resolve nsqio#846: nsqd: expose memory stats under /stats

nsqd/http.go

@@ -495,19 +495,21 @@ func (s *httpServer) doStats(w http.ResponseWriter, req *http.Request, ps httpro
 		}
 	}
 
+	ms := getMemStats()
 	if !jsonFormat {
-		return s.printStats(stats, health, startTime, uptime), nil
+		return s.printStats(stats, ms, health, startTime, uptime), nil
 	}
 
 	return struct {
 		Version   string       `json:"version"`
 		Health    string       `json:"health"`
 		StartTime int64        `json:"start_time"`
 		Topics    []TopicStats `json:"topics"`
-	}{version.Binary, health, startTime.Unix(), stats}, nil
+		Memory    *memStats    `json:"memory"`
+	}{version.Binary, health, startTime.Unix(), stats, ms}, nil
 }
 
-func (s *httpServer) printStats(stats []TopicStats, health string, startTime time.Time, uptime time.Duration) []byte {
+func (s *httpServer) printStats(stats []TopicStats, ms *memStats, health string, startTime time.Time, uptime time.Duration) []byte {
 	var buf bytes.Buffer
 	w := &buf
 	now := time.Now()
@@ -518,6 +520,17 @@ func (s *httpServer) printStats(stats []TopicStats, health string, startTime tim
 		io.WriteString(w, "\nNO_TOPICS\n")
 		return buf.Bytes()
 	}
+	fmt.Fprintf(w, "\nMemory:\n")
+	fmt.Fprintf(w, "  %-25s\t%d\n", "heap_objects", ms.HeapObjects)
+	fmt.Fprintf(w, "  %-25s\t%d\n", "heap_idle_bytes", ms.HeapIdleBytes)
+	fmt.Fprintf(w, "  %-25s\t%d\n", "heap_in_use_bytes", ms.HeapInUseBytes)
+	fmt.Fprintf(w, "  %-25s\t%d\n", "heap_released_bytes", ms.HeapReleasedBytes)
+	fmt.Fprintf(w, "  %-25s\t%d\n", "gc_pause_usec_100", ms.GCPauseUsec100)
+	fmt.Fprintf(w, "  %-25s\t%d\n", "gc_pause_usec_99", ms.GCPauseUsec99)
+	fmt.Fprintf(w, "  %-25s\t%d\n", "gc_pause_usec_95", ms.GCPauseUsec95)
+	fmt.Fprintf(w, "  %-25s\t%d\n", "next_gc_bytes", ms.NextGCBytes)
+	fmt.Fprintf(w, "  %-25s\t%d\n", "gc_total_runs", ms.GCTotalRuns)
+
 	io.WriteString(w, fmt.Sprintf("\nHealth: %s\n", health))
 	for _, t := range stats {
 		var pausedPrefix string

nsqd/stats.go

@@ -1,6 +1,7 @@
 package nsqd
 
 import (
+	"runtime"
 	"sort"
 	"sync/atomic"
 
@@ -143,3 +144,42 @@ func (n *NSQD) GetStats() []TopicStats {
 	}
 	return topics
 }
+
+type memStats struct {
+	HeapObjects       uint64 `json:"heap_objects"`
+	HeapIdleBytes     uint64 `json:"heap_idle_bytes"`
+	HeapInUseBytes    uint64 `json:"heap_in_use_bytes"`
+	HeapReleasedBytes uint64 `json:"heap_released_bytes"`
+	GCPauseUsec100    uint64 `json:"gc_pause_usec_100"`
+	GCPauseUsec99     uint64 `json:"gc_pause_usec_99"`
+	GCPauseUsec95     uint64 `json:"gc_pause_usec_95"`
+	NextGCBytes       uint64 `json:"next_gc_bytes"`
+	GCTotalRuns       uint32 `json:"gc_total_runs"`
+}
+
+func getMemStats() *memStats {
+	var ms runtime.MemStats
+	runtime.ReadMemStats(&ms)
+
+	// sort the GC pause array
+	length := len(ms.PauseNs)
+	if int(ms.NumGC) < length {
+		length = int(ms.NumGC)
+	}
+	gcPauses := make(Uint64Slice, length)
+	copy(gcPauses, ms.PauseNs[:length])
+	sort.Sort(gcPauses)
+
+	return &memStats{
+		ms.HeapObjects,
+		ms.HeapIdle,
+		ms.HeapInuse,
+		ms.HeapReleased,
+		percentile(100.0, gcPauses, len(gcPauses)) / 1000,
+		percentile(99.0, gcPauses, len(gcPauses)) / 1000,
+		percentile(95.0, gcPauses, len(gcPauses)) / 1000,
+		ms.NextGC,
+		ms.NumGC,
+	}
+
+}