restructure inotify package and add some tests

cmd/root.go

@@ -66,20 +66,23 @@ func init() {
 }
 
 func root(cmd *cobra.Command, args []string) {
-	fmt.Printf("Watching recursively    : %+v (%d)\n", rDirs, len(rDirs))
-	fmt.Printf("Watching non-recursively: %+v (%d)\n", dirs, len(dirs))
-	fmt.Printf("Printing: processes=%t file-system events=%t\n", logPS, logFS)
+	logger := logging.NewLogger()
+
 	cfg := config.Config{
 		RDirs: rDirs,
 		Dirs:  dirs,
 		LogPS: logPS,
 		LogFS: logFS,
 	}
-	logger := logging.NewLogger()
-	iw := inotify.NewInotifyWatcher()
+	iw, err := inotify.NewInotifyWatcher()
+	if err != nil {
+		logger.Errorf("Can't initialize inotify: %v", err)
+		os.Exit(1)
+	}
+	defer iw.Close()
 	pscan := process.NewProcfsScanner()
 
-	sigCh := make(chan os.Signal, 1)
+	sigCh := make(chan os.Signal)
 	signal.Notify(sigCh, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT)
 
 	exit, err := pspy.Start(cfg, logger, iw, pscan, sigCh)

internal/config/config.go

@@ -10,5 +10,5 @@ type Config struct {
 }
 
 func (c Config) String() string {
-	return fmt.Sprintf("Printing events: processes: %t | file system events: %t | Watching directories: %+v (recursive) | %+v (non-recursive)", c.LogPS, c.LogFS, c.RDirs, c.Dirs)
+	return fmt.Sprintf("Printing events: processes=%t | file-system-events=%t ||| Watching directories: %+v (recursive) | %+v (non-recursive)", c.LogPS, c.LogFS, c.RDirs, c.Dirs)
 }

internal/inotify/event.go

@@ -3,9 +3,7 @@ package inotify
 import (
 	"bytes"
 	"fmt"
-	"log"
 	"strconv"
-	"time"
 	"unsafe"
 
 	"golang.org/x/sys/unix"
@@ -37,38 +35,11 @@ var InotifyEvents = map[uint32]string{
 	(unix.IN_OPEN | unix.IN_ISDIR):          "OPEN DIR",
 }
 
-type Event struct {
-	name string
-	op   string
-}
-
-func (e Event) String() string {
-	return fmt.Sprintf("%20s | %s", e.op, e.name)
-}
-
-func newEvent(name string, mask uint32) Event {
-	e := Event{name: name}
-	op, ok := InotifyEvents[mask]
-	if !ok {
-		op = strconv.FormatInt(int64(mask), 2)
-	}
-	e.op = op
-	return e
-}
-
-func eventLogger(i *Inotify, buffers chan bufRead, print bool) {
-	// enable printing only after delay since setting up watchers causes flood of events
-	printEnabled := false
-	go func() {
-		<-time.After(1 * time.Second)
-		printEnabled = print
-	}()
-	for bf := range buffers {
-		n := bf.n
-		buf := bf.buf
-
+func parseEvents(i *Inotify, dataCh chan []byte, eventCh chan string, errCh chan error) {
+	for buf := range dataCh {
+		n := len(buf)
 		if n < unix.SizeofInotifyEvent {
-			// incomplete or erroneous read
+			errCh <- fmt.Errorf("Inotify event parser: incomplete read: n=%d", n)
 			continue
 		}
 
@@ -80,6 +51,7 @@ func eventLogger(i *Inotify, buffers chan bufRead, print bool) {
 
 			watcher, ok := i.watchers[int(sys.Wd)]
 			if !ok {
+				errCh <- fmt.Errorf("Inotify event parser: unknown watcher ID: %d", sys.Wd)
 				continue
 			}
 			name = watcher.dir + "/"
@@ -88,10 +60,15 @@ func eventLogger(i *Inotify, buffers chan bufRead, print bool) {
 				ptr += sys.Len
 			}
 
-			ev := newEvent(name, sys.Mask)
-			if printEnabled {
-				log.Printf("\x1b[32;1mFS: %+v\x1b[0m", ev)
-			}
+			eventCh <- formatEvent(name, sys.Mask)
 		}
 	}
 }
+
+func formatEvent(name string, mask uint32) string {
+	op, ok := InotifyEvents[mask]
+	if !ok {
+		op = strconv.FormatInt(int64(mask), 2)
+	}
+	return fmt.Sprintf("%20s | %s", op, name)
+}

internal/inotify/inotify.go

@@ -6,26 +6,12 @@ import (
 	"golang.org/x/sys/unix"
 )
 
