fix teardown isolation, OTel provider init order, and FastAPI install…

lite_bootstrap/bootstrappers/base.py

@@ -61,5 +61,13 @@ def bootstrap(self) -> ApplicationT:
 
     def teardown(self) -> None:
         self.is_bootstrapped = False
-        for one_instrument in self.instruments:
-            one_instrument.teardown()
+        errors: list[BaseException] = []
+        for one_instrument in reversed(self.instruments):
+            try:
+                one_instrument.teardown()
+            except Exception as e:  # noqa: BLE001, PERF203
+                logger.warning(f"Error tearing down {type(one_instrument).__name__}: {e}")
+                errors.append(e)
+        if errors:
+            msg = f"{len(errors)} instrument(s) failed during teardown"
+            raise RuntimeError(msg) from errors[0]

lite_bootstrap/bootstrappers/fastapi_bootstrapper.py

@@ -54,6 +54,10 @@ class FastAPIConfig(
     prometheus_expose_params: dict[str, typing.Any] = dataclasses.field(default_factory=dict)
 
     def __post_init__(self) -> None:
+        if not import_checker.is_fastapi_installed:
+            msg = "fastapi is not installed"
+            raise RuntimeError(msg)
+
         if not self.application:
             object.__setattr__(
                 self, "application", fastapi.FastAPI(docs_url=self.swagger_path, **self.application_kwargs)

lite_bootstrap/instruments/opentelemetry_instrument.py

@@ -104,6 +104,7 @@ def bootstrap(self) -> None:
             attributes={k: v for k, v in attributes.items() if v},
         )
         tracer_provider = TracerProvider(resource=resource)
+        set_tracer_provider(tracer_provider)
         if import_checker.is_pyroscope_installed and getattr(self.bootstrap_config, "pyroscope_endpoint", None):
             tracer_provider.add_span_processor(PyroscopeSpanProcessor())
         if self.bootstrap_config.opentelemetry_log_traces:
@@ -125,7 +126,6 @@ def bootstrap(self) -> None:
                 )
             else:
                 one_instrumentor.instrument(tracer_provider=tracer_provider)
-        set_tracer_provider(tracer_provider)
 
     def teardown(self) -> None:
         for one_instrumentor in self.bootstrap_config.opentelemetry_instrumentors:

tests/test_free_bootstrap.py

@@ -1,3 +1,5 @@
+from unittest.mock import MagicMock
+
 import pytest
 import structlog
 from structlog.testing import capture_logs
@@ -47,6 +49,25 @@ def test_free_bootstrap_logging_not_ready() -> None:
         ]
 
 
+def test_teardown_error_isolation(free_bootstrapper_config: FreeBootstrapperConfig) -> None:
+    bootstrapper = FreeBootstrapper(bootstrap_config=free_bootstrapper_config)
+    bootstrapper.bootstrap()
+
+    # Replace instruments with mocks: first raises, second succeeds.
+    bad = MagicMock()
+    bad.teardown.side_effect = RuntimeError("boom")
+    good = MagicMock()
+    bootstrapper.instruments = [bad, good]
+
+    with capture_logs() as cap_logs, pytest.raises(RuntimeError, match="1 instrument"):
+        bootstrapper.teardown()
+
+    # Both instruments attempted teardown despite the error (LIFO: good first, bad second).
+    good.teardown.assert_called_once()
+    bad.teardown.assert_called_once()
+    assert any("boom" in entry.get("event", "") for entry in cap_logs)
+
+
 @pytest.mark.parametrize(
     "package_name",
     [