Fix pool panic on slow connection with MaxRetries > 0.

Author: vmihailenco

conn.go

@@ -43,11 +43,8 @@ func (cn *conn) init(opt *Options) error {
 		return nil
 	}
 
-	// Use connection to connect to Redis.
-	pool := newSingleConnPoolConn(cn)
-
-	// Client is not closed because we want to reuse underlying connection.
-	client := newClient(opt, pool)
+	// Temp client for Auth and Select.
+	client := newClient(opt, newSingleConnPool(cn))
 
 	if opt.Password != "" {
 		if err := client.Auth(opt.Password).Err(); err != nil {

conn_test.go

@@ -0,0 +1,25 @@
+package redis_test
+
+import (
+	"net"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+
+	"gopkg.in/redis.v3"
+)
+
+var _ = Describe("newConnDialer with bad connection", func() {
+	It("should return an error", func() {
+		dialer := redis.NewConnDialer(&redis.Options{
+			Dialer: func() (net.Conn, error) {
+				return &badConn{}, nil
+			},
+			MaxRetries: 3,
+			Password:   "password",
+			DB:         1,
+		})
+		_, err := dialer()
+		Expect(err).To(MatchError("bad connection"))
+	})
+})

export_test.go

@@ -6,6 +6,8 @@ func (c *baseClient) Pool() pool {
 	return c.connPool
 }
 
+var NewConnDialer = newConnDialer
+
 func (cn *conn) SetNetConn(netcn net.Conn) {
 	cn.netcn = netcn
 }

main_test.go

@@ -232,7 +232,15 @@ func startSentinel(port, masterName, masterPort string) (*redisProcess, error) {
 
 //------------------------------------------------------------------------------
 
-var errTimeout = syscall.ETIMEDOUT
+var (
+	errTimeout = syscall.ETIMEDOUT
+)
+
+type badConnError string
+
+func (e badConnError) Error() string   { return string(e) }
+func (e badConnError) Timeout() bool   { return false }
+func (e badConnError) Temporary() bool { return false }
 
 type badConn struct {
 	net.TCPConn
@@ -250,7 +258,7 @@ func (cn *badConn) Read([]byte) (int, error) {
 	if cn.readErr != nil {
 		return 0, cn.readErr
 	}
-	return 0, net.UnknownNetworkError("badConn")
+	return 0, badConnError("bad connection")
 }
 
 func (cn *badConn) Write([]byte) (int, error) {
@@ -260,5 +268,5 @@ func (cn *badConn) Write([]byte) (int, error) {
 	if cn.writeErr != nil {
 		return 0, cn.writeErr
 	}
-	return 0, net.UnknownNetworkError("badConn")
+	return 0, badConnError("bad connection")
 }

multi.go

@@ -22,7 +22,7 @@ func (c *Client) Multi() *Multi {
 	multi := &Multi{
 		base: &baseClient{
 			opt:      c.opt,
-			connPool: newSingleConnPool(c.connPool, true),
+			connPool: newStickyConnPool(c.connPool, true),
 		},
 	}
 	multi.commandable.process = multi.process

pool.go

@@ -314,6 +314,52 @@ func (p *connPool) reaper() {
 //------------------------------------------------------------------------------
 
 type singleConnPool struct {
+	cn *conn
+}
+
+func newSingleConnPool(cn *conn) *singleConnPool {
+	return &singleConnPool{
+		cn: cn,
+	}
+}
+
+func (p *singleConnPool) First() *conn {
+	return p.cn
+}
+
+func (p *singleConnPool) Get() (*conn, error) {
+	return p.cn, nil
+}
+
+func (p *singleConnPool) Put(cn *conn) error {
+	if p.cn != cn {
+		panic("p.cn != cn")
+	}
+	return nil
+}
+
+func (p *singleConnPool) Remove(cn *conn) error {
+	if p.cn != cn {
+		panic("p.cn != cn")
+	}
+	return nil
+}
+
+func (p *singleConnPool) Len() int {
+	return 1
+}
+
+func (p *singleConnPool) FreeLen() int {
+	return 0
+}
+
+func (p *singleConnPool) Close() error {
+	return nil
+}
+
+//------------------------------------------------------------------------------
+
+type stickyConnPool struct {
 	pool     pool
 	reusable bool
 
@@ -322,27 +368,21 @@ type singleConnPool struct {
 	mx     sync.Mutex
 }
 
-func newSingleConnPool(pool pool, reusable bool) *singleConnPool {
-	return &singleConnPool{
+func newStickyConnPool(pool pool, reusable bool) *stickyConnPool {
+	return &stickyConnPool{
 		pool:     pool,
 		reusable: reusable,
 	}
 }
 
