update code content for fan-out pattern

This commit is contained in:
Edward 2020-05-07 15:08:32 +08:00
parent 5e5c367660
commit fe3617814c
4 changed files with 168 additions and 450 deletions

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@ -1,131 +1,132 @@
package fanout package fanout
import ( // Split 重复分发数据为多份
"context" // Split a channel into n channels that receive messages in a round-robin fashion.
"sync" func Split(ch <-chan int, n int) []chan int {
"sync/atomic"
"go.uber.org/zap" //get a queue of chan
) cs := make([]chan int, n)
var ( // Distributes the work in a round robin fashion among the stated number
log, _ = zap.NewDevelopment() // of channels until the main channel has been closed. In that case, close
) // all channels and return.
distributeToChannels := func(ch <-chan int, cs []chan int) {
const ( // Close every channel when the execution ends.
MaxWorkers = 16 defer func(cs []chan int) {
MaxQueueSize = 512 for _, c := range cs {
MasterQueueSize = MaxQueueSize * MaxWorkers close(c)
)
type Pipeline struct {
workers map[int]*worker
chain chan interface{}
}
func (p *Pipeline) Start(ctx context.Context) {
go func(pipe *Pipeline) {
for {
expectationWorkers := len(pipe.chain) % MaxWorkers
if expectationWorkers >= MaxWorkers {
expectationWorkers = 0
} }
}(cs)
//this version will block
for {
//get a target from ch
select { select {
case <-ctx.Done(): case val, ok := <-ch:
return
case val, ok := <-pipe.chain:
if !ok { if !ok {
return return
} }
go pipe.workers[expectationWorkers].stream(val) //send value to all channels
for _, c := range cs {
c <- val
}
} }
} }
}(p)
}
func (p *Pipeline) Dispatch(msg interface{}) {
p.chain <- msg
}
type DispatcherBuilder func() Dispatcher
func NewPipeline(d DispatcherBuilder, idle uint32, debug bool) *Pipeline {
ch := make(chan interface{}, MasterQueueSize)
wk := make(map[int]*worker)
for i := 0; i < MaxWorkers; i++ {
wk[i] = &worker{
index: uint32(i + 1),
chain: make(chan interface{}, MaxQueueSize),
mutex: new(sync.Mutex),
debug: debug,
idle: idle,
Dispatcher: d(),
}
} }
return &Pipeline{workers: wk, chain: ch}
// a worker to distribute message
go distributeToChannels(ch, cs)
return cs
} }
type Dispatcher interface { // Split2 多工作者重复分发
Before(context.Context) error // Split2 a channel into n channels that receive messages in a round-robin fashion.
After() error func Split2(ch <-chan int, n int) []<-chan int {
Process(interface{}) error
}
type worker struct { cs := make([]chan int, n)
index uint32
mutex *sync.Mutex
running bool
chain chan interface{}
debug bool
idle uint32
Dispatcher
}
func (c *worker) stream(val interface{}) { //this version will block
c.chain <- val for {
if !c.running { //get a target from ch
c.mutex.Lock() select {
c.running = true case val, ok := <-ch:
ctx, cancel := context.WithCancel(context.Background()) if !ok {
defer func(w *worker, cancel context.CancelFunc) { return cs
if w.debug {
log.Info("Worker leaving", zap.Any("index", w.index), zap.Any("idle", w.idle))
} }
err := c.After() //send value to all channels
if err != nil { for _, c := range cs {
log.Error("can not finish track issue", zap.Error(err)) go func(tmpV int) {
} c <- tmpV
cancel() }(val)
w.mutex.Unlock()
w.running = false
}(c, cancel)
err := c.Before(ctx)
if err != nil { }
log.Error("can not start worker", zap.Error(err))
} }
var idle uint32 = 0 }
return cs
}
//Split3 随机分发到不同的目的地
//Split3 a channel into n channels that receive messages in a round-robin fashion.
func Split3(ch <-chan int, n int) []<-chan int {
cs := make([]chan int, n)
// Distributes the work in a round robin fashion among the stated number
// of channels until the main channel has been closed. In that case, close
// all channels and return.
distributeToChannels := func(ch <-chan int, cs []chan<- int) {
// Close every channel when the execution ends.
defer func(cs []chan<- int) {
for _, c := range cs {
close(c)
}
}(cs)
for { for {
select { for _, c := range cs {
case msg := <-c.chain: select {
atomic.StoreUint32(&idle, 0) case val, ok := <-ch:
if msg != nil { if !ok {
err := c.Process(msg)
if err != nil {
log.Error("can not process message",
zap.Any("msg", &msg),
zap.Error(err),
)
}
}
default:
atomic.AddUint32(&idle, 1)
if i := atomic.LoadUint32(&idle); i > 0 {
if i > c.idle {
return return
} }
c <- val
} }
} }
} }
} }
go distributeToChannels(ch, cs)
return cs
}
//The first stage, gen, is a function that converts a list of integers to a channel that emits the integers in the list.
// The gen function starts a goroutine that sends the integers on the channel and closes the channel when all
// the values have been sent:
func gen(nums ...int) <-chan int {
out := make(chan int)
go func() {
defer close(out)
for _, n := range nums {
out <- n
}
}()
return out
}
//The second stage, sq, receives integers from a channel and returns a channel that emits the square of
// each received integer. After the inbound channel is closed and this stage has sent all the values downstream,
// it closes the outbound channel:
func sq(in <-chan int) <-chan int {
out := make(chan int)
go func() {
for n := range in {
out <- n * n
}
close(out)
}()
return out
} }

