update SDK to call version directly

CHANGELOG.md

@@ -40,6 +40,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#5135](https://github.com/open-telemetry/opentelemetry-python/pull/5135))
 - ci: wait for tracecontext server readiness instead of a fixed sleep in `scripts/tracecontext-integration-test.sh`
   ([#5149](https://github.com/open-telemetry/opentelemetry-python/pull/5149))
+- `opentelemetry-sdk`: only load entrypoints for resource detectors if they are configured via `OTEL_EXPERIMENTAL_RESOURCE_DETECTORS`
+  ([#5145](https://github.com/open-telemetry/opentelemetry-python/pull/5145))
 
 ## Version 1.41.0/0.62b0 (2026-04-09)
 

opentelemetry-sdk/src/opentelemetry/sdk/resources/__init__.py

@@ -71,7 +71,7 @@
 from json import dumps
 from os import environ
 from types import ModuleType
-from typing import List, Optional, cast
+from typing import Optional, cast
 from urllib import parse
 
 from opentelemetry.attributes import BoundedAttributes
@@ -80,11 +80,10 @@
     OTEL_RESOURCE_ATTRIBUTES,
     OTEL_SERVICE_NAME,
 )
-from opentelemetry.semconv.resource import ResourceAttributes
-from opentelemetry.util._importlib_metadata import (
-    entry_points,  # type: ignore[reportUnknownVariableType]
-    version,
+from opentelemetry.sdk.version import (
+    __version__ as _OPENTELEMETRY_SDK_VERSION,
 )
+from opentelemetry.semconv.resource import ResourceAttributes
 from opentelemetry.util.types import AttributeValue
 
 psutil: Optional[ModuleType] = None
@@ -159,8 +158,6 @@
 TELEMETRY_AUTO_VERSION = ResourceAttributes.TELEMETRY_AUTO_VERSION
 TELEMETRY_SDK_LANGUAGE = ResourceAttributes.TELEMETRY_SDK_LANGUAGE
 
-_OPENTELEMETRY_SDK_VERSION: str = version("opentelemetry-sdk")
-
 
 class Resource:
     """A Resource is an immutable representation of the entity producing telemetry as Attributes."""
@@ -196,48 +193,8 @@ def create(
         if not attributes:
             attributes = {}
 
-        otel_experimental_resource_detectors: list[str] = [
-            detector.strip()
-            for detector in environ.get(
-                OTEL_EXPERIMENTAL_RESOURCE_DETECTORS, ""
-            ).split(",")
-            if detector.strip()
-        ]
-
-        resource_detectors: List[ResourceDetector] = []
-
-        if "*" in otel_experimental_resource_detectors:
-            otel_experimental_resource_detectors = [
-                name
-                for name in sorted(
-                    entry_points(group="opentelemetry_resource_detector").names
-                )
-                if name != "otel"
-            ]
-            otel_experimental_resource_detectors.append("otel")
-        elif "otel" not in otel_experimental_resource_detectors:
-            otel_experimental_resource_detectors.append("otel")
-
-        for resource_detector in otel_experimental_resource_detectors:
-            try:
-                resource_detectors.append(
-                    next(
-                        iter(
-                            entry_points(
-                                group="opentelemetry_resource_detector",
-                                name=resource_detector.strip(),
-                            )  # type: ignore[reportUnknownArgumentType]
-                        )
-                    ).load()()
-                )
-            except Exception:  # pylint: disable=broad-exception-caught
-                logger.exception(
-                    "Failed to load resource detector '%s', skipping",
-                    resource_detector,
-                )
-                continue
         resource = get_aggregated_resources(
-            resource_detectors, _DEFAULT_RESOURCE
+            _build_resource_detectors(), _DEFAULT_RESOURCE
         ).merge(Resource(attributes, schema_url))
 
         if not resource.attributes.get(SERVICE_NAME, None):
@@ -324,6 +281,7 @@ def to_json(self, indent: Optional[int] = 4) -> str:
 
