/
concurrency.go
186 lines (157 loc) · 3.76 KB
/
concurrency.go
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package concurrency
import (
"context"
"fmt"
"github.com/pkg/errors"
"golang.org/x/sync/errgroup"
"golang.org/x/sync/semaphore"
"sync"
"time"
)
var (
// ErrBacklogIsNotEnough indicates the backlog is not enough
ErrBacklogIsNotEnough = errors.New("concurrency backlog is not enough")
// ErrAlreadyQuit indicates the job group is quit
ErrAlreadyQuit = errors.New("jobGroup is ready quit")
)
// JobGroup job group
type JobGroup struct {
workerSize int
backlogSize int
ctx context.Context
eg *errgroup.Group
mu sync.Mutex
sem *semaphore.Weighted
payloads chan *Payload
currWeight int // since len(channel) can't be trusted, we should use an additional integer to get the real payload weight running or in backlog
abort chan bool
quit bool
}
// NewJobGroup returns a JobGroup
func NewJobGroup(workerSize, backlogSize int) *JobGroup {
jg := &JobGroup{
workerSize: workerSize,
backlogSize: backlogSize,
}
jg.ctx = context.Background()
jg.eg = &errgroup.Group{}
jg.sem = semaphore.NewWeighted(int64(workerSize))
jg.payloads = make(chan *Payload, backlogSize+workerSize)
jg.abort = make(chan bool, 1)
return jg
}
// Start to consume the jobs
func (jg *JobGroup) Start() {
for {
select {
case <-jg.abort:
return
case payload := <-jg.payloads:
if err := jg.sem.Acquire(jg.ctx, int64(payload.weight)); err != nil {
fmt.Printf("%+v\n", errors.Wrap(err, "semaphore acquire error"))
break
}
jg.eg.Go(func() error {
jg.runPayload(payload)
return nil
})
}
}
}
func (jg *JobGroup) runPayload(payload *Payload) {
f := func() {
defer func() {
jg.mu.Lock()
defer jg.mu.Unlock()
jg.currWeight -= payload.weight
jg.sem.Release(int64(payload.weight))
if r := recover(); r != nil {
if re, ok := r.(error); ok {
fmt.Printf("%+v\n", errors.WithMessage(re, "[Recover from Panic]"))
} else {
fmt.Printf("[Recover from Panic]%v\n", r)
}
jg.sem.Release(int64(payload.weight))
}
}()
payload.f()
}
if payload.timeout == 0 {
f()
} else {
// run with timeout
ch := make(chan bool)
go func() {
f()
defer func() {
recover() // recover if the channel is closed
}()
ch <- true
}()
select {
case <-ch:
close(ch)
case <-time.After(payload.timeout):
close(ch)
if payload.cancel != nil {
payload.cancel()
}
}
}
}
// GoWithPayload commits a raw payload
func (jg *JobGroup) GoWithPayload(p *Payload) error {
if p.weight < 1 || p.weight > jg.workerSize {
return errors.Errorf("weight(%d) < 1 or > worker size(%d)", p.weight, jg.workerSize)
}
jg.mu.Lock()
defer jg.mu.Unlock()
if jg.quit {
return ErrAlreadyQuit
}
if jg.currWeight+p.weight > jg.workerSize+jg.backlogSize {
return ErrBacklogIsNotEnough
}
jg.currWeight += p.weight
jg.payloads <- p
return nil
}
// GoWithWeight commits a job to the backlog with weight
func (jg *JobGroup) GoWithWeight(weight int, f func()) error {
p := NewPayload(f)
p.SetWeight(weight)
return jg.GoWithPayload(p)
}
// Go commits a job to the backlog
func (jg *JobGroup) Go(f func()) error {
return jg.GoWithPayload(NewPayload(f))
}
// Abort the job group and returns at once, however the workers would still do its jobs
func (jg *JobGroup) Abort() {
jg.mu.Lock()
defer jg.mu.Unlock()
jg.abort <- true
jg.quit = true
}
// AbortWait the job group and wait until the workers is done
func (jg *JobGroup) AbortWait() {
jg.Abort()
_ = jg.eg.Wait()
return
}
// StopWait the job group would no longer accept new jobs and would do and wait until all the jobs in backlog is done
func (jg *JobGroup) StopWait() {
jg.mu.Lock()
jg.quit = true
jg.mu.Unlock()
var quitAfterWait bool
for {
if jg.currWeight == 0 {
quitAfterWait = true
}
_ = jg.eg.Wait()
if quitAfterWait {
return
}
}
}