Report GCP profiles from zoekt-git-index (#816)

This PR initializes the GCP profiler in the `zoekt-git-index` process so we can
examine CPU and memory usage for the indexing process itself.

cmd/zoekt-git-index/main.go

@@ -22,6 +22,7 @@ import (
 	"runtime/pprof"
 	"strings"
 
+	"github.com/sourcegraph/zoekt/internal/profiler"
 	"go.uber.org/automaxprocs/maxprocs"
 
 	"github.com/sourcegraph/zoekt/cmd"
@@ -70,6 +71,7 @@ func run() int {
 		}
 		*repoCacheDir = dir
 	}
+
 	opts := cmd.OptionsFromFlags()
 	opts.IsDelta = *isDelta
 	opts.DocumentRanksPath = *offlineRanking
@@ -107,6 +109,7 @@ func run() int {
 		opts.LanguageMap[m[0]] = ctags.StringToParser(m[1])
 	}
 
+	profiler.Init("zoekt-git-index")
 	exitStatus := 0
 	for dir, name := range gitRepos {
 		opts.RepositoryDescription.Name = name

cmd/zoekt-sourcegraph-indexserver/main.go

@@ -1277,7 +1277,7 @@ func startServer(conf rootConfig) error {
 		return err
 	}
 
-	profiler.Init("zoekt-sourcegraph-indexserver", zoekt.Version, conf.blockProfileRate)
+	profiler.Init("zoekt-sourcegraph-indexserver")
 	setCompoundShardCounter(s.IndexDir)
 
 	if conf.listen != "" {

cmd/zoekt-webserver/main.go

@@ -177,7 +177,7 @@ func main() {
 	liblog := sglog.Init(resource)
 	defer liblog.Sync()
 	tracer.Init(resource)
-	profiler.Init("zoekt-webserver", zoekt.Version, -1)
+	profiler.Init("zoekt-webserver")
 
 	if *logDir != "" {
 		if fi, err := os.Lstat(*logDir); err != nil || !fi.IsDir() {

internal/profiler/profiler.go

@@ -5,14 +5,15 @@ import (
 	"os"
 
 	"cloud.google.com/go/profiler"
+	"github.com/sourcegraph/zoekt"
 )
 
 // Init starts the supported profilers IFF the environment variable is set.
-func Init(svcName, version string, blockProfileRate int) {
+func Init(svcName string) {
 	if os.Getenv("GOOGLE_CLOUD_PROFILER_ENABLED") != "" {
 		err := profiler.Start(profiler.Config{
 			Service:        svcName,
-			ServiceVersion: version,
+			ServiceVersion: zoekt.Version,
 			MutexProfiling: true,
 			AllocForceGC:   true,
 		})