[chalmerlowe]

Problem / Context

Internal issue: b/479827845

To support uniform structured error logging and OpenTelemetry telemetry across both gRPC and REST transports in google-api-core, several foundational utilities need to handle both transport formats consistently:

1. REST ErrorInfo Accessors: GoogleAPICallError.reason, .domain, and .metadata previously assumed self._error_info was always a protobuf ErrorInfo message (as returned by gRPC google.rpc.status_pb2.Status). For REST JSON error payloads, ErrorInfo entries in error["details"] are parsed as standard Python dict objects, causing attribute access (self._error_info.reason) to fail or return None.
2. Duplicate Status Code Extraction: Status code normalization across GoogleAPICallError and raw grpc.RpcError instances (_extract_status_code) lived inside google.api_core.gapic_v1.method, preventing reuse by transport-level observability helpers.
3. Structured Log Field Allowlist: StructuredLogFormatter only recognized legacy camelCase fields and matched fields via exact set membership (in _recognized_logging_fields). It did not unpack record.json_fields or support OpenTelemetry semantic conventions (such as rpc.*, http.*, url.*, server.*, error.type, exception.*, and dynamic gcp.errors.metadata.* keys).

Solution

• google/api_core/exceptions.py:
  • Updated GoogleAPICallError.reason, .domain, and .metadata to inspect isinstance(self._error_info, dict) first before falling back to protobuf attribute access.
  • Moved _extract_status_code(exc, default=None) to google.api_core.exceptions as the single source of truth so both gapic_v1.method and transport observability helpers share one status code normalization implementation.
• google/api_core/gapic_v1/method.py:
  • Updated callers to invoke exceptions._extract_status_code directly and removed duplicate status code extraction logic and unit tests from method.py / test_method.py.
• google/api_core/client_logging.py:
  • Extended _recognized_logging_fields with OpenTelemetry semantic convention attributes, Google Cloud error domain/metadata fields (gcp.errors.domain, gcp.errors.metadata, gcp.errors.metadata.*), and trace correlation keys (logging.googleapis.com/trace, logging.googleapis.com/spanId, logging.googleapis.com/trace_sampled).
  • Pre-compiled _EXACT_FIELDS (frozenset) and _PREFIX_FIELDS (tuple) at module import time and updated StructuredLogFormatter.format to extract exact fields via getattr() (supporting @property and class-level attributes), extract dynamic wildcard prefix fields via vars(record), and unpack record.json_fields last so explicit user-provided structured fields take precedence.
• Unit Tests:
  • Added parametrized unit tests in tests/unit/test_exceptions.py and tests/unit/test_client_logging.py achieving 100% line and branch coverage on modified modules.
  • See CI results for test verification.

[gemini-code-assist]

Code Review

This pull request enhances client logging and exception handling in google-api-core. It expands recognized logging fields, optimizes field extraction using pre-compiled allowlists, and updates StructuredLogFormatter to unpack record.json_fields and extract allowed fields from vars(record). Additionally, it updates exception properties to support dictionary-based error info and centralizes the _extract_status_code utility. The review feedback suggests reversing the processing order in StructuredLogFormatter so that custom fields in json_fields take precedence over automatically extracted attributes from vars(record).

[chalmerlowe]

NOTE: To reviewer: we are moving this function out of method.py and into exceptions.py because it is primarily focused on error code extraction.

[chalmerlowe]

This test stack has been improved and moved to test_exceptions.py to align with the movement of the _extract_status_code() method to exceptions.py.