This sample shows how to define a Nexus service, implement the operation handlers, and call the operations from a workflow.

• 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 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 hello-nexus-basic-handler-namespace temporal operator namespace create --namespace hello-nexus-basic-caller-namespace temporal operator nexus endpoint create \ --name hello-nexus-basic-nexus-endpoint \ --target-namespace hello-nexus-basic-handler-namespace \ --target-task-queue my-handler-task-queue \ --description-file hello_nexus/endpoint_description.md 

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

uv run hello_nexus/handler/worker.py 

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

uv run hello_nexus/caller/app.py