redis/tx.go

102 lines
2.5 KiB
Go

package redis
import (
"gopkg.in/redis.v5/internal"
"gopkg.in/redis.v5/internal/pool"
)
// Redis transaction failed.
const TxFailedErr = internal.RedisError("redis: transaction failed")
// Tx implements Redis transactions as described in
// http://redis.io/topics/transactions. It's NOT safe for concurrent use
// by multiple goroutines, because Exec resets list of watched keys.
// If you don't need WATCH it is better to use Pipeline.
type Tx struct {
cmdable
statefulCmdable
baseClient
}
var _ Cmdable = (*Tx)(nil)
func (c *Client) newTx() *Tx {
tx := Tx{
baseClient: baseClient{
opt: c.opt,
connPool: pool.NewStickyConnPool(c.connPool.(*pool.ConnPool), true),
},
}
tx.cmdable.process = tx.Process
tx.statefulCmdable.process = tx.Process
return &tx
}
func (c *Client) Watch(fn func(*Tx) error, keys ...string) error {
tx := c.newTx()
if len(keys) > 0 {
if err := tx.Watch(keys...).Err(); err != nil {
_ = tx.Close()
return err
}
}
firstErr := fn(tx)
if err := tx.Close(); err != nil && firstErr == nil {
firstErr = err
}
return firstErr
}
// close closes the transaction, releasing any open resources.
func (c *Tx) Close() error {
_ = c.Unwatch().Err()
return c.baseClient.Close()
}
// Watch marks the keys to be watched for conditional execution
// of a transaction.
func (c *Tx) Watch(keys ...string) *StatusCmd {
args := make([]interface{}, 1+len(keys))
args[0] = "WATCH"
for i, key := range keys {
args[1+i] = key
}
cmd := NewStatusCmd(args...)
c.Process(cmd)
return cmd
}
// Unwatch flushes all the previously watched keys for a transaction.
func (c *Tx) Unwatch(keys ...string) *StatusCmd {
args := make([]interface{}, 1+len(keys))
args[0] = "UNWATCH"
for i, key := range keys {
args[1+i] = key
}
cmd := NewStatusCmd(args...)
c.Process(cmd)
return cmd
}
func (c *Tx) Pipeline() *Pipeline {
pipe := Pipeline{
exec: c.pipelineExecer(c.txPipelineProcessCmds),
}
pipe.cmdable.process = pipe.Process
pipe.statefulCmdable.process = pipe.Process
return &pipe
}
// Pipelined executes commands queued in the fn in a transaction
// and restores the connection state to normal.
//
// When using WATCH, EXEC will execute commands only if the watched keys
// were not modified, allowing for a check-and-set mechanism.
//
// Exec always returns list of commands. If transaction fails
// TxFailedErr is returned. Otherwise Exec returns error of the first
// failed command or nil.
func (c *Tx) Pipelined(fn func(*Pipeline) error) ([]Cmder, error) {
return c.Pipeline().pipelined(fn)
}