[chalmerlowe]

Problem

Several OpenTelemetry span fields did not match the Cloud SDK tracing specification:

1. HTTP attempt (Tier 4) span names: Only recorded the HTTP verb (such as POST) instead of combining the verb and the URL template.
2. Client method (Tier 3) span kind: Used CLIENT instead of INTERNAL. Tier 3 spans track the overall SDK method call, while Tier 4 spans track the outbound network attempts (CLIENT).
3. Client method (Tier 3) endpoint attributes: Did not include url.domain (or server.address and server.port when configured in ClientOptions).

Solution

• _observability.py: Updated _build_http_span_attributes to format the span name as {method} {url_template} (for example, POST /v1beta1/echo:echo).
  • Falls back to {method} when url_template is not provided.
• method.py: Updated _GapicCallable.__init__ to:
  • Set the Tier 3 span kind to SpanKind.INTERNAL.
  • Merge _extract_endpoint_attributes(client_options) into the Tier 3 span attributes so url.domain is always recorded.
• Tests and Matrix:
  • test_observability.py, test_method.py, test_method_async.py, conftest.py: Updated unit test expectations for the new span names, span kind, and url.domain attribute.
  • telemetry_requirements_matrix.csv: Updated system test expectations to match.

Notes for Reviewers

• Endpoint attributes are extracted once when the method wrapper is initialized, adding no extra work during individual RPC calls.
• Populating server.address and server.port from default transport hosts (when client_options.api_endpoint is not set by the caller) will be handled in a follow-up PR.

[gemini-code-assist]

Code Review

This pull request updates OpenTelemetry tracing in google-api-core by changing the span kind of API method wrappers from CLIENT to INTERNAL and incorporating endpoint attributes (such as url.domain, server.address, and server.port) from client_options into these spans. Additionally, HTTP span names are updated to include the URL template (e.g., "POST /v1/echo"). Tests and the telemetry requirements matrix have been updated accordingly. There are no review comments, and I have no feedback to provide.