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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,118 @@ | ||
| package main | ||
|
|
||
| import ( | ||
| "os" | ||
| "os/signal" | ||
| "syscall" | ||
|
|
||
| "github.com/rs/zerolog/log" | ||
| ) | ||
|
|
||
| type Process struct { | ||
| Process *os.Process | ||
| FinalState *os.ProcessState | ||
| } | ||
|
|
||
| func startProcess(chan_process chan *Process) (*Process, error) { | ||
| log.Info().Msg("Starting new process") | ||
|
|
||
| procAttr := os.ProcAttr{ | ||
| Files: []*os.File{os.Stdin, os.Stdout, os.Stderr}, | ||
| } | ||
|
|
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| // Ensure the children does not have the --process-manager switch | ||
| var args = make([]string, 0, len(os.Args)) | ||
| for _, v := range os.Args { | ||
| if v == "--process-manager" || v == "-process-manager" { | ||
| continue | ||
| } | ||
| args = append(args, v) | ||
| } | ||
| args = append(args, "--notify-parent") | ||
|
|
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| p := &Process{} | ||
|
|
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| proc, err := os.StartProcess(args[0], args, &procAttr) | ||
| if err != nil { | ||
| log.Error().Err(err).Msg("Error while starting new process") | ||
| return p, err | ||
| } | ||
| p.Process = proc | ||
|
|
||
| go func() { | ||
| s, _ := proc.Wait() | ||
| p.FinalState = s | ||
| chan_process <- p | ||
| }() | ||
|
|
||
| return p, err | ||
| } | ||
|
|
||
| func processManager() { | ||
| processes := map[*Process]*Process{} | ||
| chan_process := make(chan *Process) | ||
| var starting *Process | ||
|
|
||
| // Start first worker process | ||
| proc, err := startProcess(chan_process) | ||
| if err != nil { | ||
| log.Panic().Err(err).Msg("Unable to start the worker process") | ||
| } | ||
| processes[proc] = proc | ||
| starting = proc | ||
|
|
||
| // Signals | ||
| chan_signals := make(chan os.Signal, 1) | ||
| signal.Notify(chan_signals, syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP, syscall.SIGUSR1) | ||
|
|
||
| process_manager_loop: | ||
| for { | ||
| select { | ||
| case s := <-chan_signals: | ||
| switch s { | ||
| case syscall.SIGINT, syscall.SIGTERM: | ||
| log.Info().Msg("Termination signal received, forwarding to worker processes") | ||
| for _, p := range processes { | ||
| p.Process.Signal(syscall.SIGTERM) | ||
| } | ||
|
|
||
| case syscall.SIGHUP: | ||
| if starting != nil { | ||
| log.Warn().Msg("Restart signal received but a restart is already ongoing") | ||
|
|
||
| } else { | ||
| log.Info().Msg("Restart signal received, starting new worker process") | ||
| proc, err := startProcess(chan_process) | ||
| if err != nil { | ||
| log.Panic().Err(err).Msg("Unable to start the new worker process") | ||
| } | ||
| processes[proc] = proc | ||
| starting = proc | ||
| } | ||
|
|
||
| case syscall.SIGUSR1: | ||
| log.Info().Msg("New worker successfully started") | ||
| for _, p := range processes { | ||
| if p != starting { | ||
| p.Process.Signal(syscall.SIGTERM) | ||
| } | ||
| } | ||
| starting = nil | ||
| } | ||
| case p := <-chan_process: | ||
| if p == starting { | ||
| log.Error().Int("worker_pid", p.Process.Pid).Int("exit_code", p.FinalState.ExitCode()).Msg("New worker process exited unexpectedly") | ||
| starting = nil | ||
| } else { | ||
| log.Info().Int("worker_pid", p.Process.Pid).Int("exit_code", p.FinalState.ExitCode()).Msg("Worker process exited") | ||
| } | ||
|
|
||
| delete(processes, p) | ||
|
|
||
| if len(processes) == 0 { | ||
| log.Info().Msg("All worker processes have ended") | ||
| break process_manager_loop | ||
| } | ||
| } | ||
| } | ||
| } |