OpenTelemetry Sample

This sample shows how to configure OpenTelemetry to capture workflow traces and SDK metrics.

For this sample, the optional open_telemetry dependency group must be included. To include, run:

poetry install --with open_telemetry

To run, first see README.md for prerequisites. Then run the following to start an Aspire OTEL collector

docker compose up

Now, from this directory, start the worker in its own terminal:

poetry run python worker.py

Then, in another terminal, run the following to execute the workflow:

poetry run python starter.py

The workflow should complete with the hello result.

Now view the Aspire UI at http://localhost:18888/.

To view metrics sent describing the worker and the workflow that was executed, select Metrics on the left and under "Select a resource" select "temporal-core-sdk". It may look like this:

To view workflow spans, select Traces on the left and under "Select a resource" select "temporal-core-sdk". It may look like this:

Note, in-workflow spans do not have a time associated with them. This is by intention since due to replay. In OpenTelemetry, only the process that started the span may end it. But in Temporal a span may cross workers/processes. Therefore we intentionally start-then-end in-workflow spans immediately. So while the start time and hierarchy is accurate, the duration is not.