Fix loki exit on jaeger agent not being present

cmd/loki/main.go

@@ -51,12 +51,17 @@ func main() {
 	util.InitLogger(&config.Server)
 
 	// Setting the environment variable JAEGER_AGENT_HOST enables tracing
-	trace := tracing.NewFromEnv(fmt.Sprintf("loki-%s", config.Target))
+	trace, err := tracing.NewFromEnv(fmt.Sprintf("loki-%s", config.Target))
+	if err != nil {
+		level.Error(util.Logger).Log("msg", "error in initializing tracing. tracing will not be enabled", "err", err)
+	}
 	defer func() {
-		if err := trace.Close(); err != nil {
-			level.Error(util.Logger).Log("msg", "error closing tracing", "err", err)
-			os.Exit(1)
+		if trace != nil {
+			if err := trace.Close(); err != nil {
+				level.Error(util.Logger).Log("msg", "error closing tracing", "err", err)
+			}
 		}
+
 	}()
 
 	// Start Loki

go.mod

@@ -49,7 +49,7 @@ require (
 	github.com/tonistiigi/fifo v0.0.0-20190226154929-a9fb20d87448
 	github.com/uber/jaeger-client-go v2.20.1+incompatible
 	github.com/ugorji/go v1.1.7 // indirect
-	github.com/weaveworks/common v0.0.0-20200206153930-760e36ae819a
+	github.com/weaveworks/common v0.0.0-20200310113808-2708ba4e60a4
 	go.etcd.io/etcd v0.0.0-20190815204525-8f85f0dc2607 // indirect
 	golang.org/x/net v0.0.0-20191112182307-2180aed22343
 	google.golang.org/grpc v1.25.1

go.sum

@@ -770,8 +770,9 @@ github.com/ugorji/go v1.1.7/go.mod h1:kZn38zHttfInRq0xu/PH0az30d+z6vm202qpg1oXVM
 github.com/ugorji/go/codec v1.1.7 h1:2SvQaVZ1ouYrrKKwoSk2pzd4A9evlKJb9oTL+OaLUSs=
 github.com/ugorji/go/codec v1.1.7/go.mod h1:Ax+UKWsSmolVDwsd+7N3ZtXu+yMGCf907BLYF3GoBXY=
 github.com/urfave/cli v1.20.0/go.mod h1:70zkFmudgCuE/ngEzBv17Jvp/497gISqfk5gWijbERA=
-github.com/weaveworks/common v0.0.0-20200206153930-760e36ae819a h1:4Sm4LnEnP1yQ2NeNgGqLTuN2xrTvcBOU+EsljpB8Ed0=
 github.com/weaveworks/common v0.0.0-20200206153930-760e36ae819a/go.mod h1:6enWAqfQBFrE8X/XdJwZr8IKgh1chStuFR0mjU/UOUw=
+github.com/weaveworks/common v0.0.0-20200310113808-2708ba4e60a4 h1:H1CjeKf1q/bL7OBvb6KZclHsvnGRGr0Tsuy6y5rtFEc=
+github.com/weaveworks/common v0.0.0-20200310113808-2708ba4e60a4/go.mod h1:6enWAqfQBFrE8X/XdJwZr8IKgh1chStuFR0mjU/UOUw=
 github.com/weaveworks/promrus v1.2.0 h1:jOLf6pe6/vss4qGHjXmGz4oDJQA+AOCqEL3FvvZGz7M=
 github.com/weaveworks/promrus v1.2.0/go.mod h1:SaE82+OJ91yqjrE1rsvBWVzNZKcHYFtMUyS1+Ogs/KA=
 github.com/xanzy/go-gitlab v0.15.0/go.mod h1:8zdQa/ri1dfn8eS3Ir1SyfvOKlw7WBJ8DVThkpGiXrs=