bugfix: panic case by concurrent write map

example/web.go

@@ -2,9 +2,10 @@ package main
 
 import (
 	"errors"
-	"github.com/gin-gonic/gin"
-	limiter "github.com/julianshen/gin-limiter"
 	"time"
+
+	"github.com/gin-gonic/gin"
+	limiter "github.com/sinuxlee/gin-limiter"
 )
 
 func main() {

go.mod

@@ -0,0 +1,10 @@
+module ginlimiter
+
+go 1.14
+
+require (
+	github.com/gin-gonic/gin v1.7.4
+	github.com/juju/ratelimit v1.0.1
+	github.com/julianshen/gin-limiter v0.0.0-20161123033831-fc39b5e90fe7
+	github.com/sinuxlee/gin-limiter v0.0.0-20161123033831-fc39b5e90fe7
+)

go.sum

@@ -0,0 +1,52 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/gin-contrib/sse v0.1.0 h1:Y/yl/+YNO8GZSjAhjMsSuLt29uWRFHdHYUb5lYOV9qE=
+github.com/gin-contrib/sse v0.1.0/go.mod h1:RHrZQHXnP2xjPF+u1gW/2HnVO7nvIa9PG3Gm+fLHvGI=
+github.com/gin-gonic/gin v1.7.4 h1:QmUZXrvJ9qZ3GfWvQ+2wnW/1ePrTEJqPKMYEU3lD/DM=
+github.com/gin-gonic/gin v1.7.4/go.mod h1:jD2toBW3GZUr5UMcdrwQA10I7RuaFOl/SGeDjXkfUtY=
+github.com/go-playground/assert/v2 v2.0.1/go.mod h1:VDjEfimB/XKnb+ZQfWdccd7VUvScMdVu0Titje2rxJ4=
+github.com/go-playground/locales v0.13.0 h1:HyWk6mgj5qFqCT5fjGBuRArbVDfE4hi8+e8ceBS/t7Q=
+github.com/go-playground/locales v0.13.0/go.mod h1:taPMhCMXrRLJO55olJkUXHZBHCxTMfnGwq/HNwmWNS8=
+github.com/go-playground/universal-translator v0.17.0 h1:icxd5fm+REJzpZx7ZfpaD876Lmtgy7VtROAbHHXk8no=
+github.com/go-playground/universal-translator v0.17.0/go.mod h1:UkSxE5sNxxRwHyU+Scu5vgOQjsIJAF8j9muTVoKLVtA=
+github.com/go-playground/validator/v10 v10.4.1 h1:pH2c5ADXtd66mxoE0Zm9SUhxE20r7aM3F26W0hOn+GE=
+github.com/go-playground/validator/v10 v10.4.1/go.mod h1:nlOn6nFhuKACm19sB/8EGNn9GlaMV7XkbRSipzJ0Ii4=
+github.com/golang/protobuf v1.3.3 h1:gyjaxf+svBWX08ZjK86iN9geUJF0H6gp2IRKX6Nf6/I=
+github.com/golang/protobuf v1.3.3/go.mod h1:vzj43D7+SQXF/4pzW/hwtAqwc6iTitCiVSaWz5lYuqw=
+github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
+github.com/json-iterator/go v1.1.9/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
+github.com/juju/ratelimit v1.0.1 h1:+7AIFJVQ0EQgq/K9+0Krm7m530Du7tIz0METWzN0RgY=
+github.com/juju/ratelimit v1.0.1/go.mod h1:qapgC/Gy+xNh9UxzV13HGGl/6UXNN+ct+vwSgWNm/qk=
+github.com/julianshen/gin-limiter v0.0.0-20161123033831-fc39b5e90fe7 h1:hlGKdRwZ0XLX3Sattpx6nqkvI0XFpIpvH7JK1u6ODbs=
+github.com/julianshen/gin-limiter v0.0.0-20161123033831-fc39b5e90fe7/go.mod h1:rmrkiYPm2yvC0bT9+XTQO9jN1af7kUcdMSGXHLYfptk=
+github.com/leodido/go-urn v1.2.0 h1:hpXL4XnriNwQ/ABnpepYM/1vCLWNDfUNts8dX3xTG6Y=
+github.com/leodido/go-urn v1.2.0/go.mod h1:+8+nEpDfqqsY+g338gtMEUOtuK+4dEMhiQEgxpxOKII=
+github.com/mattn/go-isatty v0.0.12 h1:wuysRhFDzyxgEmMf5xjvJ2M9dZoWAXNNr5LSBS7uHXY=
+github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
+github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
+github.com/modern-go/reflect2 v0.0.0-20180701023420-4b7aa43c6742/go.mod h1:bx2lNnkwVCuqBIxFjflWJWanXIb3RllmbCylyMrvgv0=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/sinuxlee/gin-limiter v0.0.0-20161123033831-fc39b5e90fe7 h1:A+9wLkHkmbbv9M/M8ReHewvr5HSSRRJ34RznBcbmzrw=
+github.com/sinuxlee/gin-limiter v0.0.0-20161123033831-fc39b5e90fe7/go.mod h1:SKnCZ7y8dTDByHRCimQN3qWAI3YPav9kjaC8Djbvveg=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
+github.com/ugorji/go v1.1.7 h1:/68gy2h+1mWMrwZFeD1kQialdSzAb432dtpeJ42ovdo=
+github.com/ugorji/go v1.1.7/go.mod h1:kZn38zHttfInRq0xu/PH0az30d+z6vm202qpg1oXVMw=
+github.com/ugorji/go/codec v1.1.7 h1:2SvQaVZ1ouYrrKKwoSk2pzd4A9evlKJb9oTL+OaLUSs=
+github.com/ugorji/go/codec v1.1.7/go.mod h1:Ax+UKWsSmolVDwsd+7N3ZtXu+yMGCf907BLYF3GoBXY=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9 h1:psW17arqaxU48Z5kZ0CQnkZWQJsqcURM6tKiBApRjXI=
+golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200116001909-b77594299b42 h1:vEOn+mP2zCOVzKckCZy6YsCtDblrpj/w7B9nxGNELpg=
+golang.org/x/sys v0.0.0-20200116001909-b77594299b42/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.8 h1:obN1ZagJSUGI0Ek/LBmuj4SNLPfIny3KsKFopxRdj10=
+gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

