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More robust script handling and code cleanup

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In this commit, I have made the script handling dramatically more
robust, and the code has been cleaned up a fair amount. We no longer
have to manually set is restarting or anything like that, and we dont
rely on a fragile exit code system.
This commit is contained in:
Zoe
2025-10-07 16:15:05 +00:00
parent 4a70260ea5
commit dcd8d810f0
2 changed files with 162 additions and 134 deletions
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252
main.go
View File

@@ -54,10 +54,8 @@ type Script struct {
command *exec.Cmd
mutex sync.Mutex
scriptName string
isRestarting bool
wg sync.WaitGroup
// the exit code of the script, only set after the script has exited
exitCode int
// notified with the exit code of the script when it exits
exitCode chan int
}
type ZQDGR struct {
@@ -137,7 +135,7 @@ func (zqdgr *ZQDGR) NewScript(scriptName string, args ...string) *Script {
zqdgr: zqdgr,
command: command,
scriptName: scriptName,
isRestarting: false,
exitCode: make(chan int),
}
}
@@ -145,45 +143,49 @@ func (s *Script) Start() error {
s.mutex.Lock()
defer s.mutex.Unlock()
s.wg.Add(1)
err := s.command.Start()
if err != nil {
s.wg.Done()
return err
}
go func() {
err := s.command.Wait()
if err != nil {
if exitError, ok := err.(*exec.ExitError); ok {
s.exitCode = exitError.ExitCode()
} else {
// Other errors (e.g., process not found, permission denied)
if !s.isRestarting {
log.Printf("Error waiting for script %s: %v", s.scriptName, err)
s.exitCode = 1
}
}
}
processState, err := s.command.Process.Wait()
slog.Debug("Script exited", "script", s.scriptName, "error", err)
if !s.isRestarting {
s.wg.Done()
}
s.exitCode <- processState.ExitCode()
}()
return err
}
func (s *Script) Stop(lock bool) error {
if lock {
s.mutex.Lock()
defer s.mutex.Unlock()
// it is the caller's responsibility to lock the mutex before calling this function
func (s *Script) Stop() error {
slog.Debug("Making sure process is still alive")
if runtime.GOOS == "windows" {
if _, err := os.FindProcess(s.command.Process.Pid); err != nil {
// process is already dead
return nil
}
} else {
process, err := os.FindProcess(s.command.Process.Pid)
if err != nil {
return err
}
// Sending signal 0 checks for existence and permissions
err = process.Signal(syscall.Signal(0))
if err != nil {
return nil
}
}
s.isRestarting = true
slog.Debug("Process is still alive, sending signal")
dead := make(chan bool)
go func() {
s.command.Wait()
dead <- true
}()
if s.command.Process != nil {
var signal syscall.Signal
switch s.zqdgr.Config.ShutdownSignal {
case "SIGINT":
@@ -196,22 +198,10 @@ func (s *Script) Stop(lock bool) error {
signal = syscall.SIGKILL
}
// make sure the process is not dead
if s.command.ProcessState != nil && s.command.ProcessState.Exited() {
return nil
}
if err := syscall.Kill(-s.command.Process.Pid, signal); err != nil {
log.Printf("error killing previous process: %v", err)
return err
}
}
dead := make(chan bool)
go func() {
s.command.Wait()
dead <- true
}()
shutdownTimeout := s.zqdgr.Config.ShutdownTimeout
if shutdownTimeout == 0 {
@@ -237,7 +227,7 @@ func (s *Script) Restart() error {
s.mutex.Lock()
err := s.Stop(false)
err := s.Stop()
if err != nil {
s.mutex.Unlock()
return err