 
 _EMPTY_RESOURCE = Resource({})
+
 _DEFAULT_RESOURCE = Resource(
     {
         TELEMETRY_SDK_LANGUAGE: "python",
@@ -517,6 +475,73 @@ def detect(self) -> "Resource":
         )
 
 
+def _build_resource_detectors() -> list["ResourceDetector"]:
+    """Returns the ordered list of resource detectors to use for Resource.create.
+
+    Fast path: if no extra detectors are configured, returns only
+    OTELResourceDetector without scanning entry_points.
+
+    "otel" (OTELResourceDetector) defaults to last position so that
+    OTEL_RESOURCE_ATTRIBUTES and OTEL_SERVICE_NAME take highest merge priority,
+    but an explicit position in OTEL_EXPERIMENTAL_RESOURCE_DETECTORS is respected.
+    """
+    detector_names: list[str] = list(
+        dict.fromkeys(
+            [
+                name.strip()
+                for name in environ.get(
+                    OTEL_EXPERIMENTAL_RESOURCE_DETECTORS, ""
+                ).split(",")
+                if name.strip()
+            ]
+            + ["otel"]
+        )
+    )
+
+    # Fast path: only the built-in "otel" detector — no entry_points scan needed.
+    if detector_names == ["otel"]:
+        return [OTELResourceDetector()]
+
+    # pylint: disable=import-outside-toplevel
+    from opentelemetry.util._importlib_metadata import (  # noqa: PLC0415
+        entry_points,  # type: ignore[reportUnknownVariableType]
+    )
+
+    if "*" in detector_names:
+        registered = set(
+            name
+            for name in entry_points(
+                group="opentelemetry_resource_detector"
+            ).names  # type: ignore[reportUnknownArgumentType]
+            if name != "otel"
+        )
+        expansion = sorted(registered - set(detector_names))
+        idx = detector_names.index("*")
+        detector_names = (
+            detector_names[:idx] + expansion + detector_names[idx + 1 :]
+        )
+
+    detectors: list[ResourceDetector] = []
+    for name in detector_names:
+        try:
+            detectors.append(
+                next(
+                    iter(
+                        entry_points(
+                            group="opentelemetry_resource_detector",
+                            name=name,
+                        )  # type: ignore[reportUnknownArgumentType]
+                    )
+                ).load()()
+            )
+        except Exception:  # pylint: disable=broad-exception-caught
+            logger.exception(
+                "Failed to load resource detector '%s', skipping",
+                name,
+            )
+    return detectors
+
+
 def get_aggregated_resources(
     detectors: Sequence["ResourceDetector"],
     initial_resource: typing.Optional[Resource] = None,

opentelemetry-sdk/tests/resources/test_resources.py

@@ -688,7 +688,7 @@ def test_resource_detector_entry_points_default(self):
         environ, {OTEL_EXPERIMENTAL_RESOURCE_DETECTORS: "mock"}, clear=True
     )
     @patch(
-        "opentelemetry.sdk.resources.entry_points",
+        "opentelemetry.util._importlib_metadata.entry_points",
         Mock(
             return_value=[
                 Mock(
@@ -827,7 +827,8 @@ def side_effect(*args, **kwargs):
             )
 
         with patch(
-            "opentelemetry.sdk.resources.entry_points", side_effect=side_effect
+            "opentelemetry.util._importlib_metadata.entry_points",
+            side_effect=side_effect,
         ):
             resource = Resource({}).create()
 
@@ -851,7 +852,8 @@ def side_effect(*args, **kwargs):
             return real_entry_points(*args, **kwargs)
 
         with patch(
-            "opentelemetry.sdk.resources.entry_points", side_effect=side_effect
+            "opentelemetry.util._importlib_metadata.entry_points",
+            side_effect=side_effect,
         ):
             resource = Resource({}).create()