docs: document resource detectors and Sentry profiling on free-threaded CPython

docs/introduction/configuration.md

@@ -170,6 +170,24 @@ For FastStream there is additionally:
   health-check span is recorded unless `opentelemetry_generate_health_check_spans` is False, and any
   `opentelemetry_instrumentors` are applied.
 
+### Resource
+
+The `Resource` is built with the SDK's `Resource.create`, so OpenTelemetry resource detectors work
+with no lite-bootstrap setting. Name them, comma-separated, in `OTEL_EXPERIMENTAL_RESOURCE_DETECTORS`;
+each name is an entry point in the `opentelemetry_resource_detector` group. The SDK registers
+`process`, `os` and `host`; separately installed detector packages register their own names:
+
+```bash
+OTEL_EXPERIMENTAL_RESOURCE_DETECTORS=process,os
+```
+
+`OTEL_RESOURCE_ATTRIBUTES` is honoured as well.
+
+The attributes lite-bootstrap sets (`service.name`, `service.namespace`, `service.version`,
+`container.name`) are merged last and override anything a detector or environment variable supplies.
+`service_name` defaults to `"micro-service"`, so `OTEL_SERVICE_NAME` is overridden unless `service_name`
+is empty: set `opentelemetry_service_name` or `service_name` instead.
+
 
 ## Pyroscope
 
@@ -187,6 +205,23 @@ Additional parameters:
 
 When OpenTelemetry is also enabled, a `PyroscopeSpanProcessor` is automatically added to the tracer provider. It tags root spans with a `pyroscope.profile.id` attribute and sets Pyroscope thread tags so that traces and profiles can be linked in the Grafana UI.
 
+`pyroscope-io` publishes no free-threaded wheels, so the `pyroscope` extra cannot install on
+free-threaded CPython ([#171](https://github.com/modern-python/lite-bootstrap/issues/171)). Sentry's
+continuous profiler is pure Python and runs there; enable it through `sentry_additional_params`:
+
+```python
+import sentry_sdk
+
+config = FreeConfig(
+    sentry_dsn="https://key@sentry.example.com/1",
+    sentry_additional_params={"profile_session_sample_rate": 1.0, "profile_lifecycle": "manual"},
+)
+FreeBootstrapper(config).bootstrap()
+sentry_sdk.profiler.start_profiler()
+```
+
+Read more about Sentry's profiling options [here](https://docs.sentry.io/platforms/python/profiling/).
+
 ## Structlog
 
 Structlog is bootstrapped by default. To opt out, set `logging_enabled=False`.

tests/instruments/test_opentelemetry_instrument.py

@@ -1,4 +1,5 @@
 import logging
+import os
 import re
 import sys
 import typing
@@ -122,6 +123,46 @@ def test_opentelemetry_sampler_wins_over_sampler_env_vars(monkeypatch: pytest.Mo
         instrument.teardown()
 
 
+@pytest.mark.parametrize(
+    ("config", "expected_service_name"),
+    [
+        (OpenTelemetryConfig(opentelemetry_log_traces=True), "micro-service"),
+        (OpenTelemetryConfig(opentelemetry_log_traces=True, service_name="configured"), "configured"),
+        (
+            OpenTelemetryConfig(
+                opentelemetry_log_traces=True, service_name="configured", opentelemetry_service_name="otel-configured"
+            ),
+            "otel-configured",
+        ),
+    ],
+)
+def test_opentelemetry_configured_service_name_wins_over_env(
+    monkeypatch: pytest.MonkeyPatch, config: OpenTelemetryConfig, expected_service_name: str
+) -> None:
+    monkeypatch.setenv("OTEL_SERVICE_NAME", "from-env")
+    instrument = OpenTelemetryInstrument(bootstrap_config=config)
+    try:
+        instrument.bootstrap()
+        assert instrument._tracer_provider is not None  # noqa: SLF001
+        assert instrument._tracer_provider.resource.attributes["service.name"] == expected_service_name  # noqa: SLF001
+    finally:
+        instrument.teardown()
+
+
+def test_opentelemetry_resource_detectors_enrich_resource(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("OTEL_EXPERIMENTAL_RESOURCE_DETECTORS", "process")
+    monkeypatch.setenv("OTEL_RESOURCE_ATTRIBUTES", "deployment.environment=from-env")
+    instrument = OpenTelemetryInstrument(bootstrap_config=OpenTelemetryConfig(opentelemetry_log_traces=True))
+    try:
+        instrument.bootstrap()
+        assert instrument._tracer_provider is not None  # noqa: SLF001
+        attributes = instrument._tracer_provider.resource.attributes  # noqa: SLF001
+        assert attributes["process.pid"] == os.getpid()
+        assert attributes["deployment.environment"] == "from-env"
+    finally:
+        instrument.teardown()
+
+
 def test_opentelemetry_instrument_teardown_shuts_down_tracer_provider() -> None:
     instrument = OpenTelemetryInstrument(
         bootstrap_config=OpenTelemetryConfig(opentelemetry_log_traces=True),