init

Signed-off-by: storyicon <yuanchao@bilibili.com>

pkg/util/concurrent/errgroup.go

@@ -0,0 +1,72 @@
+// Copyright 2021 storyicon@foxmail.com
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package concurrent
+
+import (
+	"context"
+	"sync"
+)
+
+// ErrGroup is another ErrGroup implement
+type ErrGroup struct {
+	ctx    context.Context
+	cancel context.CancelFunc
+	limit  chan struct{}
+
+	errOnce sync.Once
+	err     error
+
+	wg sync.WaitGroup
+}
+
+// NewErrGroup is used to create a new ErrGroup
+func NewErrGroup(ctx context.Context, concurrency int) *ErrGroup {
+	ctx, cancel := context.WithCancel(ctx)
+	return &ErrGroup{
+		ctx:    ctx,
+		cancel: cancel,
+		limit:  make(chan struct{}, concurrency),
+	}
+}
+
+// Wait is used to wait ErrGroup finish
+func (g *ErrGroup) Wait() error {
+	g.wg.Wait()
+	g.cancel()
+	return g.err
+}
+
+// Go is used to start a new goroutine
+func (g *ErrGroup) Go(f func(ctx context.Context) error) {
+	if g.err != nil {
+		return
+	}
+
+	g.limit <- struct{}{}
+	g.wg.Add(1)
+	go func() {
+		defer func() {
+			<-g.limit
+			g.wg.Done()
+		}()
+		if err := f(g.ctx); err != nil {
+			g.cancel()
+			g.errOnce.Do(func() {
+				g.err = err
+				g.cancel()
+			})
+		}
+	}()
+}