Event based Resume the suspended Workflow (EventTemplate)

[sarabala1979]

Summary

The workflow needs to be suspended and wait for the event to resume it. This is very similar to suspendtemplate which is currently suspending workflow, so it can be resumed based on the manual intervention or duration.

Please give examples of your use case, e.g. when would you use this.

Proposal

The event template needs to support multiple event sources.

1. Kafka
2. Kubernetes Event
3. SQS
4. SNS

Sample template format

- name: eventTmpl
    event:
      source:
        kafka:
          url: kafka.argo-events:9092
          topic: topic-2
          partition: "1"
      condition:
         jsonExpression: ".event.source.type == resume"

---

Message from the maintainers:

If you wish to see this enhancement implemented please add a 👍 reaction to this issue! We often sort issues this way to know what to prioritize.

[sarabala1979]

Sample Workflow

apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: event-template-
spec:
  entrypoint: event
  templates:
  - name: event
    steps:
    - - name: build
        template: whalesay
    - - name: event
        template: eventTmpl
    - - name: release
        template: whalesay

  - name: eventTmpl
      event:
        source:
          kafka:
            url: kafka.argo-events:9092
            topic: topic-2
            partition: "1"
        condition:
          jsonExpression: ".event.source.type == resume"
          
  - name: whalesay
    container:
      image: docker/whalesay
      command: [cowsay]
      args: ["hello world"]

[zachaller]

Not sure of the plans to work more closely with say argo-events, but if argo-workflows just supported a lower common denominator like http, argo workflows then could use argo events to do all the other integrations like kafka, sqs etc. I do like this feature and think we could use it a well.

[alexec]

@alexec is demoing web hook events at community meeting and that might solve this use case.

[agilgur5]

but if argo-workflows just supported a lower common denominator like http

This exactly is possible with the API these days, such as with argo suspend and Intermediate Inputs.

I'm not sure how long that has been possible for to reference.

@alexec is demoing web hook events at community meeting and that might solve this use case.

Webhooks also have a page these days as have a few other similar approaches