Support applying parameters for complete trigger spec

[VaibhavPage]

This feature will allow replacing anything in trigger template on the fly. It will be very helpful in cases where triggger workflow is stored on S3 or Git and user wants to figure out the url, bucket or repo name based on the event payload. Also to make it easier for user, this change would differentiate parameters for trigger template and for workflow template.

[dtaniwaki]

I'm not sure when we use WorkflowParameters over TemplateParameter. Could you provide some examples in the PR?

[VaibhavPage]

Sure. I'll update the PR with the examples

[VaibhavPage]

For now consider this example ,

# The event payload for this example =
#
#  {
#   "name": "trigger-wf-1",
#   "namespace": "argo-events",
#   "bucket": "mybucket",
#   "key": "hello.yaml",
#   "image": "docker/busybox",
#  }
#
# The example refers to workflow stored on a S3 bucket. With normal sensor spec, you would hard-code the S3 bucket name, object key and other things in trigger.
# But user would like to have dynamic trigger spec where depending on the data in the payload.
# The example data payload contains information like bucket, key, name, namespace which is used to replace the placeholders in trigger spec.
# The image in payload will be used to replace the image in the workflow.
#
apiVersion: argoproj.io/v1alpha1
kind: Sensor
metadata:
  name: webhook-with-context-sensor
  labels:
    sensors.argoproj.io/sensor-controller-instanceid: argo-events
spec:
  deploySpec:
    spec:
      containers:
        - name: "sensor"
          image: "argoproj/sensor"
          imagePullPolicy: Always
      serviceAccountName: argo-events-sa
  dependencies:
    - name: "webhook-gateway:foo"
  eventProtocol:
    type: "HTTP"
    http:
      port: "9300"
  triggers:
    - template:
        name: THIS_WILL_BE_REPLACED_BY name
        resource:
          namespace: THIS_WILL_BE_REPLACED_BY namespace
          group: argoproj.io
          version: v1alpha1
          kind: Workflow
          source:
            s3:
              bucket:
                name: THIS_WILL_BE_REPLACED_BY bucket
                key: THIS_WILL_BE_REPLACED_BY key
              endpoint: minio-service.argo-events:9000
              insecure: true
              accessKey:
                key: accesskey
                name: artifacts-minio
              secretKey:
                key: secretkey
                name: artifacts-minio
      # Apply parameter at template
      templateParameters:
        - src:
            event: "webhook-gateway-http:foo"
            path: name
          dest: name
        - src:
            event: "webhook-gateway-http:foo"
            path: namespace
          dest: resource.namespace
        - src:
            event: "webhook-gateway-http:foo"
            path: bucket
          dest: resource.source.s3.bucket.name
        - src:
            event: "webhook-gateway-http:foo"
            path: key
          dest: resource.source.s3.bucket.key
      # Apply parameter for workflow
      workflowParameters:
        - src:
            event: "webhook-gateway-http:foo"
            path: image
          dest: spec.templates.0.container.image

[dtaniwaki]

Thank you for the example. I think I understand which is applied where. So, if is the workflow parameter applied only for workflow? What happenes if a user wants to trigger a pod?

[VaibhavPage]

You can apply workflowParameters on any kubernetes resource. I now realize workflowParameters may not be the apt name 😅 , it should be renamed to actionParameters or something more intuitive. open for suggestions.

[dtaniwaki]

Yeah, the name WorkflowParameter may confuse users.
How about ResourceParameter?

[VaibhavPage]

ResourceParameter is already the name of the struct. https://github.com/argoproj/argo-events/blob/be258c6085528c1945b43a1cb2e8f86a58389d86/pkg/apis/sensor/v1alpha1/types.go#L202:6

[VaibhavPage]

Or maybe we can rename ResourceParameter struct to Parameter and have WorkflowParameter renamed to ResourceParameter

[dtaniwaki]

Sounds good. Maybe, TriggerParameter instead of Parameter for the struct name because it's a parameter of Trigger?

[VaibhavPage]

I am planning to get rid of ResourceObj and resource key within the trigger, because we are not triggering anything except a k8s resource. Also will replace custiom gvk struct with k8s gvk struct.

Also nuking namespace and labels from trigger template. These fields complicate things unnecessary.

[VaibhavPage]

@magaldima @dtaniwaki updated the pr. please review

[dtaniwaki]

Overall, looks great to me! I left one comment about the name convention although it's trivial.

[dtaniwaki]

I left one comment about hack/generate-proto.sh.

[dtaniwaki]

lgtm!