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- package redis
-
- import (
- "context"
- "sync"
-
- "github.com/go-redis/redis/v8/internal/pool"
- )
-
- type pipelineExecer func(context.Context, []Cmder) error
-
- // Pipeliner is an mechanism to realise Redis Pipeline technique.
- //
- // Pipelining is a technique to extremely speed up processing by packing
- // operations to batches, send them at once to Redis and read a replies in a
- // singe step.
- // See https://redis.io/topics/pipelining
- //
- // Pay attention, that Pipeline is not a transaction, so you can get unexpected
- // results in case of big pipelines and small read/write timeouts.
- // Redis client has retransmission logic in case of timeouts, pipeline
- // can be retransmitted and commands can be executed more then once.
- // To avoid this: it is good idea to use reasonable bigger read/write timeouts
- // depends of your batch size and/or use TxPipeline.
- type Pipeliner interface {
- StatefulCmdable
- Len() int
- Do(ctx context.Context, args ...interface{}) *Cmd
- Process(ctx context.Context, cmd Cmder) error
- Close() error
- Discard() error
- Exec(ctx context.Context) ([]Cmder, error)
- }
-
- var _ Pipeliner = (*Pipeline)(nil)
-
- // Pipeline implements pipelining as described in
- // http://redis.io/topics/pipelining. It's safe for concurrent use
- // by multiple goroutines.
- type Pipeline struct {
- cmdable
- statefulCmdable
-
- ctx context.Context
- exec pipelineExecer
-
- mu sync.Mutex
- cmds []Cmder
- closed bool
- }
-
- func (c *Pipeline) init() {
- c.cmdable = c.Process
- c.statefulCmdable = c.Process
- }
-
- // Len returns the number of queued commands.
- func (c *Pipeline) Len() int {
- c.mu.Lock()
- ln := len(c.cmds)
- c.mu.Unlock()
- return ln
- }
-
- // Do queues the custom command for later execution.
- func (c *Pipeline) Do(ctx context.Context, args ...interface{}) *Cmd {
- cmd := NewCmd(ctx, args...)
- _ = c.Process(ctx, cmd)
- return cmd
- }
-
- // Process queues the cmd for later execution.
- func (c *Pipeline) Process(ctx context.Context, cmd Cmder) error {
- c.mu.Lock()
- c.cmds = append(c.cmds, cmd)
- c.mu.Unlock()
- return nil
- }
-
- // Close closes the pipeline, releasing any open resources.
- func (c *Pipeline) Close() error {
- c.mu.Lock()
- _ = c.discard()
- c.closed = true
- c.mu.Unlock()
- return nil
- }
-
- // Discard resets the pipeline and discards queued commands.
- func (c *Pipeline) Discard() error {
- c.mu.Lock()
- err := c.discard()
- c.mu.Unlock()
- return err
- }
-
- func (c *Pipeline) discard() error {
- if c.closed {
- return pool.ErrClosed
- }
- c.cmds = c.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 (c *Pipeline) Exec(ctx context.Context) ([]Cmder, error) {
- c.mu.Lock()
- defer c.mu.Unlock()
-
- if c.closed {
- return nil, pool.ErrClosed
- }
-
- if len(c.cmds) == 0 {
- return nil, nil
- }
-
- cmds := c.cmds
- c.cmds = nil
-
- return cmds, c.exec(ctx, cmds)
- }
-
- func (c *Pipeline) Pipelined(ctx context.Context, fn func(Pipeliner) error) ([]Cmder, error) {
- if err := fn(c); err != nil {
- return nil, err
- }
- cmds, err := c.Exec(ctx)
- _ = c.Close()
- return cmds, err
- }
-
- func (c *Pipeline) Pipeline() Pipeliner {
- return c
- }
-
- func (c *Pipeline) TxPipelined(ctx context.Context, fn func(Pipeliner) error) ([]Cmder, error) {
- return c.Pipelined(ctx, fn)
- }
-
- func (c *Pipeline) TxPipeline() Pipeliner {
- return c
- }
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