add tests for fswatcher package

internal/fswatcher/event.go

@@ -2,20 +2,18 @@ package fswatcher
 
 import (
 	"fmt"
-
-	"github.com/dominicbreuker/pspy/internal/fswatcher/inotify"
 )
 
-func parseEvents(i *inotify.Inotify, dataCh chan []byte, eventCh chan string, errCh chan error) {
+func parseEvents(i Inotify, dataCh chan []byte, eventCh chan string, errCh chan error) {
 	for buf := range dataCh {
 		var ptr uint32
 		for len(buf[ptr:]) > 0 {
 			event, size, err := i.ParseNextEvent(buf[ptr:])
+			ptr += size
 			if err != nil {
 				errCh <- fmt.Errorf("parsing events: %v", err)
 				continue
 			}
-			ptr += size
 			eventCh <- fmt.Sprintf("%20s | %s", event.Op, event.Name)
 		}
 	}

internal/fswatcher/fswatcher.go

@@ -0,0 +1,105 @@
+package fswatcher
+
+import (
+	"fmt"
+
+	"github.com/dominicbreuker/pspy/internal/fswatcher/inotify"
+	"github.com/dominicbreuker/pspy/internal/fswatcher/walker"
+)
+
+type Inotify interface {
+	Init() error
+	Watch(dir string) error
+	NumWatchers() int
+	Read(buf []byte) (int, error)
+	ParseNextEvent(buf []byte) (*inotify.Event, uint32, error)
+	Close() error
+}
+
+type Walker interface {
+	Walk(dir string, depth int) (chan string, chan error, chan struct{})
+}
+
+type FSWatcher struct {
+	i           Inotify
+	w           Walker
+	maxWatchers int
+}
+
+func NewFSWatcher() (*FSWatcher, error) {
+	return &FSWatcher{
+		i:           inotify.NewInotify(),
+		w:           walker.NewWalker(),
+		maxWatchers: inotify.MaxWatchers,
+	}, nil
+}
+
+func (iw *FSWatcher) Close() {
+	iw.i.Close()
+}
+
+func (fs *FSWatcher) Init(rdirs, dirs []string) (chan error, chan struct{}) {
+	errCh := make(chan error)
+	doneCh := make(chan struct{})
+
+	go func() {
+		err := fs.i.Init()
+		if err != nil {
+			errCh <- fmt.Errorf("setting up inotify: %v", err)
+		}
+		for _, dir := range rdirs {
+			addWatchers(dir, -1, fs.i, fs.maxWatchers, fs.w, errCh)
+		}
+		for _, dir := range dirs {
+			addWatchers(dir, 0, fs.i, fs.maxWatchers, fs.w, errCh)
+		}
+		close(doneCh)
+	}()
+
+	return errCh, doneCh
+}
+
+func addWatchers(dir string, depth int, i Inotify, maxWatchers int, w Walker, errCh chan error) {
+	dirCh, walkErrCh, doneCh := w.Walk(dir, depth)
+loop:
+	for {
+		if maxWatchers > 0 && i.NumWatchers() >= maxWatchers {
+			close(doneCh)
+			break loop
+		}
+		select {
+		case err := <-walkErrCh:
+			errCh <- fmt.Errorf("adding inotift watchers: %v", err)
+		case dir, ok := <-dirCh:
+			if !ok {
+				break loop
+			}
+			if err := i.Watch(dir); err != nil {
+				errCh <- fmt.Errorf("Can't create watcher: %v", err)
+			}
+		}
+	}
+}
+
+func (fs *FSWatcher) Start(rdirs, dirs []string, errCh chan error) (chan struct{}, chan string, error) {
+	err := fs.i.Init()
+	if err != nil {
+		return nil, nil, fmt.Errorf("setting up inotify: %v", err)
+	}
+
+	for _, dir := range rdirs {
+		addWatchers(dir, -1, fs.i, fs.maxWatchers, fs.w, errCh)
+	}
+	for _, dir := range dirs {
+		addWatchers(dir, 0, fs.i, fs.maxWatchers, fs.w, errCh)
+	}
+
+	triggerCh := make(chan struct{})
+	dataCh := make(chan []byte)
+	go Observe(fs.i, triggerCh, dataCh, errCh)
+
+	eventCh := make(chan string)
+	go parseEvents(fs.i, dataCh, eventCh, errCh)
+
+	return triggerCh, eventCh, nil
+}

