distributedtracing

Distributed tracing sample

Demonstrates application trace propagation into Durable Task Scheduler using OTLP/HTTP and a real OpenTelemetry collector.

Features

• Starts a caller span and schedules an orchestration under that trace.
• Uses a local loopback HTTP target instead of an external dependency.
• Exports application spans over OTLP/HTTP to a collector.
• Verifies the collector file exporter received the caller and local HTTP spans under the same trace ID.
• Reads DTS history and verifies persisted trace context shares the caller trace.

DTS orchestration/activity/timer spans are service-owned. This sample validates the trace context recorded in history and does not claim that the local worker duplicates service spans.

Prerequisites

• DTS_CONNECTION_STRING for DTS.
• A real OpenTelemetry Collector reachable through OTEL_EXPORTER_OTLP_ENDPOINT or OTEL_EXPORTER_OTLP_TRACES_ENDPOINT.
• OTEL_CAPTURE_FILE, mounted/readable by both the collector and this process.

Collector config for local/CI runs is provided in otel-collector-config.yaml. Use otel/opentelemetry-collector-contrib:0.160.0, which includes the file exporter. The trace file may live outside the repository, but the same host file must be mounted into the collector and exposed to the sample through OTEL_CAPTURE_FILE.

Collector contract: inside the collector container, set OTEL_CAPTURE_FILE=/output/traces.json. In the sample process, set OTEL_CAPTURE_FILE to the corresponding host path. The sample reads that host file back and requires each expected span name to belong to the current trace ID, so stale data from earlier runs is ignored.

Run

Start a collector in one shell:

cd samples/distributedtracing
export HOST_OTEL_CAPTURE_FILE="${HOST_OTEL_CAPTURE_FILE:-$PWD/otel-traces.json}"
docker run --rm \
  -p 4317:4317 -p 4318:4318 \
  -v "$PWD/otel-collector-config.yaml:/etc/otelcol/config.yaml:ro" \
  -v "$(dirname "$HOST_OTEL_CAPTURE_FILE"):/output" \
  -e OTEL_CAPTURE_FILE="/output/$(basename "$HOST_OTEL_CAPTURE_FILE")" \
  otel/opentelemetry-collector-contrib:0.160.0 \
  --config=/etc/otelcol/config.yaml

Run the sample from another shell:

cd samples/distributedtracing
export OTEL_CAPTURE_FILE="${HOST_OTEL_CAPTURE_FILE:-$PWD/otel-traces.json}"
export OTEL_EXPORTER_OTLP_ENDPOINT="http://localhost:4318"
go run .

Expected outcome

The process exits 0 and prints:

SAMPLE_OK distributedtracing

Cleanup

The orchestration is recursively terminated/purged before worker shutdown. The sample does not create cloud telemetry resources.

Required validation variants

Integration validation should start the real OTLP collector with this config and execute go run .. Do not clear an open collector file; unique trace IDs disambiguate repeated runs.