func executeRootScript(script []*dockerscript.Command) error {
if len(rootPlugins) > 0 {
// If there are root plugins, wrap the script inside them
var (
rootCmd *dockerscript.Command
lastCmd *dockerscript.Command
)
for _, plugin := range rootPlugins {
pluginCmd := &dockerscript.Command{
Args: []string{plugin},
}
if rootCmd == nil {
rootCmd = pluginCmd
} else {
lastCmd.Children = []*dockerscript.Command{pluginCmd}
}
lastCmd = pluginCmd
}
lastCmd.Children = script
script = []*dockerscript.Command{rootCmd}
}
handlers, err := Handlers(introspect)
if err != nil {
return err
}
defer handlers.Close()
var tasks sync.WaitGroup
defer func() {
Debugf("Waiting for introspection...\n")
tasks.Wait()
Debugf("DONE Waiting for introspection\n")
}()
if introspect != nil {
tasks.Add(1)
go func() {
Debugf("starting introspection\n")
defer Debugf("done with introspection\n")
defer tasks.Done()
introspect.Send(data.Empty().Set("cmd", "log", "stdout").Set("message", "introspection worked!").Bytes(), nil)
Debugf("XXX starting reading introspection messages\n")
r := beam.NewRouter(handlers)
r.NewRoute().All().Handler(func(p []byte, a *os.File) error {
Logf("[INTROSPECTION] %s\n", beam.MsgDesc(p, a))
return handlers.Send(p, a)
})
n, err := beam.Copy(r, introspect)
Debugf("XXX done reading %d introspection messages: %v\n", n, err)
}()
}
if err := executeScript(handlers, script); err != nil {
return err
}
return nil
}
// 1) Find a handler for the command (if no handler, fail)
// 2) Attach new in & out pair to the handler
// 3) [in the background] Copy handler output to our own output
// 4) [in the background] Run the handler
// 5) Recursively executeScript() all children commands and wait for them to complete
// 6) Wait for handler to return and (shortly afterwards) output copy to complete
// 7) Profit
func executeCommand(out beam.Sender, cmd *dockerscript.Command) error {
if flX {
fmt.Printf("+ %v\n", strings.Replace(strings.TrimRight(cmd.String(), "\n"), "\n", "\n+ ", -1))
}
Debugf("executeCommand(%s)\n", strings.Join(cmd.Args, " "))
defer Debugf("executeCommand(%s) DONE\n", strings.Join(cmd.Args, " "))
if len(cmd.Args) == 0 {
return fmt.Errorf("empty command")
}
Debugf("[executeCommand] sending job '%s'\n", strings.Join(cmd.Args, " "))
job, err := beam.SendConn(out, data.Empty().Set("cmd", cmd.Args...).Set("type", "job").Bytes())
if err != nil {
return fmt.Errorf("%v\n", err)
}
var tasks sync.WaitGroup
tasks.Add(1)
Debugf("[executeCommand] spawning background copy of the output of '%s'\n", strings.Join(cmd.Args, " "))
go func() {
if out != nil {
Debugf("[executeCommand] background copy of the output of '%s'\n", strings.Join(cmd.Args, " "))
n, err := beam.Copy(out, job)
if err != nil {
Fatalf("[executeCommand] [%s] error during background copy: %v\n", strings.Join(cmd.Args, " "), err)
}
Debugf("[executeCommand] background copy done of the output of '%s': copied %d messages\n", strings.Join(cmd.Args, " "), n)
}
tasks.Done()
}()
// depth-first execution of children commands
// executeScript() blocks until all commands are completed
Debugf("[executeCommand] recursively running children of '%s'\n", strings.Join(cmd.Args, " "))
executeScript(job, cmd.Children)
Debugf("[executeCommand] DONE recursively running children of '%s'\n", strings.Join(cmd.Args, " "))
job.CloseWrite()
Debugf("[executeCommand] closing the input of '%s' (all children are completed)\n", strings.Join(cmd.Args, " "))
Debugf("[executeCommand] waiting for background copy of '%s' to complete...\n", strings.Join(cmd.Args, " "))
tasks.Wait()
Debugf("[executeCommand] background copy of '%s' complete! This means the job completed.\n", strings.Join(cmd.Args, " "))
return nil
}