Pipeliner expose queued commands (#3496)

* Pipeliner expose queued commands

Signed-off-by: Xiaolong Chen <fukua95@gmail.com>

* add tests and update some comments

Signed-off-by: Xiaolong Chen <fukua95@gmail.com>

---------

Signed-off-by: Xiaolong Chen <fukua95@gmail.com>

commands.go

@@ -253,6 +253,7 @@ var (
 	_ Cmdable = (*Tx)(nil)
 	_ Cmdable = (*Ring)(nil)
 	_ Cmdable = (*ClusterClient)(nil)
+	_ Cmdable = (*Pipeline)(nil)
 )
 
 type cmdable func(ctx context.Context, cmd Cmder) error

pipeline.go

@@ -7,7 +7,7 @@ import (
 
 type pipelineExecer func(context.Context, []Cmder) error
 
-// Pipeliner is an mechanism to realise Redis Pipeline technique.
+// Pipeliner is a 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
@@ -23,21 +23,24 @@ type pipelineExecer func(context.Context, []Cmder) error
 type Pipeliner interface {
 	StatefulCmdable
 
-	// Len is to obtain the number of commands in the pipeline that have not yet been executed.
+	// Len obtains the number of commands in the pipeline that have not yet been executed.
 	Len() int
 
 	// Do is an API for executing any command.
 	// If a certain Redis command is not yet supported, you can use Do to execute it.
 	Do(ctx context.Context, args ...interface{}) *Cmd
 
-	// Process is to put the commands to be executed into the pipeline buffer.
+	// Process puts the commands to be executed into the pipeline buffer.
 	Process(ctx context.Context, cmd Cmder) error
 
-	// Discard is to discard all commands in the cache that have not yet been executed.
+	// Discard discards all commands in the pipeline buffer that have not yet been executed.
 	Discard()
 
-	// Exec is to send all the commands buffered in the pipeline to the redis-server.
+	// Exec sends all the commands buffered in the pipeline to the redis server.
 	Exec(ctx context.Context) ([]Cmder, error)
+
+	// Cmds returns the list of queued commands.
+	Cmds() []Cmder
 }
 
 var _ Pipeliner = (*Pipeline)(nil)
@@ -119,3 +122,7 @@ func (c *Pipeline) TxPipelined(ctx context.Context, fn func(Pipeliner) error) ([
 func (c *Pipeline) TxPipeline() Pipeliner {
 	return c
 }
+
+func (c *Pipeline) Cmds() []Cmder {
+	return c.cmds
+}

pipeline_test.go

@@ -36,6 +36,30 @@ var _ = Describe("pipelining", func() {
 		Expect(get.Val()).To(Equal(""))
 	})
 
+	It("exports queued commands", func() {
+		p := client.Pipeline()
+		cmds := p.Cmds()
+		Expect(cmds).To(BeEmpty())
+
+		p.Set(ctx, "foo", "bar", 0)
+		p.Get(ctx, "foo")
+		cmds = p.Cmds()
+		Expect(cmds).To(HaveLen(p.Len()))
+		Expect(cmds[0].Name()).To(Equal("set"))
+		Expect(cmds[1].Name()).To(Equal("get"))
+
+		cmds, err := p.Exec(ctx)
+		Expect(err).NotTo(HaveOccurred())
+		Expect(cmds).To(HaveLen(2))
+		Expect(cmds[0].Name()).To(Equal("set"))
+		Expect(cmds[0].(*redis.StatusCmd).Val()).To(Equal("OK"))
+		Expect(cmds[1].Name()).To(Equal("get"))
+		Expect(cmds[1].(*redis.StringCmd).Val()).To(Equal("bar"))
+
+		cmds = p.Cmds()
+		Expect(cmds).To(BeEmpty())
+	})
+
 	assertPipeline := func() {
 		It("returns no errors when there are no commands", func() {
 			_, err := pipe.Exec(ctx)