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hugo/common/rungroup/rungroup.go

94 lines
2.0 KiB
Go

// Copyright 2024 The Hugo Authors. All rights reserved.
//
// 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 rungroup
import (
"context"
"golang.org/x/sync/errgroup"
)
// Group is a group of workers that can be used to enqueue work and wait for
// them to finish.
type Group[T any] interface {
Enqueue(T) error
Wait() error
}
type runGroup[T any] struct {
ctx context.Context
g *errgroup.Group
ch chan T
}
// Config is the configuration for a new Group.
type Config[T any] struct {
NumWorkers int
Handle func(context.Context, T) error
}
// Run creates a new Group with the given configuration.
func Run[T any](ctx context.Context, cfg Config[T]) Group[T] {
if cfg.NumWorkers <= 0 {
cfg.NumWorkers = 1
}
if cfg.Handle == nil {
panic("Handle must be set")
}
g, ctx := errgroup.WithContext(ctx)
// Buffered for performance.
ch := make(chan T, cfg.NumWorkers)
for i := 0; i < cfg.NumWorkers; i++ {
g.Go(func() error {
for {
select {
case <-ctx.Done():
return nil
case v, ok := <-ch:
if !ok {
return nil
}
if err := cfg.Handle(ctx, v); err != nil {
return err
}
}
}
})
}
return &runGroup[T]{
ctx: ctx,
g: g,
ch: ch,
}
}
// Enqueue enqueues a new item to be handled by the workers.
func (r *runGroup[T]) Enqueue(t T) error {
select {
case <-r.ctx.Done():
return nil
case r.ch <- t:
}
return nil
}
// Wait waits for all workers to finish and returns the first error.
func (r *runGroup[T]) Wait() error {
close(r.ch)
return r.g.Wait()
}