-type InotifyWatcher struct{}
-
-func NewInotifyWatcher() *InotifyWatcher {
-	return &InotifyWatcher{}
-}
-
-func (i *InotifyWatcher) Setup(rdirs, dirs []string) (chan struct{}, chan string, error) {
-	triggerCh := make(chan struct{})
-	fsEventCh := make(chan string)
-	return triggerCh, fsEventCh, nil
-}
-
 type Inotify struct {
 	fd       int
 	watchers map[int]*watcher
-	ping     chan struct{}
-	paused   bool
 }
 
-func NewInotify(ping chan struct{}, print bool) (*Inotify, error) {
+func NewInotify() (*Inotify, error) {
 	fd, errno := unix.InotifyInit1(unix.IN_CLOEXEC)
 	if fd == -1 {
 		return nil, fmt.Errorf("Can't init inotify: %d", errno)
@@ -34,16 +20,13 @@ func NewInotify(ping chan struct{}, print bool) (*Inotify, error) {
 	i := &Inotify{
 		fd:       fd,
 		watchers: make(map[int]*watcher),
-		ping:     ping,
-		paused:   false,
 	}
-	go watch(i, print)
 
 	return i, nil
 }
 
 func (i *Inotify) Watch(dir string) error {
-	w, err := newWatcher(i.fd, dir, i.ping)
+	w, err := newWatcher(i.fd, dir)
 	if err != nil {
 		return fmt.Errorf("creating watcher: %v", err)
 	}
@@ -58,14 +41,6 @@ func (i *Inotify) Close() error {
 	return nil
 }
 
-func (i *Inotify) Pause() {
-	i.paused = true
-}
-
-func (i *Inotify) UnPause() {
-	i.paused = false
-}
-
 func (i *Inotify) NumWatchers() int {
 	return len(i.watchers)
 }
@@ -81,24 +56,3 @@ func (i *Inotify) String() string {
 		return fmt.Sprintf("Watching %d directories", len(i.watchers))
 	}
 }
-
-type bufRead struct {
-	n   int
-	buf []byte
-}
-
-func watch(i *Inotify, print bool) {
-	buf := make([]byte, 5*unix.SizeofInotifyEvent)
-	buffers := make(chan bufRead)
-	go eventLogger(i, buffers, print)
-	for {
-		n, _ := unix.Read(i.fd, buf)
-		if !i.paused {
-			i.ping <- struct{}{}
-		}
-		buffers <- bufRead{
-			n:   n,
-			buf: buf,
-		}
-	}
-}

internal/inotify/observer.go

@@ -0,0 +1,23 @@
+package inotify
+
+import (
+	"fmt"
+
+	"golang.org/x/sys/unix"
+)
+
+func Observe(i *Inotify, triggerCh chan struct{}, dataCh chan []byte, errCh chan error) {
+	buf := make([]byte, 5*unix.SizeofInotifyEvent)
+
+	for {
+		n, errno := unix.Read(i.fd, buf)
+		if n == -1 {
+			errCh <- fmt.Errorf("reading from inotify fd: errno: %d", errno)
+			return
+		}
+		triggerCh <- struct{}{}
+		bufCopy := make([]byte, n)
+		copy(bufCopy, buf)
+		dataCh <- bufCopy
+	}
+}

internal/inotify/setup.go

@@ -0,0 +1,69 @@
+package inotify
+
+import (
+	"fmt"
+
+	"github.com/dominicbreuker/pspy/internal/inotify/walker"
+)
+
+type InotifyWatcher struct {
+	i *Inotify
+}
+
+func (iw *InotifyWatcher) Close() {
+	iw.i.Close()
+}
+
+func NewInotifyWatcher() (*InotifyWatcher, error) {
+	i, err := 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 := getLimit()
+	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, maxWatchers int, errCh chan error) {
+	dirCh, doneCh := walker.Walk(dir, depth, errCh)
+loop:
+	for {
+		if maxWatchers > 0 && i.NumWatchers() >= maxWatchers {
+			close(doneCh)
+			break loop
+		}
+		select {
+		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/inotify/walker/walker.go

@@ -3,22 +3,32 @@ package walker
 import (
 	"fmt"
 	"io/ioutil"
+	"os"
 	"path/filepath"
 )
 
