Feat: task pool for goroutines

pkg/task/pool.go

@@ -1,21 +1,120 @@
 package task
 
+import "sync"
+
+// Pool 带有最大配额的goroutines任务池
 type Pool struct {
 	// 容量
 	capacity int
+	// 初始容量
+	initialCapacity int
+
 	// 终止信号
 	terminateSignal chan error
 	// 全部任务完成的信号
 	finishSignal chan bool
+	// 有空余位置的信号
+	freeSignal chan bool
+
+	// 是否已关闭
+	closed bool
+	// 是否正在等待任务结束
+	waiting bool
+
+	// 互斥锁
+	lock sync.Mutex
+	// 等待队列
+	pending []Job
 }
 
-type Worker interface {
+// Job 任务
+type Job interface {
+	// 任务处理方法，如果error不为nil，
+	// 任务池会关闭并中止接受新任务
 	Do() error
 }
 
-func (pool *Pool) Submit(worker Worker) {
-	err := worker.Do()
+// NewGoroutinePool 创建一个容量为capacity的任务池
+func NewGoroutinePool(capacity int) *Pool {
+	pool := &Pool{
+		capacity:        capacity,
+		initialCapacity: capacity,
+		terminateSignal: make(chan error),
+		finishSignal:    make(chan bool),
+		freeSignal:      make(chan bool),
+	}
+	go pool.Schedule()
+	return pool
+}
+
+// Schedule 为等待队列的任务分配Worker，以及检测错误状态、所有任务完成
+func (pool *Pool) Schedule() {
+	for {
+		select {
+		case <-pool.freeSignal:
+			// 有新的空余名额
+			pool.lock.Lock()
+			if len(pool.pending) > 0 {
+				// 有待处理的任务，开始处理
+				var job Job
+				job, pool.pending = pool.pending[0], pool.pending[1:]
+				go pool.start(job)
+			} else {
+				if pool.waiting && pool.capacity == pool.initialCapacity {
+					// 所有任务已结束
+					pool.lock.Unlock()
+					pool.finishSignal <- true
+					return
+				}
+				pool.lock.Unlock()
+			}
+		case <-pool.terminateSignal:
+			// 有任务意外中止，则发送完成信号
+			pool.finishSignal <- true
+			return
+		}
+	}
+}
+
+// Wait 等待队列中所有任务完成或有Job返回错误中止
+func (pool *Pool) Wait() {
+	pool.lock.Lock()
+	pool.waiting = true
+	pool.lock.Unlock()
+	_ = <-pool.finishSignal
+}
+
+// Submit 提交新任务
+func (pool *Pool) Submit(job Job) {
+	if pool.closed {
+		return
+	}
+
+	pool.lock.Lock()
+	if pool.capacity < 1 {
+		// 容量为空时，加入等待队列
+		pool.pending = append(pool.pending, job)
+		pool.lock.Unlock()
+		return
+	}
+
+	// 还有空闲容量时，开始执行任务
+	go pool.start(job)
+}
+
+// 开始执行任务
+func (pool *Pool) start(job Job) {
+	pool.capacity--
+	pool.lock.Unlock()
+
+	err := job.Do()
 	if err != nil {
+		pool.closed = true
 		close(pool.terminateSignal)
 	}
+
+	pool.lock.Lock()
+	pool.capacity++
+	pool.lock.Unlock()
+	pool.freeSignal <- true
 }

pkg/task/pool_test.go

@@ -0,0 +1,48 @@
+package task
+
+import (
+	"errors"
+	"fmt"
+	"testing"
+	"time"
+)
+
+type testJob struct {
+	id    string
+	sleep time.Duration
+}
+
+func (job testJob) Do() error {
+	fmt.Printf("任务%s开始执行\n", job.id)
+	time.Sleep(job.sleep * time.Second)
+	fmt.Printf("任务%s执行完毕\n", job.id)
+	if job.id == "3" {
+		return errors.New("error")
+	}
+	return nil
+}
+
+func TestPool_Submit(t *testing.T) {
+	pool := NewGoroutinePool(1)
+	task1 := testJob{
+		id:    "1",
+		sleep: 5,
+	}
+	task2 := testJob{
+		id:    "2",
+		sleep: 5,
+	}
+	task3 := testJob{
+		id:    "3",
+		sleep: 2,
+	}
+	task4 := testJob{
+		id:    "4",
+		sleep: 5,
+	}
+	pool.Submit(task1)
+	pool.Submit(task2)
+	pool.Submit(task3)
+	pool.Submit(task4)
+	pool.Wait()
+}