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// Copyright 2022 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package watcher
import (
"context"
"io/fs"
"os"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/process"
"github.com/fsnotify/fsnotify"
)
// CreateWatcherOpts are options to configure the watcher
type CreateWatcherOpts struct {
// PathsCallback is used to set the required paths to watch
PathsCallback func(func(path, name string, d fs.DirEntry, err error) error) error
// BeforeCallback is called before any files are watched
BeforeCallback func()
// Between Callback is called between after a watched event has occurred
BetweenCallback func()
// AfterCallback is called as this watcher ends
AfterCallback func()
}
// CreateWatcher creates a watcher labelled with the provided description and running with the provided options.
// The created watcher will create a subcontext from the provided ctx and register it with the process manager.
func CreateWatcher(ctx context.Context, desc string, opts *CreateWatcherOpts) {
go run(ctx, desc, opts)
}
func run(ctx context.Context, desc string, opts *CreateWatcherOpts) {
if opts.BeforeCallback != nil {
opts.BeforeCallback()
}
if opts.AfterCallback != nil {
defer opts.AfterCallback()
}
ctx, _, finished := process.GetManager().AddTypedContext(ctx, "Watcher: "+desc, process.SystemProcessType, true)
defer finished()
log.Trace("Watcher loop starting for %s", desc)
defer log.Trace("Watcher loop ended for %s", desc)
watcher, err := fsnotify.NewWatcher()
if err != nil {
log.Error("Unable to create watcher for %s: %v", desc, err)
return
}
if err := opts.PathsCallback(func(path, _ string, d fs.DirEntry, err error) error {
if err != nil && !os.IsNotExist(err) {
return err
}
log.Trace("Watcher: %s watching %q", desc, path)
_ = watcher.Add(path)
return nil
}); err != nil {
log.Error("Unable to create watcher for %s: %v", desc, err)
_ = watcher.Close()
return
}
// Note we don't call the BetweenCallback here
for {
select {
case event, ok := <-watcher.Events:
if !ok {
_ = watcher.Close()
return
}
log.Debug("Watched file for %s had event: %v", desc, event)
case err, ok := <-watcher.Errors:
if !ok {
_ = watcher.Close()
return
}
log.Error("Error whilst watching files for %s: %v", desc, err)
case <-ctx.Done():
_ = watcher.Close()
return
}
// Recreate the watcher - only call the BetweenCallback after the new watcher is set-up
_ = watcher.Close()
watcher, err = fsnotify.NewWatcher()
if err != nil {
log.Error("Unable to create watcher for %s: %v", desc, err)
return
}
if err := opts.PathsCallback(func(path, _ string, _ fs.DirEntry, err error) error {
if err != nil {
return err
}
_ = watcher.Add(path)
return nil
}); err != nil {
log.Error("Unable to create watcher for %s: %v", desc, err)
_ = watcher.Close()
return
}
// Inform our BetweenCallback that there has been an event
if opts.BetweenCallback != nil {
opts.BetweenCallback()
}
}
}
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