This sample shows how to create a Nexus service that is backed by a long-running workflow and exposes operations that execute updates and queries against that workflow. The long-running workflow, and the updates/queries are private implementation detail of the nexus service: the caller does not know how the operations are implemented.

• service.py - shared Nexus service definition
• caller - a caller workflow that executes Nexus operations, together with a worker and starter code
• handler - Nexus operation handlers, together with a workflow used by one of the Nexus operations, and a worker that polls for both workflow, activity, and Nexus tasks.

Start a Temporal server. (See the main samples repo README).

Run the following to create the caller and handler namespaces, and the Nexus endpoint:

temporal operator namespace create --namespace nexus-sync-operations-handler-namespace
temporal operator namespace create --namespace nexus-sync-operations-caller-namespace

temporal operator nexus endpoint create \
  --name nexus-sync-operations-nexus-endpoint \
  --target-namespace nexus-sync-operations-handler-namespace \
  --target-task-queue nexus-sync-operations-handler-task-queue \
  --description-file nexus_sync_operations/endpoint_description.md

In one terminal, run the Temporal worker in the handler namespace:

uv run nexus_sync_operations/handler/worker.py

In another terminal, run the Temporal worker in the caller namespace and start the caller workflow:

uv run nexus_sync_operations/caller/app.py