[Vendor] Update go-redis to v8.5.0 (#13749)

* Update go-redis to v8.4.0

* github.com/go-redis/redis/v8  v8.4.0 -> v8.5.0

* Apply suggestions from code review

Co-authored-by: zeripath <art27@cantab.net>

* TODO

* Use the Queue termination channel as the default context for pushes

Signed-off-by: Andrew Thornton <art27@cantab.net>

* missed one

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: zeripath <art27@cantab.net>

vendor/github.com/go-redis/redis/v8/pipeline.go

@@ -0,0 +1,137 @@
+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
+	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
+}
+
+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
+}