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@ -1,140 +0,0 @@
package fanout
import (
"context"
"fmt"
"log"
"sync"
"testing"
"time"
)
func TestFanInOut(T *testing.T) {
ctx, cancelFunc := context.WithCancel(context.Background())
defer cancelFunc()
var errList []chan error
nChan, err, err := generateNumbers(ctx)
if err != nil {
log.Fatal(err)
}
errList = append(errList, err)
fChannel, errList, err := fanout(ctx, nChan, squareNumbers)
errList = append(errList, errList...)
res, errRes, err := fanin(fChannel, errList)
go func() {
for {
select {
case r := <-res:
v, ok := r.(int)
if !ok {
// TODO
_ = ok
}
fmt.Println(v)
case e := <-errRes:
fmt.Println(e)
}
}
}()
fmt.Println("finished")
time.Sleep(10 * time.Duration(time.Second))
}
type Op func(context.Context, chan interface{}) (chan interface{}, chan error, error)
func generateNumbers(ctx context.Context) (chan interface{}, chan error, error) {
fmt.Println("generateNumbers called")
out := make(chan interface{}, 100)
err := make(chan error, 100)
go func() {
defer close(out)
defer close(err)
for i := 0; i < 10; i++ {
fmt.Println("gen: ", i)
out <- i
}
}()
return out, err, nil
}
func fanout(ctx context.Context, in chan interface{}, fct Op) ([]chan interface{}, []chan error, error) {
fmt.Println("fanout called")
var out []chan interface{}
var errList []chan error
for i := 0; i < 5; i++ {
res, err, err := fct(ctx, in)
// Todo: manage error
_ = err
out = append(out, res)
errList = append(errList, err)
}
return out, errList, nil
}
func squareNumbers(ctx context.Context, in chan interface{}) (chan interface{}, chan error, error) {
fmt.Println("squareNumbers called")
out := make(chan interface{}, 100)
err := make(chan error, 100)
go func() {
for v := range in {
num, _ := v.(int)
squared := num * num
select {
case out <- squared:
case <-ctx.Done():
fmt.Println("ctx done")
return
}
}
close(out)
}()
return out, err, nil
}
func fanin(ins []chan interface{}, errList []chan error) (chan interface{}, chan error, error) {
fmt.Println("fanin called")
out := make(chan interface{}, 100)
errout := make(chan error, 100)
var waitgroup sync.WaitGroup
length := len(ins) + len(errList)
waitgroup.Add(length)
for _, v := range ins {
go func(w chan interface{}) {
for val := range w {
out <- val
}
waitgroup.Done()
}(v)
}
for _, e := range errList {
go func(err chan error) {
for v := range err {
errout <- v
}
waitgroup.Done()
}(e)
}
go func() {
waitgroup.Wait()
close(out)
close(errout)
}()
return out, errout, nil
}

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@ -1 +1,64 @@
package fanout package fanout
import (
"fmt"
"sync"
"testing"
)
func TestMultiFanOutNumbersSeq(T *testing.T) {
//一路输入源
dataStreams := []int{13, 44, 56, 99, 9, 45, 67, 90, 78, 23}
//generator integer stream
inputChan := gen(dataStreams...)
// transfer to
ch := sq(inputChan)
// split it to 3 channel
// 重复分发
outArray := Split(ch, 3)
var wg sync.WaitGroup
wg.Add(len(outArray))
for i := 0; i < len(outArray); i++ {
go func(in <-chan int, index int) {
sum := 0
for item := range in {
sum += item
}
fmt.Println("worker:", index, sum)
wg.Done()
}(outArray[i], i)
}
wg.Wait()
}
func TestManualFanOutNumbersSeq(T *testing.T) {
//一路输入源
dataStreams := []int{13, 44, 56, 99, 9, 45, 67, 90, 78, 23}
// generate the common channel with inputs
inputChan1 := gen(dataStreams...)
inputChan2 := gen(dataStreams...)
//Manual Fan-out to 2 Go-routine
c1 := sq(inputChan1)
c2 := sq(inputChan2)
fmt.Print("c1 queue: ")
for n := range c1 {
fmt.Print(n, " ")
}
fmt.Println()
fmt.Print("c2 queue: ")
for n := range c2 {
fmt.Print(n, " ")
}
fmt.Println()
}

