README
¶
SizedWaitGroup
SizedWaitGroup has the same role and API as sync.WaitGroup but it adds a limit of the amount of goroutines started concurrently.
SizedWaitGroup adds the feature of limiting the maximum number of concurrently started routines. It could for example be used to start multiples routines querying a database but without sending too much queries in order to not overload the given database.
Example
package main
import (
"fmt"
"math/rand"
"time"
"github.com/remeh/sizedwaitgroup"
)
func main() {
rand.Seed(time.Now().UnixNano())
// Typical use-case:
// 50 queries must be executed as quick as possible
// but without overloading the database, so only
// 8 routines should be started concurrently.
swg := sizedwaitgroup.New(8)
for i := 0; i < 50; i++ {
swg.Add()
go func(i int) {
defer swg.Done()
query(i)
}(i)
}
swg.Wait()
}
func query(i int) {
fmt.Println(i)
ms := i + 500 + rand.Intn(500)
time.Sleep(time.Duration(ms) * time.Millisecond)
}
License
MIT
Copyright
Rémy Mathieu © 2016
Documentation
¶
Overview ¶
Package sizedwaitgroup 提供带并发限制能力的 WaitGroup 实现
基于 sync.WaitGroup，能够限制同时运行的协程数量，避免对下游资源造成过载。 Rémy Mathieu © 2016
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type SizedWaitGroup ¶
type SizedWaitGroup struct {
Size int
// contains filtered or unexported fields
}
SizedWaitGroup has the same role and close to the same API as the Golang sync.WaitGroup but adds a limit of the amount of goroutines started concurrently.
func New ¶
func New(limit int) SizedWaitGroup
New creates a SizedWaitGroup. The limit parameter is the maximum amount of goroutines which can be started concurrently.
func (*SizedWaitGroup) Add ¶
func (s *SizedWaitGroup) Add()
Add increments the internal WaitGroup counter. It can be blocking if the limit of spawned goroutines has been reached. It will stop blocking when Done is been called.
See sync.WaitGroup documentation for more information.
func (*SizedWaitGroup) AddWithContext ¶
func (s *SizedWaitGroup) AddWithContext(ctx context.Context) error
AddWithContext increments the internal WaitGroup counter. It can be blocking if the limit of spawned goroutines has been reached. It will stop blocking when Done is been called, or when the context is canceled. Returns nil on success or an error if the context is canceled before the lock is acquired.
See sync.WaitGroup documentation for more information.
func (*SizedWaitGroup) Done ¶
func (s *SizedWaitGroup) Done()
Done decrements the SizedWaitGroup counter. See sync.WaitGroup documentation for more information.
func (*SizedWaitGroup) Wait ¶
func (s *SizedWaitGroup) Wait()
Wait blocks until the SizedWaitGroup counter is zero. See sync.WaitGroup documentation for more information.
Source Files