limiter.go

@@ -2,10 +2,12 @@ package ginlimiter
 
 import (
 	"errors"
+	"fmt"
+	"sync"
+	"time"
+
 	"github.com/gin-gonic/gin"
 	"github.com/juju/ratelimit"
-	"time"
-	"fmt"
 )
 
 type RateKeyFunc func(ctx *gin.Context) (string, error)
@@ -14,7 +16,7 @@ type RateLimiterMiddleware struct {
 	fillInterval time.Duration
 	capacity     int64
 	ratekeygen   RateKeyFunc
-	limiters     map[string]*ratelimit.Bucket
+	limiters     sync.Map // [string]*ratelimit.Bucket
 }
 
 func (r *RateLimiterMiddleware) get(ctx *gin.Context) (*ratelimit.Bucket, error) {
@@ -24,12 +26,12 @@ func (r *RateLimiterMiddleware) get(ctx *gin.Context) (*ratelimit.Bucket, error)
 		return nil, err
 	}
 
-	if limiter, existed := r.limiters[key]; existed {
-		return limiter, nil
+	if limiter, existed := r.limiters.Load(key); existed {
+		return limiter.(*ratelimit.Bucket), nil
 	}
 
 	limiter := ratelimit.NewBucketWithQuantum(r.fillInterval, r.capacity, r.capacity)
-	r.limiters[key] = limiter
+	r.limiters.Store(key, limiter)
 	return limiter, nil
 }
 
@@ -38,7 +40,7 @@ func (r *RateLimiterMiddleware) Middleware() gin.HandlerFunc {
 		limiter, err := r.get(ctx)
 		if err != nil || limiter.TakeAvailable(1) == 0 {
 			if err == nil {
-				err = errors.New("Too many requests")
+				err = errors.New("too many requests")
 			}
 			ctx.AbortWithError(429, err)
 		} else {
@@ -50,11 +52,9 @@ func (r *RateLimiterMiddleware) Middleware() gin.HandlerFunc {
 }
 
 func NewRateLimiter(interval time.Duration, capacity int64, keyGen RateKeyFunc) *RateLimiterMiddleware {
-	limiters := make(map[string]*ratelimit.Bucket)
 	return &RateLimiterMiddleware{
-		interval,
-		capacity,
-		keyGen,
-		limiters,
+		fillInterval: interval,
+		capacity:     capacity,
+		ratekeygen:   keyGen,
 	}
 }

limiter_test.go

@@ -0,0 +1,21 @@
+package ginlimiter
+
+import (
+	"net/http"
+	"testing"
+	"time"
+
+	"github.com/gin-gonic/gin"
+)
+
+func TestRateLimiter(t *testing.T) {
+	r := gin.Default()
+	r.Use(NewRateLimiter(time.Second, 5000, func(ctx *gin.Context) (string, error) {
+		return "", nil
+	}).Middleware())
+
+	r.GET("/", func(ctx *gin.Context) {
+		ctx.String(http.StatusOK, "OK")
+	})
+	r.Run(":8086")
+}