feat: migrate from home-rolled to standard gRPC middleware

The home-rolled middleware was introduced before the standard
`otelgrpc.NewClientHandler()` and `otelgrpc.NewServerHandler()` were
available.

The standard middleware measures the same things as the home-rolled one
(request count and request duration) and a few other metrics
(such as request/response size histograms).

dialservice.go

@@ -20,11 +20,9 @@ func DialService(ctx context.Context, target string, opts ...grpc.DialOption) (*
 		target,
 		append(
 			[]grpc.DialOption{
+				grpc.WithStatsHandler(otelgrpc.NewClientHandler()),
 				grpc.WithDefaultServiceConfig(run.config.Client.AsServiceConfigJSON()),
 				grpc.WithChainUnaryInterceptor(
-					//nolint:staticcheck // package is deprecated, replace when possible
-					otelgrpc.UnaryClientInterceptor(),
-					run.metricMiddleware.GRPCUnaryClientInterceptor,
 					run.requestLoggerMiddleware.GRPCUnaryClientInterceptor,
 					run.clientMiddleware.GRPCUnaryClientInterceptor,
 				),

go.mod

@@ -20,7 +20,6 @@ require (
 	go.opentelemetry.io/contrib/instrumentation/runtime v0.53.0
 	go.opentelemetry.io/otel v1.28.0
 	go.opentelemetry.io/otel/bridge/opencensus v1.28.0
-	go.opentelemetry.io/otel/metric v1.28.0
 	go.opentelemetry.io/otel/sdk v1.28.0
 	go.opentelemetry.io/otel/sdk/metric v1.28.0
 	go.uber.org/zap v1.27.0
@@ -64,6 +63,7 @@ require (
 	github.com/tklauser/numcpus v0.8.0 // indirect
 	github.com/yusufpapurcu/wmi v1.2.4 // indirect
 	go.opencensus.io v0.24.0 // indirect
+	go.opentelemetry.io/otel/metric v1.28.0 // indirect
 	go.opentelemetry.io/otel/trace v1.28.0 // indirect
 	go.uber.org/multierr v1.10.0 // indirect
 	golang.org/x/crypto v0.25.0 // indirect

grpcserver.go

@@ -19,21 +19,16 @@ func NewGRPCServer(ctx context.Context, opts ...grpc.ServerOption) *grpc.Server
 		panic("cloudrunner.NewGRPCServer: must be called with a context from cloudrunner.Run")
 	}
 	serverOptions := []grpc.ServerOption{
+		grpc.StatsHandler(otelgrpc.NewServerHandler()),
 		grpc.ChainUnaryInterceptor(
-			//nolint:staticcheck // package is deprecated, replace when possible
-			otelgrpc.UnaryServerInterceptor(),
-			run.loggerMiddleware.GRPCUnaryServerInterceptor, // adds context logger
-			run.traceMiddleware.GRPCServerUnaryInterceptor,  // needs the context logger
-			run.metricMiddleware.GRPCUnaryServerInterceptor,
+			run.loggerMiddleware.GRPCUnaryServerInterceptor,        // adds context logger
+			run.traceMiddleware.GRPCServerUnaryInterceptor,         // needs the context logger
 			run.requestLoggerMiddleware.GRPCUnaryServerInterceptor, // needs to run after trace
 			run.serverMiddleware.GRPCUnaryServerInterceptor,        // needs to run after request logger
 		),
 		grpc.ChainStreamInterceptor(
-			//nolint:staticcheck // package is deprecated, replace when possible
-			otelgrpc.StreamServerInterceptor(),
 			run.loggerMiddleware.GRPCStreamServerInterceptor,
 			run.traceMiddleware.GRPCStreamServerInterceptor,
-			run.metricMiddleware.GRPCStreamServerInterceptor,
 			run.requestLoggerMiddleware.GRPCStreamServerInterceptor,
 			run.serverMiddleware.GRPCStreamServerInterceptor,
 		),

run.go

@@ -13,7 +13,6 @@ import (
 
 	"go.einride.tech/cloudrunner/cloudclient"
 	"go.einride.tech/cloudrunner/cloudconfig"
-	"go.einride.tech/cloudrunner/cloudmonitoring"
 	"go.einride.tech/cloudrunner/cloudotel"
 	"go.einride.tech/cloudrunner/cloudprofiler"
 	"go.einride.tech/cloudrunner/cloudrequestlog"
@@ -101,10 +100,6 @@ func Run(fn func(context.Context) error, options ...Option) (err error) {
 	if run.requestLoggerMiddleware.MessageTransformer == nil {
 		run.requestLoggerMiddleware.MessageTransformer = protosensitive.Redact
 	}
-	run.metricMiddleware, err = cloudmonitoring.NewMetricMiddleware()
-	if err != nil {
-		return fmt.Errorf("cloudrunner.Run: %w", err)
-	}
 	ctx = withRunContext(ctx, &run)
 	ctx = cloudruntime.WithConfig(ctx, run.config.Runtime)
 	logger, err := cloudzap.NewLogger(run.config.Logger)
@@ -182,7 +177,6 @@ type runContext struct {
 	clientMiddleware          cloudclient.Middleware
 	requestLoggerMiddleware   cloudrequestlog.Middleware
 	traceMiddleware           cloudtrace.Middleware
-	metricMiddleware          cloudmonitoring.MetricMiddleware
 	securityHeadersMiddleware cloudserver.SecurityHeadersMiddleware
 }