Add fgfprof to Loki and Promtail. (#3424)

Signed-off-by: Cyril Tovena <cyril.tovena@gmail.com>

go.mod

@@ -19,6 +19,7 @@ require (
 	github.com/drone/envsubst v1.0.2
 	github.com/dustin/go-humanize v1.0.0
 	github.com/fatih/color v1.9.0
+	github.com/felixge/fgprof v0.9.1
 	github.com/fluent/fluent-bit-go v0.0.0-20190925192703-ea13c021720c
 	github.com/go-kit/kit v0.10.0
 	github.com/go-logfmt/logfmt v0.5.0

pkg/loki/loki.go

@@ -9,6 +9,7 @@ import (
 
 	frontend "github.com/cortexproject/cortex/pkg/frontend/v1"
 	"github.com/cortexproject/cortex/pkg/querier/worker"
+	"github.com/felixge/fgprof"
 
 	"github.com/grafana/loki/pkg/storage/stores/shipper/compactor"
 
@@ -239,6 +240,8 @@ func (t *Loki) Run() error {
 	// This adds a way to see the config and the changes compared to the defaults
 	t.Server.HTTP.Path("/config").HandlerFunc(configHandler(t.cfg, newDefaultConfig()))
 
+	t.Server.HTTP.Path("/debug/fgprof").Handler(fgprof.Handler())
+
 	// Let's listen for events from this manager, and log them.
 	healthy := func() { level.Info(util_log.Logger).Log("msg", "Loki started") }
 	stopped := func() { level.Info(util_log.Logger).Log("msg", "Loki stopped") }

pkg/promtail/server/server.go

@@ -13,6 +13,7 @@ import (
 	"syscall"
 	"text/template"
 
+	"github.com/felixge/fgprof"
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/pkg/errors"
@@ -99,8 +100,8 @@ func New(cfg Config, log log.Logger, tms *targets.TargetManagers) (Server, error
 	serv.HTTP.PathPrefix("/static/").Handler(http.FileServer(ui.Assets))
 	serv.HTTP.Path("/service-discovery").Handler(http.HandlerFunc(serv.serviceDiscovery))
 	serv.HTTP.Path("/targets").Handler(http.HandlerFunc(serv.targets))
+	serv.HTTP.Path("/debug/fgprof").Handler(fgprof.Handler())
 	return serv, nil
-
 }
 
 // serviceDiscovery serves the service discovery page.
@@ -261,6 +262,7 @@ func (s *noopServer) Run() error {
 	level.Info(s.log).Log("msg", "received shutdown signal", "sig", sig)
 	return nil
 }
+
 func (s *noopServer) Shutdown() {
 	s.sigs <- syscall.SIGTERM
 }

vendor/modules.txt

@@ -351,6 +351,7 @@ github.com/facette/natsort
 ## explicit
 github.com/fatih/color
 # github.com/felixge/fgprof v0.9.1
+## explicit
 github.com/felixge/fgprof
 # github.com/felixge/httpsnoop v1.0.1
 github.com/felixge/httpsnoop