[opentelemetry-instrumentation-grpc] Add support for metrics

[lorenzoronzani]

Description

I am adding metrics support inside gRPC servers and client.
I am following semantic conventions.

Server & Client:

• Added possibility to provide a meter_provider to create histogram.
• Added methods to collect metrics inside the interceptor.
• Added tests to verify common happy paths and bad paths.

I edited also aio components to integrate new edits.

Fixes # (issue)

Issue 3375

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?

I am in a system that doesn't allow me to have all required packages, I found this solution to run my tests.

• Execute uv run --no-sync pytest instrumentation/opentelemetry-instrumentation-grpc/tests/ --ignore=instrumentation/opentelemetry-instrumentation-grpc/tests/protobuf/ -q

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, I need help on this point

[Copilot]

Pull request overview

Adds OpenTelemetry RPC duration metrics to the opentelemetry-instrumentation-grpc package (sync + asyncio), aligning with the RPC metrics semantic conventions by emitting rpc.client.call.duration and rpc.server.call.duration histograms and validating them via new unit tests.

Changes:

• Added duration histogram creation and recording to gRPC client/server interceptors (sync + grpc.aio), including metric attributes like rpc.system.name, rpc.method, and rpc.response.status_code.
• Extended public interceptor factories to accept meter_provider, and plumbed meter/target information into client interceptors for server.address/server.port.
• Added new metric-focused test suites for sync and asyncio client/server paths, plus a changelog entry.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
instrumentation/opentelemetry-instrumentation-grpc/src/opentelemetry/instrumentation/grpc/_server.py	Records rpc.server.call.duration with semconv attributes.
instrumentation/opentelemetry-instrumentation-grpc/src/opentelemetry/instrumentation/grpc/_client.py	Records rpc.client.call.duration, parses channel target for server attributes.
instrumentation/opentelemetry-instrumentation-grpc/src/opentelemetry/instrumentation/grpc/_aio_server.py	Adds duration recording to aio server interceptor paths.
instrumentation/opentelemetry-instrumentation-grpc/src/opentelemetry/instrumentation/grpc/_aio_client.py	Adds duration recording hooks for aio client interceptor paths.
instrumentation/opentelemetry-instrumentation-grpc/src/opentelemetry/instrumentation/grpc/init.py	Exposes meter_provider/target plumbing for interceptor factories and client instrumentors.
instrumentation/opentelemetry-instrumentation-grpc/tests/test_server_interceptor_metrics.py	New sync server duration metric tests (OK + error + streaming).
instrumentation/opentelemetry-instrumentation-grpc/tests/test_client_interceptor_metrics.py	New sync client duration metric tests (OK + error + streaming).
instrumentation/opentelemetry-instrumentation-grpc/tests/test_aio_server_interceptor_metrics.py	New aio server duration metric tests.
instrumentation/opentelemetry-instrumentation-grpc/tests/test_aio_client_interceptor_metrics.py	New aio client duration metric tests.
.changelog/4621.added	Changelog entry for adding gRPC RPC duration metrics.

Comments suppressed due to low confidence (3)

instrumentation/opentelemetry-instrumentation-grpc/src/opentelemetry/instrumentation/grpc/_client.py:239

• If invoker(...) raises a non-grpc.RpcError exception (e.g., a local serialization / interceptor error before the RPC completes), status_code remains StatusCode.OK, so the metric will incorrectly report an OK response. Consider mapping non-grpc.RpcError failures to grpc.StatusCode.UNKNOWN (or skip recording) so rpc.response.status_code/error.type reflect failure.

            except Exception as exc:
                if isinstance(exc, grpc.RpcError):
                    status_code = exc.code()
                    span.set_attribute(
                        RPC_GRPC_STATUS_CODE,
                        status_code.value[0],
                    )
                span.set_status(
                    Status(
                        status_code=StatusCode.ERROR,
                        description=f"{type(exc).__name__}: {exc}",
                    )
                )
                span.record_exception(exc)

instrumentation/opentelemetry-instrumentation-grpc/src/opentelemetry/instrumentation/grpc/_server.py:402

• Same as unary path: on an uncaught exception in a streaming handler, the wrapped context’s status code will remain OK, but gRPC will return UNKNOWN. This will cause rpc.server.call.duration to be tagged with rpc.response.status_code=OK. Consider ensuring a non-OK status (e.g., UNKNOWN) is recorded when exceptions escape the handler.

                    self._record_duration(
                        handler_call_details,
                        start_time,
                        context._code,
                    )

instrumentation/opentelemetry-instrumentation-grpc/src/opentelemetry/instrumentation/grpc/_aio_server.py:160

• In the async streaming server interceptor, uncaught exceptions will leave context._self_code as OK, so the duration metric will be tagged with rpc.response.status_code=OK even though gRPC returns UNKNOWN. Consider updating the wrapped context code on exception before recording metrics.

                    except Exception as error:
                        # pylint:disable=unidiomatic-typecheck
                        if type(error) != Exception:  # noqa: E721
                            span.record_exception(error)
                        raise error

                    finally:
                        self._record_duration(
                            handler_call_details,
                            start_time,
                            context._self_code,
                        )

[lorenzoronzani]

Just an update:

I am integrating comments, unfortunately I didn't have time to do that before.

[Copilot]

Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 11 comments.

[lorenzoronzani]

@aabmass, @emdneto What do you think about the current solution?

[lzchen]

@lmolkova
Were there discussions around semantic conventions related to rpc metrics that you brought up in the last SIG that this PR depended on?