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redis.go
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redis.go
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package redis
import (
"context"
"errors"
"fmt"
"net"
"sync/atomic"
"time"
"github.com/redis/go-redis/v9/internal"
"github.com/redis/go-redis/v9/internal/hscan"
"github.com/redis/go-redis/v9/internal/pool"
"github.com/redis/go-redis/v9/internal/proto"
)
// Scanner internal/hscan.Scanner exposed interface.
type Scanner = hscan.Scanner
// Nil reply returned by Redis when key does not exist.
const Nil = proto.Nil
// SetLogger set custom log
func SetLogger(logger internal.Logging) {
internal.Logger = logger
}
//------------------------------------------------------------------------------
type Hook interface {
DialHook(next DialHook) DialHook
ProcessHook(next ProcessHook) ProcessHook
ProcessPipelineHook(next ProcessPipelineHook) ProcessPipelineHook
}
type (
DialHook func(ctx context.Context, network, addr string) (net.Conn, error)
ProcessHook func(ctx context.Context, cmd Cmder) error
ProcessPipelineHook func(ctx context.Context, cmds []Cmder) error
)
type hooksMixin struct {
slice []Hook
initial hooks
current hooks
}
func (hs *hooksMixin) initHooks(hooks hooks) {
hs.initial = hooks
hs.chain()
}
type hooks struct {
dial DialHook
process ProcessHook
pipeline ProcessPipelineHook
txPipeline ProcessPipelineHook
}
func (h *hooks) setDefaults() {
if h.dial == nil {
h.dial = func(ctx context.Context, network, addr string) (net.Conn, error) { return nil, nil }
}
if h.process == nil {
h.process = func(ctx context.Context, cmd Cmder) error { return nil }
}
if h.pipeline == nil {
h.pipeline = func(ctx context.Context, cmds []Cmder) error { return nil }
}
if h.txPipeline == nil {
h.txPipeline = func(ctx context.Context, cmds []Cmder) error { return nil }
}
}
// AddHook is to add a hook to the queue.
// Hook is a function executed during network connection, command execution, and pipeline,
// it is a first-in-first-out stack queue (FIFO).
// You need to execute the next hook in each hook, unless you want to terminate the execution of the command.
// For example, you added hook-1, hook-2:
//
// client.AddHook(hook-1, hook-2)
//
// hook-1:
//
// func (Hook1) ProcessHook(next redis.ProcessHook) redis.ProcessHook {
// return func(ctx context.Context, cmd Cmder) error {
// print("hook-1 start")
// next(ctx, cmd)
// print("hook-1 end")
// return nil
// }
// }
//
// hook-2:
//
// func (Hook2) ProcessHook(next redis.ProcessHook) redis.ProcessHook {
// return func(ctx context.Context, cmd redis.Cmder) error {
// print("hook-2 start")
// next(ctx, cmd)
// print("hook-2 end")
// return nil
// }
// }
//
// The execution sequence is:
//
// hook-1 start -> hook-2 start -> exec redis cmd -> hook-2 end -> hook-1 end
//
// Please note: "next(ctx, cmd)" is very important, it will call the next hook,
// if "next(ctx, cmd)" is not executed, the redis command will not be executed.
