Writing a workflow with activity code in Java & Golang

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1

Is it possible to write a workflow in temporal where some activities are written in Java while others in Golang?
I am initiating the workflow in Java code, workflow code itself is written using Java SDK, however workflow activities are written in Golang. Is there an example that illustrates a similar setup ?

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2

We definitely need to write such a sample. In the meantime, you have to do it yourself.

  • Make sure that both Java and Go workers share the same domain (this is not a hard requirement, but simplifies things).
  • Make sure that Go and Java workers are using different task queue names to route tasks appropriately.
  • You can either create Java activities interface that mirrors Go activities signatures or use non strongly typed ActivityStub interface to invoke them directly by name.
  • When initializing activity stub pass Go task queue name to it as an option.

Something like:

    ActivityOptions options =
        ActivityOptions.newBuilder()
            .setTaskQueue(GO_ACTIVITIES)
            .setStartToCloseTimeout(Duration.ofSeconds(20))
            .build();
   ActivityStub goActivities = Workflow.newUntypedActivityStub(options);
   String result = goActivities.execute("MyGoActivity1", String.class, arg1, arg2);
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3

Is this the same if the workflow starter is in Java and the workflow itself is in Go? Suppose I have a workflow in a Go function with signature func Deploy(ctx workflow.Context, customer string), how should the Workflow interface look in Java? Does casing matter?

4

The Java uses the workflow interface short name as the workflow name. So in Java you need to have something like:

@WorkflowInterface
public interface Deploy {
  // whatever
}
5

I’m puzzled. You map the Go function name to the Java interface name?
Then which method should be added to the interface to map the same set of arguments?

6

Yes, the Go function name is mapped to the Java interface name for workflows.

The method annotated with @WorkflowMethod should have the matching arguments. The name of the method doesn’t matter.

7

This is a pattern that we can expect to work with future releases of temporal ?

8

Yes, we don’t plan to do any changes that would break running workflows.