Refactor

Author: dandavison

nexus_sync_operations/handler/service_handler.py

@@ -21,22 +21,21 @@
 
 @nexusrpc.handler.service_handler(service=GreetingService)
 class GreetingServiceHandler:
-    # This nexus service is backed by a long-running "entity" workflow. This means that the workflow
-    # is always running in the background, allowing the service to be stateful and durable. The
-    # service interacts with it via messages (updates and queries). All of this is implementation
-    # detail private to the nexus handler: the nexus caller does not know how the operations are
-    # implemented or what is providing the backing storage.
-    LONG_RUNNING_WORKFLOW_ID = "nexus-sync-operations-greeting-workflow"
+    def __init__(self, workflow_id: str):
+        self.workflow_id = workflow_id
 
     @classmethod
-    async def start(cls, client: Client, task_queue: str) -> None:
+    async def create(
+        cls, workflow_id: str, client: Client, task_queue: str
+    ) -> GreetingServiceHandler:
         # Start the long-running "entity" workflow, if it is not already running.
         await client.start_workflow(
             GreetingWorkflow.run,
-            id=cls.LONG_RUNNING_WORKFLOW_ID,
+            id=workflow_id,
             task_queue=task_queue,
             id_conflict_policy=WorkflowIDConflictPolicy.USE_EXISTING,
         )
+        return cls(workflow_id)
 
     @property
     def greeting_workflow_handle(self) -> WorkflowHandle[GreetingWorkflow, str]:
@@ -48,7 +47,7 @@ def greeting_workflow_handle(self) -> WorkflowHandle[GreetingWorkflow, str]:
         # long-running work in a nexus operation handler, use
         # temporalio.nexus.workflow_run_operation (see the hello_nexus sample).
         return nexus.client().get_workflow_handle_for(
-            GreetingWorkflow.run, self.LONG_RUNNING_WORKFLOW_ID
+            GreetingWorkflow.run, self.workflow_id
         )
 
     # 👉 This is a handler for a nexus operation whose internal implementation involves executing a

nexus_sync_operations/handler/worker.py

@@ -22,8 +22,12 @@ async def main(client: Optional[Client] = None):
         "localhost:7233",
         namespace=NAMESPACE,
     )
-    greeting_service_handler = GreetingServiceHandler()
-    await greeting_service_handler.start(client, TASK_QUEUE)
+
+    # Create the nexus service handler instance, starting the long-running entity workflow that
+    # backs the Nexus service
+    greeting_service_handler = await GreetingServiceHandler.create(
+        "nexus-sync-operations-greeting-workflow", client, TASK_QUEUE
+    )
 
     async with Worker(
         client,

tests/nexus_sync_operations/nexus_sync_operations_test.py

@@ -92,11 +92,6 @@ async def _run_caller_workflow(client: Client, workflow: Type):
         client=client,
     )
     try:
-        await (
-            nexus_sync_operations.handler.service_handler.GreetingServiceHandler.start(
-                client, nexus_sync_operations.handler.worker.TASK_QUEUE
-            )
-        )
         handler_worker_task = asyncio.create_task(
             nexus_sync_operations.handler.worker.main(client)
         )
@@ -115,12 +110,6 @@ async def _run_caller_workflow(client: Client, workflow: Type):
             nexus_sync_operations.handler.worker.interrupt_event.set()
             await handler_worker_task
             nexus_sync_operations.handler.worker.interrupt_event.clear()
-            try:
-                await client.get_workflow_handle(
-                    nexus_sync_operations.handler.service_handler.GreetingServiceHandler.LONG_RUNNING_WORKFLOW_ID
-                ).terminate()
-            except Exception:
-                pass
     finally:
         await delete_nexus_endpoint(
             id=create_response.endpoint.id,