96 lines
1.6 KiB
Go
96 lines
1.6 KiB
Go
// Package externalcmd allows to launch external commands.
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package externalcmd
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import (
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"errors"
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"fmt"
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"os"
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"time"
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)
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const (
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restartPause = 5 * time.Second
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)
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var errTerminated = errors.New("terminated")
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// OnExitFunc is the prototype of onExit.
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type OnExitFunc func(error)
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// Environment is a Cmd environment.
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type Environment map[string]string
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// Cmd is an external command.
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type Cmd struct {
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Pool *Pool
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Cmdstr string
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Restart bool
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Env Environment
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OnExit OnExitFunc
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// in
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terminate chan struct{}
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}
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// Start starts the command.
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func (c *Cmd) Start() {
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if c.OnExit == nil {
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c.OnExit = func(_ error) {}
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}
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c.terminate = make(chan struct{})
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c.Pool.wg.Add(1)
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go c.run()
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}
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// Close closes the command. It doesn't wait for the command to exit.
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func (c *Cmd) Close() {
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close(c.terminate)
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}
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func (c *Cmd) run() {
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defer c.Pool.wg.Done()
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// replace variables in both Linux and Windows, in order to allow using the
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// same commands on both of them.
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cmdstr := os.Expand(c.Cmdstr, func(variable string) string {
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if value, ok := c.Env[variable]; ok {
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return value
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}
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return os.Getenv(variable)
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})
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env := append([]string(nil), os.Environ()...)
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for key, val := range c.Env {
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env = append(env, key+"="+val)
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}
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for {
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err := c.runOSSpecific(cmdstr, env)
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if errors.Is(err, errTerminated) {
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return
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}
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if !c.Restart {
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if err != nil {
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c.OnExit(err)
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}
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return
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}
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if err != nil {
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c.OnExit(err)
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} else {
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c.OnExit(fmt.Errorf("command exited with code 0"))
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}
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select {
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case <-time.After(restartPause):
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case <-c.terminate:
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return
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}
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}
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}
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