nexus/observability

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Nexus Operation observability events in caller Workflow

Synchronous Nexus Operations surface in the caller Workflow with NexusOperationScheduled and NexusOperationCompleted events in the Event history. Asynchronous Nexus Operations surface with NexusOperationScheduled, NexusOperationStarted, and NexusOperationCompleted events.

Temporal Web UI shows Nexus Operation events in Workflow history

When a caller Workflow invokes a Nexus Operation, the Workflow execution history in the Temporal Web UI displays NexusOperationScheduled, NexusOperationStarted, and NexusOperationCompleted events. The Web UI allows switching between Namespaces to view both caller and handler Workflow executions.

Workflow execution with Nexus events

When a caller Workflow executes a Nexus Operation, the event history includes three event types: NexusOperationScheduled (when the operation is initiated), NexusOperationStarted (when the handler begins processing), and NexusOperationCompleted (when the operation finishes).

Nexus Operation events in caller workflow history

Nexus Operations report events in the caller Workflow's Event history. The events reported depend on the operation type: For asynchronous Nexus Operations, three events are reported: 'NexusOperationScheduled', 'NexusOperationStarted', and 'NexusOperationCompleted'. For synchronous Nexus Operations, two events are reported: 'NexusOperationScheduled' and 'NexusOperationCompleted'. Note that 'NexusOperationStarted' is not reported for synchronous operations.

Nexus metrics available for monitoring performance

SDK and Cloud latency metrics are available for monitoring Nexus performance.

Asynchronous Nexus Operation events in caller history

Asynchronous Nexus Operations surface in the caller Workflow's Event history with three events: `NexusOperationScheduled`, `NexusOperationStarted`, and `NexusOperationCompleted`.

View pending Nexus Operations with Temporal CLI

Use `temporal workflow describe -w <ID>` to show pending Nexus Operations in the caller Workflow and any attached callbacks on the handler Workflow. Use `temporal workflow show -w <ID>` to include Nexus events in the caller's Event history.

OpenTelemetry support for Nexus Operations

The `@temporalio/interceptors-opentelemetry` package supports Nexus Operations with automatic trace context propagation from the caller Workflow to the handler. Use the `OpenTelemetryPlugin` to auto-register Nexus interceptors alongside Activity and Workflow interceptors. The plugin creates spans: `StartNexusOperation:service/operation` on the caller side, and `RunStartNexusOperation:service/operation` and `RunCancelNexusOperation:service/operation` on the handler side.

Enable OpenTelemetry for Nexus with plugin

Enable OpenTelemetry tracing for Nexus by instantiating the `OpenTelemetryPlugin` and registering it with the Worker: `const plugin = new OpenTelemetryPlugin({ resource: myResource, spanProcessor: mySpanProcessor }); const worker = await Worker.create({ ..., plugins: [plugin], nexusServices: [myServiceHandler] })`.

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