From 6aff955f073ecffe34524c957876cce8951c1a44 Mon Sep 17 00:00:00 2001
From: Valentin Vesvalo <vesvalo@mail.ru>
Date: Mon, 28 Jan 2019 17:47:32 +0300
Subject: [PATCH] add histogram metric type and more common metrics naming

---
 prometheus.go      | 21 ++++++++++++++++-----
 prometheus_test.go | 26 +++++++++++++++++++++++++-
 2 files changed, 41 insertions(+), 6 deletions(-)

diff --git a/prometheus.go b/prometheus.go
index d63427e..e3550b1 100644
--- a/prometheus.go
+++ b/prometheus.go
@@ -42,17 +42,27 @@ func NewHandlerWrapper(opts ...server.Option) server.HandlerWrapper {
 		[]string{"method", "status"},
 	)
 
-	timeCounter := prometheus.NewSummaryVec(
+	timeCounterSummary := prometheus.NewSummaryVec(
 		prometheus.SummaryOpts{
-			Name:        fmt.Sprintf("%s_request_duration_microseconds", defaultMetricPrefix),
-			Help:        "Service method request latencies in microseconds",
+			Name:        fmt.Sprintf("%s_upstream_latency_microseconds", defaultMetricPrefix),
+			Help:        "Service backend method request latencies in microseconds",
+			ConstLabels: md,
+		},
+		[]string{"method"},
+	)
+
+	timeCounterHistogram := prometheus.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Name:        fmt.Sprintf("%s_request_duration_seconds", defaultMetricPrefix),
+			Help:        "Service method request time in seconds",
 			ConstLabels: md,
 		},
 		[]string{"method"},
 	)
 
 	prometheus.MustRegister(opsCounter)
-	prometheus.MustRegister(timeCounter)
+	prometheus.MustRegister(timeCounterSummary)
+	prometheus.MustRegister(timeCounterHistogram)
 
 	return func(fn server.HandlerFunc) server.HandlerFunc {
 		return func(ctx context.Context, req server.Request, rsp interface{}) error {
@@ -60,7 +70,8 @@ func NewHandlerWrapper(opts ...server.Option) server.HandlerWrapper {
 
 			timer := prometheus.NewTimer(prometheus.ObserverFunc(func(v float64) {
 				us := v * 1000000 // make microseconds
-				timeCounter.WithLabelValues(name).Observe(us)
+				timeCounterSummary.WithLabelValues(name).Observe(us)
+				timeCounterHistogram.WithLabelValues(name).Observe(v)
 			}))
 			defer timer.ObserveDuration()
 
diff --git a/prometheus_test.go b/prometheus_test.go
index 4b8ab44..9fffe86 100644
--- a/prometheus_test.go
+++ b/prometheus_test.go
@@ -85,7 +85,7 @@ func TestPrometheusMetrics(t *testing.T) {
 
 	list, _ := prometheus.DefaultGatherer.Gather()
 
-	metric := findMetricByName(list, dto.MetricType_SUMMARY, "micro_request_duration_microseconds")
+	metric := findMetricByName(list, dto.MetricType_SUMMARY, "micro_upstream_latency_microseconds")
 
 	for _, v := range metric.Metric[0].Label {
 		switch *v.Name {
@@ -109,6 +109,30 @@ func TestPrometheusMetrics(t *testing.T) {
 	assert.Equal(t, uint64(2), *metric.Metric[0].Summary.SampleCount)
 	assert.True(t, *metric.Metric[0].Summary.SampleSum > 0)
 
+	metric = findMetricByName(list, dto.MetricType_HISTOGRAM, "micro_request_duration_seconds")
+
+	for _, v := range metric.Metric[0].Label {
+		switch *v.Name {
+		case "micro_dc":
+			assert.Equal(t, "dc1", *v.Value)
+		case "micro_node":
+			assert.Equal(t, "node1", *v.Value)
+		case "micro_version":
+			assert.Equal(t, version, *v.Value)
+		case "micro_id":
+			assert.Equal(t, id, *v.Value)
+		case "micro_name":
+			assert.Equal(t, name, *v.Value)
+		case "method":
+			assert.Equal(t, "Test.Method", *v.Value)
+		default:
+			t.Fatalf("unknown %v with %v", *v.Name, *v.Value)
+		}
+	}
+
+	assert.Equal(t, uint64(2), *metric.Metric[0].Histogram.SampleCount)
+	assert.True(t, *metric.Metric[0].Histogram.SampleSum > 0)
+
 	metric = findMetricByName(list, dto.MetricType_COUNTER, "micro_request_total")
 
 	for _, v := range metric.Metric[0].Label {