How to cascade workflow cancellation to related workflows in golang

Developer Corner
1

I’ve been reading @maxim 's articles 1 & 2 on how to implement a cleanup() method when a cancellation occurs but I’m stuck. The documentation (too many links for a new user) seems to only talk about passing that cancellation to the activity which is different from what I want.

The pseudo code what I’m trying to do is something like this:

func MyWorkflow(ctx workflow.Context, request MyWorkflowRequest) error {
	// Register signal channels
	// ...

	// Related workflows
	relatedWorkflowIds := []string{
		//...
	}

	// Handle cancellation from this point forward, anywhere in the workflow
	go func(ctx workflow.Context) {
		for {
			select {
			case <-ctx.Done():
				// Cascade cancellation to related workflows
				fmt.Println("Context cancelled:", ctx.Err())
				newCtx, _ := workflow.NewDisconnectedContext(ctx)
				client, err := clients.NewClient() 
				for _, workflowId := range relatedWorkflowIds {
					err = client.CancelWorkflow(newCtx.Background(), workflowId, "")
					if err != nil {
						log.Fatalln("Unable to cancel Workflow Execution", err)
					}
				}
				return
			}
		}
	}(ctx)

	// Do some activities

	// sleep for set period

	// Do some more activities
	return nil
}

This doesn’t seem to work because of something @maxim said about the context is not the same as the go-lang’s standard context I think.

2

You cannot use the client in the workflow code as it performs direct IO. All calls through the client must be done from activities.

Are you trying to cancel a child workflow or some unrelated workflow?

3

it’s a different workflow (not a child). Although, I’m considering switching to child workflows if this is not achievable. I would be OK with calling an activity that triggers the cascade. My issue with the documentation is that it talks about canceling an activity that is already running.

4

For unrelated workflow use RequestCancelExternalWorkflow.