PLT-4357 adding performance monitoring (#4622)

* WIP

* WIP

* Adding metrics collection

* updating vendor packages

* Adding metrics to config

* Adding admin console page for perf monitoring

* Updating glide

* switching to tylerb/graceful

vendor/github.com/tylerb/graceful/graceful.go

@@ -6,9 +6,7 @@ import (
 	"net"
 	"net/http"
 	"os"
-	"os/signal"
 	"sync"
-	"syscall"
 	"time"
 )
 
@@ -299,7 +297,7 @@ func (srv *Server) Serve(listener net.Listener) error {
 	interrupt := srv.interruptChan()
 	// Set up the interrupt handler
 	if !srv.NoSignalHandling {
-		signal.Notify(interrupt, syscall.SIGINT, syscall.SIGTERM)
+		signalNotify(interrupt)
 	}
 	quitting := make(chan struct{})
 	go srv.handleInterrupt(interrupt, quitting, listener)
@@ -336,8 +334,7 @@ func (srv *Server) Stop(timeout time.Duration) {
 	defer srv.stopLock.Unlock()
 
 	srv.Timeout = timeout
-	interrupt := srv.interruptChan()
-	interrupt <- syscall.SIGINT
+	sendSignalInt(srv.interruptChan())
 }
 
 // StopChan gets the stop channel which will block until

vendor/github.com/tylerb/graceful/signal.go

@@ -0,0 +1,17 @@
+//+build !appengine
+
+package graceful
+
+import (
+	"os"
+	"os/signal"
+	"syscall"
+)
+
+func signalNotify(interrupt chan<- os.Signal) {
+	signal.Notify(interrupt, syscall.SIGINT, syscall.SIGTERM)
+}
+
+func sendSignalInt(interrupt chan<- os.Signal) {
+	interrupt <- syscall.SIGINT
+}

vendor/github.com/tylerb/graceful/signal_appengine.go

@@ -0,0 +1,13 @@
+//+build appengine
+
+package graceful
+
+import "os"
+
+func signalNotify(interrupt chan<- os.Signal) {
+	// Does not notify in the case of AppEngine.
+}
+
+func sendSignalInt(interrupt chan<- os.Signal) {
+	// Does not send in the case of AppEngine.
+}