Add proper SingleConnPool implementation

Author: vmihailenco

cluster.go

@@ -787,15 +787,15 @@ func (c *ClusterClient) process(ctx context.Context, cmd Cmder) error {
 		}
 
 		// If slave is loading - pick another node.
-		if c.opt.ReadOnly && internal.IsLoadingError(err) {
+		if c.opt.ReadOnly && isLoadingError(err) {
 			node.MarkAsFailing()
 			node = nil
 			continue
 		}
 
 		var moved bool
 		var addr string
-		moved, ask, addr = internal.IsMovedError(err)
+		moved, ask, addr = isMovedError(err)
 		if moved || ask {
 			node, err = c.nodes.Get(addr)
 			if err != nil {
@@ -804,12 +804,12 @@ func (c *ClusterClient) process(ctx context.Context, cmd Cmder) error {
 			continue
 		}
 
-		if err == pool.ErrClosed || internal.IsReadOnlyError(err) {
+		if err == pool.ErrClosed || isReadOnlyError(err) {
 			node = nil
 			continue
 		}
 
-		if internal.IsRetryableError(err, true) {
+		if isRetryableError(err, true) {
 			// First retry the same node.
 			if attempt == 0 {
 				continue
@@ -1173,9 +1173,9 @@ func (c *ClusterClient) pipelineReadCmds(
 			continue
 		}
 
-		if c.opt.ReadOnly && internal.IsLoadingError(err) {
+		if c.opt.ReadOnly && isLoadingError(err) {
 			node.MarkAsFailing()
-		} else if internal.IsRedisError(err) {
+		} else if isRedisError(err) {
 			continue
 		}
 
@@ -1192,7 +1192,7 @@ func (c *ClusterClient) pipelineReadCmds(
 func (c *ClusterClient) checkMovedErr(
 	cmd Cmder, err error, failedCmds *cmdsMap,
 ) bool {
-	moved, ask, addr := internal.IsMovedError(err)
+	moved, ask, addr := isMovedError(err)
 
 	if moved {
 		c.state.LazyReload()
@@ -1346,7 +1346,7 @@ func (c *ClusterClient) txPipelineReadQueued(
 			continue
 		}
 
-		if c.checkMovedErr(cmd, err, failedCmds) || internal.IsRedisError(err) {
+		if c.checkMovedErr(cmd, err, failedCmds) || isRedisError(err) {
 			continue
 		}
 
@@ -1418,7 +1418,7 @@ func (c *ClusterClient) WatchContext(ctx context.Context, fn func(*Tx) error, ke
 			c.state.LazyReload()
 		}
 
-		moved, ask, addr := internal.IsMovedError(err)
+		moved, ask, addr := isMovedError(err)
 		if moved || ask {
 			node, err = c.nodes.Get(addr)
 			if err != nil {
@@ -1427,15 +1427,15 @@ func (c *ClusterClient) WatchContext(ctx context.Context, fn func(*Tx) error, ke
 			continue
 		}
 
-		if err == pool.ErrClosed || internal.IsReadOnlyError(err) {
+		if err == pool.ErrClosed || isReadOnlyError(err) {
 			node, err = c.slotMasterNode(slot)
 			if err != nil {
 				return err
 			}
 			continue
 		}
 
-		if internal.IsRetryableError(err, true) {
+		if isRetryableError(err, true) {
 			continue
 		}
 

internal/error.go renamed to error.go

@@ -1,20 +1,18 @@
-package internal
+package redis
 
 import (
 	"context"
-	"errors"
 	"io"
 	"net"
 	"strings"
 
+	"github.com/go-redis/redis/internal/pool"
 	"github.com/go-redis/redis/internal/proto"
 )
 
-var ErrSingleConnPoolClosed = errors.New("redis: SingleConnPool is closed")
-
-func IsRetryableError(err error, retryTimeout bool) bool {
+func isRetryableError(err error, retryTimeout bool) bool {
 	switch err {
-	case nil, context.Canceled, context.DeadlineExceeded:
+	case nil, context.Canceled, context.DeadlineExceeded, pool.ErrBadConn:
 		return false
 	case io.EOF:
 		return true
@@ -25,9 +23,6 @@ func IsRetryableError(err error, retryTimeout bool) bool {
 		}
 		return true
 	}
-	if err == ErrSingleConnPoolClosed {
-		return true
-	}
 
 	s := err.Error()
 	if s == "ERR max number of clients reached" {
@@ -45,18 +40,20 @@ func IsRetryableError(err error, retryTimeout bool) bool {
 	return false
 }
 
-func IsRedisError(err error) bool {
+func isRedisError(err error) bool {
 	_, ok := err.(proto.RedisError)
 	return ok
 }
 
-func IsBadConn(err error, allowTimeout bool) bool {
-	if err == nil {
+func isBadConn(err error, allowTimeout bool) bool {
+	switch err {
+	case nil:
 		return false
+	case pool.ErrBadConn:
+		return true
 	}
-	if IsRedisError(err) {
-		// #790
-		return IsReadOnlyError(err)
+	if isRedisError(err) {
+		return isReadOnlyError(err) // #790
 	}
 	if allowTimeout {
 		if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
@@ -66,8 +63,8 @@ func IsBadConn(err error, allowTimeout bool) bool {
 	return true
 }
 
-func IsMovedError(err error) (moved bool, ask bool, addr string) {
-	if !IsRedisError(err) {
+func isMovedError(err error) (moved bool, ask bool, addr string) {
+	if !isRedisError(err) {
 		return
 	}
 
@@ -89,10 +86,10 @@ func IsMovedError(err error) (moved bool, ask bool, addr string) {
 	return
 }
 
-func IsLoadingError(err error) bool {
+func isLoadingError(err error) bool {
 	return strings.HasPrefix(err.Error(), "LOADING ")
 }
 
-func IsReadOnlyError(err error) bool {
+func isReadOnlyError(err error) bool {
 	return strings.HasPrefix(err.Error(), "READONLY ")
 }

example_test.go

@@ -151,6 +151,27 @@ func ExampleClient() {
 	// missing_key does not exist
 }
 
+func ExampleConn() {
+	conn := redisdb.Conn()
+
+	err := conn.ClientSetName("foobar").Err()
+	if err != nil {
+		panic(err)
+	}
+
+	// Open other connections.
+	for i := 0; i < 10; i++ {
+		go redisdb.Ping()
+	}
+
+	s, err := conn.ClientGetName().Result()
+	if err != nil {
+		panic(err)
+	}
+	fmt.Println(s)
+	// Output: foobar
+}
+
 func ExampleClient_Set() {
 	// Last argument is expiration. Zero means the key has no
 	// expiration time.