@@ -251,8 +241,6 @@ func (s *Script) Restart() error {
return nil
}
s.isRestarting = false
s.mutex.Unlock()
err = s.Start()
@@ -274,10 +262,6 @@ func (s *Script) Restart() error {
return err
}
func (s *Script) Wait() {
s.wg.Wait()
}
func (wsServer *WSServer) handleWs(w http.ResponseWriter, r *http.Request) {
conn, err := wsServer.upgrader.Upgrade(w, r, nil)
if err != nil {
@@ -328,33 +312,76 @@ func (zqdgr *ZQDGR) loadConfig() error {
return nil
}
func validatePattern(pattern string) ([]string, error) {
var paternArray []string
var currentPattern string
inMatch := false
// iterate over every letter in the pattern
for _, p := range pattern {
if string(p) == "{" {
if inMatch {
return nil, fmt.Errorf("unexpected { in pattern")
}
inMatch = true
}
if string(p) == "}" {
if !inMatch {
return nil, fmt.Errorf("enexpected } in pattern")
}
inMatch = false
}
if string(p) == "," && !inMatch {
paternArray = append(paternArray, currentPattern)
currentPattern = ""
continue
}
currentPattern += string(p)
}
if inMatch {
return nil, fmt.Errorf("unmatched } in pattern")
}
if currentPattern != "" {
paternArray = append(paternArray, currentPattern)
}
return paternArray, nil
}
func main() {
var err error
// var err error
var debugMode bool
noWs := flag.Bool("no-ws", false, "Disable WebSocket server")
configDir := flag.String("config", ".", "Path to the config directory")
disableReloadConfig := flag.Bool("no-reload-config", false, "Do not restart ZQDGR on config file change")
flag.StringVar(configDir, "C", *configDir, "Path to the config directory")
disableReloadConfig := flag.Bool("no-reload-config", false, "Do not restart ZQDGR on config file change")
flag.Parse()
debugModeVal, ok := os.LookupEnv("ZQDGR_DEBUG")
if ok {
debugMode, err = strconv.ParseBool(debugModeVal)
if err != nil {
log.Fatal(err)
}
// if ParseBool returns an error, ZQDGR_DEBUG is not a bool
debugMode, _ = strconv.ParseBool(os.Getenv("ZQDGR_DEBUG"))
if debugMode {
slog.SetLogLoggerLevel(slog.LevelDebug)
}
}
originalArgs := os.Args
os.Args = flag.Args()
zqdgr := NewZQDGR(*noWs, *configDir)
expandedConfigDir, err := filepath.Abs(*configDir)
if err != nil {
log.Fatal(err)
}
slog.Debug("noWS", "noWs", *noWs, "configDir", *configDir, "expandedConfigDir", expandedConfigDir, "disableReloadConfig", *disableReloadConfig)
zqdgr := NewZQDGR(*noWs, expandedConfigDir)
if zqdgr == nil {
return
}
@@ -362,10 +389,13 @@ func main() {
var command string
var commandArgs []string
// command name trimmed by flags.Args()
// os.Args ~= [script, --, arguments]
for i, arg := range os.Args {
if arg == "--" {
if i+2 < len(os.Args) {
commandArgs = os.Args[i+2:]
slog.Debug("Found double-dash", "i", i, "len(os.Args)", len(os.Args), "os.Args", os.Args)
if len(os.Args)-i > 1 {
commandArgs = os.Args[i+1:]
}
break
}
@@ -378,6 +408,8 @@ func main() {
commandArgs = append(commandArgs, arg)
}
slog.Debug("Collected", "command", command, "commandArgs", commandArgs)
watchMode := false
var scriptName string
switch command {
@@ -520,13 +552,7 @@ func main() {
log.Fatal("please specify a script to run")
}
watchMode = true
for i := range commandArgs {
if strings.HasPrefix(commandArgs[i], "-") {
continue
}
scriptName = commandArgs[i]
}
scriptName = commandArgs[0]
default:
scriptName = command
}
@@ -544,7 +570,9 @@ func main() {
log.Println("Received signal, exiting...")
