Initial commit

1 files changed, 400 insertions, 0 deletions

diff --git a/plugins/reload/watcher.go b/plugins/reload/watcher.go
new file mode 100644
index 00000000..721495c3
--- /dev/null
+++ b/plugins/reload/watcher.go
@@ -0,0 +1,400 @@
+package reload
+
+import (
+	"errors"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+)
+
+var ErrorSkip = errors.New("file is skipped")
+var NoWalkerConfig = errors.New("should add at least one walker config, when reload is set to true")
+
+// SimpleHook is used to filter by simple criteria, CONTAINS
+type SimpleHook func(filename string, pattern []string) error
+
+// An Event describes an event that is received when files or directory
+// changes occur. It includes the os.FileInfo of the changed file or
+// directory and the type of event that's occurred and the full path of the file.
+type Event struct {
+	path string
+	info os.FileInfo
+
+	service string // type of service, http, grpc, etc...
+}
+
+type WatcherConfig struct {
+	// service name
+	serviceName string
+
+	// recursive or just add by singe directory
+	recursive bool
+
+	// directories used per-service
+	directories []string
+
+	// simple hook, just CONTAINS
+	filterHooks func(filename string, pattern []string) error
+
+	// path to file with files
+	files map[string]os.FileInfo
+
+	// ignored directories, used map for O(1) amortized get
+	ignored map[string]struct{}
+
+	// filePatterns to ignore
+	filePatterns []string
+}
+
+type Watcher struct {
+	// main event channel
+	Event chan Event
+	close chan struct{}
+
+	//=============================
+	mu *sync.Mutex
+
+	// indicates is walker started or not
+	started bool
+
+	// config for each service
+	// need pointer here to assign files
+	watcherConfigs map[string]WatcherConfig
+}
+
+// Options is used to set Watcher Options
+type Options func(*Watcher)
+
+// NewWatcher returns new instance of File Watcher
+func NewWatcher(configs []WatcherConfig, options ...Options) (*Watcher, error) {
+	w := &Watcher{
+		Event: make(chan Event),
+		mu:    &sync.Mutex{},
+
+		close: make(chan struct{}),
+
+		//workingDir:     workDir,
+		watcherConfigs: make(map[string]WatcherConfig),
+	}
+
+	// add watcherConfigs by service names
+	for _, v := range configs {
+		w.watcherConfigs[v.serviceName] = v
+	}
+
+	// apply options
+	for _, option := range options {
+		option(w)
+	}
+	err := w.initFs()
+	if err != nil {
+		return nil, err
+	}
+
+	return w, nil
+}
+
+// initFs makes initial map with files
+func (w *Watcher) initFs() error {
+	for srvName, config := range w.watcherConfigs {
+		fileList, err := w.retrieveFileList(srvName, config)
+		if err != nil {
+			return err
+		}
+		// workaround. in golang you can't assign to map in struct field
+		tmp := w.watcherConfigs[srvName]
+		tmp.files = fileList
+		w.watcherConfigs[srvName] = tmp
+	}
+	return nil
+}
+
+// ConvertIgnored is used to convert slice to map with ignored files
+func ConvertIgnored(ignored []string) (map[string]struct{}, error) {
+	if len(ignored) == 0 {
+		return nil, nil
+	}
+
+	ign := make(map[string]struct{}, len(ignored))
+	for i := 0; i < len(ignored); i++ {
+		abs, err := filepath.Abs(ignored[i])
+		if err != nil {
+			return nil, err
+		}
+		ign[abs] = struct{}{}
+	}
+
+	return ign, nil
+
+}
+
+// GetAllFiles returns all files initialized for particular company
+func (w *Watcher) GetAllFiles(serviceName string) []os.FileInfo {
+	var ret []os.FileInfo
+
+	for _, v := range w.watcherConfigs[serviceName].files {
+		ret = append(ret, v)
+	}
+
+	return ret
+}
+
+// https://en.wikipedia.org/wiki/Inotify
+// SetMaxFileEvents sets max file notify events for Watcher
+// In case of file watch errors, this value can be increased system-wide
+// For linux: set --> fs.inotify.max_user_watches = 600000 (under /etc/<choose_name_here>.conf)
+// Add apply: sudo sysctl -p --system
+//func SetMaxFileEvents(events int) Options {
+//	return func(watcher *Watcher) {
+//		watcher.maxFileWatchEvents = events
+//	}
+//
+//}
+
+// pass map from outside
+func (w *Watcher) retrieveFilesSingle(serviceName, path string) (map[string]os.FileInfo, error) {
+	stat, err := os.Stat(path)
+	if err != nil {
+		return nil, err
+	}
+
+	filesList := make(map[string]os.FileInfo, 10)
+	filesList[path] = stat
+
+	// if it's not a dir, return
+	if !stat.IsDir() {
+		return filesList, nil
+	}
+
+	fileInfoList, err := ioutil.ReadDir(path)
+	if err != nil {
+		return nil, err
+	}
+
+	// recursive calls are slow in compare to goto
+	// so, we will add files with goto pattern
+outer:
+	for i := 0; i < len(fileInfoList); i++ {
+		// if file in ignored --> continue
+		if _, ignored := w.watcherConfigs[serviceName].ignored[path]; ignored {
+			continue
+		}
+
+		// if filename does not contain pattern --> ignore that file
+		if w.watcherConfigs[serviceName].filePatterns != nil && w.watcherConfigs[serviceName].filterHooks != nil {
+			err = w.watcherConfigs[serviceName].filterHooks(fileInfoList[i].Name(), w.watcherConfigs[serviceName].filePatterns)
+			if err == ErrorSkip {