func (hs *hooksMixin) AddHook(hook Hook) {
hs.slice = append(hs.slice, hook)
hs.chain()
}
func (hs *hooksMixin) chain() {
hs.initial.setDefaults()
hs.current.dial = hs.initial.dial
hs.current.process = hs.initial.process
hs.current.pipeline = hs.initial.pipeline
hs.current.txPipeline = hs.initial.txPipeline
for i := len(hs.slice) - 1; i >= 0; i-- {
if wrapped := hs.slice[i].DialHook(hs.current.dial); wrapped != nil {
hs.current.dial = wrapped
}
if wrapped := hs.slice[i].ProcessHook(hs.current.process); wrapped != nil {
hs.current.process = wrapped
}
if wrapped := hs.slice[i].ProcessPipelineHook(hs.current.pipeline); wrapped != nil {
hs.current.pipeline = wrapped
}
if wrapped := hs.slice[i].ProcessPipelineHook(hs.current.txPipeline); wrapped != nil {
hs.current.txPipeline = wrapped
}
}
}
func (hs *hooksMixin) clone() hooksMixin {
clone := *hs
l := len(clone.slice)
clone.slice = clone.slice[:l:l]
return clone
}
func (hs *hooksMixin) withProcessHook(ctx context.Context, cmd Cmder, hook ProcessHook) error {
for i := len(hs.slice) - 1; i >= 0; i-- {
if wrapped := hs.slice[i].ProcessHook(hook); wrapped != nil {
hook = wrapped
}
}
return hook(ctx, cmd)
}
func (hs *hooksMixin) withProcessPipelineHook(
ctx context.Context, cmds []Cmder, hook ProcessPipelineHook,
) error {
for i := len(hs.slice) - 1; i >= 0; i-- {
if wrapped := hs.slice[i].ProcessPipelineHook(hook); wrapped != nil {
hook = wrapped
}
}
return hook(ctx, cmds)
}
func (hs *hooksMixin) dialHook(ctx context.Context, network, addr string) (net.Conn, error) {
return hs.current.dial(ctx, network, addr)
}
func (hs *hooksMixin) processHook(ctx context.Context, cmd Cmder) error {
return hs.current.process(ctx, cmd)
}
func (hs *hooksMixin) processPipelineHook(ctx context.Context, cmds []Cmder) error {
return hs.current.pipeline(ctx, cmds)
}
func (hs *hooksMixin) processTxPipelineHook(ctx context.Context, cmds []Cmder) error {
return hs.current.txPipeline(ctx, cmds)
}
//------------------------------------------------------------------------------
type baseClient struct {
opt *Options
connPool pool.Pooler
onClose func() error // hook called when client is closed
}
func (c *baseClient) clone() *baseClient {
clone := *c
return &clone
}
func (c *baseClient) withTimeout(timeout time.Duration) *baseClient {
opt := c.opt.clone()
opt.ReadTimeout = timeout
opt.WriteTimeout = timeout
clone := c.clone()
clone.opt = opt
return clone
}
func (c *baseClient) String() string {
return fmt.Sprintf("Redis<%s db:%d>", c.getAddr(), c.opt.DB)
}
func (c *baseClient) newConn(ctx context.Context) (*pool.Conn, error) {
cn, err := c.connPool.NewConn(ctx)
if err != nil {
return nil, err
}
err = c.initConn(ctx, cn)
if err != nil {
_ = c.connPool.CloseConn(cn)
return nil, err
}
return cn, nil
}
func (c *baseClient) getConn(ctx context.Context) (*pool.Conn, error) {
if c.opt.Limiter != nil {
err := c.opt.Limiter.Allow()
if err != nil {
return nil, err
}
}
cn, err := c._getConn(ctx)
if err != nil {
if c.opt.Limiter != nil {
c.opt.Limiter.ReportResult(err)
}
return nil, err
}
return cn, nil
}
func (c *baseClient) _getConn(ctx context.Context) (*pool.Conn, error) {
cn, err := c.connPool.Get(ctx)
if err != nil {
return nil, err
}
if cn.Inited {
return cn, nil
}
if err := c.initConn(ctx, cn); err != nil {
c.connPool.Remove(ctx, cn, err)
if err := errors.Unwrap(err); err != nil {
return nil, err
}
return nil, err
}
return cn, nil
}
func (c *baseClient) initConn(ctx context.Context, cn *pool.Conn) error {
if cn.Inited {
return nil
}
cn.Inited = true
username, password := c.opt.Username, c.opt.Password
if c.opt.CredentialsProvider != nil {
username, password = c.opt.CredentialsProvider()
}
connPool := pool.NewSingleConnPool(c.connPool, cn)
conn := newConn(c.opt, connPool)
var auth bool
protocol := c.opt.Protocol
// By default, use RESP3 in current version.
