feat: run local --watch flag

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/dustin/go-humanize v1.0.1
 	github.com/fatih/color v1.16.0
 	github.com/fatih/structs v1.1.0
+	github.com/fsnotify/fsnotify v1.7.0
 	github.com/golang/mock v1.6.0
 	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510
 	github.com/google/uuid v1.4.0

go.sum

@@ -81,6 +81,8 @@ github.com/fatih/color v1.16.0 h1:zmkK9Ngbjj+K0yRhTVONQh1p/HknKYSlNT+vZCzyokM=
 github.com/fatih/color v1.16.0/go.mod h1:fL2Sau1YI5c0pdGEVCbKQbLXB6edEj1ZgiY4NijnWvE=
 github.com/fatih/structs v1.1.0 h1:Q7juDM0QtcnhCpeyLGQKyg4TOIghuNXrkL32pHAUMxo=
 github.com/fatih/structs v1.1.0/go.mod h1:9NiDSp5zOcgEDl+j00MP/WkGVPOlPRLejGD8Ga6PJ7M=
+github.com/fsnotify/fsnotify v1.7.0 h1:8JEhPFa5W2WU7YfeZzPNqzMP6Lwt7L2715Ggo0nosvA=
+github.com/fsnotify/fsnotify v1.7.0/go.mod h1:40Bi/Hjc2AVfZrqy+aj+yEI+/bRxZnMJyTJwOpGvigM=
 github.com/go-gl/glfw v0.0.0-20190409004039-e6da0acd62b1/go.mod h1:vR7hzQXu2zJy9AVAgeJqvqgH9Q5CA+iKCZ2gyEVpxRU=
 github.com/go-gl/glfw/v3.3/glfw v0.0.0-20191125211704-12ad95a8df72/go.mod h1:tQ2UAYgL5IevRw8kRxooKSPJfGvJ9fJQFa0TUsXzTg8=
 github.com/go-gl/glfw/v3.3/glfw v0.0.0-20200222043503-6f7a984d4dc4/go.mod h1:tQ2UAYgL5IevRw8kRxooKSPJfGvJ9fJQFa0TUsXzTg8=

internal/pkg/cli/file/filetest/watchertest.go

@@ -0,0 +1,38 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package filetest
+
+import "github.com/fsnotify/fsnotify"
+
+// Double is a test double for file.RecursiveWatcher
+type Double struct {
+	EventsFn func() <-chan fsnotify.Event
+	ErrorsFn func() <-chan error
+}
+
+// Add is a no-op for Double.
+func (d *Double) Add(string) error {
+	return nil
+}
+
+// Close is a no-op for Double.
+func (d *Double) Close() error {
+	return nil
+}
+
+// Events calls the stubbed function.
+func (d *Double) Events() <-chan fsnotify.Event {
+	if d.EventsFn == nil {
+		return nil
+	}
+	return d.EventsFn()
+}
+
+// Errors calls the stubbed function.
+func (d *Double) Errors() <-chan error {
+	if d.ErrorsFn == nil {
+		return nil
+	}
+	return d.ErrorsFn()
+}

internal/pkg/cli/file/hidden.go

@@ -0,0 +1,13 @@
+//go:build !windows
+
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package file
+
+import "path/filepath"
+
+// IsHiddenFile returns true if the file is hidden on non-windows.
+func IsHiddenFile(filename string) (bool, error) {
+	return filepath.Base(filename)[0] == '.', nil
+}

internal/pkg/cli/file/hidden_windows.go

@@ -0,0 +1,21 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package file
+
+import (
+	"syscall"
+)
+
+// IsHiddenFile returns true if the file is hidden on windows.
+func IsHiddenFile(filename string) (bool, error) {
+	pointer, err := syscall.UTF16PtrFromString(filename)
+	if err != nil {
+		return false, err
+	}
+	attributes, err := syscall.GetFileAttributes(pointer)
+	if err != nil {
+		return false, err
+	}
+	return attributes&syscall.FILE_ATTRIBUTE_HIDDEN != 0, nil
+}

