From 279123f4a7ceb427b280e55fb8c707d2f2c9d114 Mon Sep 17 00:00:00 2001
From: Shyunn <114235843+ShyunnY@users.noreply.github.com>
Date: Sat, 29 Jul 2023 16:51:43 +0800
Subject: [PATCH] feat: add prometheus summary metrics (#3440)

Co-authored-by: chen quan <chenquan.dev@gmail.com>
---
 core/metric/histogram_test.go |  3 --
 core/metric/summary.go        | 65 +++++++++++++++++++++++++++++++++
 core/metric/summary_test.go   | 68 +++++++++++++++++++++++++++++++++++
 core/proc/shutdown.go         |  2 ++
 4 files changed, 135 insertions(+), 3 deletions(-)
 create mode 100644 core/metric/summary.go
 create mode 100644 core/metric/summary_test.go

diff --git a/core/metric/histogram_test.go b/core/metric/histogram_test.go
index 4c2f8933..4874617b 100644
--- a/core/metric/histogram_test.go
+++ b/core/metric/histogram_test.go
@@ -6,7 +6,6 @@ import (
 
 	"github.com/prometheus/client_golang/prometheus/testutil"
 	"github.com/stretchr/testify/assert"
-	"github.com/zeromicro/go-zero/core/proc"
 )
 
 func TestNewHistogramVec(t *testing.T) {
@@ -48,6 +47,4 @@ func TestHistogramObserve(t *testing.T) {
 
 	err := testutil.CollectAndCompare(hv.histogram, strings.NewReader(metadata+val))
 	assert.Nil(t, err)
-
-	proc.Shutdown()
 }
diff --git a/core/metric/summary.go b/core/metric/summary.go
new file mode 100644
index 00000000..ecab0cbe
--- /dev/null
+++ b/core/metric/summary.go
@@ -0,0 +1,65 @@
+package metric
+
+import (
+	prom "github.com/prometheus/client_golang/prometheus"
+	"github.com/zeromicro/go-zero/core/proc"
+	"github.com/zeromicro/go-zero/core/prometheus"
+)
+
+type (
+	// A SummaryVecOpts is a summary vector options
+	SummaryVecOpts struct {
+		VecOpt     VectorOpts
+		Objectives map[float64]float64
+	}
+
+	// A SummaryVec interface represents a summary vector.
+	SummaryVec interface {
+		// Observe adds observation v to labels.
+		Observe(v float64, labels ...string)
+		close() bool
+	}
+
+	promSummaryVec struct {
+		summary *prom.SummaryVec
+	}
+)
+
+// NewSummaryVec return a SummaryVec
+func NewSummaryVec(cfg *SummaryVecOpts) SummaryVec {
+	if cfg == nil {
+		return nil
+	}
+
+	vec := prom.NewSummaryVec(
+		prom.SummaryOpts{
+			Namespace:  cfg.VecOpt.Namespace,
+			Subsystem:  cfg.VecOpt.Subsystem,
+			Name:       cfg.VecOpt.Name,
+			Help:       cfg.VecOpt.Help,
+			Objectives: cfg.Objectives,
+		},
+		cfg.VecOpt.Labels,
+	)
+	prom.MustRegister(vec)
+	sv := &promSummaryVec{
+		summary: vec,
+	}
+	proc.AddShutdownListener(func() {
+		sv.close()
+	})
+
+	return sv
+}
+
+func (sv *promSummaryVec) Observe(v float64, labels ...string) {
+	if !prometheus.Enabled() {
+		return
+	}
+
+	sv.summary.WithLabelValues(labels...).Observe(v)
+}
+
+func (sv *promSummaryVec) close() bool {
+	return prom.Unregister(sv.summary)
+}
diff --git a/core/metric/summary_test.go b/core/metric/summary_test.go
new file mode 100644
index 00000000..6a599d90
--- /dev/null
+++ b/core/metric/summary_test.go
@@ -0,0 +1,68 @@
+package metric
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/prometheus/client_golang/prometheus/testutil"
+	"github.com/stretchr/testify/assert"
+	"github.com/zeromicro/go-zero/core/proc"
+)
+
+func TestNewSummaryVec(t *testing.T) {
+	summaryVec := NewSummaryVec(&SummaryVecOpts{
+		VecOpt: VectorOpts{
+			Namespace: "http_server",
+			Subsystem: "requests",
+			Name:      "duration_quantiles",
+			Help:      "rpc client requests duration(ms) φ quantiles ",
+			Labels:    []string{"method"},
+		},
+		Objectives: map[float64]float64{
+			0.5: 0.01,
+			0.9: 0.01,
+		},
+	})
+	defer summaryVec.close()
+	summaryVecNil := NewSummaryVec(nil)
+	assert.NotNil(t, summaryVec)
+	assert.Nil(t, summaryVecNil)
+}
+
+func TestSummaryObserve(t *testing.T) {
+	startAgent()
+	summaryVec := NewSummaryVec(&SummaryVecOpts{
+		VecOpt: VectorOpts{
+			Namespace: "http_server",
+			Subsystem: "requests",
+			Name:      "duration_quantiles",
+			Help:      "rpc client requests duration(ms) φ quantiles ",
+			Labels:    []string{"method"},
+		},
+		Objectives: map[float64]float64{
+			0.3: 0.01,
+			0.6: 0.01,
+			1:   0.01,
+		},
+	})
+	defer summaryVec.close()
+	sv := summaryVec.(*promSummaryVec)
+	sv.Observe(100, "GET")
+	sv.Observe(200, "GET")
+	sv.Observe(300, "GET")
+	metadata := `
+		# HELP http_server_requests_duration_quantiles rpc client requests duration(ms) φ quantiles 
+		# TYPE http_server_requests_duration_quantiles summary
+`
+	val := `
+		http_server_requests_duration_quantiles{method="GET",quantile="0.3"} 100
+		http_server_requests_duration_quantiles{method="GET",quantile="0.6"} 200
+		http_server_requests_duration_quantiles{method="GET",quantile="1"} 300
+		http_server_requests_duration_quantiles_sum{method="GET"} 600
+		http_server_requests_duration_quantiles_count{method="GET"} 3
+`
+
+	err := testutil.CollectAndCompare(sv.summary, strings.NewReader(metadata+val))
+	assert.Nil(t, err)
+	proc.Shutdown()
+}
diff --git a/core/proc/shutdown.go b/core/proc/shutdown.go
index 6e4e0bd5..ece547d5 100644
--- a/core/proc/shutdown.go
+++ b/core/proc/shutdown.go
@@ -96,4 +96,6 @@ func (lm *listenerManager) notifyListeners() {
 		group.RunSafe(listener)
 	}
 	group.Wait()
+
+	lm.listeners = nil
 }