if protocol < 2 {
protocol = 3
}
// for redis-server versions that do not support the HELLO command,
// RESP2 will continue to be used.
if err := conn.Hello(ctx, protocol, username, password, "").Err(); err == nil {
auth = true
} else if !isRedisError(err) {
// When the server responds with the RESP protocol and the result is not a normal
// execution result of the HELLO command, we consider it to be an indication that
// the server does not support the HELLO command.
// The server may be a redis-server that does not support the HELLO command,
// or it could be DragonflyDB or a third-party redis-proxy. They all respond
// with different error string results for unsupported commands, making it
// difficult to rely on error strings to determine all results.
return err
}
if !c.opt.DisableIndentity {
libName := ""
libVer := Version()
libInfo := LibraryInfo{LibName: &libName}
conn.ClientSetInfo(ctx, libInfo)
libInfo = LibraryInfo{LibVer: &libVer}
conn.ClientSetInfo(ctx, libInfo)
}
_, err := conn.Pipelined(ctx, func(pipe Pipeliner) error {
if !auth && password != "" {
if username != "" {
pipe.AuthACL(ctx, username, password)
} else {
pipe.Auth(ctx, password)
}
}
if c.opt.DB > 0 {
pipe.Select(ctx, c.opt.DB)
}
if c.opt.readOnly {
pipe.ReadOnly(ctx)
}
if c.opt.ClientName != "" {
pipe.ClientSetName(ctx, c.opt.ClientName)
}
return nil
})
if err != nil {
return err
}
if c.opt.OnConnect != nil {
return c.opt.OnConnect(ctx, conn)
}
return nil
}
func (c *baseClient) releaseConn(ctx context.Context, cn *pool.Conn, err error) {
if c.opt.Limiter != nil {
c.opt.Limiter.ReportResult(err)
}
if isBadConn(err, false, c.opt.Addr) {
c.connPool.Remove(ctx, cn, err)
} else {
c.connPool.Put(ctx, cn)
}
}
func (c *baseClient) withConn(
ctx context.Context, fn func(context.Context, *pool.Conn) error,
) error {
cn, err := c.getConn(ctx)
if err != nil {
return err
}
var fnErr error
defer func() {
c.releaseConn(ctx, cn, fnErr)
}()
fnErr = fn(ctx, cn)
return fnErr
}
func (c *baseClient) dial(ctx context.Context, network, addr string) (net.Conn, error) {
return c.opt.Dialer(ctx, network, addr)
}
func (c *baseClient) process(ctx context.Context, cmd Cmder) error {
var lastErr error
for attempt := 0; attempt <= c.opt.MaxRetries; attempt++ {
attempt := attempt
retry, err := c._process(ctx, cmd, attempt)
if err == nil || !retry {
return err
}
lastErr = err
}
return lastErr
}
func (c *baseClient) _process(ctx context.Context, cmd Cmder, attempt int) (bool, error) {
if attempt > 0 {
if err := internal.Sleep(ctx, c.retryBackoff(attempt)); err != nil {
return false, err
}
}
retryTimeout := uint32(0)
if err := c.withConn(ctx, func(ctx context.Context, cn *pool.Conn) error {
if err := cn.WithWriter(c.context(ctx), c.opt.WriteTimeout, func(wr *proto.Writer) error {
return writeCmd(wr, cmd)
}); err != nil {
atomic.StoreUint32(&retryTimeout, 1)
return err
}
if err := cn.WithReader(c.context(ctx), c.cmdTimeout(cmd), cmd.readReply); err != nil {
if cmd.readTimeout() == nil {
atomic.StoreUint32(&retryTimeout, 1)
} else {
atomic.StoreUint32(&retryTimeout, 0)
}
return err
}
return nil
}); err != nil {
retry := shouldRetry(err, atomic.LoadUint32(&retryTimeout) == 1)
return retry, err
}
return false, nil
}
func (c *baseClient) retryBackoff(attempt int) time.Duration {
return internal.RetryBackoff(attempt, c.opt.MinRetryBackoff, c.opt.MaxRetryBackoff)
}
func (c *baseClient) cmdTimeout(cmd Cmder) time.Duration {
if timeout := cmd.readTimeout(); timeout != nil {
t := *timeout
if t == 0 {
return 0
}
return t + 10*time.Second
}
return c.opt.ReadTimeout
}
// Close closes the client, releasing any open resources.
