chore: add fgprof handler (#114)

Author: dkharms

go.mod

@@ -13,6 +13,7 @@ require (
 	github.com/aws/aws-sdk-go-v2/service/s3 v1.84.0
 	github.com/c2h5oh/datasize v0.0.0-20200112174442-28bbd4740fee
 	github.com/cep21/circuit/v3 v3.2.2
+	github.com/felixge/fgprof v0.9.5
 	github.com/golang/mock v1.6.0
 	github.com/google/uuid v1.6.0
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.27.1
@@ -61,7 +62,6 @@ require (
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
-	github.com/felixge/fgprof v0.9.5 // indirect
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
 	github.com/google/pprof v0.0.0-20250422154841-e1f9c1950416 // indirect
 	github.com/mitchellh/mapstructure v1.5.0 // indirect

network/debugserver/debugserver.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"time"
 
+	"github.com/felixge/fgprof"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"go.uber.org/atomic"
 	"go.uber.org/zap"
@@ -53,6 +54,9 @@ func initHandler(ready *atomic.Bool) http.Handler {
 	mux.HandleFunc("/live", liveness)
 	mux.HandleFunc("/ready", readiness(ready))
 	mux.Handle("/log/level", logger.Handler())
+	// fgprof can collect CPU profile even for Off-CPU goroutines.
+	// It's useful for measurement for any operations that force goroutines to block.
+	mux.Handle("/debug/fgprof", fgprof.Handler())
 
 	return mux
 }