niki/vendor/github.com/redis/go-redis/v9/tx.go

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2024-02-18 10:42:21 +00:00
package redis
import (
"context"
"github.com/redis/go-redis/v9/internal/pool"
"github.com/redis/go-redis/v9/internal/proto"
)
// TxFailedErr transaction redis failed.
const TxFailedErr = proto.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, use Pipeline instead.
type Tx struct {
baseClient
cmdable
statefulCmdable
hooksMixin
}
func (c *Client) newTx() *Tx {
tx := Tx{
baseClient: baseClient{
opt: c.opt,
connPool: pool.NewStickyConnPool(c.connPool),
},
hooksMixin: c.hooksMixin.clone(),
}
tx.init()
return &tx
}
func (c *Tx) init() {
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,
})
}
func (c *Tx) Process(ctx context.Context, cmd Cmder) error {
err := c.processHook(ctx, cmd)
cmd.SetErr(err)
return err
}
// Watch prepares a transaction and marks the keys to be watched
// for conditional execution if there are any keys.
//
// The transaction is automatically closed when fn exits.
func (c *Client) Watch(ctx context.Context, fn func(*Tx) error, keys ...string) error {
tx := c.newTx()
defer tx.Close(ctx)
if len(keys) > 0 {
if err := tx.Watch(ctx, keys...).Err(); err != nil {
return err
}
}
return fn(tx)
}
// Close closes the transaction, releasing any open resources.
func (c *Tx) Close(ctx context.Context) error {
_ = c.Unwatch(ctx).Err()
return c.baseClient.Close()
}
// Watch marks the keys to be watched for conditional execution
// of a transaction.
func (c *Tx) Watch(ctx context.Context, keys ...string) *StatusCmd {
args := make([]interface{}, 1+len(keys))
args[0] = "watch"
for i, key := range keys {
args[1+i] = key
}
cmd := NewStatusCmd(ctx, args...)
_ = c.Process(ctx, cmd)
return cmd
}
// Unwatch flushes all the previously watched keys for a transaction.
func (c *Tx) Unwatch(ctx context.Context, keys ...string) *StatusCmd {
args := make([]interface{}, 1+len(keys))
args[0] = "unwatch"
for i, key := range keys {
args[1+i] = key
}
cmd := NewStatusCmd(ctx, args...)
_ = c.Process(ctx, cmd)
return cmd
}
// Pipeline creates a pipeline. Usually it is more convenient to use Pipelined.
func (c *Tx) Pipeline() Pipeliner {
pipe := Pipeline{
exec: func(ctx context.Context, cmds []Cmder) error {
return c.processPipelineHook(ctx, cmds)
},
}
pipe.init()
return &pipe
}
// Pipelined executes commands queued in the fn outside of the transaction.
// Use TxPipelined if you need transactional behavior.
func (c *Tx) Pipelined(ctx context.Context, fn func(Pipeliner) error) ([]Cmder, error) {
return c.Pipeline().Pipelined(ctx, fn)
}
// TxPipelined executes commands queued in the fn in the transaction.
//
// 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 an error of the first
// failed command or nil.
func (c *Tx) TxPipelined(ctx context.Context, fn func(Pipeliner) error) ([]Cmder, error) {
return c.TxPipeline().Pipelined(ctx, fn)
}
// TxPipeline creates a pipeline. Usually it is more convenient to use TxPipelined.
func (c *Tx) 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 wrapMultiExec(ctx context.Context, cmds []Cmder) []Cmder {
if len(cmds) == 0 {
panic("not reached")
}
cmdsCopy := make([]Cmder, len(cmds)+2)
cmdsCopy[0] = NewStatusCmd(ctx, "multi")
copy(cmdsCopy[1:], cmds)
cmdsCopy[len(cmdsCopy)-1] = NewSliceCmd(ctx, "exec")
return cmdsCopy
}