Add Jaeger distributed tracing support

prog/app.go

@@ -23,6 +23,7 @@ import (
 	"github.com/weaveworks/common/middleware"
 	"github.com/weaveworks/common/network"
 	"github.com/weaveworks/common/signals"
+	"github.com/weaveworks/common/tracing"
 	"github.com/weaveworks/go-checkpoint"
 	"github.com/weaveworks/scope/app"
 	"github.com/weaveworks/scope/app/multitenant"
@@ -202,6 +203,9 @@ func appMain(flags appFlags) {
 	setLogFormatter(flags.logPrefix)
 	runtime.SetBlockProfileRate(flags.blockProfileRate)
 
+	traceCloser := tracing.NewFromEnv(fmt.Sprintf("scope-%s", flags.serviceName))
+	defer traceCloser.Close()
+
 	defer log.Info("app exiting")
 	rand.Seed(time.Now().UnixNano())
 	app.UniqueID = strconv.FormatInt(rand.Int63(), 16)

prog/main.go

@@ -167,6 +167,7 @@ type appFlags struct {
 	userIDHeader              string
 	externalUI                bool
 	metricsGraphURL           string
+	serviceName               string
 
 	blockProfileRate int
 
@@ -369,6 +370,7 @@ func setupFlags(flags *flags) {
 	flag.StringVar(&flags.app.userIDHeader, "app.userid.header", "", "HTTP header to use as userid")
 	flag.BoolVar(&flags.app.externalUI, "app.externalUI", false, "Point to externally hosted static UI assets")
 	flag.StringVar(&flags.app.metricsGraphURL, "app.metrics-graph", "", "Enable extended metrics graph by providing a templated URL (supports :orgID and :query). Example: --app.metric-graph=/prom/:orgID/notebook/new")
+	flag.StringVar(&flags.app.serviceName, "app.service-name", "app", "The name for this service which should be reported in instrumentation")
 
 	flag.IntVar(&flags.app.blockProfileRate, "app.block.profile.rate", 0, "If more than 0, enable block profiling. The profiler aims to sample an average of one blocking event per rate nanoseconds spent blocked.")
 

prog/probe.go

@@ -18,6 +18,7 @@ import (
 	"github.com/weaveworks/common/network"
 	"github.com/weaveworks/common/sanitize"
 	"github.com/weaveworks/common/signals"
+	"github.com/weaveworks/common/tracing"
 	"github.com/weaveworks/go-checkpoint"
 	"github.com/weaveworks/scope/common/hostname"
 	"github.com/weaveworks/scope/common/weave"
@@ -93,6 +94,9 @@ func probeMain(flags probeFlags, targets []appclient.Target) {
 	setLogLevel(flags.logLevel)
 	setLogFormatter(flags.logPrefix)
 
+	traceCloser := tracing.NewFromEnv("scope-probe")
+	defer traceCloser.Close()
+
 	// Setup in memory metrics sink
 	inm := metrics.NewInmemSink(time.Minute, 2*time.Minute)
 	sig := metrics.DefaultInmemSignal(inm)