hello_child_workflow.py

import asyncio
from dataclasses import dataclass

from temporalio import workflow
from temporalio.client import Client
from temporalio.worker import Worker


@dataclass
class ComposeGreetingInput:
    greeting: str
    name: str


@workflow.defn
class ComposeGreetingWorkflow:
    @workflow.run
    async def run(self, input: ComposeGreetingInput) -> str:
        return f"{input.greeting}, {input.name}!"


@workflow.defn
class GreetingWorkflow:
    @workflow.run
    async def run(self, name: str) -> str:
        return await workflow.execute_child_workflow(
            ComposeGreetingWorkflow.run,
            ComposeGreetingInput("Hello", name),
            id="hello-child-workflow-workflow-child-id",
        )


async def main():
    # Start client
    client = await Client.connect("localhost:7233")

    # Run a worker for the workflow
    async with Worker(
        client,
        task_queue="hello-child-workflow-task-queue",
        workflows=[GreetingWorkflow, ComposeGreetingWorkflow],
    ):

        # While the worker is running, use the client to run the workflow and
        # print out its result. Note, in many production setups, the client
        # would be in a completely separate process from the worker.
        result = await client.execute_workflow(
            GreetingWorkflow.run,
            "World",
            id="hello-child-workflow-workflow-id",
            task_queue="hello-child-workflow-task-queue",
        )
        print(f"Result: {result}")


if __name__ == "__main__":
    asyncio.run(main())