51 lines
1.4 KiB
Go
51 lines
1.4 KiB
Go
// In the previous example we looked at
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// [spawning external processes](spawning-processes). We
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// do this when we need an external process accessible to
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// a running Go process. Sometimes we just want to
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// completely replace the current Go process with another
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// (perhaps non-Go) one. To do this we'll use Go's
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// implementation of the classic
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// <a href="http://en.wikipedia.org/wiki/Exec_(operating_system)"><code>exec</code></a>
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// function.
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package main
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import (
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"os"
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"os/exec"
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"syscall"
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)
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func main() {
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// For our example we'll exec `ls`. Go requires an
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// absolute path to the binary we want to execute, so
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// we'll use `exec.LookPath` to find it (probably
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// `/bin/ls`).
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binary, lookErr := exec.LookPath("ls")
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if lookErr != nil {
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panic(lookErr)
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}
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// `Exec` requires arguments in slice form (as
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// apposed to one big string). We'll give `ls` a few
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// common arguments. Note that the first argument should
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// be the program name.
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args := []string{"ls", "-a", "-l", "-h"}
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// `Exec` also needs a set of [environment variables](environment-variables)
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// to use. Here we just provide our current
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// environment.
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env := os.Environ()
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// Here's the actual `syscall.Exec` call. If this call is
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// successful, the execution of our process will end
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// here and be replaced by the `/bin/ls -a -l -h`
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// process. If there is an error we'll get a return
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// value.
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execErr := syscall.Exec(binary, args, env)
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if execErr != nil {
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panic(execErr)
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}
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}
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