[fswatcher] File Reconciler w/ Resync Interval

Signed-off-by: hfuss <hayden.fuss@kaleido.io>

pkg/fswatcher/fswatcher.go

@@ -20,6 +20,7 @@ import (
 	"context"
 	"os"
 	"path"
+	"time"
 
 	"github.com/fsnotify/fsnotify"
 	"github.com/hyperledger/firefly-common/pkg/fftypes"
@@ -35,9 +36,19 @@ import (
 // - Only fires if the data in the file is different to the last notification
 // - Does not reload the config - that's the caller's responsibility
 func Watch(ctx context.Context, fullFilePath string, onChange, onClose func()) error {
+	return sync(ctx, fullFilePath, onChange, onClose, nil, nil)
+}
+
+// Reconcile behaves the same as Watch, except it allows for running the onSync func on a provided
+// interval. The default re-sync internal is 1m.
+func Reconcile(ctx context.Context, fullFilePath string, onChange, onClose, onSync func(), resyncInterval *time.Duration) error {
+	return sync(ctx, fullFilePath, onChange, onClose, onSync, resyncInterval)
+}
+
+func sync(ctx context.Context, fullFilePath string, onChange, onClose, onSync func(), resyncInterval *time.Duration) error {
 	filePath := path.Dir(fullFilePath)
 	fileName := path.Base(fullFilePath)
-	log.L(ctx).Debugf("Starting file listener for '%s' in directory '%s'", fileName, filePath)
+	log.L(ctx).Debugf("Starting file reconciler for '%s' in directory '%s'", fileName, filePath)
 
 	watcher, err := fsnotify.NewWatcher()
 	if err == nil {
@@ -46,7 +57,7 @@ func Watch(ctx context.Context, fullFilePath string, onChange, onClose func()) e
 			if onClose != nil {
 				onClose()
 			}
-		}, watcher.Events, watcher.Errors)
+		}, onSync, resyncInterval, watcher.Events, watcher.Errors)
 		err = watcher.Add(filePath)
 	}
 	if err != nil {
@@ -56,9 +67,18 @@ func Watch(ctx context.Context, fullFilePath string, onChange, onClose func()) e
 	return nil
 }
 
-func fsListenerLoop(ctx context.Context, fullFilePath string, onChange, onClose func(), events chan fsnotify.Event, errors chan error) {
+func fsListenerLoop(ctx context.Context, fullFilePath string, onChange, onClose, onSync func(), resyncInterval *time.Duration, events chan fsnotify.Event, errors chan error) {
 	defer onClose()
 
+	timeout := resyncInterval
+	if timeout == nil {
+		timeout = func() *time.Duration {
+			defaultTimeout := time.Minute
+			return &defaultTimeout
+		}()
+	}
+	log.L(ctx).Debugf("re-sync interval set to '%s'", *timeout)
+
 	var lastHash *fftypes.Bytes32
 	for {
 		select {
@@ -83,6 +103,15 @@ func fsListenerLoop(ctx context.Context, fullFilePath string, onChange, onClose
 					lastHash = dataHash
 				}
 			}
+		case <-time.After(*timeout):
+			if onSync != nil {
+				data, err := os.ReadFile(fullFilePath)
+				if err == nil {
+					dataHash := fftypes.HashString(string(data))
+					log.L(ctx).Infof("Config file re-sync. Event=Resync Name=%s Size=%d Hash=%s", fullFilePath, len(data), dataHash)
+					onSync()
+				}
+			}
 		case err, ok := <-errors:
 			if ok {
 				log.L(ctx).Errorf("FSEvent error: %s", err)

pkg/fswatcher/fswatcher_test.go

@@ -21,14 +21,15 @@ import (
 	"fmt"
 	"os"
 	"testing"
+	"time"
 
 	"github.com/fsnotify/fsnotify"
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/viper"
 	"github.com/stretchr/testify/assert"
 )
 
-func TestFileListenerE2E(t *testing.T) {
+func TestFileReconcilerE2E(t *testing.T) {
 
 	logrus.SetLevel(logrus.DebugLevel)
 	tmpDir := t.TempDir()
@@ -47,14 +48,20 @@ func TestFileListenerE2E(t *testing.T) {
 	// Start listener on config file
 	fsListenerDone := make(chan struct{})
 	fsListenerFired := make(chan bool)
+	reSyncFired := make(chan bool)
+	reSyncInterval := 1 * time.Second
 	ctx, cancelCtx := context.WithCancel(context.Background())
-	err := Watch(ctx, filePath, func() {
+	err := Reconcile(ctx, filePath, func() {
 		err := viper.ReadInConfig()
 		assert.NoError(t, err)
 		fsListenerFired <- true
 	}, func() {
 		close(fsListenerDone)
-	})
+	}, func() {
+		err := viper.ReadInConfig()
+		assert.NoError(t, err)
+		reSyncFired <- true
+	}, &reSyncInterval)
 	assert.NoError(t, err)
 
 	// Delete and rename in another file
@@ -63,6 +70,7 @@ func TestFileListenerE2E(t *testing.T) {
 	os.Rename(fmt.Sprintf("%s/another.yaml", tmpDir), fmt.Sprintf("%s/test.yaml", tmpDir))
 	<-fsListenerFired
 	assert.Equal(t, "two", viper.Get("ut_conf"))
+	<-reSyncFired
 
 	defer func() {
 		cancelCtx()
@@ -74,7 +82,7 @@ func TestFileListenerE2E(t *testing.T) {
 
 }
 
-func TestFileListenerFail(t *testing.T) {
+func TestFileWatcherFail(t *testing.T) {
 
 	logrus.SetLevel(logrus.DebugLevel)
 	tmpDir := t.TempDir()
@@ -95,7 +103,7 @@ func TestFileListenerLogError(t *testing.T) {
 	defer cancelCtx()
 	errors := make(chan error)
 	fsListenerDone := make(chan struct{})
-	go fsListenerLoop(ctx, "somefile", func() {}, func() { close(fsListenerDone) }, make(chan fsnotify.Event), errors)
+	go fsListenerLoop(ctx, "somefile", func() {}, func() { close(fsListenerDone) }, nil, nil, make(chan fsnotify.Event), errors)
 
 	errors <- fmt.Errorf("pop")
 	cancelCtx()