| Sometimes we'd like our Go programs to intelligently handle [Unix signals](http://en.wikipedia.org/wiki/Unix_signal). For example, we might want a server to gracefully shutdown when it receives a `SIGTERM`, or a command-line tool to stop processing input if it receives a `SIGINT`. Here's how to handle signals in Go with channels. | ||
package main |
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import ( |
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"fmt" |
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"os" |
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"os/signal" |
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"syscall" |
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) |
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func main() { |
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| Go signal notification works by sending `os.Signal` values on a channel. We'll create a channel to receive these notifications (we'll also make one to notify us when the program can exit). | sigs := make(chan os.Signal, 1) |
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done := make(chan bool, 1) |
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| `signal.Notify` registers the given channel to receive notifications of the specified signals. | signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM) |
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| This goroutine executes a blocking receive for signals. When it gets one it'll print it out and then notify the program that it can finish. | go func() { |
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sig := <-sigs |
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fmt.Println() |
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fmt.Println(sig) |
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done <- true |
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}() |
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| The program will wait here until it gets the expected signal (as indicated by the goroutine above sending a value on `done`) and then exit. | fmt.Println("awaiting signal") |
awaiting signal |
<-done |
terminated |
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fmt.Println("exiting") |
exiting |
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} |