dagger-pytest-otel

A pytest plugin for OpenTelemetry instrumentation with Dagger.

This plugin automatically instruments pytest tests with OpenTelemetry spans, enabling test visibility in Dagger's TUI and Dagger Cloud.

Features

• Zero configuration: Automatically creates spans for each test
• TRACEPARENT propagation: Inherits trace context from Dagger
• Session spans: Creates a parent span for the entire test session
• Test hierarchy: Captures module, class, and function information
• Outcome tracking: Records test pass/fail/skip status
• Log capture: Forwards Python logs to OpenTelemetry
• Exception recording: Records test exceptions on spans

Installation

pip install dagger-pytest-otel

Usage

Once installed, the plugin is automatically enabled. No code changes are required in your tests.

With Dagger

When running tests through Dagger, the TRACEPARENT environment variable is automatically set, and test spans will appear in the Dagger TUI and Dagger Cloud.

The pytest module bundles this plugin. A module that builds its own test container installs it:

# In your Dagger module
@function
async def test(self, source: dagger.Directory) -> str:
    return await (
        dag.container()
        .from_("python:3.11-slim")
        .with_directory("/src", source)
        .with_workdir("/src")
        .with_exec(["pip", "install", "pytest", "dagger-pytest-otel"])
        .with_exec(["pytest", "-v"])
        .stdout()
    )

Standalone

You can also use the plugin standalone with any OTLP-compatible backend:

export OTEL_EXPORTER_OTLP_ENDPOINT="http://localhost:4318"
export TRACEPARENT="00-abc123...-def456...-01"  # Optional parent trace
pytest

The plugin sends OTLP over HTTP to an http:// or https:// endpoint, and over gRPC to an endpoint without a scheme. OTEL_EXPORTER_OTLP_PROTOCOL (grpc or http/protobuf) overrides that choice, and OTEL_EXPORTER_OTLP_TRACES_PROTOCOL or OTEL_EXPORTER_OTLP_LOGS_PROTOCOL overrides it for one signal; any other value sends http/protobuf with a warning. gRPC needs the opentelemetry-exporter-otlp-proto-grpc package; without it, the plugin warns and exports nothing.

Disabling

To disable instrumentation:

pytest --no-otel

Span Attributes

Each test span includes the following attributes:

Session spans also include test.suite.run.status. Their test.suite.name is the pytest rootdir relative to the nearest directory holding .git, or the rootdir's name at that directory or outside Git; 0.3.0 used the absolute path.

Spans and logs report the service name pytest, unless OTEL_SERVICE_NAME or OTEL_RESOURCE_ATTRIBUTES sets one.

Test output

Captured stdout and stderr output is exported as OpenTelemetry logs on the active test span using Dagger's stdio.stream attribute. Python logging records are also forwarded as OpenTelemetry logs and mapped to stdout or stderr by severity.

Python's root logger drops records below WARNING before the plugin sees them. Set pytest's log_level, for example with --log-level=INFO, to forward INFO records too.

Development

cd pytest/dagger_pytest_otel
uv run pytest

License

Apache-2.0