[otelgrpc] add metric rpc.server.duration support

[fatsheep9146]

Signed-off-by: Ziqi Zhao [email protected]

Enhance instrumentation library otelgrpc for grpc to satisfy opentelemetry grpc server metric semantic conventions.

This pr is meant to add metric rpc.server.duration for the first step.

I use example code to test, and produce the data for unary and stream request

{
    "Name": "rpc.server.duration{service.name=unknown_service:main,telemetry.sdk.language=go,telemetry.sdk.name=opentelemetry,telemetry.sdk.version=1.9.0,instrumentation.name=go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc,instrumentation.version=semver:0.34.0,net.peer.ip=127.0.0.1,net.peer.port=55809,rpc.grpc.status_code=0,rpc.method=SayHelloServerStream,rpc.service=api.HelloService,rpc.system=grpc}",
    "Sum": 502.366387
},
{
    "Name": "rpc.server.duration{service.name=unknown_service:main,telemetry.sdk.language=go,telemetry.sdk.name=opentelemetry,telemetry.sdk.version=1.9.0,instrumentation.name=go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc,instrumentation.version=semver:0.34.0,net.peer.ip=127.0.0.1,net.peer.port=55809,rpc.grpc.status_code=0,rpc.method=SayHelloBidiStream,rpc.service=api.HelloService,rpc.system=grpc}",
    "Sum": 253.394227
}

[dmathieu]

You need to run go mod tidy from the otelgrpc package to fix the tests. Also, this will need a changelog entry.

[codecov[bot]]

Codecov Report

Merging #2700 (41f7fb7) into main (bba2c55) will increase coverage by 0.0%. The diff coverage is 63.6%.

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #2700   +/-   ##
=====================================
  Coverage   69.3%   69.4%           
=====================================
  Files        145     146    +1     
  Lines       6729    6752   +23     
=====================================
+ Hits        4667    4689   +22     
+ Misses      1948    1946    -2     
- Partials     114     117    +3     

Impacted Files	Coverage Δ
...ogle.golang.org/grpc/otelgrpc/metadata_supplier.go	51.1% <51.1%> (ø)
...entation/google.golang.org/grpc/otelgrpc/config.go	65.1% <80.0%> (ø)
...ion/google.golang.org/grpc/otelgrpc/interceptor.go	83.0% <100.0%> (-0.6%)	:arrow_down:

[fatsheep9146]

@dmathieu @Aneurysm9 All checks are passed, could you help review this again?

[fatsheep9146]

Could you help review this again? @dmathieu

[fatsheep9146]

@Aneurysm9 @jmacd @MrAlias @hanyuancheung

Could you help review this again?

[devnev]

Hi, stumbled across this, and had two questions about the units

• ~Why milliseconds? Looks like its a float64 anyway, so the position of the decimal makes no technical difference, so seconds would seem like a better choice simply for being the SI standard.~ nevermind, spotted the unit specification in the upstream spec.
• Does the unit need to be indicated somewhere? I had to dig into the recording code to find it.

[fatsheep9146]

@devnev I think you can visit here to find the info about all metrics. https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/semantic_conventions/rpc.md#rpc-server

Hi, stumbled across this, and had two questions about the units

• ~Why milliseconds? Looks like its a float64 anyway, so the position of the decimal makes no technical difference, so seconds would seem like a better choice simply for being the SI standard.~ nevermind, spotted the unit specification in the upstream spec.
• Does the unit need to be indicated somewhere? I had to dig into the recording code to find it.

[fatsheep9146]

ping @pellared @Aneurysm9 @MrAlias @jmacd @dashpole @MadVikingGod @evantorrie @XSAM , could you help review this again?

[fatsheep9146]

ping @pellared @Aneurysm9 @MrAlias @jmacd @dashpole @MadVikingGod @evantorrie @XSAM could you help review this?

[MrAlias]

Is the plan to add the other specified metrics (https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/semantic_conventions/rpc.md#rpc-server) in follow on PRs? If so, can you open an issue to track the work?

[fatsheep9146]

Is the plan to add the other specified metrics (https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/semantic_conventions/rpc.md#rpc-server) in follow on PRs? If so, can you open an issue to track the work?

Absolutely, I already open an issue #2840 to track, and I will add the metric one by one. @MrAlias

[fatsheep9146]

Could you help review this again? @MrAlias

[fatsheep9146]

@jmacd @pellared @Aneurysm9 Could you help review this again?

[liufuyang]

BTW... The new spec is moved to https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/semantic_conventions/rpc-metrics.md