internal/fswatcher/fswatcher_test.go

@@ -0,0 +1,127 @@
+package fswatcher
+
+import (
+	"errors"
+	"reflect"
+	"testing"
+	"time"
+
+	"github.com/dominicbreuker/pspy/internal/fswatcher/inotify"
+)
+
+func TestInit(t *testing.T) {
+	i := NewMockInotify()
+	w := &MockWalker{
+		subdirs: map[string][]string{
+			"mydir1": []string{"dir1", "dir2"},
+			"mydir2": []string{"dir3"},
+			"dir1":   []string{"another-dir"},
+		},
+	}
+	fs := &FSWatcher{
+		i:           i,
+		w:           w,
+		maxWatchers: 999,
+	}
+	rdirs := []string{"mydir1"}
+	dirs := []string{"mydir2"}
+
+	errCh, doneCh := fs.Init(rdirs, dirs)
+
+loop:
+	for {
+		select {
+		case <-doneCh:
+			break loop
+		case err := <-errCh:
+			t.Errorf("Unexpected error: %v", err)
+		case <-time.After(1 * time.Second):
+			t.Fatalf("Test timeout")
+		}
+	}
+
+	if !reflect.DeepEqual(i.watching, []string{"mydir1", "dir1", "another-dir", "dir2", "mydir2"}) {
+		t.Fatalf("Watching wrong directories: %+v", i.watching)
+	}
+}
+
+// mocks
+
+// Mock Inotify
+
+type MockInotify struct {
+	initialized bool
+	watching    []string
+}
+
+func NewMockInotify() *MockInotify {
+	return &MockInotify{
+		initialized: false,
+		watching:    make([]string, 0),
+	}
+}
+
+func (i *MockInotify) Init() error {
+	i.initialized = true
+	return nil
+}
+
+func (i *MockInotify) Watch(dir string) error {
+	if !i.initialized {
+		return errors.New("Not yet initialized")
+	}
+	i.watching = append(i.watching, dir)
+	return nil
+}
+
+func (i *MockInotify) NumWatchers() int {
+	return len(i.watching)
+}
+
+func (i *MockInotify) Read(buf []byte) (int, error) {
+	return 32, nil
+}
+
+func (i *MockInotify) ParseNextEvent(buf []byte) (*inotify.Event, uint32, error) {
+	return &inotify.Event{Name: "name", Op: "CREATE"}, 32, nil
+}
+
+func (i *MockInotify) Close() error {
+	if !i.initialized {
+		return errors.New("Not yet initialized")
+	}
+	return nil
+}
+
+// Mock Walker
+
+type MockWalker struct {
+	subdirs map[string][]string
+}
+
+func (w *MockWalker) Walk(dir string, depth int) (chan string, chan error, chan struct{}) {
+	dirCh := make(chan string)
+	errCh := make(chan error)
+	doneCh := make(chan struct{})
+
+	go func() {
+		defer close(dirCh)
+		sendDir(w, depth, dir, dirCh)
+	}()
+
+	return dirCh, errCh, doneCh
+}
+
+func sendDir(w *MockWalker, depth int, dir string, dirCh chan string) {
+	dirCh <- dir
+	if depth == 0 {
+		return
+	}
+	subdirs, ok := w.subdirs[dir]
+	if !ok {
+		return
+	}
+	for _, sdir := range subdirs {
+		sendDir(w, depth-1, sdir, dirCh)
+	}
+}

internal/fswatcher/inotify.go

@@ -1,58 +0,0 @@
-package fswatcher
-
-import (
-	"fmt"
-
-	"golang.org/x/sys/unix"
-)
-
-type Inotify struct {
-	fd       int
-	watchers map[int]*watcher
-}
-
-func NewInotify() (*Inotify, error) {
-	fd, errno := unix.InotifyInit1(unix.IN_CLOEXEC)
-	if fd == -1 {
-		return nil, fmt.Errorf("Can't init inotify: %d", errno)
-	}
-
-	i := &Inotify{
-		fd:       fd,
-		watchers: make(map[int]*watcher),
-	}
-
-	return i, nil
-}
-
-func (i *Inotify) Watch(dir string) error {
-	w, err := newWatcher(i.fd, dir)
-	if err != nil {
-		return fmt.Errorf("creating watcher: %v", err)
-	}
-	i.watchers[w.wd] = w
-	return nil
-}
-
-func (i *Inotify) Close() error {
-	if err := unix.Close(i.fd); err != nil {
-		return fmt.Errorf("closing inotify file descriptor: %v", err)
-	}
-	return nil
-}
-
-func (i *Inotify) NumWatchers() int {
-	return len(i.watchers)
-}
-
-func (i *Inotify) String() string {
-	if len(i.watchers) < 20 {
-		dirs := make([]string, 0)
-		for _, w := range i.watchers {
-			dirs = append(dirs, w.dir)
-		}
-		return fmt.Sprintf("Watching: %v", dirs)
-	} else {
-		return fmt.Sprintf("Watching %d directories", len(i.watchers))
-	}
-}

internal/fswatcher/inotify/inotify.go

@@ -13,6 +13,17 @@ import (
 
 const maximumWatchersFile = "/proc/sys/fs/inotify/max_user_watches"
 