if script.command != nil {
script.Stop(true)
script.mutex.Lock()
script.Stop()
script.mutex.Unlock()
}
os.Exit(0)
@@ -568,48 +596,21 @@ func main() {
}
// make sure the pattern is valid
var paternArray []string
var currentPattern string
inMatch := false
// iterate over every letter in the pattern
for _, p := range zqdgr.Config.Pattern {
if string(p) == "{" {
if inMatch {
log.Fatal("unmatched { in pattern")
patternArray, err := validatePattern(zqdgr.Config.Pattern)
if err != nil {
log.Fatal(err)
}
inMatch = true
for _, pattern := range zqdgr.Config.ExcludedGlobs {
_, err := validatePattern(pattern)
if err != nil {
log.Fatal(err)
}
if string(p) == "}" {
if !inMatch {
log.Fatal("unmatched } in pattern")
}
inMatch = false
}
if string(p) == "," && !inMatch {
paternArray = append(paternArray, currentPattern)
currentPattern = ""
inMatch = false
continue
}
currentPattern += string(p)
}
if inMatch {
log.Fatal("unmatched } in pattern")
}
if currentPattern != "" {
paternArray = append(paternArray, currentPattern)
}
watcherConfig := WatcherConfig{
excludedGlobs: globList(zqdgr.Config.ExcludedGlobs),
pattern: paternArray,
pattern: patternArray,
}
watcher, err := NewWatcher(&watcherConfig)
@@ -629,13 +630,12 @@ func main() {
log.Fatal(err)
}
// We use this timer to deduplicate events.
// tailing edge debounce of file system events
var (
// Wait 100ms for new events; each new event resets the timer.
waitFor = 100 * time.Millisecond
// Keep track of the timers, as path → timer.
mu sync.Mutex
// watched filepath -> timer
timers = make(map[string]*time.Timer)
)
go func() {
@@ -657,7 +657,15 @@ func main() {
if event.Op&fsnotify.Remove == fsnotify.Remove || event.Op&fsnotify.Write == fsnotify.Write || event.Op&fsnotify.Create == fsnotify.Create {
slog.Debug("File changed", "file", event.Name)
if strings.HasSuffix(event.Name, "zqdgr.config.json") {
fullEventPath, err := filepath.Abs(event.Name)
if err != nil {
log.Fatal(err)
}
slog.Debug("expanded event path", "path", fullEventPath)
// check against the fullpath to make sure that the config file that was changed is
// actually the one we are using
if fullEventPath == filepath.Join(zqdgr.WorkingDirectory, "zqdgr.config.json") {
// re-exec the exact same command
if !*disableReloadConfig {
fmt.Println("zqdgr.config.json has changed, restarting...")
@@ -666,11 +674,15 @@ func main() {
log.Fatal(err)
}
err = script.Stop(true)
script.mutex.Lock()
err = script.Stop()
if err != nil {
log.Fatal(err)
}
script.mutex.Unlock()
err = syscall.Exec(executable, originalArgs, os.Environ())
if err != nil {
log.Fatal(err)
@@ -680,11 +692,18 @@ func main() {
}
}
if pathShouldBeTracked(&watcherConfig, event.Name) && event.Op&fsnotify.Create == fsnotify.Create {
if pathShouldBeTracked(&watcherConfig, event.Name) {
if event.Op&fsnotify.Create == fsnotify.Create {
slog.Debug("Adding new file to watcher", "file", event.Name)
watcher.(NotifyWatcher).watcher.Add(event.Name)
}
if event.Op&fsnotify.Remove == fsnotify.Remove {
slog.Debug("Removing file from watcher", "file", event.Name)
watcher.(NotifyWatcher).watcher.Remove(event.Name)
}
}
if pathMatches(&watcherConfig, event.Name) {
script.Restart()
}
@@ -715,8 +734,17 @@ func main() {
}
}
}()
// block until the script exits with a zero (aka, it normally exited on its own)
for {
exitCode := <-script.exitCode
slog.Debug("Script exited", "script", scriptName, "exitCode", exitCode)
if exitCode == 0 {
os.Exit(0)
}
}
}
script.Wait()
os.Exit(script.exitCode)
// block until the script exits
os.Exit(<-script.exitCode)
}

2
zqdgr.config.json
View File

@@ -1,6 +1,6 @@
{
"name": "zqdgr",
"version": "0.0.5",
"version": "0.0.6",
"description": "zqdgr is a quick and dirty Golang runner",
"author": "juls0730",
"license": "BSL-1.0",