//
// It is rare to Close a Client, as the Client is meant to be
// long-lived and shared between many goroutines.
func (c *baseClient) Close() error {
var firstErr error
if c.onClose != nil {
if err := c.onClose(); err != nil {
firstErr = err
}
}
if err := c.connPool.Close(); err != nil && firstErr == nil {
firstErr = err
}
return firstErr
}
func (c *baseClient) getAddr() string {
return c.opt.Addr
}
func (c *baseClient) processPipeline(ctx context.Context, cmds []Cmder) error {
if err := c.generalProcessPipeline(ctx, cmds, c.pipelineProcessCmds); err != nil {
return err
}
return cmdsFirstErr(cmds)
}
func (c *baseClient) processTxPipeline(ctx context.Context, cmds []Cmder) error {
if err := c.generalProcessPipeline(ctx, cmds, c.txPipelineProcessCmds); err != nil {
return err
}
return cmdsFirstErr(cmds)
}
type pipelineProcessor func(context.Context, *pool.Conn, []Cmder) (bool, error)
func (c *baseClient) generalProcessPipeline(
ctx context.Context, cmds []Cmder, p pipelineProcessor,
) error {
var lastErr error
for attempt := 0; attempt <= c.opt.MaxRetries; attempt++ {
if attempt > 0 {
if err := internal.Sleep(ctx, c.retryBackoff(attempt)); err != nil {
setCmdsErr(cmds, err)
return err
}
}
// Enable retries by default to retry dial errors returned by withConn.
canRetry := true
lastErr = c.withConn(ctx, func(ctx context.Context, cn *pool.Conn) error {
var err error
canRetry, err = p(ctx, cn, cmds)
return err
})
if lastErr == nil || !canRetry || !shouldRetry(lastErr, true) {
return lastErr
}
}
return lastErr
}
func (c *baseClient) pipelineProcessCmds(
ctx context.Context, cn *pool.Conn, cmds []Cmder,
) (bool, error) {
if err := cn.WithWriter(c.context(ctx), c.opt.WriteTimeout, func(wr *proto.Writer) error {
return writeCmds(wr, cmds)
}); err != nil {
setCmdsErr(cmds, err)
return true, err
}
if err := cn.WithReader(c.context(ctx), c.opt.ReadTimeout, func(rd *proto.Reader) error {
return pipelineReadCmds(rd, cmds)
}); err != nil {
return true, err
}
return false, nil
}
func pipelineReadCmds(rd *proto.Reader, cmds []Cmder) error {
for i, cmd := range cmds {
err := cmd.readReply(rd)
cmd.SetErr(err)
if err != nil && !isRedisError(err) {
setCmdsErr(cmds[i+1:], err)
return err
}
}
// Retry errors like "LOADING redis is loading the dataset in memory".
return cmds[0].Err()
}
func (c *baseClient) txPipelineProcessCmds(
ctx context.Context, cn *pool.Conn, cmds []Cmder,
) (bool, error) {
if err := cn.WithWriter(c.context(ctx), c.opt.WriteTimeout, func(wr *proto.Writer) error {
return writeCmds(wr, cmds)
}); err != nil {
setCmdsErr(cmds, err)
return true, err
}
if err := cn.WithReader(c.context(ctx), c.opt.ReadTimeout, func(rd *proto.Reader) error {
statusCmd := cmds[0].(*StatusCmd)
// Trim multi and exec.
