package server import ( "fmt" "io/fs" "log/slog" "os" "path" "path/filepath" "slices" "time" "go.alanpearce.eu/website/internal/log" "github.com/fsnotify/fsnotify" "github.com/pkg/errors" ) type FileWatcher struct { *fsnotify.Watcher } var ( ignores = []string{ "*.templ", "*.go", } checkSettleInterval = 200 * time.Millisecond ) func matches(name string) func(string) bool { return func(pattern string) bool { matched, err := path.Match(pattern, name) if err != nil { log.Warn("error checking watcher ignores", "error", err) } return matched } } func ignored(pathname string) bool { return slices.ContainsFunc(ignores, matches(path.Base(pathname))) } func NewFileWatcher() (*FileWatcher, error) { watcher, err := fsnotify.NewWatcher() if err != nil { return nil, errors.WithMessage(err, "could not create watcher") } return &FileWatcher{watcher}, nil } func (watcher FileWatcher) AddRecursive(from string) error { log.Debug("walking directory tree", "root", from) err := filepath.WalkDir(from, func(path string, entry fs.DirEntry, err error) error { if err != nil { return errors.WithMessagef(err, "could not walk directory %s", path) } if entry.IsDir() { log.Debug("adding directory to watcher", "path", path) if err = watcher.Add(path); err != nil { return errors.WithMessagef(err, "could not add directory %s to watcher", path) } } return nil }) return errors.WithMessage(err, "error walking directory tree") } func (watcher FileWatcher) Start(callback func(string)) { var timer *time.Timer for { select { case event := <-watcher.Events: if !ignored(event.Name) { log.Debug("watcher event", "name", event.Name, "op", event.Op.String()) if event.Has(fsnotify.Create) || event.Has(fsnotify.Rename) { f, err := os.Stat(event.Name) if err != nil { slog.Error( fmt.Sprintf("error handling %s event: %v", event.Op.String(), err), ) } else if f.IsDir() { err = watcher.Add(event.Name) if err != nil { slog.Error(fmt.Sprintf("error adding new folder to watcher: %v", err)) } } } if event.Has(fsnotify.Rename) || event.Has(fsnotify.Write) || event.Has(fsnotify.Create) || event.Has(fsnotify.Chmod) { if timer == nil { timer = time.AfterFunc(checkSettleInterval, func() { callback(event.Name) }) } timer.Reset(checkSettleInterval) } } case err := <-watcher.Errors: slog.Error(fmt.Sprintf("error in watcher: %v", err)) } } }