+				continue outer
+			}
+		}
+
+		filesList[fileInfoList[i].Name()] = fileInfoList[i]
+	}
+
+	return filesList, nil
+}
+
+func (w *Watcher) StartPolling(duration time.Duration) error {
+	w.mu.Lock()
+	if w.started {
+		w.mu.Unlock()
+		return errors.New("already started")
+	}
+
+	w.started = true
+	w.mu.Unlock()
+
+	return w.waitEvent(duration)
+}
+
+// this is blocking operation
+func (w *Watcher) waitEvent(d time.Duration) error {
+	ticker := time.NewTicker(d)
+	for {
+		select {
+		case <-w.close:
+			ticker.Stop()
+			// just exit
+			// no matter for the pollEvents
+			return nil
+		case <-ticker.C:
+			// this is not very effective way
+			// because we have to wait on Lock
+			// better is to listen files in parallel, but, since that would be used in debug... TODO
+			for serviceName, config := range w.watcherConfigs {
+				go func(sn string, c WatcherConfig) {
+					fileList, _ := w.retrieveFileList(sn, c)
+					w.pollEvents(c.serviceName, fileList)
+				}(serviceName, config)
+			}
+		}
+	}
+
+}
+
+// retrieveFileList get file list for service
+func (w *Watcher) retrieveFileList(serviceName string, config WatcherConfig) (map[string]os.FileInfo, error) {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	fileList := make(map[string]os.FileInfo)
+	if config.recursive {
+		// walk through directories recursively
+		for _, dir := range config.directories {
+			// full path is workdir/relative_path
+			fullPath, err := filepath.Abs(dir)
+			if err != nil {
+				return nil, err
+			}
+			list, err := w.retrieveFilesRecursive(serviceName, fullPath)
+			if err != nil {
+				return nil, err
+			}
+
+			for k, v := range list {
+				fileList[k] = v
+			}
+		}
+		return fileList, nil
+	}
+
+	for _, dir := range config.directories {
+		// full path is workdir/relative_path
+		fullPath, err := filepath.Abs(dir)
+		if err != nil {
+			return nil, err
+		}
+
+		// list is pathToFiles with files
+		list, err := w.retrieveFilesSingle(serviceName, fullPath)
+		if err != nil {
+			return nil, err
+		}
+
+		for pathToFile, file := range list {
+			fileList[pathToFile] = file
+		}
+	}
+
+	return fileList, nil
+}
+
+func (w *Watcher) retrieveFilesRecursive(serviceName, root string) (map[string]os.FileInfo, error) {
+	fileList := make(map[string]os.FileInfo)
+
+	return fileList, filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		// If path is ignored and it's a directory, skip the directory. If it's
+		// ignored and it's a single file, skip the file.
+		_, ignored := w.watcherConfigs[serviceName].ignored[path]
+		if ignored {
+			if info.IsDir() {
+				// if it's dir, ignore whole
+				return filepath.SkipDir
+			}
+			return nil
+		}
+
+		// if filename does not contain pattern --> ignore that file
+		err = w.watcherConfigs[serviceName].filterHooks(info.Name(), w.watcherConfigs[serviceName].filePatterns)
+		if err == ErrorSkip {
+			return nil
+		}
+
+		// Add the path and it's info to the file list.
+		fileList[path] = info
+		return nil
+	})
+}
+
+func (w *Watcher) pollEvents(serviceName string, files map[string]os.FileInfo) {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	// Store create and remove events for use to check for rename events.
+	creates := make(map[string]os.FileInfo)
+	removes := make(map[string]os.FileInfo)
+
+	// Check for removed files.
+	for pth, info := range w.watcherConfigs[serviceName].files {
+		if _, found := files[pth]; !found {
+			removes[pth] = info
+		}
+	}
+
+	// Check for created files, writes and chmods.
+	for pth, info := range files {
+		if info.IsDir() {
+			continue
+		}
+		oldInfo, found := w.watcherConfigs[serviceName].files[pth]
+		if !found {
+			// A file was created.
+			creates[pth] = info
+			continue
+		}
+		if oldInfo.ModTime() != info.ModTime() {
+			w.watcherConfigs[serviceName].files[pth] = info
+			w.Event <- Event{
+				path:    pth,
+				info:    info,
+				service: serviceName,
+			}
+		}
+		if oldInfo.Mode() != info.Mode() {
+			w.watcherConfigs[serviceName].files[pth] = info
+			w.Event <- Event{
+				path:    pth,
+				info:    info,
+				service: serviceName,
+			}
+		}
+	}
+
+	//Check for renames and moves.
+	for path1, info1 := range removes {
+		for path2, info2 := range creates {
+			if sameFile(info1, info2) {
+				e := Event{
+					path:    path2,
+					info:    info2,
+					service: serviceName,
+				}
+
+				// remove initial path
+				delete(w.watcherConfigs[serviceName].files, path1)
+				// update with new
+				w.watcherConfigs[serviceName].files[path2] = info2
+
+
+				w.Event <- e
+			}
+		}
+	}
+
+	//Send all the remaining create and remove events.
+	for pth, info := range creates {
+		w.watcherConfigs[serviceName].files[pth] = info
+		w.Event <- Event{
+			path:    pth,
+			info:    info,
+			service: serviceName,
+		}
+	}
+	for pth, info := range removes {
+		delete(w.watcherConfigs[serviceName].files, pth)
+		w.Event <- Event{
+			path:    pth,
+			info:    info,
+			service: serviceName,
+		}
+	}
+}
+
+func (w *Watcher) Stop() {
+	w.close <- struct{}{}
+}