
            - repo-one
            - repo-two
      githubApp:
        privateKey:
          name: github-app-credentials
          key: private-key.pem
        appID: 123456
        installationID: 12345678
      webhook:
        endpoint: /push
        port: "12000"
        method: POST
        url: https://webhooks.example.com/github
      events:
        - push
      contentType: json
      active: true

Key settings:

Setting Purpose
githubApp GitHub App auth (preferred over personal tokens)
webhook.url External URL where GitHub sends events
events GitHub event types to listen for
service.ports Internal service for ingress routing

Ingress Required

The EventSource runs an internal HTTP server. You need an Ingress or Gateway to expose webhook.url to GitHub. The service name follows the pattern <eventsource-name>-eventsource-svc.

Dynamic Repository Lists with Helm

When managing many repositories, use Helm templating to generate the EventSource dynamically:

# values.yaml
github:
  repositories:
    - owner: my-org
      names:
        - api-service
        - web-frontend
        - worker-backend
    - owner: other-org
      names:
        - shared-library

# templates/github-eventsource.yaml
apiVersion: argoproj.io/v1alpha1
kind: EventSource
metadata:
  name: github
spec:
  github:
    github:
      repositories:
        {{- range .Values.github.repositories }}
        - owner: {{ .owner }}
          names:
            {{- range .names }}
            - {{ . }}
            {{- end }}
        {{- end }}
      # ... rest of config

This pattern allows you to:

  • Add repositories by updating values.yaml instead of editing templates
  • Use different repository lists per environment
  • Keep EventSource configuration DRY across multiple deployments

Resource Limits

Always set resource limits on EventSource pods:

spec:
  template:
    container:
      resources:
        requests:
          cpu: 50m
          memory: 1Gi
        limits:
          cpu: 200m
          memory: 1Gi
      env:
        - name: LOG_LEVEL
          value: error  # Reduce log noise in production
    serviceAccountName: eventsource-sa
  replicas: 1

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