trimmedCmds := cmds[1 : len(cmds)-1]
if err := txPipelineReadQueued(rd, statusCmd, trimmedCmds); err != nil {
setCmdsErr(cmds, err)
return err
}
return pipelineReadCmds(rd, trimmedCmds)
}); err != nil {
return false, err
}
return false, nil
}
func txPipelineReadQueued(rd *proto.Reader, statusCmd *StatusCmd, cmds []Cmder) error {
// Parse +OK.
if err := statusCmd.readReply(rd); err != nil {
return err
}
// Parse +QUEUED.
for range cmds {
if err := statusCmd.readReply(rd); err != nil && !isRedisError(err) {
return err
}
}
// Parse number of replies.
line, err := rd.ReadLine()
if err != nil {
if err == Nil {
err = TxFailedErr
}
return err
}
if line[0] != proto.RespArray {
return fmt.Errorf("redis: expected '*', but got line %q", line)
}
return nil
}
func (c *baseClient) context(ctx context.Context) context.Context {
if c.opt.ContextTimeoutEnabled {
return ctx
}
return context.Background()
}
//------------------------------------------------------------------------------
// Client is a Redis client representing a pool of zero or more underlying connections.
// It's safe for concurrent use by multiple goroutines.
//
// Client creates and frees connections automatically; it also maintains a free pool
// of idle connections. You can control the pool size with Config.PoolSize option.
type Client struct {
*baseClient
cmdable
hooksMixin
}
// NewClient returns a client to the Redis Server specified by Options.
func NewClient(opt *Options) *Client {
opt.init()
c := Client{
baseClient: &baseClient{
opt: opt,
},
}
c.init()
c.connPool = newConnPool(opt, c.dialHook)
return &c
}
func (c *Client) init() {
c.cmdable = c.Process
c.initHooks(hooks{
dial: c.baseClient.dial,
process: c.baseClient.process,
pipeline: c.baseClient.processPipeline,
txPipeline: c.baseClient.processTxPipeline,
})
}
func (c *Client) WithTimeout(timeout time.Duration) *Client {
clone := *c
clone.baseClient = c.baseClient.withTimeout(timeout)
clone.init()
return &clone
}
func (c *Client) Conn() *Conn {
return newConn(c.opt, pool.NewStickyConnPool(c.connPool))
}
// Do create a Cmd from the args and processes the cmd.
func (c *Client) Do(ctx context.Context, args ...interface{}) *Cmd {
cmd := NewCmd(ctx, args...)
_ = c.Process(ctx, cmd)
return cmd
}
func (c *Client) Process(ctx context.Context, cmd Cmder) error {
err := c.processHook(ctx, cmd)
cmd.SetErr(err)
return err
}
// Options returns read-only Options that were used to create the client.
func (c *Client) Options() *Options {
return c.opt
}
type PoolStats pool.Stats
// PoolStats returns connection pool stats.
func (c *Client) PoolStats() *PoolStats {
stats := c.connPool.Stats()
return (*PoolStats)(stats)
}
func (c *Client) Pipelined(ctx context.Context, fn func(Pipeliner) error) ([]Cmder, error) {
return c.Pipeline().Pipelined(ctx, fn)
}
func (c *Client) Pipeline() Pipeliner {
pipe := Pipeline{
exec: pipelineExecer(c.processPipelineHook),
}
pipe.init()
return &pipe
}
func (c *Client) TxPipelined(ctx context.Context, fn func(Pipeliner) error) ([]Cmder, error) {
return c.TxPipeline().Pipelined(ctx, fn)
}
// TxPipeline acts like Pipeline, but wraps queued commands with MULTI/EXEC.
func (c *Client) TxPipeline() Pipeliner {
pipe := Pipeline{
exec: func(ctx context.Context, cmds []Cmder) error {
cmds = wrapMultiExec(ctx, cmds)
return c.processTxPipelineHook(ctx, cmds)
},
}
pipe.init()
return &pipe
}
func (c *Client) pubSub() *PubSub {
pubsub := &PubSub{
opt: c.opt,
newConn: func(ctx context.Context, channels []string) (*pool.Conn, error) {
return c.newConn(ctx)
},
closeConn: c.connPool.CloseConn,
}
pubsub.init()
return pubsub
}
// Subscribe subscribes the client to the specified channels.