internal/pkg/cli/file/watch.go

@@ -0,0 +1,100 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package file
+
+import (
+	"io/fs"
+	"path/filepath"
+
+	"github.com/fsnotify/fsnotify"
+)
+
+// RecursiveWatcher wraps an fsnotify Watcher to recursively watch all files in a directory.
+type RecursiveWatcher struct {
+	fsnotifyWatcher *fsnotify.Watcher
+	done            chan struct{}
+	closed          bool
+	events          chan fsnotify.Event
+	errors          chan error
+}
+
+// NewRecursiveWatcher returns a RecursiveWatcher which notifies when changes are made to files inside a recursive directory tree.
+func NewRecursiveWatcher(buffer uint) (*RecursiveWatcher, error) {
+	watcher, err := fsnotify.NewBufferedWatcher(buffer)
+	if err != nil {
+		return nil, err
+	}
+
+	rw := &RecursiveWatcher{
+		events:          make(chan fsnotify.Event, buffer),
+		errors:          make(chan error),
+		fsnotifyWatcher: watcher,
+		done:            make(chan struct{}),
+		closed:          false,
+	}
+
+	go rw.start()
+
+	return rw, nil
+}
+
+// Add recursively adds a directory tree to the list of watched files.
+func (rw *RecursiveWatcher) Add(path string) error {
+	if rw.closed {
+		return fsnotify.ErrClosed
+	}
+	return filepath.WalkDir(path, func(p string, d fs.DirEntry, err error) error {
+		if err != nil {
+			// swallow error from WalkDir, don't attempt to add to watcher.
+			return nil
+		}
+		if d.IsDir() {
+			return rw.fsnotifyWatcher.Add(p)
+		}
+		return nil
+	})
+}
+
+// Events returns the events channel.
+func (rw *RecursiveWatcher) Events() <-chan fsnotify.Event {
+	return rw.events
+}
+
+// Errors returns the errors channel.
+func (rw *RecursiveWatcher) Errors() <-chan error {
+	return rw.errors
+}
+
+// Close closes the RecursiveWatcher.
+func (rw *RecursiveWatcher) Close() error {
+	if !rw.closed {
+		rw.closed = true
+		close(rw.done)
+		return rw.fsnotifyWatcher.Close()
+	}
+	return nil
+}
+
+func (rw *RecursiveWatcher) start() {
+	for {
+		select {
+		case <-rw.done:
+			close(rw.events)
+			close(rw.errors)
+			return
+		case event := <-rw.fsnotifyWatcher.Events:
+			// handle recursive watch
+			switch event.Op {
+			case fsnotify.Create:
+				if err := rw.Add(event.Name); err != nil {
+					rw.errors <- err
+				}
+			}
+
+			rw.events <- event
+		case err := <-rw.fsnotifyWatcher.Errors:
+			rw.errors <- err
+		}
+	}
+}

