From 09f4b85a66bace53cf1e6a808de53cdd17c59c08 Mon Sep 17 00:00:00 2001
From: Ivan Kozlovic <ivan.kozlovic@apcera.com>
Date: Thu, 27 Apr 2017 16:33:55 -0600
Subject: [PATCH] [ADDED] Ability to get the server's HTTP Handler

This will allow applications (for instance NATS Streaming Server)
to add new endpoints to the NATS http server.

Resolves #480
---
 server/monitor_test.go   | 14 ++++++++++++++
 server/pse/pse_darwin.go |  4 ++--
 server/server.go         | 16 ++++++++++++++++
 3 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/server/monitor_test.go b/server/monitor_test.go
index dac4398f..07c49fa8 100644
--- a/server/monitor_test.go
+++ b/server/monitor_test.go
@@ -1348,3 +1348,17 @@ func TestConcurrentMonitoring(t *testing.T) {
 	default:
 	}
 }
+
+func TestMonitorHandler(t *testing.T) {
+	s := runMonitorServer()
+	defer s.Shutdown()
+	handler := s.HTTPHandler()
+	if handler == nil {
+		t.Fatal("HTTP Handler should be set")
+	}
+	s.Shutdown()
+	handler = s.HTTPHandler()
+	if handler != nil {
+		t.Fatal("HTTP Handler should be nil")
+	}
+}
diff --git a/server/pse/pse_darwin.go b/server/pse/pse_darwin.go
index 31ea2755..e1c2ae50 100644
--- a/server/pse/pse_darwin.go
+++ b/server/pse/pse_darwin.go
@@ -3,18 +3,18 @@
 package pse
 
 import (
-	"errors"
 	"fmt"
 	"os"
 	"os/exec"
 )
 
+// ProcUsage returns CPU usage
 func ProcUsage(pcpu *float64, rss, vss *int64) error {
 	pidStr := fmt.Sprintf("%d", os.Getpid())
 	out, err := exec.Command("ps", "o", "pcpu=,rss=,vsz=", "-p", pidStr).Output()
 	if err != nil {
 		*rss, *vss = -1, -1
-		return errors.New(fmt.Sprintf("ps call failed:%v", err))
+		return fmt.Errorf("ps call failed:%v", err)
 	}
 	fmt.Sscanf(string(out), "%f %d %d", pcpu, rss, vss)
 	*rss *= 1024 // 1k blocks, want bytes.
diff --git a/server/server.go b/server/server.go
index 35fc1fdc..a82718f8 100644
--- a/server/server.go
+++ b/server/server.go
@@ -66,6 +66,7 @@ type Server struct {
 	done          chan bool
 	start         time.Time
 	http          net.Listener
+	httpHandler   http.Handler
 	httpReqStats  map[string]uint64
 	routeListener net.Listener
 	routeInfo     Info
@@ -505,14 +506,29 @@ func (s *Server) startMonitoring(secure bool) {
 		WriteTimeout:   2 * time.Second,
 		MaxHeaderBytes: 1 << 20,
 	}
+	s.mu.Lock()
+	s.httpHandler = mux
+	s.mu.Unlock()
 
 	go func() {
 		srv.Serve(s.http)
 		srv.Handler = nil
+		s.mu.Lock()
+		s.httpHandler = nil
+		s.mu.Unlock()
 		s.done <- true
 	}()
 }
 
+// HTTPHandler returns the http.Handler object used to handle monitoring
+// endpoints. It will return nil if the server is not configured for
+// monitoring, or if the server has not been started yet (Server.Start()).
+func (s *Server) HTTPHandler() http.Handler {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.httpHandler
+}
+
 func (s *Server) createClient(conn net.Conn) *client {
 	c := &client{srv: s, nc: conn, opts: defaultOpts, mpay: s.info.MaxPayload, start: time.Now()}