-func Walk(root string, depth int) (dirCh chan string, errCh chan error, doneCh chan struct{}) {
+const maxInt = int(^uint(0) >> 1)
+
+func Walk(root string, depth int, errCh chan error) (dirCh chan string, doneCh chan struct{}) {
+	if depth < 0 {
+		depth = maxInt
+	}
 	dirCh = make(chan string)
-	errCh = make(chan error)
 	doneCh = make(chan struct{})
 
 	go func() {
 		descent(root, depth-1, dirCh, errCh, doneCh)
 		close(dirCh)
 	}()
-	return dirCh, errCh, doneCh
+	return dirCh, doneCh
 }
 
 func descent(dir string, depth int, dirCh chan string, errCh chan error, doneCh chan struct{}) {
+	_, err := os.Stat(dir)
+	if err != nil {
+		errCh <- fmt.Errorf("Can't walk directory %s: %v", dir, err)
+		return
+	}
 	select {
 	case dirCh <- dir:
 	case <-doneCh:

internal/inotify/walker/walker_test.go

@@ -0,0 +1,84 @@
+package walker
+
+import (
+	"reflect"
+	"strings"
+	"testing"
+)
+
+func TestWalk(t *testing.T) {
+	tests := []struct {
+		root   string
+		depth  int
+		errCh  chan error
+		result []string
+		errs   []string
+	}{
+		{root: "testdata", depth: 999, errCh: newErrCh(), result: []string{
+			"testdata",
+			"testdata/subdir",
+			"testdata/subdir/subsubdir",
+		}, errs: make([]string, 0)},
+		{root: "testdata", depth: -1, errCh: newErrCh(), result: []string{
+			"testdata",
+			"testdata/subdir",
+			"testdata/subdir/subsubdir",
+		}, errs: []string{}},
+		{root: "testdata", depth: 1, errCh: newErrCh(), result: []string{
+			"testdata",
+			"testdata/subdir",
+		}, errs: []string{}},
+		{root: "testdata", depth: 0, errCh: newErrCh(), result: []string{
+			"testdata",
+		}, errs: []string{}},
+		{root: "testdata/subdir", depth: 1, errCh: newErrCh(), result: []string{
+			"testdata/subdir",
+			"testdata/subdir/subsubdir",
+		}, errs: []string{}},
+		{root: "testdata/non-existing-dir", depth: 1, errCh: newErrCh(), result: []string{}, errs: []string{"Can't walk directory testdata/non-existing-dir"}},
+	}
+
+	for i, tt := range tests {
+		dirCh, doneCh := Walk(tt.root, tt.depth, tt.errCh)
+		dirs, errs := getAllDirsAndErrors(dirCh, tt.errCh)
+
+		if !reflect.DeepEqual(dirs, tt.result) {
+			t.Fatalf("[%d] Wrong number of dirs found: %+v", i, dirs)
+		}
+		if !reflect.DeepEqual(errs, tt.errs) {
+			t.Fatalf("[%d] Wrong number of errs found: %+v vs %+v", i, errs, tt.errs)
+		}
+		close(doneCh)
+	}
+
+}
+
+func getAllDirsAndErrors(dirCh chan string, errCh chan error) ([]string, []string) {
+	dirs := make([]string, 0)
+	errs := make([]string, 0)
+
+	doneDirsCh := make(chan struct{})
+	go func() {
+		for d := range dirCh {
+			dirs = append(dirs, d)
+		}
+		close(errCh)
+		close(doneDirsCh)
+	}()
+
+	doneErrsCh := make(chan struct{})
+	go func() {
+		for err := range errCh {
+			tokens := strings.SplitN(err.Error(), ":", 2)
+			errs = append(errs, tokens[0])
+		}
+		close(doneErrsCh)
+	}()
+	<-doneDirsCh
+	<-doneErrsCh
+	return dirs, errs
+}
+
+func newErrCh() chan error {
+	return make(chan error)
+}

internal/inotify/watcher.go

@@ -17,7 +17,7 @@ type watcher struct {
 	dir string
 }
 
-func newWatcher(fd int, dir string, ping chan struct{}) (*watcher, error) {
+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)
@@ -28,7 +28,7 @@ func newWatcher(fd int, dir string, ping chan struct{}) (*watcher, error) {
 	}, nil
 }
 
