only server side spans should be recorded

Signed-off-by: Roman Dmytrenko <[email protected]>

Author: erka

.mockery.yml

@@ -44,3 +44,9 @@ packages:
     interfaces:
       Provider: {}
       Manager: {}
+  google.golang.org/grpc/stats:
+    interfaces:
+      Handler: {}
+    config:
+      pkgname: otel
+      dir: "./internal/otel/"

cmd/flipt/main.go

@@ -34,7 +34,6 @@ import (
 	"go.flipt.io/flipt/internal/secrets"
 	"go.flipt.io/flipt/internal/telemetry"
 	"go.opentelemetry.io/contrib/bridges/otelzap"
-	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
 	"go.opentelemetry.io/otel/log/global"
 	"go.opentelemetry.io/otel/sdk/log"
 	"go.uber.org/zap"
@@ -457,7 +456,7 @@ func run(ctx context.Context, logger *zap.Logger, cfg *config.Config) error {
 
 	// in-process client connection for grpc services
 	ipch := &inprocgrpc.Channel{}
-	ipch = ipch.WithStatsHandler(otelgrpc.NewServerHandler())
+	ipch = ipch.WithStatsHandler(otel.NewInprocStatsHandler())
 
 	var grpcOptions []cmd.GRPCServerOption
 	if forceMigrate {

go.mod

@@ -546,6 +546,8 @@ require (
 replace (
 	github.com/codahale/hdrhistogram => github.com/HdrHistogram/hdrhistogram-go v0.9.0
 	github.com/dgrijalva/jwt-go v3.2.0+incompatible => github.com/golang-jwt/jwt/v4 v4.2.0
+	// replace with fork while changes are in review
+	// https://github.com/fullstorydev/grpchan/pull/83
 	github.com/fullstorydev/grpchan => github.com/erka/grpchan v0.0.0-20251014172820-9b4242e94974
 )
 

internal/cmd/grpc.go

@@ -46,7 +46,6 @@ import (
 	rpcanalytics "go.flipt.io/flipt/rpc/v2/analytics"
 	rpcenv "go.flipt.io/flipt/rpc/v2/environments"
 	rpcevaluationv2 "go.flipt.io/flipt/rpc/v2/evaluation"
-	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
 	opentelemetry "go.opentelemetry.io/otel"
 	metricsdk "go.opentelemetry.io/otel/sdk/metric"
 	tracesdk "go.opentelemetry.io/otel/sdk/trace"
@@ -372,7 +371,6 @@ func NewGRPCServer(
 	grpcOpts := []grpc.ServerOption{
 		grpc.ChainUnaryInterceptor(unaryInterceptors...),
 		grpc.ChainStreamInterceptor(streamInterceptors...),
-		grpc.StatsHandler(otelgrpc.NewServerHandler()),
 		grpc.KeepaliveParams(keepalive.ServerParameters{
 			MaxConnectionIdle:     cfg.Server.GRPCConnectionMaxIdleTime,
 			MaxConnectionAge:      cfg.Server.GRPCConnectionMaxAge,

internal/otel/stats.go

@@ -0,0 +1,28 @@
+package otel
+
+import (
+	"context"
+
+	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
+	"google.golang.org/grpc/stats"
+)
+
+var _ stats.Handler = (*statsHandler)(nil)
+
+type statsHandler struct {
+	stats.Handler
+}
+
+// HandleRPC processes the RPC stats.
+// It ignores client stats to avoid double spans with the same GRPC call.
+func (w *statsHandler) HandleRPC(ctx context.Context, s stats.RPCStats) {
+	if s.IsClient() {
+		return
+	}
+	w.Handler.HandleRPC(ctx, s)
+}
+
+// NewInprocStatsHandler creates a new gRPC stats handler for telemetry.
+func NewInprocStatsHandler() stats.Handler {
+	return &statsHandler{Handler: otelgrpc.NewServerHandler()}
+}