Fix ECS resource detector populating container.name with the hostname

[rdbisme]

Description

The AwsEcsResourceDetector populates the container.name resource attribute with socket.gethostname(). On ECS tasks using the awsvpc network mode the container hostname is the IP-like private DNS name of the ENI (e.g. ip-10-0-2-100.us-west-2.compute.internal), so container.name ends up being an "IP name" instead of the actual container name.

When the metadata endpoint v4 is available (which the detector already queries), the container-level response contains the container name as defined in the task definition (field Name, e.g. curl). This PR uses that value for container.name when the v4 endpoint is present, and keeps the hostname as a fallback (v3-only path, or a response without a Name field).

No existing issue was filed for this; the fix follows the metadata response documented at https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task-metadata-endpoint-v4.html#task-metadata-endpoint-v4-response

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?

• python -m pytest sdk-extension/opentelemetry-sdk-extension-aws/tests/resource/test_ecs.py — 4 passed.
  The v4 EC2/Fargate tests now mock socket.gethostname() to return the IP-like name while expecting container.name: "curl" from the metadata fixtures, proving the metadata value overrides the hostname. The v3 test keeps covering the hostname fallback.
• ruff check on the changed source and test files — clean.

Does This PR Require a Core Repo Change?

• Yes. - Link to PR:
• No.

Checklist:

See contributing.md for styleguide, changelog guidelines, and more.

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

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: rdbisme / name: Ruben Di Battista (5e8f361, 6fc3288)

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Waiting on reviewers · refreshed 2026-08-21 01:51 UTC

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[rdbisme]

@srprash @jj22ee