53 lines
1.4 KiB
Go
53 lines
1.4 KiB
Go
// Go's _select_ lets you wait on multiple channel
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// operations. Combining goroutines and channels with
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// select is powerful feature of Go.
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package main
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import "time"
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import "fmt"
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func main() {
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// For our example we'll select accross two channels.
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c1 := make(chan string)
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c2 := make(chan string)
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// This third channel will indicate when we're done
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// and can exit the program.
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d := make(chan bool, 1)
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// The first two channels will receive a value after
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// some amount of time, to simulate e.g. blocking RPC
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// operations executing in concurrent goroutines.
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go func() {
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time.Sleep(time.Second * 1)
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c1 <- "one"
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}()
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go func() {
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time.Sleep(time.Second * 2)
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c2 <- "two"
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}()
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// We'll use `select` to await both of these values
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// simultaneously, printing each one as it arrives.
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// Once we've received both, we'll send a value to the
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// `d` channel indicating that we're ready to proceed.
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go func() {
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for i := 0; i < 2; i++ {
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select {
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case msg1 := <-c1:
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fmt.Println("received", msg1)
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case msg2 := <-c2:
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fmt.Println("received", msg2)
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}
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}
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d <- true
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}()
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// Since all other code is running in concurrent
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// goroutines, we'll executing a blocking receive
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// here to await completion of our example.
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<-d
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}
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