+// MaxWatchers is the maximum number of inotify watches supported by the Kernel
+// set to -1 if the number cannot be determined
+var MaxWatchers int = -1
+
+func init() {
+	mw, err := getMaxWatchers()
+	if err == nil {
+		MaxWatchers = mw
+	}
+}
+
 type Inotify struct {
 	FD       int
 	Watchers map[int]*Watcher
@@ -28,17 +39,20 @@ type Event struct {
 	Op   string
 }
 
-func NewInotify() (*Inotify, error) {
-	fd, errno := unix.InotifyInit1(unix.IN_CLOEXEC)
-	if fd < 0 {
-		return nil, fmt.Errorf("initializing inotify: errno: %d", errno)
-	}
-
-	i := &Inotify{
-		FD:       fd,
+func NewInotify() *Inotify {
+	return &Inotify{
+		FD:       0,
 		Watchers: make(map[int]*Watcher),
 	}
-	return i, nil
+}
+
+func (i *Inotify) Init() error {
+	fd, errno := unix.InotifyInit1(unix.IN_CLOEXEC)
+	if fd < 0 {
+		return fmt.Errorf("initializing inotify: errno: %d", errno)
+	}
+	i.FD = fd
+	return nil
 }
 
 func (i *Inotify) Watch(dir string) error {
@@ -112,7 +126,7 @@ func (i *Inotify) String() string {
 	}
 }
 
-func GetMaxWatchers() (int, error) {
+func getMaxWatchers() (int, error) {
 	b, err := ioutil.ReadFile(maximumWatchersFile)
 	if err != nil {
 		return 0, fmt.Errorf("reading from %s: %v", maximumWatchersFile, err)

internal/fswatcher/inotify/inotify_test.go

@@ -9,7 +9,9 @@ import (
 )
 
 func TestInotify(t *testing.T) {
-	i, err := NewInotify()
+	i := NewInotify()
+
+	err := i.Init()
 	expectNoError(t, err)
 
 	err = i.Watch("testdata/folder")

internal/fswatcher/observer.go

@@ -1,11 +1,10 @@
 package fswatcher
 
 import (
-	"github.com/dominicbreuker/pspy/internal/fswatcher/inotify"
 	"golang.org/x/sys/unix"
 )
 
-func Observe(i *inotify.Inotify, triggerCh chan struct{}, dataCh chan []byte, errCh chan error) {
+func Observe(i Inotify, triggerCh chan struct{}, dataCh chan []byte, errCh chan error) {
 	buf := make([]byte, 5*unix.SizeofInotifyEvent)
 
 	for {

internal/fswatcher/setup.go

@@ -1,72 +0,0 @@
-package fswatcher
-
-import (
-	"fmt"
-
-	"github.com/dominicbreuker/pspy/internal/fswatcher/inotify"
-	"github.com/dominicbreuker/pspy/internal/fswatcher/walker"
-)
-
-type InotifyWatcher struct {
-	i *inotify.Inotify
-}
-
-func (iw *InotifyWatcher) Close() {
-	iw.i.Close()
-}
-
-func NewInotifyWatcher() (*InotifyWatcher, error) {
-	i, err := inotify.NewInotify()
-	if err != nil {
-		return nil, fmt.Errorf("setting up inotify: %v", err)
-	}
-	return &InotifyWatcher{
-		i: i,
-	}, nil
-}
-
-func (iw *InotifyWatcher) Setup(rdirs, dirs []string, errCh chan error) (chan struct{}, chan string, error) {
-	maxWatchers, err := inotify.GetMaxWatchers()
-	if err != nil {
-		errCh <- fmt.Errorf("Can't get inotify watcher limit...: %v\n", err)
-		maxWatchers = -1
-	}
-
-	for _, dir := range rdirs {
-		addWatchers(dir, -1, iw.i, maxWatchers, errCh)
-	}
-	for _, dir := range dirs {
-		addWatchers(dir, 0, iw.i, maxWatchers, errCh)
-	}
-
-	triggerCh := make(chan struct{})
-	dataCh := make(chan []byte)
-	go Observe(iw.i, triggerCh, dataCh, errCh)
-
-	eventCh := make(chan string)
-	go parseEvents(iw.i, dataCh, eventCh, errCh)
-
-	return triggerCh, eventCh, nil
-}
-
-func addWatchers(dir string, depth int, i *inotify.Inotify, maxWatchers int, errCh chan error) {
-	dirCh, walkErrCh, doneCh := walker.Walk(dir, depth)
-loop:
-	for {
-		if maxWatchers > 0 && i.NumWatchers() >= maxWatchers {
-			close(doneCh)
-			break loop
-		}
-		select {
-		case err := <-walkErrCh:
-			errCh <- fmt.Errorf("adding inotift watchers: %v", err)
-		case dir, ok := <-dirCh:
-			if !ok {
-				break loop
-			}
-			if err := i.Watch(dir); err != nil {
-				errCh <- fmt.Errorf("Can't create watcher: %v", err)
-			}
-		}
-	}
-}

internal/fswatcher/walker/walker.go

@@ -7,9 +7,15 @@ import (
 	"path/filepath"
 )
 
