Merge pull request #89 from tomwilkie/build

Embed the git commit id in a go file and print it on startup.

Makefile

@@ -11,6 +11,7 @@ SCOPE_IMAGE=$(DOCKERHUB_USER)/scope
 SCOPE_EXPORT=scope.tar
 SCOPE_UI_BUILD_EXPORT=scope_ui_build.tar
 SCOPE_UI_BUILD_IMAGE=$(DOCKERHUB_USER)/scope-ui-build
+GIT_REVISION=$(shell git rev-parse HEAD)
 
 all: $(SCOPE_EXPORT)
 
@@ -25,7 +26,7 @@ $(PROBE_EXE): probe/*.go report/*.go xfer/*.go
 
 $(APP_EXE) $(PROBE_EXE):
 	go get -tags netgo ./$(@D)
-	go build -ldflags "-extldflags \"-static\"" -tags netgo -o $@ ./$(@D)
+	go build -ldflags "-extldflags \"-static\" -X main.version $(GIT_REVISION)" -tags netgo -o $@ ./$(@D)
 
 static: client/dist/scripts/bundle.js
 	esc -o app/static.go -prefix client/dist client/dist

app/main.go

@@ -18,6 +18,9 @@ import (
 	"github.com/weaveworks/scope/xfer"
 )
 
+// Set during buildtime.
+var version = "unknown"
+
 func main() {
 	var (
 		defaultProbes = []string{fmt.Sprintf("localhost:%d", xfer.ProbePort), fmt.Sprintf("scope.weave.local:%d", xfer.ProbePort)}
@@ -63,7 +66,7 @@ func main() {
 		defer os.Remove(*pidfile)
 	}
 
-	log.Printf("starting")
+	log.Printf("app starting, version %s", version)
 
 	// Collector deals with the probes, and generates merged reports.
 	xfer.MaxBackoff = 10 * time.Second

probe/main.go

@@ -18,6 +18,9 @@ import (
 	"github.com/weaveworks/scope/xfer"
 )
 
+// Set during buildtime.
+var version = "unknown"
+
 func main() {
 	var (
 		httpListen         = flag.String("http.listen", "", "listen address for HTTP profiling and instrumentation server")
@@ -39,6 +42,8 @@ func main() {
 		os.Exit(1)
 	}
 
+	log.Printf("probe starting, version %s", version)
+
 	procspy.SetProcRoot(*procRoot)
 
 	if *httpListen != "" {