feat(config): wire container resource detector via entry point loading#5004

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MikeGoldsmith wants to merge 19 commits intoopen-telemetry:mainfrom

MikeGoldsmith:mike/config-resource-detector-container

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MikeGoldsmith commented Mar 20, 2026 •

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Description

Implements container resource detector support in create_resource() for the declarative configuration pipeline, as part of the ongoing work tracked in the following PRs:

What's included

Wires detection_development.detectors[].container in the config to ContainerResourceDetector from the contrib package opentelemetry-resource-detector-containerid
Uses a lazy import rather than a hard dependency: if the contrib package is installed it is used transparently; if absent a warning is logged with an actionable install instruction
Respects the detection_development.attributes include/exclude glob filter (shared infrastructure from feat(config): add resource and propagator creation from declarative config #4979)
Explicit config attributes always take priority over detector-produced values
6 new tests covering detector opt-in, warning on missing package, contrib package usage (mocked), and explicit attribute override

Design note: why a lazy import rather than a core implementation?

Unlike the process, host, and service detectors, container detection (container.id via /proc/self/cgroup) is not implemented in the Python core SDK — it lives in the opentelemetry-resource-detector-containerid contrib package. This is consistent with other SDKs:

SDK	Container detector
Java	`opentelemetry-java-instrumentation` (contrib)
JS	No implementation — silently skipped
PHP	Contrib package
Python	Contrib package (`opentelemetry-resource-detector-containerid`)
C++	Core (recent addition under a preview flag)

Rather than adding a hard install_requires dependency on a contrib package from the core SDK, or silently skipping (JS approach), this PR uses Python's idiomatic lazy import pattern — the same technique used for optional extras elsewhere in the SDK (e.g. gRPC in OTLP exporters).

Open question for reviewers: Given that C++ has moved container detection into core, should Python do the same? That would remove the contrib dependency entirely and make the behaviour consistent with process/host/service. Happy to implement that in a follow-up if the community prefers it.

Type of change

Bug fix (non-breaking change which fixes an issue)
New feature (non-breaking change which adds functionality)
Breaking change (fix or feature that would cause existing functionality to not work as expected)
This change requires a documentation update

How Has This Been Tested?

6 unit tests in tests/_configuration/test_resource.py
Includes tests for missing package (warning), contrib package usage (mocked), and explicit override

Does This PR Require a Contrib Repo Change?

Yes.
No.

Checklist:

Followed the style guidelines of this project
Changelogs have been updated
Unit tests have been added
Documentation has been updated

Assisted-by: Claude Sonnet 4.6

MikeGoldsmith added 11 commits

March 13, 2026 13:04


          config: add resource and propagator creation from declarative config

5c26f00

Implements create_resource() and create_propagator()/configure_propagator()
for the declarative file configuration. Resource creation does not read
OTEL_RESOURCE_ATTRIBUTES or run any detectors (matches Java/JS SDK behavior).
Propagator configuration always calls set_global_textmap to override Python's
default tracecontext+baggage, setting a noop CompositePropagator when no
propagator is configured.

Assisted-by: Claude Sonnet 4.6


          update changelog with PR number

Assisted-by: Claude Sonnet 4.6


          fix pylint, pyright and ruff errors in resource/propagator config

8329ae4

- _resource.py: refactor _coerce_attribute_value to dispatch table to
  avoid too-many-return-statements; fix short variable names k/v ->
  attr_key/attr_val; fix return type of _sdk_default_attributes to
  dict[str, str] to satisfy pyright
- _propagator.py: rename short variable names e -> exc, p -> propagator
- test_resource.py: move imports to top level; split TestCreateResource
  (25 methods) into three focused classes to satisfy too-many-public-methods
- test_propagator.py: add pylint disable for protected-access

Assisted-by: Claude Sonnet 4.6


          address review feedback: use _DEFAULT_RESOURCE, fix bool_array coercion

506d816

- replace _sdk_default_attributes() with _DEFAULT_RESOURCE from resources module
- move _coerce_bool into dispatch tables for both scalar and array bool types,
  fixing a bug where bool_array with string values like "false" would coerce
  incorrectly via plain bool() (non-empty string -> True)
- add test for bool_array with string values to cover the bug

Assisted-by: Claude Sonnet 4.6


          fix linter

8232d48


          Merge branch 'main' of github.com:open-telemetry/opentelemetry-python…

6ed3425

… into mike/config-resource-propagator


          address review feedback: single coercion table, simplify attributes m…

99753f9

…erge

- collapse _SCALAR_COERCIONS and _ARRAY_COERCIONS into a single _COERCIONS
  dict using an _array() factory, reducing _coerce_attribute_value to two lines
- process attributes_list before attributes so explicit attributes naturally
  overwrite list entries without needing an explicit guard

Assisted-by: Claude Sonnet 4.6


          use Callable type annotation on _array helper

8ba91d8

Assisted-by: Claude Sonnet 4.6


          Merge remote-tracking branch 'upstream/main' into mike/config-resourc…

516aecc

…e-propagator


          add detection infrastructure foundations for resource detectors

9cfdcce

Adds _run_detectors() stub and _filter_attributes() to create_resource(),
providing the shared scaffolding for detector PRs to build on. Detectors
are opt-in: nothing runs unless explicitly listed under
detection_development.detectors in the config. The include/exclude
attribute filter mirrors other SDK behaviour.