+type Walker struct{}
+
+func NewWalker() *Walker {
+	return &Walker{}
+}
+
 const maxInt = int(^uint(0) >> 1)
 
-func Walk(root string, depth int) (dirCh chan string, errCh chan error, doneCh chan struct{}) {
+func (w *Walker) Walk(root string, depth int) (dirCh chan string, errCh chan error, doneCh chan struct{}) {
 	if depth < 0 {
 		depth = maxInt
 	}

internal/fswatcher/walker/walker_test.go

@@ -39,7 +39,8 @@ func TestWalk(t *testing.T) {
 	}
 
 	for i, tt := range tests {
-		dirCh, errCh, doneCh := Walk(tt.root, tt.depth)
+		w := &Walker{}
+		dirCh, errCh, doneCh := w.Walk(tt.root, tt.depth)
 		dirs, errs := getAllDirsAndErrors(dirCh, errCh)
 
 		if !reflect.DeepEqual(dirs, tt.result) {

internal/fswatcher/watcher.go

@@ -1,44 +0,0 @@
-package fswatcher
-
-import (
-	"fmt"
-	"io/ioutil"
-	"strconv"
-	"strings"
-
-	"golang.org/x/sys/unix"
-)
-
-const events = unix.IN_ALL_EVENTS
-const MaximumWatchersFile = "/proc/sys/fs/inotify/max_user_watches"
-
-type watcher struct {
-	wd  int
-	dir string
-}
-
-func newWatcher(fd int, dir string) (*watcher, error) {
-	wd, errno := unix.InotifyAddWatch(fd, dir, events)
-	if wd == -1 {
-		return nil, fmt.Errorf("adding watcher on %s: %d", dir, errno)
-	}
-	return &watcher{
-		wd:  wd,
-		dir: dir,
-	}, nil
-}
-
-func getLimit() (int, error) {
-	b, err := ioutil.ReadFile(MaximumWatchersFile)
-	if err != nil {
-		return 0, fmt.Errorf("reading from %s: %v", MaximumWatchersFile, err)
-	}
-
-	s := strings.TrimSpace(string(b))
-	m, err := strconv.Atoi(s)
-	if err != nil {
-		return 0, fmt.Errorf("converting to integer: %v", err)
-	}
-
-	return m, nil
-}

internal/pspy/pspy.go

@@ -14,22 +14,22 @@ type Logger interface {
 	Eventf(format string, v ...interface{})
 }
 
-type InotifyWatcher interface {
-	Setup(rdirs, dirs []string, errCh chan error) (chan struct{}, chan string, error)
+type FSWatcher interface {
+	Start(rdirs, dirs []string, errCh chan error) (chan struct{}, chan string, error)
 }
 
 type ProcfsScanner interface {
 	Setup(triggerCh chan struct{}, interval time.Duration) (chan string, error)
 }
 
-func Start(cfg config.Config, logger Logger, inotify InotifyWatcher, pscan ProcfsScanner, sigCh chan os.Signal) (chan struct{}, error) {
+func Start(cfg config.Config, logger Logger, inotify FSWatcher, pscan ProcfsScanner, sigCh chan os.Signal) (chan struct{}, error) {
 	logger.Infof("Config: %+v\n", cfg)
 
 	// log all errors
 	errCh := make(chan error, 10)
 	go logErrors(errCh, logger)
 
-	triggerCh, fsEventCh, err := inotify.Setup(cfg.RDirs, cfg.Dirs, errCh)
+	triggerCh, fsEventCh, err := inotify.Start(cfg.RDirs, cfg.Dirs, errCh)
 	if err != nil {
 		logger.Errorf("Can't set up inotify watchers: %v\n", err)
 		return nil, errors.New("inotify error")

internal/pspy/pspy_test.go

@@ -104,7 +104,7 @@ func newMockInotifyWatcher(setupErr error) *mockInotifyWatcher {
 	}
 }
 
-func (i *mockInotifyWatcher) Setup(rdirs, dirs []string, errCh chan error) (chan struct{}, chan string, error) {
+func (i *mockInotifyWatcher) Start(rdirs, dirs []string, errCh chan error) (chan struct{}, chan string, error) {
 	if i.setupErr != nil {
 		return nil, nil, i.setupErr
 	}