Add fixes against race conditions

.github/workflows/run-tests.yml

@@ -0,0 +1,20 @@
+name: Run tests
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - uses: actions/setup-go@v2
+        with:
+          go-version: '^1.14'
+      - name: Test
+        run: make test

Makefile

@@ -0,0 +1,2 @@
+test:
+	go test -v -race ./...

README.md

@@ -1,3 +1,5 @@
+[![Tests](https://github.com/penglongli/gin-metrics/actions/workflows/go.yml/badge.svg?branch=master)](https://github.com/penglongli/gin-metrics/actions/workflows/run-tests.yml)
+
 # gin-metrics
 gin-gonic/gin metrics exporter for Prometheus.
 

bloom/bloom.go

@@ -2,13 +2,15 @@ package bloom
 
 import (
 	"github.com/bits-and-blooms/bitset"
+	"sync"
 )
 
 const defaultSize = 2 << 24
 
 var seeds = []uint{7, 11, 13, 31, 37, 61}
 
 type BloomFilter struct {
+	mu    sync.Mutex
 	Set   *bitset.BitSet
 	Funcs [6]simpleHash
 }
@@ -23,12 +25,18 @@ func NewBloomFilter() *BloomFilter {
 }
 
 func (bf *BloomFilter) Add(value string) {
+	bf.mu.Lock()
+	defer bf.mu.Unlock()
+
 	for _, f := range bf.Funcs {
 		bf.Set.Set(f.hash(value))
 	}
 }
 
 func (bf *BloomFilter) Contains(value string) bool {
+	bf.mu.Lock()
+	defer bf.mu.Unlock()
+
 	if value == "" {
 		return false
 	}

ginmetrics/middleware_test.go

@@ -0,0 +1,109 @@
+package ginmetrics_test
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"sync"
+	"testing"
+
+	"github.com/gin-gonic/gin"
+
+	"github.com/penglongli/gin-metrics/ginmetrics"
+)
+
+func init() {
+	gin.SetMode(gin.ReleaseMode)
+}
+
+func TestMiddlewareSamePort(t *testing.T) {
+	r := newRouter()
+
+	ts := httptest.NewServer(r)
+	defer ts.Close()
+
+	var wg sync.WaitGroup
+	nLoops := 1000
+	wg.Add(nLoops)
+
+	for i := 0; i < nLoops; i++ {
+		go func(t *testing.T, i int) {
+			res, err := http.Get(ts.URL + fmt.Sprintf("/product/%d", i))
+			if err != nil {
+				t.Errorf("Expected nil, received %s", err.Error())
+			}
+
+			if res.StatusCode != http.StatusOK {
+				t.Errorf("Expected %d, received %d", http.StatusOK, res.StatusCode)
+			}
+			wg.Done()
+		}(t, i)
+	}
+
+	wg.Wait()
+}
+
+func TestMiddlewareDifferentPort(t *testing.T) {
+	appRouter, metricsRouter := newRouterSeparateMetrics()
+
+	ts := httptest.NewServer(appRouter)
+	tms := httptest.NewServer(metricsRouter)
+
+	defer ts.Close()
+	defer tms.Close()
+
+	var wg sync.WaitGroup
+	nLoops := 1000
+	wg.Add(nLoops)
+
+	for i := 0; i < nLoops; i++ {
+		go func(t *testing.T, i int) {
+			res, err := http.Get(ts.URL + fmt.Sprintf("/product/%d", i))
+			if err != nil {
+				t.Errorf("Expected nil, received %s", err.Error())
+			}
+
+			if res.StatusCode != http.StatusOK {
+				t.Errorf("Expected %d, received %d", http.StatusOK, res.StatusCode)
+			}
+			wg.Done()
+		}(t, i)
+	}
+
+	wg.Wait()
+}
+
+func newRouterSeparateMetrics() (*gin.Engine, *gin.Engine) {
+	appRouter := gin.New()
+	metricRouter := gin.Default()
+
+	m := ginmetrics.GetMonitor()
+	m.UseWithoutExposingEndpoint(appRouter)
+	m.Expose(metricRouter)
+
+	appRouter.GET("/product/:id", func(ctx *gin.Context) {
+		ctx.JSON(200, map[string]string{
+			"productId": ctx.Param("id"),
+		})
+	})
+
+	return appRouter, metricRouter
+}
+
+func newRouter() *gin.Engine {
+	r := gin.New()
+
+	m := ginmetrics.GetMonitor()
+	m.SetMetricPath("/metrics")
+	m.SetSlowTime(10)
+	m.SetDuration([]float64{0.1, 0.3, 1.2, 5, 10})
+	m.Use(r)
+
+	r.GET("/product/:id", func(ctx *gin.Context) {
+		ctx.JSON(200, map[string]string{
+			"productId": ctx.Param("id"),
+		})
+	})
+
+	return r
+}

ginmetrics/types.go

@@ -3,6 +3,8 @@ package ginmetrics
 import (
 	"github.com/pkg/errors"
 	"github.com/prometheus/client_golang/prometheus"
+
+	"sync"
 )
 
 type MetricType int
@@ -19,8 +21,10 @@ const (
 )
 
 var (
+	once    sync.Once
+	monitor *Monitor
+
 	defaultDuration = []float64{0.1, 0.3, 1.2, 5, 10}
-	monitor         *Monitor
 
 	promTypeHandler = map[MetricType]func(metric *Metric) error{
 		Counter:   counterHandler,
@@ -41,14 +45,15 @@ type Monitor struct {
 // GetMonitor used to get global Monitor object,
 // this function returns a singleton object.
 func GetMonitor() *Monitor {
-	if monitor == nil {
+	once.Do(func() {
 		monitor = &Monitor{
 			metricPath:  defaultMetricPath,
 			slowTime:    defaultSlowTime,
 			reqDuration: defaultDuration,
 			metrics:     make(map[string]*Metric),
 		}
-	}
+	})
+
 	return monitor
 }
 

ginmetrics/types_test.go

@@ -0,0 +1,20 @@
+package ginmetrics
+
+import (
+	"sync"
+	"testing"
+)
+
+func TestSingletonRacing(t *testing.T) {
+	var wg sync.WaitGroup
+	nLoops := 1000
+	wg.Add(nLoops)
+	for i := 0; i < nLoops; i++ {
+		go func() {
+			GetMonitor()
+			wg.Done()
+		}()
+	}
+
+	wg.Wait()
+}