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@ -1,206 +0,0 @@
# Implementation
We can activate worker base on traffic of parent channel
```go
package concurrency
import (
"context"
"io"
"sync"
"sync/atomic"
"bitbucket.org/sakariai/sakari/log"
"bitbucket.org/sakariai/sakari/log/field"
)
const (
MaxWorkers = 32
MaxQueueSize = 128
)
var (
running uint32 = 0
)
type Pipeline struct {
workers []*worker
chain chan interface{}
}
func (p *Pipeline) Start() {
distributeToChannels := func(ch chan interface{}, cs []*worker) {
writer := cs[0] //first worker must stream as default
for {
for _, c := range cs {
expectationWorkers := uint32(len(ch)/(MaxQueueSize/MaxWorkers)) + 1
select {
case val := <-ch:
runningWorker := atomic.LoadUint32(&running)
if c.index <= runningWorker || c.index <= expectationWorkers {
writer = c
}
if c.debug {
log.Info("Worker receiving", field.Any("index", writer.index), field.Any("running", runningWorker), field.Any("no# workers", expectationWorkers))
}
go writer.stream(val)
}
}
}
}
go distributeToChannels(p.chain, p.workers)
}
func (p *Pipeline) Dispatch(msg interface{}) {
p.chain <- msg
}
type DispatcherBuilder func() Dispatcher
func NewPipeline(d DispatcherBuilder, ch chan interface{}, idle uint32, debug bool) *Pipeline {
wk := make([]*worker, 0, MaxWorkers)
for i := 0; i < MaxWorkers; i++ {
wk = append(wk,
&worker{
index: uint32(i + 1),
chain: make(chan interface{}, MaxQueueSize),
mutex: new(sync.Mutex),
debug: debug,
idle: idle,
Dispatcher: d(),
})
}
return &Pipeline{workers: wk, chain: ch}
}
type Dispatcher interface {
Before(context.Context) error
After() error
Process(interface{}) error
}
type worker struct {
index uint32
mutex *sync.Mutex
running bool
chain chan interface{}
debug bool
idle uint32
Dispatcher
}
func (c *worker) stream(val interface{}) {
c.chain <- val
if !c.running {
c.mutex.Lock()
c.running = true
atomic.AddUint32(&running, 1)
defer atomic.AddUint32(&running, ^uint32(1-1))
ctx, cancel := context.WithCancel(context.Background())
err := c.Before(ctx)
if err != nil {
log.Error("can not start worker", field.Error(err))
}
defer func(w *worker, cancel context.CancelFunc) {
if w.debug {
log.Info("Worker leaving", field.Any("index", w.index), field.Any("idle", w.idle))
}
err := c.After()
if err != nil {
log.Error("can not finish track issue", field.Error(err))
}
cancel()
w.mutex.Unlock()
w.running = false
}(c, cancel)
var idle uint32 = 0
for {
select {
case msg := <-c.chain:
atomic.StoreUint32(&idle, 0)
if msg != nil {
err := c.Process(msg)
if err != nil {
log.Error("can not process message",
field.Any("msg", &msg),
field.Error(err),
)
}
if err == io.EOF {
return
}
}
default:
atomic.AddUint32(&idle, 1)
if i := atomic.LoadUint32(&idle); i > 0 {
if i > c.idle {
return
}
if c.debug {
log.Info("Idle", field.Any("worker index", c.index), field.Any("idle", idle))
}
}
}
}
}
}
```
## Usage
```go
import concurrency
type taggingDispatcher struct {
Address string
stream proto.Havilah_StreamMetricClient
conn *grpc.ClientConn
}
func (d *taggingDispatcher) Before(ctx context.Context) error {
conn, err := grpc.Dial(d.Address, grpc.WithInsecure())
if err != nil {
return err
}
d.conn = conn
client := proto.NewHavilahClient(conn)
stream, err := client.StreamMetric(ctx)
if err != nil {
return err
}
d.stream = stream
return nil
}
func (d *taggingDispatcher) After() error {
_, err := d.stream.CloseAndRecv()
e := d.conn.Close()
if e != nil {
log.Error("close havilah connection error", field.Error(e))
}
return err
}
func (d *taggingDispatcher) Process(msg interface{}) error {
return d.stream.Send(msg.(*proto.Tagging))
}
tagging := &Tagging{
topic: topic,
pipeline: concurrency.NewPipeline(func() concurrency.Dispatcher {
return &taggingDispatcher{Address: address}
}, ch, idle, debug),
}
tagging.pipeline.Start()
func main(){
tagging.pipeline.Dispatch(youStruct{})
}
```