feat(config): wire id_generator from declarative configuration to TracerProvider (#5363)

* feat(config): wire id_generator from declarative configuration to TracerProvider

* add changelog fragment

* fix: add _additional_properties decorator to IdGenerator model

* fix: rename changelog to .added, pass plugin kwargs, add hasattr check

* fix: apply ruff formatting

* fix: apply ruff formatting

* Apply suggestion from @xrmx

* Apply suggestion from @xrmx

---------

Co-authored-by: Riccardo Magliocchetti <riccardo.magliocchetti@gmail.com>

Author: aman-panjwani

.changelog/5363.added

@@ -0,0 +1 @@
+`opentelemetry-sdk`: wire id_generator from declarative configuration to TracerProvider

opentelemetry-sdk/src/opentelemetry/sdk/_configuration/_tracer_provider.py

@@ -25,6 +25,9 @@
 from opentelemetry.sdk._configuration.models import (
     ExperimentalOtlpFileExporter as ExperimentalOtlpFileExporterConfig,
 )
+from opentelemetry.sdk._configuration.models import (
+    IdGenerator as IdGeneratorConfig,
+)
 from opentelemetry.sdk._configuration.models import (
     OtlpGrpcExporter as OtlpGrpcExporterConfig,
 )
@@ -84,6 +87,7 @@
     SimpleSpanProcessor,
     SpanExporter,
 )
+from opentelemetry.sdk.trace.id_generator import IdGenerator, RandomIdGenerator
 from opentelemetry.sdk.trace.sampling import (
     ALWAYS_OFF,
     ALWAYS_ON,
@@ -348,6 +352,26 @@ def _create_sampler(config: SamplerConfig) -> Sampler:
     )
 
 
+def _create_id_generator(config: IdGeneratorConfig) -> IdGenerator:
+    """Create an IdGenerator from config.
+
+    Built-in ``random`` resolves to ``RandomIdGenerator``; unknown names
+    load from the ``opentelemetry_id_generator`` entry point group (the
+    same group ``OTEL_PYTHON_ID_GENERATOR`` uses today).
+    """
+    if config.random is not None:
+        return RandomIdGenerator()
+    if config.additional_properties:
+        name, plugin_config = next(iter(config.additional_properties.items()))
+        return load_entry_point("opentelemetry_id_generator", name)(
+            **(plugin_config or {})
+        )
+    raise ConfigurationError(
+        "No id_generator type specified in config. "
+        "Supported built-in types: random."
+    )
+
+
 def _create_parent_based_sampler(config: ParentBasedSamplerConfig) -> Sampler:
     """Create a ParentBased sampler from config, applying SDK defaults for absent delegates."""
     root = (
@@ -431,6 +455,11 @@ def create_tracer_provider(
         if config is not None and config.sampler is not None
         else _DEFAULT_SAMPLER
     )
+    id_generator = (
+        _create_id_generator(config.id_generator)
+        if config is not None and config.id_generator is not None
+        else None
+    )
     span_limits = (
         _create_span_limits(config.limits)
         if config is not None and config.limits is not None
@@ -447,6 +476,7 @@ def create_tracer_provider(
         resource=resource,
         sampler=sampler,
         span_limits=span_limits,
+        id_generator=id_generator,
     )
 
     if config is not None:

opentelemetry-sdk/tests/_configuration/test_tracer_provider.py

@@ -42,6 +42,9 @@
 from opentelemetry.sdk._configuration.models import (
     ExperimentalSpanParent as SpanParentConfig,
 )
+from opentelemetry.sdk._configuration.models import (
+    IdGenerator as IdGeneratorConfig,
+)
 from opentelemetry.sdk._configuration.models import (
     OtlpGrpcExporter as OtlpGrpcExporterConfig,
 )
@@ -82,6 +85,7 @@
     ConsoleSpanExporter,
     SimpleSpanProcessor,
 )
+from opentelemetry.sdk.trace.id_generator import RandomIdGenerator
 from opentelemetry.sdk.trace.sampling import (
     ALWAYS_OFF,
     ALWAYS_ON,
@@ -852,3 +856,54 @@ def test_absent_limits_do_not_read_env_vars(self):
             provider = self._create_with_limits(SpanLimitsConfig())
         self.assertEqual(provider._span_limits.max_span_attributes, 128)
         self.assertEqual(provider._span_limits.max_events, 128)
+
+
+class TestCreateIdGenerator(unittest.TestCase):
+    """Tests for _create_id_generator and id_generator wiring in create_tracer_provider."""
+
+    @staticmethod
+    def _make_provider(id_generator_config):
+        return create_tracer_provider(
+            TracerProviderConfig(
+                processors=[], id_generator=id_generator_config
+            )
+        )
+
+    def test_absent_id_generator_uses_sdk_default(self):
+        """When id_generator is omitted, the SDK's default RandomIdGenerator is used."""
+        provider = create_tracer_provider(TracerProviderConfig(processors=[]))
+        self.assertIsInstance(provider.id_generator, RandomIdGenerator)
+
+    def test_builtin_random_id_generator(self):
+        """Built-in 'random' id_generator resolves to RandomIdGenerator."""
+        provider = self._make_provider(IdGeneratorConfig(random={}))
+        self.assertIsInstance(provider.id_generator, RandomIdGenerator)
+
+    def test_plugin_id_generator_loaded_via_entry_point(self):
+        """Unknown id_generator name is loaded from opentelemetry_id_generator entry point group."""
+        mock_generator = MagicMock()
+        mock_class = MagicMock(return_value=mock_generator)
+        with patch(
+            "opentelemetry.sdk._configuration._common.entry_points",
+            return_value=[MagicMock(**{"load.return_value": mock_class})],
+        ):
+            # pylint: disable=unexpected-keyword-arg
+            provider = self._make_provider(
+                IdGeneratorConfig(my_custom_generator={})
+            )
+        self.assertIs(provider.id_generator, mock_generator)
+
+    def test_unknown_id_generator_raises_configuration_error(self):
+        """Unknown id_generator name with no matching entry point raises ConfigurationError."""
+        with patch(
+            "opentelemetry.sdk._configuration._common.entry_points",
+            return_value=[],
+        ):
+            with self.assertRaises(ConfigurationError):
+                # pylint: disable=unexpected-keyword-arg
+                self._make_provider(IdGeneratorConfig(no_such_generator={}))
+
+    def test_empty_id_generator_raises_configuration_error(self):
+        """Empty IdGenerator config (no type specified) raises ConfigurationError."""
+        with self.assertRaises(ConfigurationError):
+            self._make_provider(IdGeneratorConfig())