Logic Apps Standard OpenTelemetry: no span for Service Bus-triggered runs when the message has a Diagnostic-Id

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Logic Apps Standard OpenTelemetry: no span for Service Bus-triggered runs when the message has a Diagnostic-Id

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Logic Apps Standard, stateful workflows, OpenTelemetry enabled with telemetryMode OpenTelemetry in host.json and the OTEL_EXPORTER_OTLP settings. The workflow uses the built-in Service Bus topic trigger (peek-lock) and then calls an HTTP API.

When the Service Bus message has no Diagnostic-Id property, every run is exported as a root span. When the message has a sampled Diagnostic-Id (flags 01), the run joins that trace: its "Workflow run starts/ends" logs carry the trace id and the HTTP API receives a traceparent in the same trace. But the Logic App's own span is never exported, so the trace has a gap. This also happened with OTEL_TRACES_SAMPLER set to always_on. HTTP-triggered workflows in the same app export correctly parented spans.

Is this a known issue, and is there a setting or runtime version that makes Service Bus-triggered runs with a Diagnostic-Id export their span?

SS 0 Reputation points

2026-11-05T15:16:18.9433333+00:00

Correction after more testing: the spans we saw exported without a Diagnostic-Id are not workflow runs. They are the Functions trigger invocation spans ("Executing 'Functions.<workflow name>'"), one per received batch of messages, always as a root. The workflow run itself never exports a span in the runs we checked, with or without a Diagnostic-Id.

What the Diagnostic-Id changes is only the sampling of the run's outgoing calls. Without it, the HTTP API the workflow calls records no span for the request, although the same API records spans for requests that arrive without any trace context, so the call appears to carry an unsampled traceparent. With a sampled Diagnostic-Id, the API receives a sampled traceparent in that trace, but its parent span (from the workflow run) is never exported.

Also, the trigger invocation span is exported only now and then: one out of 19 invocations across two Logic Apps within an hour.

So the question becomes: is the workflow run (and its actions) supposed to export spans in OpenTelemetry mode for Service Bus-triggered workflows, and why is the trigger invocation span exported only sometimes?

Your answer

SS 0 Reputation points

2026-11-05T15:16:18.9433333+00:00

Correction after more testing: the spans we saw exported without a Diagnostic-Id are not workflow runs. They are the Functions trigger invocation spans ("Executing 'Functions.<workflow name>'"), one per received batch of messages, always as a root. The workflow run itself never exports a span in the runs we checked, with or without a Diagnostic-Id.

What the Diagnostic-Id changes is only the sampling of the run's outgoing calls. Without it, the HTTP API the workflow calls records no span for the request, although the same API records spans for requests that arrive without any trace context, so the call appears to carry an unsampled traceparent. With a sampled Diagnostic-Id, the API receives a sampled traceparent in that trace, but its parent span (from the workflow run) is never exported.

Also, the trigger invocation span is exported only now and then: one out of 19 invocations across two Logic Apps within an hour.

So the question becomes: is the workflow run (and its actions) supposed to export spans in OpenTelemetry mode for Service Bus-triggered workflows, and why is the trigger invocation span exported only sometimes?