mirror of
https://github.com/crazybber/go-pattern-examples.git
synced 2024-11-24 20:56:03 +03:00
147 lines
3.0 KiB
Go
147 lines
3.0 KiB
Go
package fanout
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import (
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"context"
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"sync"
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"sync/atomic"
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"go.uber.org/zap" //https://github.com/uber-go/zap
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//Blazing fast, structured, leveled logging in Go.
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)
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var (
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log, _ = zap.NewDevelopment()
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)
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//Settings of pipeline
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const (
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MaxWorkers = 16
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MaxQueueSize = 512
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MasterQueueSize = MaxQueueSize * MaxWorkers
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)
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//IDispatcher Message
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type IDispatcher interface {
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Before(context.Context) error
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After() error
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Process(interface{}) error
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}
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//worker each work will dispatch message to several channels
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type worker struct {
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index uint32
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mutex *sync.Mutex
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running bool
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chain chan interface{}
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debug bool
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idle uint32
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dispatcher IDispatcher //hold a dispacher，需要自己实现一个dispatcher 工厂
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}
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//Pipeline of workers
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type Pipeline struct {
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workers map[int]*worker
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chain chan interface{}
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}
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//DispatcherBuilder create Dispatcher
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type DispatcherBuilder func() IDispatcher
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//Start run
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func (p *Pipeline) Start(ctx context.Context) {
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go func(pipe *Pipeline) {
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for {
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expectationWorkers := len(pipe.chain) % MaxWorkers
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if expectationWorkers >= MaxWorkers {
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expectationWorkers = 0
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}
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select {
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case <-ctx.Done():
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return
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case val, ok := <-pipe.chain:
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if !ok {
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return
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}
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go pipe.workers[expectationWorkers].stream(val)
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}
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}
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}(p)
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}
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//Dispatch message to chains
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func (p *Pipeline) Dispatch(msg interface{}) {
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p.chain <- msg
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}
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//NewPipeline create a Workflow with a dispacher builder and some workers
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func NewPipeline(d DispatcherBuilder, idle uint32, debug bool) *Pipeline {
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ch := make(chan interface{}, MasterQueueSize)
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wk := make(map[int]*worker)
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for i := 0; i < MaxWorkers; i++ {
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wk[i] = &worker{
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index: uint32(i + 1),
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chain: make(chan interface{}, MaxQueueSize),
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mutex: new(sync.Mutex),
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debug: debug,
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idle: idle,
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dispatcher: d(), //build real dispatcher
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}
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}
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return &Pipeline{workers: wk, chain: ch}
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}
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func (c *worker) stream(val interface{}) {
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c.chain <- val
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if !c.running {
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c.mutex.Lock()
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c.running = true
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ctx, cancel := context.WithCancel(context.Background())
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defer func(w *worker, cancel context.CancelFunc) {
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if w.debug {
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log.Info("Worker leaving", zap.Any("index", w.index), zap.Any("idle", w.idle))
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}
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if c.dispatcher != nil {
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err := c.dispatcher.After()
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if err != nil {
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log.Error("can not finish track issue", zap.Error(err))
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}
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}
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cancel()
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w.mutex.Unlock()
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w.running = false
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}(c, cancel)
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if c.dispatcher != nil {
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err := c.dispatcher.Before(ctx)
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if err != nil {
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log.Error("can not start worker", zap.Error(err))
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}
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}
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var idle uint32 = 0
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for {
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select {
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case msg := <-c.chain:
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atomic.StoreUint32(&idle, 0)
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if msg != nil && c.dispatcher != nil {
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err := c.dispatcher.Process(msg)
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if err != nil {
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log.Error("can not process message", zap.Any("msg", &msg), zap.Error(err))
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}
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}
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default:
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atomic.AddUint32(&idle, 1)
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if i := atomic.LoadUint32(&idle); i > 0 {
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if i > c.idle {
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return
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}
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}
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}
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}
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}
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}
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