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122 lines
3.2 KiB
Go
122 lines
3.2 KiB
Go
package redis
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import (
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"context"
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"errors"
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)
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type pipelineExecer func(context.Context, []Cmder) error
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// Pipeliner is an mechanism to realise Redis Pipeline technique.
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//
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// Pipelining is a technique to extremely speed up processing by packing
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// operations to batches, send them at once to Redis and read a replies in a
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// single step.
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// See https://redis.io/topics/pipelining
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//
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// Pay attention, that Pipeline is not a transaction, so you can get unexpected
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// results in case of big pipelines and small read/write timeouts.
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// Redis client has retransmission logic in case of timeouts, pipeline
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// can be retransmitted and commands can be executed more then once.
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// To avoid this: it is good idea to use reasonable bigger read/write timeouts
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// depends of your batch size and/or use TxPipeline.
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type Pipeliner interface {
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StatefulCmdable
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// Len is to obtain the number of commands in the pipeline that have not yet been executed.
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Len() int
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// Do is an API for executing any command.
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// If a certain Redis command is not yet supported, you can use Do to execute it.
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Do(ctx context.Context, args ...interface{}) *Cmd
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// Process is to put the commands to be executed into the pipeline buffer.
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Process(ctx context.Context, cmd Cmder) error
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// Discard is to discard all commands in the cache that have not yet been executed.
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Discard()
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// Exec is to send all the commands buffered in the pipeline to the redis-server.
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Exec(ctx context.Context) ([]Cmder, error)
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}
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var _ Pipeliner = (*Pipeline)(nil)
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// Pipeline implements pipelining as described in
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// http://redis.io/topics/pipelining.
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// Please note: it is not safe for concurrent use by multiple goroutines.
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type Pipeline struct {
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cmdable
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statefulCmdable
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exec pipelineExecer
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cmds []Cmder
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}
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func (c *Pipeline) init() {
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c.cmdable = c.Process
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c.statefulCmdable = c.Process
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}
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// Len returns the number of queued commands.
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func (c *Pipeline) Len() int {
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return len(c.cmds)
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}
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// Do queues the custom command for later execution.
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func (c *Pipeline) Do(ctx context.Context, args ...interface{}) *Cmd {
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cmd := NewCmd(ctx, args...)
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if len(args) == 0 {
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cmd.SetErr(errors.New("redis: please enter the command to be executed"))
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return cmd
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}
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_ = c.Process(ctx, cmd)
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return cmd
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}
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// Process queues the cmd for later execution.
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func (c *Pipeline) Process(ctx context.Context, cmd Cmder) error {
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c.cmds = append(c.cmds, cmd)
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return nil
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}
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// Discard resets the pipeline and discards queued commands.
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func (c *Pipeline) Discard() {
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c.cmds = c.cmds[:0]
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}
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// Exec executes all previously queued commands using one
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// client-server roundtrip.
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//
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// Exec always returns list of commands and error of the first failed
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// command if any.
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func (c *Pipeline) Exec(ctx context.Context) ([]Cmder, error) {
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if len(c.cmds) == 0 {
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return nil, nil
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}
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cmds := c.cmds
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c.cmds = nil
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return cmds, c.exec(ctx, cmds)
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}
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func (c *Pipeline) Pipelined(ctx context.Context, fn func(Pipeliner) error) ([]Cmder, error) {
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if err := fn(c); err != nil {
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return nil, err
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}
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return c.Exec(ctx)
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}
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func (c *Pipeline) Pipeline() Pipeliner {
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return c
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}
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func (c *Pipeline) TxPipelined(ctx context.Context, fn func(Pipeliner) error) ([]Cmder, error) {
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return c.Pipelined(ctx, fn)
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}
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func (c *Pipeline) TxPipeline() Pipeliner {
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return c
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}
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