-func WatcherLimit() (int, error) {
+func getLimit() (int, error) {
 	b, err := ioutil.ReadFile(MaximumWatchersFile)
 	if err != nil {
 		return 0, fmt.Errorf("reading from %s: %v", MaximumWatchersFile, err)

internal/process/process.go

@@ -17,6 +17,11 @@ func NewProcfsScanner() *ProcfsScanner {
 
 func (p *ProcfsScanner) Setup(triggerCh chan struct{}, interval time.Duration) (chan string, error) {
 	psEventCh := make(chan string)
+	go func() {
+		for {
+			<-triggerCh
+		}
+	}()
 	return psEventCh, nil
 }
 

internal/pspy/pspy.go

@@ -2,15 +2,10 @@ package pspy
 
 import (
 	"errors"
-	"fmt"
-	"log"
 	"os"
 	"time"
 
 	"github.com/dominicbreuker/pspy/internal/config"
-	"github.com/dominicbreuker/pspy/internal/inotify"
-	"github.com/dominicbreuker/pspy/internal/process"
-	"github.com/dominicbreuker/pspy/internal/walker"
 )
 
 type Logger interface {
@@ -20,7 +15,7 @@ type Logger interface {
 }
 
 type InotifyWatcher interface {
-	Setup(rdirs, dirs []string) (chan struct{}, chan string, error)
+	Setup(rdirs, dirs []string, errCh chan error) (chan struct{}, chan string, error)
 }
 
 type ProcfsScanner interface {
@@ -30,7 +25,11 @@ type ProcfsScanner interface {
 func Start(cfg config.Config, logger Logger, inotify InotifyWatcher, pscan ProcfsScanner, sigCh chan os.Signal) (chan struct{}, error) {
 	logger.Infof("Config: %+v\n", cfg)
 
-	triggerCh, fsEventCh, err := inotify.Setup(cfg.RDirs, cfg.Dirs)
+	// log all errors
+	errCh := make(chan error, 10)
+	go logErrors(errCh, logger)
+
+	triggerCh, fsEventCh, err := inotify.Setup(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")
@@ -41,8 +40,10 @@ func Start(cfg config.Config, logger Logger, inotify InotifyWatcher, pscan Procf
 		return nil, errors.New("procfs scanner error")
 	}
 
-	exit := make(chan struct{})
+	// ignore all file system events created on startup
+	drainChanFor(fsEventCh, 1*time.Second)
 
+	exit := make(chan struct{})
 	go func() {
 		for {
 			select {
@@ -63,72 +64,89 @@ func Start(cfg config.Config, logger Logger, inotify InotifyWatcher, pscan Procf
 	return exit, nil
 }
 
-const MaxInt = int(^uint(0) >> 1)
-
-func Watch(rdirs, dirs []string, logPS, logFS bool) {
-	maxWatchers, err := inotify.WatcherLimit()
-	if err != nil {
-		log.Printf("Can't get inotify watcher limit...: %v\n", err)
+func logErrors(errCh chan error, logger Logger) {
+	for {
+		err := <-errCh
+		logger.Errorf("ERROR: %v\n", err)
 	}
-	log.Printf("Inotify watcher limit: %d (/proc/sys/fs/inotify/max_user_watches)\n", maxWatchers)
-
-	ping := make(chan struct{})
-	in, err := inotify.NewInotify(ping, logFS)
-	if err != nil {
-		log.Fatalf("Can't init inotify: %v", err)
-	}
-	defer in.Close()
-
-	for _, dir := range rdirs {
-		addWatchers(dir, MaxInt, in, maxWatchers)
-	}
-	for _, dir := range dirs {
-		addWatchers(dir, 0, in, maxWatchers)
-	}
-
-	log.Printf("Inotify watchers set up: %s - watching now\n", in)
-
-	procList := process.NewProcList()
-
-	ticker := time.NewTicker(100 * time.Millisecond)
+}
 
+func drainChanFor(c chan string, d time.Duration) {
 	for {
 		select {
-		case <-ticker.C:
-			refresh(in, procList, logPS)
-		case <-ping:
-			refresh(in, procList, logPS)
+		case <-c:
+		case <-time.After(d):
+			return
 		}
 	}
 }
 
