go-events package簡介

這是一個建立於 的文章，其中的資訊可能已經有所發展或是發生改變。

go-events實現了一種處理event的機制，其核心概念是Sink（定義在event.go）：

// Event marks items that can be sent as events.type Event interface{}// Sink accepts and sends events.type Sink interface {    // Write an event to the Sink. If no error is returned, the caller will    // assume that all events have been committed to the sink. If an error is    // received, the caller may retry sending the event.    Write(event Event) error    // Close the sink, possibly waiting for pending events to flush.    Close() error}

可以把Sink想象成一個“池子”，它提供了2個方法：Write往“池子”裡發訊息，Close是不用時關閉這個“池子”。 其它幾個檔案其實都是圍繞Sink做文章，構造出各種功能。舉個例子：

package mainimport (    "fmt"    "github.com/docker/go-events"    "time")type eventRecv struct {    name string}func (e *eventRecv)Write(event events.Event) error {    fmt.Printf("%s receives %d\n", e.name, event.(int))    return nil}func (e *eventRecv)Close() error {    return nil}func createEventRecv(name string) *eventRecv {    return &eventRecv{name}}func main() {    e1 := createEventRecv("Foo")    e2 := createEventRecv("Bar")    bc := events.NewBroadcaster(e1, e2)    bc.Write(1)    bc.Write(2)    time.Sleep(time.Second)}

執行結果如下：

Foo receives 1Bar receives 1Foo receives 2Bar receives 2

NewBroadcaster作用是把一個event發送到多個Sink。

再看一個使用NewQueue的例子：

package mainimport (    "fmt"    "github.com/docker/go-events"    "time")type eventRecv struct {    name string}func (e *eventRecv)Write(event events.Event) error {    fmt.Printf("%s receives %d\n", e.name, event)    return nil}func (e *eventRecv)Close() error {    return nil}func createEventRecv(name string) *eventRecv {    return &eventRecv{name}}func main() {    q := events.NewQueue(createEventRecv("Foo"))    q.Write(1)    q.Write(2)    time.Sleep(time.Second)}

執行結果如下：

Foo receives 1Foo receives 2