refactor: replace semaphore with trylock

chainflag · Oct 16, 2021 · ec79304 · ec79304
1 parent cbc9a0a
commit ec79304
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Showing 3 changed files with 11 additions and 10 deletions.
diff --git a/go.mod b/go.mod
@@ -4,10 +4,10 @@ module github.com/chainflag/eth-faucet
 go 1.16
 
 require (
+	github.com/LK4D4/trylock v0.0.0-20191027065348-ff7e133a5c54
 	github.com/ReneKroon/ttlcache/v2 v2.8.1
 	github.com/agiledragon/gomonkey/v2 v2.2.0
 	github.com/ethereum/go-ethereum v1.10.9
 	github.com/sirupsen/logrus v1.8.1
 	github.com/urfave/negroni v1.0.0
-	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
 )
diff --git a/go.sum b/go.sum
@@ -34,6 +34,8 @@ github.com/Azure/go-autorest/tracing v0.5.0/go.mod h1:r/s2XiOKccPW3HrqB+W0TQzfbt
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
 github.com/DATA-DOG/go-sqlmock v1.3.3/go.mod h1:f/Ixk793poVmq4qj/V1dPUg2JEAKC73Q5eFN3EC/SaM=
+github.com/LK4D4/trylock v0.0.0-20191027065348-ff7e133a5c54 h1:sg9CWNOhr58hMGmJ0q7x7jQ/B1RK/GyHNmeaYCJos9M=
+github.com/LK4D4/trylock v0.0.0-20191027065348-ff7e133a5c54/go.mod h1:uHbOgfPowb74TKlV4AR5Az2haG6evxzM8Lmj1Xil25E=
 github.com/OneOfOne/xxhash v1.2.2/go.mod h1:HSdplMjZKSmBqAxg5vPj2TmRDmfkzw+cTzAElWljhcU=
 github.com/ReneKroon/ttlcache/v2 v2.8.1 h1:0Exdyt5+vEsdRoFO1T7qDIYM3gq/ETbeYV+vjgcPxZk=
 github.com/ReneKroon/ttlcache/v2 v2.8.1/go.mod h1:mBxvsNY+BT8qLLd6CuAJubbKo6r0jh3nb5et22bbfGY=

diff --git a/internal/server/server.go b/internal/server/server.go
@@ -8,9 +8,9 @@ import (
 	"strconv"
 	"time"
 
+	"github.com/LK4D4/trylock"
 	log "github.com/sirupsen/logrus"
 	"github.com/urfave/negroni"
-	"golang.org/x/sync/semaphore"
 
 	"github.com/chainflag/eth-faucet/internal/chain"
 	"github.com/chainflag/eth-faucet/web"
@@ -20,17 +20,16 @@ const AddressKey string = "address"
 
 type Server struct {
 	chain.TxBuilder
+	mutex trylock.Mutex
 	cfg   *Config
 	queue chan string
-	sem   *semaphore.Weighted
 }
 
 func NewServer(builder chain.TxBuilder, cfg *Config) *Server {
 	return &Server{
 		TxBuilder: builder,
 		cfg:       cfg,
 		queue:     make(chan string, cfg.queueCap),
-		sem:       semaphore.NewWeighted(1),
 	}
 }
 
@@ -63,8 +62,8 @@ func (s *Server) consumeQueue() {
 		return
 	}
 
-	s.sem.Acquire(context.Background(), 1)
-	defer s.sem.Release(1)
+	s.mutex.Lock()
+	defer s.mutex.Unlock()
 	for len(s.queue) != 0 {
 		address := <-s.queue
 		txHash, err := s.Transfer(context.Background(), address, s.cfg.payout)
@@ -87,8 +86,8 @@ func (s *Server) handleClaim() http.HandlerFunc {
 		}
 
 		address := r.PostFormValue(AddressKey)
-		// The semaphore can be acquired only if the work queue is empty
-		if len(s.queue) != 0 || !s.sem.TryAcquire(1) {
+		// Try to lock mutex if the work queue is empty
+		if len(s.queue) != 0 || !s.mutex.TryLock() {
 			select {
 			case s.queue <- address:
 				log.WithFields(log.Fields{
@@ -103,10 +102,10 @@ func (s *Server) handleClaim() http.HandlerFunc {
 			return
 		}
 
-		ctx, cancel := context.WithTimeout(r.Context(), 3*time.Second)
+		ctx, cancel := context.WithTimeout(r.Context(), 5*time.Second)
 		defer cancel()
 		txHash, err := s.Transfer(ctx, address, s.cfg.payout)
-		s.sem.Release(1)
+		s.mutex.Unlock()
 		if err != nil {
 			log.WithError(err).Error("Failed to send transaction")
 			http.Error(w, err.Error(), http.StatusInternalServerError)