-func addWatchers(dir string, depth int, in *inotify.Inotify, maxWatchers int) {
-	dirCh, errCh, doneCh := walker.Walk(dir, depth)
-loop:
-	for {
-		if in.NumWatchers() >= maxWatchers {
-			close(doneCh)
-			break loop
-		}
-		select {
-		case dir, ok := <-dirCh:
-			if !ok {
-				break loop
-			}
-			if err := in.Watch(dir); err != nil {
-				fmt.Fprintf(os.Stderr, "Can't create watcher: %v\n", err)
-			}
-		case err := <-errCh:
-			fmt.Fprintf(os.Stderr, "Error walking filesystem: %v\n", err)
-		}
-	}
-}
+// const MaxInt = int(^uint(0) >> 1)
 
-func refresh(in *inotify.Inotify, pl *process.ProcList, print bool) {
-	in.Pause()
-	if err := pl.Refresh(print); err != nil {
-		log.Printf("ERROR refreshing process list: %v", err)
-	}
-	time.Sleep(5 * time.Millisecond)
-	in.UnPause()
-}
+// func Watch(rdirs, dirs []string, logPS, logFS bool) {
+// 	maxWatchers, err := inotify.WatcherLimit()
+// 	if err != nil {
+// 		log.Printf("Can't get inotify watcher limit...: %v\n", err)
+// 	}
+// 	log.Printf("Inotify watcher limit: %d (/proc/sys/fs/inotify/max_user_watches)\n", maxWatchers)
+
+// 	ping := make(chan struct{})
+// 	in, err := inotify.NewInotify(ping, logFS)
+// 	if err != nil {
+// 		log.Fatalf("Can't init inotify: %v", err)
+// 	}
+// 	defer in.Close()
+
+// 	for _, dir := range rdirs {
+// 		addWatchers(dir, MaxInt, in, maxWatchers)
+// 	}
+// 	for _, dir := range dirs {
+// 		addWatchers(dir, 0, in, maxWatchers)
+// 	}
+
+// 	log.Printf("Inotify watchers set up: %s - watching now\n", in)
+
+// 	procList := process.NewProcList()
+
+// 	ticker := time.NewTicker(100 * time.Millisecond)
+
+// 	for {
+// 		select {
+// 		case <-ticker.C:
+// 			refresh(in, procList, logPS)
+// 		case <-ping:
+// 			refresh(in, procList, logPS)
+// 		}
+// 	}
+// }
+
+// func addWatchers(dir string, depth int, in *inotify.Inotify, maxWatchers int) {
+// 	dirCh, errCh, doneCh := walker.Walk(dir, depth)
+// loop:
+// 	for {
+// 		if in.NumWatchers() >= maxWatchers {
+// 			close(doneCh)
+// 			break loop
+// 		}
+// 		select {
+// 		case dir, ok := <-dirCh:
+// 			if !ok {
+// 				break loop
+// 			}
+// 			if err := in.Watch(dir); err != nil {
+// 				fmt.Fprintf(os.Stderr, "Can't create watcher: %v\n", err)
+// 			}
+// 		case err := <-errCh:
+// 			fmt.Fprintf(os.Stderr, "Error walking filesystem: %v\n", err)
+// 		}
+// 	}
+// }
+
+// func refresh(in *inotify.Inotify, pl *process.ProcList, print bool) {
+// 	in.Pause()
+// 	if err := pl.Refresh(print); err != nil {
+// 		log.Printf("ERROR refreshing process list: %v", err)
+// 	}
+// 	time.Sleep(5 * time.Millisecond)
+// 	in.UnPause()
+// }

internal/pspy/pspy_test.go

@@ -92,6 +92,7 @@ type mockInotifyWatcher struct {
 	triggerCh chan struct{}
 	fsEventCh chan string
 	setupErr  error
+	closed    bool
 }
 
 func newMockInotifyWatcher(setupErr error) *mockInotifyWatcher {
@@ -99,16 +100,21 @@ func newMockInotifyWatcher(setupErr error) *mockInotifyWatcher {
 		triggerCh: make(chan struct{}),
 		fsEventCh: make(chan string),
 		setupErr:  setupErr,
+		closed:    false,
 	}
 }
 
-func (i *mockInotifyWatcher) Setup(rdirs, dirs []string) (chan struct{}, chan string, error) {
+func (i *mockInotifyWatcher) Setup(rdirs, dirs []string, errCh chan error) (chan struct{}, chan string, error) {
 	if i.setupErr != nil {
 		return nil, nil, i.setupErr
 	}
 	return i.triggerCh, i.fsEventCh, nil
 }
 
+func (i mockInotifyWatcher) Close() {
+	i.closed = true
+}
+
 // ProcfsScanner
 
 type mockProcfsScanner struct {