Provide cadvisor stats as prometheus metrics

Author: discordianfish

cadvisor.go

@@ -43,6 +43,8 @@ var httpAuthRealm = flag.String("http_auth_realm", "localhost", "HTTP auth realm
 var httpDigestFile = flag.String("http_digest_file", "", "HTTP digest file for the web UI")
 var httpDigestRealm = flag.String("http_digest_realm", "localhost", "HTTP digest file for the web UI")
 
+var prometheusEndpoint = flag.String("prometheus_endpoint", "/metrics", "Endpoint to expose Prometheus metrics on")
+
 func main() {
 	defer glog.Flush()
 	flag.Parse()
@@ -72,7 +74,7 @@ func main() {
 	mux := http.DefaultServeMux
 
 	// Register all HTTP handlers.
-	err = cadvisorHttp.RegisterHandlers(mux, containerManager, *httpAuthFile, *httpAuthRealm, *httpDigestFile, *httpDigestRealm)
+	err = cadvisorHttp.RegisterHandlers(mux, containerManager, *httpAuthFile, *httpAuthRealm, *httpDigestFile, *httpDigestRealm, *prometheusEndpoint)
 	if err != nil {
 		glog.Fatalf("Failed to register HTTP handlers: %v", err)
 	}

http/handlers.go

@@ -24,12 +24,14 @@ import (
 	"github.com/google/cadvisor/healthz"
 	httpMux "github.com/google/cadvisor/http/mux"
 	"github.com/google/cadvisor/manager"
+	"github.com/google/cadvisor/metrics"
 	"github.com/google/cadvisor/pages"
 	"github.com/google/cadvisor/pages/static"
 	"github.com/google/cadvisor/validate"
+	"github.com/prometheus/client_golang/prometheus"
 )
 
-func RegisterHandlers(mux httpMux.Mux, containerManager manager.Manager, httpAuthFile, httpAuthRealm, httpDigestFile, httpDigestRealm string) error {
+func RegisterHandlers(mux httpMux.Mux, containerManager manager.Manager, httpAuthFile, httpAuthRealm, httpDigestFile, httpDigestRealm, prometheusEndpoint string) error {
 	// Basic health handler.
 	if err := healthz.RegisterHandler(mux); err != nil {
 		return fmt.Errorf("failed to register healthz handler: %s", err)
@@ -83,6 +85,10 @@ func RegisterHandlers(mux httpMux.Mux, containerManager manager.Manager, httpAut
 		}
 	}
 
+	collector := metrics.NewPrometheusCollector(containerManager)
+	prometheus.MustRegister(collector)
+	http.Handle(prometheusEndpoint, prometheus.Handler())
+
 	return nil
 }