redis/pipeline.go

107 lines
2.0 KiB
Go

package redis
import (
"sync"
"sync/atomic"
"gopkg.in/redis.v4/internal/pool"
)
// Pipeline implements pipelining as described in
// http://redis.io/topics/pipelining. It's safe for concurrent use
// by multiple goroutines.
type Pipeline struct {
commandable
exec func([]Cmder) error
mu sync.Mutex // protects cmds
cmds []Cmder
closed int32
}
func (pipe *Pipeline) process(cmd Cmder) {
pipe.mu.Lock()
pipe.cmds = append(pipe.cmds, cmd)
pipe.mu.Unlock()
}
// Close closes the pipeline, releasing any open resources.
func (pipe *Pipeline) Close() error {
atomic.StoreInt32(&pipe.closed, 1)
pipe.Discard()
return nil
}
func (pipe *Pipeline) isClosed() bool {
return atomic.LoadInt32(&pipe.closed) == 1
}
// Discard resets the pipeline and discards queued commands.
func (pipe *Pipeline) Discard() error {
defer pipe.mu.Unlock()
pipe.mu.Lock()
if pipe.isClosed() {
return pool.ErrClosed
}
pipe.cmds = pipe.cmds[:0]
return nil
}
// Exec executes all previously queued commands using one
// client-server roundtrip.
//
// Exec always returns list of commands and error of the first failed
// command if any.
func (pipe *Pipeline) Exec() ([]Cmder, error) {
if pipe.isClosed() {
return nil, pool.ErrClosed
}
defer pipe.mu.Unlock()
pipe.mu.Lock()
if len(pipe.cmds) == 0 {
return pipe.cmds, nil
}
cmds := pipe.cmds
pipe.cmds = nil
return cmds, pipe.exec(cmds)
}
func (pipe *Pipeline) pipelined(fn func(*Pipeline) error) ([]Cmder, error) {
if err := fn(pipe); err != nil {
return nil, err
}
cmds, err := pipe.Exec()
_ = pipe.Close()
return cmds, err
}
func execCmds(cn *pool.Conn, cmds []Cmder) ([]Cmder, error) {
if err := writeCmd(cn, cmds...); err != nil {
setCmdsErr(cmds, err)
return cmds, err
}
var firstCmdErr error
var failedCmds []Cmder
for _, cmd := range cmds {
err := cmd.readReply(cn)
if err == nil {
continue
}
if firstCmdErr == nil {
firstCmdErr = err
}
if shouldRetry(err) {
failedCmds = append(failedCmds, cmd)
}
}
return failedCmds, firstCmdErr
}