// Channels can be omitted to create empty subscription.
// Note that this method does not wait on a response from Redis, so the
// subscription may not be active immediately. To force the connection to wait,
// you may call the Receive() method on the returned *PubSub like so:
//
// sub := client.Subscribe(queryResp)
// iface, err := sub.Receive()
// if err != nil {
// // handle error
// }
//
// // Should be *Subscription, but others are possible if other actions have been
// // taken on sub since it was created.
// switch iface.(type) {
// case *Subscription:
// // subscribe succeeded
// case *Message:
// // received first message
// case *Pong:
// // pong received
// default:
// // handle error
// }
//
// ch := sub.Channel()
func (c *Client) Subscribe(ctx context.Context, channels ...string) *PubSub {
pubsub := c.pubSub()
if len(channels) > 0 {
_ = pubsub.Subscribe(ctx, channels...)
}
return pubsub
}
// PSubscribe subscribes the client to the given patterns.
// Patterns can be omitted to create empty subscription.
func (c *Client) PSubscribe(ctx context.Context, channels ...string) *PubSub {
pubsub := c.pubSub()
if len(channels) > 0 {
_ = pubsub.PSubscribe(ctx, channels...)
}
return pubsub
}
// SSubscribe Subscribes the client to the specified shard channels.
// Channels can be omitted to create empty subscription.
func (c *Client) SSubscribe(ctx context.Context, channels ...string) *PubSub {
pubsub := c.pubSub()
if len(channels) > 0 {
_ = pubsub.SSubscribe(ctx, channels...)
}
return pubsub
}
//------------------------------------------------------------------------------
// Conn represents a single Redis connection rather than a pool of connections.
// Prefer running commands from Client unless there is a specific need
// for a continuous single Redis connection.
type Conn struct {
baseClient
cmdable
statefulCmdable
hooksMixin
}
func newConn(opt *Options, connPool pool.Pooler) *Conn {
c := Conn{
baseClient: baseClient{
opt: opt,
connPool: connPool,
},
}
c.cmdable = c.Process
c.statefulCmdable = c.Process
c.initHooks(hooks{
dial: c.baseClient.dial,
process: c.baseClient.process,
pipeline: c.baseClient.processPipeline,
txPipeline: c.baseClient.processTxPipeline,
})
return &c
}
func (c *Conn) Process(ctx context.Context, cmd Cmder) error {
err := c.processHook(ctx, cmd)
cmd.SetErr(err)
return err
}
func (c *Conn) Pipelined(ctx context.Context, fn func(Pipeliner) error) ([]Cmder, error) {
return c.Pipeline().Pipelined(ctx, fn)
}
func (c *Conn) Pipeline() Pipeliner {
pipe := Pipeline{
exec: c.processPipelineHook,
}
pipe.init()
return &pipe
}
func (c *Conn) TxPipelined(ctx context.Context, fn func(Pipeliner) error) ([]Cmder, error) {
return c.TxPipeline().Pipelined(ctx, fn)
}
// TxPipeline acts like Pipeline, but wraps queued commands with MULTI/EXEC.
func (c *Conn) TxPipeline() Pipeliner {
pipe := Pipeline{
exec: func(ctx context.Context, cmds []Cmder) error {
cmds = wrapMultiExec(ctx, cmds)
return c.processTxPipelineHook(ctx, cmds)
},
}
pipe.init()
return &pipe
}