Assisted-by: Claude Sonnet 4.6


          move service.name default into base resource

103ff08

Merges service.name=unknown_service into base before running detectors,
so detectors (e.g. service) can override it. Previously it was added to
config_attrs and merged last, which would have silently overridden any
detector-provided service.name.

Assisted-by: Claude Sonnet 4.6

MikeGoldsmith added a commit to MikeGoldsmith/opentelemetry-python that referenced this pull request


          add changelog entry for container resource detector (open-telemetry#5004

be1fb24

)

Assisted-by: Claude Sonnet 4.6

MikeGoldsmith added 3 commits

March 20, 2026 18:22


          remove unused logging import from _propagator.py

7f51034

Assisted-by: Claude Sonnet 4.6


          wire container resource detector in declarative config

e42f1d8

When `resource.detection_development.detectors[].container` is set in
the config file, attempt to use `ContainerResourceDetector` from the
`opentelemetry-resource-detector-containerid` contrib package. Unlike
the process, host, and service detectors which are implemented in the
core SDK, container detection is not available in core. Rather than
adding a hard dependency on the contrib package, we use a lazy import:
if the package is installed it is used transparently; if absent a
warning is logged with an actionable install instruction.

This mirrors the approach taken by other SDKs: JS explicitly skips
container detection when no implementation is available, and PHP also
defers container detection to a contrib package.

See: open-telemetry/opentelemetry-configuration#570

Assisted-by: Claude Sonnet 4.6


          add changelog entry for container resource detector (open-telemetry#5004

327e168

)

Assisted-by: Claude Sonnet 4.6

MikeGoldsmith force-pushed the mike/config-resource-detector-container branch from be1fb24 to 327e168 Compare

March 20, 2026 19:46


          merge upstream/main and fix pylint no-self-use in TestContainerResour…

473a78e

…ceDetector

Assisted-by: Claude Sonnet 4.6

MikeGoldsmith marked this pull request as ready for review

March 29, 2026 16:36

MikeGoldsmith requested a review from a team as a code owner

March 29, 2026 16:36


          add pylint disables for lazy container import in _resource.py

22fe70d

Assisted-by: Claude Sonnet 4.6

tammy-baylis-swi reviewed

View reviewed changes

opentelemetry-sdk/src/opentelemetry/sdk/_configuration/_resource.py Outdated

                   """
+                  if detector_config.container is not None:
+                      # The container detector is not part of the core SDK. It is provided
+                      # by the opentelemetry-resource-detector-containerid contrib package.

Contributor

tammy-baylis-swi Mar 30, 2026

I wondered about this when looking at the other PRs. I think the warning approach is a reasonable way about this.

tammy-baylis-swi approved these changes

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MikeGoldsmith mentioned this pull request

ci: add GHA to add PRs to project board when marked ready for review #5026

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pmcollins reviewed

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opentelemetry-sdk/src/opentelemetry/sdk/_configuration/_resource.py Outdated Show resolved Hide resolved

MikeGoldsmith added 2 commits

April 1, 2026 21:11


          merge upstream/main

c59bdf1

Assisted-by: Claude Sonnet 4.6


          load container detector via entry point instead of lazy import

ce15811

Matches the env-var config counterpart (OTEL_EXPERIMENTAL_RESOURCE_DETECTORS)
and avoids a hard import dependency on the contrib package. Tests updated
to mock entry_points instead of sys.modules.

Assisted-by: Claude Sonnet 4.6

github-project-automation bot added this to Python PR digest

MikeGoldsmith changed the title ~~feat(config): wire container resource detector via lazy contrib import~~ feat(config): wire container resource detector via entry point loading

MikeGoldsmith moved this to Approved PRs in Python PR digest

pmcollins reviewed

View reviewed changes

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

+                              "installed; install it to enable container detection"
+                          )
+                      else:
+                          detected_attrs.update(ep.load()().detect().attributes)

Member

pmcollins Apr 2, 2026

Looks like the env var version uses get_aggregated_resources(). Maybe this should too for consistency -- wdyt?


          Merge branch 'main' into mike/config-resource-detector-container

c1e521f

aabmass approved these changes

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

+                      ep = next(
+                          iter(
+                              entry_points(
+                                  group="opentelemetry_resource_detector", name="container"

Member

aabmass Apr 3, 2026

Are the resource detector names standardized for declarative config? I feel like this block of code could be used to generically load any of the detector_config.* detectors. It would also work for out-of-source detectors generically.

Although maybe it's better as a follow up, wdyt?

herin049 approved these changes

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