docs: add simple example (#9)

Signed-off-by: Bo-Yi Wu <[email protected]>

Author: appleboy

README.md

@@ -8,7 +8,7 @@ Queue is a Golang library for spawning and managing a Goroutine pool, Alloowing
 ## Features
 
 * [x] Support [buffered channel](https://gobyexample.com/channel-buffering) queue.
-* [x] Support [NSQ](https://nsq.io/) (A realtime distributed messaging platform)
+* [x] Support [NSQ](https://nsq.io/) (A realtime distributed messaging platform) as backend.
 
 ## Installation
 
@@ -17,3 +17,140 @@ go get github.com/appleboy/queue
 ```
 
 ## Usage
+
+First to create new job as `QueueMessage` interface:
+
+```go
+type job struct {
+	message string
+}
+
+func (j *job) Bytes() []byte {
+	return []byte(j.message)
+}
+```
+
+Second to create the new worker, use buffered channel as example:
+
+```go
+	// define the worker
+	w := simple.NewWorker(
+		simple.WithQueueNum(taskN),
+		simple.WithRunFunc(func(m queue.QueuedMessage) error {
+			j, ok := m.(*job)
+			if !ok {
+				return errors.New("message is not job type")
+			}
+
+			rets <- j.message
+			return nil
+		}),
+	)
+```
+
+Third to create queue and initialize multiple worker, receive all job message:
+
+```go
+	// define the queue
+	q, err := queue.NewQueue(
+		queue.WithWorkerCount(5),
+		queue.WithWorker(w),
+	)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// start the five worker
+	q.Start()
+
+	// assign tasks in queue
+	for i := 0; i < taskN; i++ {
+		go func(i int) {
+			q.Queue(&job{
+				message: fmt.Sprintf("handle the job: %d", i+1),
+			})
+		}(i)
+	}
+
+	// wait until all tasks done
+	for i := 0; i < taskN; i++ {
+		fmt.Println("message:", <-rets)
+		time.Sleep(50 * time.Millisecond)
+	}
+
+	q.Shutdown()
+	q.Wait()
+```
+
+Full example code as below or [try it in playground](https://play.golang.org/p/DlhCQgZZ1Bb).
+
+```go
+package main
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"time"
+
+	"github.com/appleboy/queue"
+	"github.com/appleboy/queue/simple"
+)
+
+type job struct {
+	message string
+}
+
+func (j *job) Bytes() []byte {
+	return []byte(j.message)
+}
+
+func main() {
+	taskN := 100
+	rets := make(chan string, taskN)
+
+	// define the worker
+	w := simple.NewWorker(
+		simple.WithQueueNum(taskN),
+		simple.WithRunFunc(func(m queue.QueuedMessage) error {
+			j, ok := m.(*job)
+			if !ok {
+				return errors.New("message is not job type")
+			}
+
+			rets <- j.message
+			return nil
+		}),
+	)
+
+	// define the queue
+	q, err := queue.NewQueue(
+		queue.WithWorkerCount(5),
+		queue.WithWorker(w),
+	)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// start the five worker
+	q.Start()
+
+	// assign tasks in queue
+	for i := 0; i < taskN; i++ {
+		go func(i int) {
+			q.Queue(&job{
+				message: fmt.Sprintf("handle the job: %d", i+1),
+			})
+		}(i)
+	}
+
+	// wait until all tasks done
+	for i := 0; i < taskN; i++ {
+		fmt.Println("message:", <-rets)
+		time.Sleep(50 * time.Millisecond)
+	}
+
+	q.Shutdown()
+	q.Wait()
+}
+```

_example/simple/go.mod

@@ -0,0 +1,5 @@
+module example
+
+go 1.16
+
+require github.com/appleboy/queue v0.0.4-0.20210725052905-4ef008157945 // indirect

_example/simple/go.sum

@@ -0,0 +1,12 @@
+github.com/appleboy/queue v0.0.3 h1:rntqVTm6ilh80VCVQjwA0vDMCl1cfveq6GS6X98fKwE=
+github.com/appleboy/queue v0.0.3/go.mod h1:6Mn0z4hURZW/26huvRXG0SJ4o7pBdo6hOryRiegy/4Q=
+github.com/appleboy/queue v0.0.4-0.20210725052905-4ef008157945 h1:Mec41QJ0hGDtbyfWgHfuXKqTu0a8hSIIBhL3sNbNjqQ=
+github.com/appleboy/queue v0.0.4-0.20210725052905-4ef008157945/go.mod h1:6Mn0z4hURZW/26huvRXG0SJ4o7pBdo6hOryRiegy/4Q=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/golang/snappy v0.0.1/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
+github.com/nsqio/go-nsq v1.0.8/go.mod h1:vKq36oyeVXgsS5Q8YEO7WghqidAVXQlcFxzQbQTuDEY=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

_example/simple/main.go

@@ -0,0 +1,68 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"time"
+
+	"github.com/appleboy/queue"
+	"github.com/appleboy/queue/simple"
+)
+
+type job struct {
+	message string
+}
+
+func (j *job) Bytes() []byte {
+	return []byte(j.message)
+}
+
+func main() {
+	taskN := 100
+	rets := make(chan string, taskN)
+
+	// define the worker
+	w := simple.NewWorker(
+		simple.WithQueueNum(taskN),
+		simple.WithRunFunc(func(m queue.QueuedMessage) error {
+			j, ok := m.(*job)
+			if !ok {
+				return errors.New("message is not job type")
+			}
+
+			rets <- j.message
+			return nil
+		}),
+	)
+
+	// define the queue
+	q, err := queue.NewQueue(
+		queue.WithWorkerCount(5),
+		queue.WithWorker(w),
+	)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// start the five worker
+	q.Start()
+
+	// assign tasks in queue
+	for i := 0; i < taskN; i++ {
+		go func(i int) {
+			q.Queue(&job{
+				message: fmt.Sprintf("handle the job: %d", i+1),
+			})
+		}(i)
+	}
+
+	// wait until all tasks done
+	for i := 0; i < taskN; i++ {
+		fmt.Println("message:", <-rets)
+		time.Sleep(50 * time.Millisecond)
+	}
+
+	q.Shutdown()
+	q.Wait()
+}