-func newSingleConnPoolConn(cn *conn) *singleConnPool {
-	return &singleConnPool{
-		cn: cn,
-	}
-}
-
-func (p *singleConnPool) First() *conn {
+func (p *stickyConnPool) First() *conn {
 	p.mx.Lock()
 	cn := p.cn
 	p.mx.Unlock()
 	return cn
 }
 
-func (p *singleConnPool) Get() (*conn, error) {
+func (p *stickyConnPool) Get() (*conn, error) {
 	defer p.mx.Unlock()
 	p.mx.Lock()
 
@@ -362,15 +402,13 @@ func (p *singleConnPool) Get() (*conn, error) {
 	return p.cn, nil
 }
 
-func (p *singleConnPool) put() (err error) {
-	if p.pool != nil {
-		err = p.pool.Put(p.cn)
-	}
+func (p *stickyConnPool) put() (err error) {
+	err = p.pool.Put(p.cn)
 	p.cn = nil
 	return err
 }
 
-func (p *singleConnPool) Put(cn *conn) error {
+func (p *stickyConnPool) Put(cn *conn) error {
 	defer p.mx.Unlock()
 	p.mx.Lock()
 	if p.cn != cn {
@@ -382,30 +420,32 @@ func (p *singleConnPool) Put(cn *conn) error {
 	return nil
 }
 
-func (p *singleConnPool) remove() (err error) {
-	if p.pool != nil {
-		err = p.pool.Remove(p.cn)
-	}
+func (p *stickyConnPool) remove() (err error) {
+	err = p.pool.Remove(p.cn)
 	p.cn = nil
 	return err
 }
 
-func (p *singleConnPool) Remove(cn *conn) error {
+func (p *stickyConnPool) Remove(cn *conn) error {
 	defer p.mx.Unlock()
 	p.mx.Lock()
 	if p.cn == nil {
 		panic("p.cn == nil")
 	}
-	if cn != nil && cn != p.cn {
-		panic("cn != p.cn")
+	if cn != nil && p.cn != cn {
+		panic("p.cn != cn")
 	}
 	if p.closed {
 		return errClosed
 	}
-	return p.remove()
+	if cn == nil {
+		return p.remove()
+	} else {
+		return nil
+	}
 }
 
-func (p *singleConnPool) Len() int {
+func (p *stickyConnPool) Len() int {
 	defer p.mx.Unlock()
 	p.mx.Lock()
 	if p.cn == nil {
@@ -414,7 +454,7 @@ func (p *singleConnPool) Len() int {
 	return 1
 }
 
-func (p *singleConnPool) FreeLen() int {
+func (p *stickyConnPool) FreeLen() int {
 	defer p.mx.Unlock()
 	p.mx.Lock()
 	if p.cn == nil {
@@ -423,7 +463,7 @@ func (p *singleConnPool) FreeLen() int {
 	return 0
 }
 
-func (p *singleConnPool) Close() error {
+func (p *stickyConnPool) Close() error {
 	defer p.mx.Unlock()
 	p.mx.Lock()
 	if p.closed {

pool_test.go

@@ -11,7 +11,7 @@ import (
 	"gopkg.in/redis.v3"
 )
 
-var _ = Describe("Pool", func() {
+var _ = Describe("pool", func() {
 	var client *redis.Client
 
 	var perform = func(n int, cb func()) {

pubsub.go

@@ -29,7 +29,7 @@ func (c *Client) PubSub() *PubSub {
 	return &PubSub{
 		baseClient: &baseClient{
 			opt:      c.opt,
-			connPool: newSingleConnPool(c.connPool, false),
+			connPool: newStickyConnPool(c.connPool, false),
 		},
 	}
 }

redis_test.go

@@ -161,7 +161,8 @@ var _ = Describe("Client", func() {
 		Expect(err).NotTo(HaveOccurred())
 
 		cn.SetNetConn(&badConn{})
-		Expect(client.Pool().Put(cn)).NotTo(HaveOccurred())
+		err = client.Pool().Put(cn)
+		Expect(err).NotTo(HaveOccurred())
 
 		err = client.Ping().Err()
 		Expect(err).NotTo(HaveOccurred())

sentinel.go

@@ -90,7 +90,7 @@ func (c *sentinelClient) PubSub() *PubSub {
 	return &PubSub{
 		baseClient: &baseClient{
 			opt:      c.opt,
-			connPool: newSingleConnPool(c.connPool, false),
+			connPool: newStickyConnPool(c.connPool, false),
 		},
 	}
 }