internal/pkg/cli/file/watch_integration_test.go

@@ -0,0 +1,141 @@
+//go:build integration || localintegration
+
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package file_test
+
+import (
+	"fmt"
+	"io/fs"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/aws/copilot-cli/internal/pkg/cli/file"
+	"github.com/fsnotify/fsnotify"
+	"github.com/stretchr/testify/require"
+)
+
+func TestRecursiveWatcher(t *testing.T) {
+	var (
+		watcher        *file.RecursiveWatcher
+		tmp            string
+		eventsExpected []fsnotify.Event
+		eventsActual   []fsnotify.Event
+	)
+
+	tmp = os.TempDir()
+	eventsActual = make([]fsnotify.Event, 0)
+	eventsExpected = []fsnotify.Event{
+		{
+			Name: fmt.Sprintf("%s/watch/subdir/testfile", tmp),
+			Op:   fsnotify.Create,
+		},
+		{
+			Name: fmt.Sprintf("%s/watch/subdir/testfile", tmp),
+			Op:   fsnotify.Chmod,
+		},
+		{
+			Name: fmt.Sprintf("%s/watch/subdir/testfile", tmp),
+			Op:   fsnotify.Write,
+		},
+		{
+			Name: fmt.Sprintf("%s/watch/subdir/testfile", tmp),
+			Op:   fsnotify.Write,
+		},
+		{
+			Name: fmt.Sprintf("%s/watch/subdir", tmp),
+			Op:   fsnotify.Rename,
+		},
+		{
+			Name: fmt.Sprintf("%s/watch/subdir2", tmp),
+			Op:   fsnotify.Create,
+		},
+		{
+			Name: fmt.Sprintf("%s/watch/subdir", tmp),
+			Op:   fsnotify.Rename,
+		},
+		{
+			Name: fmt.Sprintf("%s/watch/subdir2/testfile", tmp),
+			Op:   fsnotify.Rename,
+		},
+		{
+			Name: fmt.Sprintf("%s/watch/subdir2/testfile2", tmp),
+			Op:   fsnotify.Create,
+		},
+		{
+			Name: fmt.Sprintf("%s/watch/subdir2/testfile2", tmp),
+			Op:   fsnotify.Remove,
+		},
+	}
+
+	t.Run("Setup Watcher", func(t *testing.T) {
+		err := os.MkdirAll(fmt.Sprintf("%s/watch/subdir", tmp), 0755)
+		require.NoError(t, err)
+
+		watcher, err = file.NewRecursiveWatcher(uint(len(eventsExpected)))
+		require.NoError(t, err)
+	})
+
+	t.Run("Watch", func(t *testing.T) {
+		// SETUP
+		err := watcher.Add(fmt.Sprintf("%s/watch", tmp))
+		require.NoError(t, err)
+
+		eventsCh := watcher.Events()
+		errorsCh := watcher.Errors()
+
+		expectEvents := func(t *testing.T, n int) []fsnotify.Event {
+			receivedEvents := []fsnotify.Event{}
+			for i := 0; i < n; i++ {
+				select {
+				case e := <-eventsCh:
+					receivedEvents = append(receivedEvents, e)
+				case <-time.After(time.Second):
+				}
+			}
+			return receivedEvents
+		}
+
+		// WATCH
+		file, err := os.Create(fmt.Sprintf("%s/watch/subdir/testfile", tmp))
+		require.NoError(t, err)
+		eventsActual = append(eventsActual, expectEvents(t, 1)...)
+
+		err = os.Chmod(fmt.Sprintf("%s/watch/subdir/testfile", tmp), 0755)
+		require.NoError(t, err)
+		eventsActual = append(eventsActual, expectEvents(t, 1)...)
+
+		err = os.WriteFile(fmt.Sprintf("%s/watch/subdir/testfile", tmp), []byte("write to file"), fs.ModeAppend)
+		require.NoError(t, err)
+		eventsActual = append(eventsActual, expectEvents(t, 2)...)
+
+		err = file.Close()
+		require.NoError(t, err)
+
+		err = os.Rename(fmt.Sprintf("%s/watch/subdir", tmp), fmt.Sprintf("%s/watch/subdir2", tmp))
+		require.NoError(t, err)
+		eventsActual = append(eventsActual, expectEvents(t, 3)...)
+
+		err = os.Rename(fmt.Sprintf("%s/watch/subdir2/testfile", tmp), fmt.Sprintf("%s/watch/subdir2/testfile2", tmp))
+		require.NoError(t, err)
+		eventsActual = append(eventsActual, expectEvents(t, 2)...)
+
+		err = os.Remove(fmt.Sprintf("%s/watch/subdir2/testfile2", tmp))
+		require.NoError(t, err)
+		eventsActual = append(eventsActual, expectEvents(t, 1)...)
+
+		// CLOSE
+		err = watcher.Close()
+		require.NoError(t, err)
+		require.Empty(t, errorsCh)
+
+		require.Equal(t, eventsExpected, eventsActual)
+	})
+
+	t.Run("Clean", func(t *testing.T) {
+		err := os.RemoveAll(fmt.Sprintf("%s/watch", tmp))
+		require.NoError(t, err)
+	})
+}

internal/pkg/cli/flag.go

@@ -71,6 +71,7 @@ const (
 	envVarOverrideFlag = "env-var-override"
 	proxyFlag          = "proxy"
 	proxyNetworkFlag   = "proxy-network"
+	watchFlag          = "watch"
 
 	// Flags for CI/CD.
 	githubURLFlag         = "github-url"
@@ -324,6 +325,7 @@ Format: [container]:KEY=VALUE. Omit container name to apply to all containers.`
 Example: --port-override 5000:80 binds localhost:5000 to the service's port 80.`
 	proxyFlagDescription        = `Optional. Proxy outbound requests to your environment's VPC.`
 	proxyNetworkFlagDescription = `Optional. Set the IP Network used by --proxy.`
+	watchFlagDescription        = `Optional. Watch changes to local files and restart containers when updated.`
 
 	svcManifestFlagDescription = `Optional. Name of the environment in which the service was deployed;
 output the manifest file used for that deployment.`