[chalmerlowe]

Summary

Aligns HTTP Tier 3 (GAPIC client) and Tier 4 (wire attempt) OpenTelemetry span statuses and semantic attributes in google-api-core with the OpenTelemetry HTTP semantic conventions and the Cloud SDK Observability specification.

HTTP Tier 4 (Wire Attempt) Spans (_observability.py)

• Set rpc.system.name = "http": Previously omitted on Tier 4 HTTP spans; _TraceContext._build_http_span_attributes now sets "rpc.system.name": "http" so HTTP attempt spans consistently identify the transport system alongside Tier 3 spans.
• Keep 2xx Span Status UNSET: Previously, _TraceContext.record_response explicitly set StatusCode.OK on < 400 responses. It now leaves < 400 client spans UNSET per OpenTelemetry semantic conventions (matching gRPC Tier 4 and Tier 3 spans).
• Populate error.type and status.message on 4xx/5xx Responses: Previously, Tier 4 HTTP error attributes were only recorded in record_error when an exception escaped _TraceContext.__exit__, leaving retried >= 400 responses without error.type or status.message. _TraceContext.record_response now sets error.type to the HTTP status code string (e.g., "400", "503") and extracts status.message from the error response payload on >= 400 responses.

HTTP Tier 3 (GAPIC Client) Spans (_observability.py, gapic_v1/method.py)

• Propagate url.template and http.response.status_code to Parent Tier 3 Spans: Previously, Tier 3 HTTP spans had no visibility into wire-level URL templates or HTTP status codes. _TraceContext.__enter__ and record_response now propagate url.template (from the first HTTP attempt) and http.response.status_code (from the latest HTTP response) to the recording parent Tier 3 span.
• Extract HTTP Status Codes, Dict ErrorInfo, and Clean Error Messages on Failed Tier 3 Spans: Previously, _extract_error_attributes in gapic_v1/method.py only inspected attribute-based ErrorInfo objects and fell back to canonical gRPC status names (e.g., "UNAVAILABLE") for error.type and target_exc.message (which in from_http_response prepends "POST http://...: ") for status.message. When an exception wraps an HTTP response or carries a dict error_info (from JSON format_http_response_error), _extract_error_attributes now:
  • Extracts domain, reason, and metadata from dict error_info payloads as well as protobuf ErrorInfo objects.
  • Records the HTTP status code string (e.g., "400", "503") as error.type when no ErrorInfo.reason is present.
  • Extracts the clean error message from the HTTP response body for status.message before falling back to target_exc.message.

Compliance Verification (gapic-generator)

• Updated test_span_compliance.py and telemetry_requirements_matrix.csv to enforce exact status.message equality (replacing substring matching) and validate cross-tier attribute inheritance between Tier 4 and Tier 3 HTTP spans (_assert_t3_t4_inheritance).

[gemini-code-assist]

Code Review

This pull request enhances HTTP telemetry tracking by adding rpc.system.name to HTTP spans, extracting detailed error messages from HTTP responses, and propagating status codes and URL templates to parent spans. Unit tests and system requirements matrices have been updated accordingly. The review feedback suggests wrapping the extraction of response attributes (text and reason) and the access of parent span attributes in try-except blocks with warning logging to prevent potential runtime exceptions from crashing the main application flow.