add new watch flag for up command

Signed-off-by: Nikhil Sharma <nikhilsharma230303@gmail.com>

commands/up.go

@@ -5,21 +5,27 @@ package commands
 
 import (
 	"fmt"
+	"os"
+	"path/filepath"
+	"time"
 
+	"github.com/fsnotify/fsnotify"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 )
 
 var (
 	skipPush   bool
 	skipDeploy bool
+	watch      bool
 )
 
 func init() {
 
 	upFlagset := pflag.NewFlagSet("up", pflag.ExitOnError)
 	upFlagset.BoolVar(&skipPush, "skip-push", false, "Skip pushing function to remote registry")
 	upFlagset.BoolVar(&skipDeploy, "skip-deploy", false, "Skip function deployment")
+	upFlagset.BoolVar(&watch, "watch", false, "Watch for changes in files and re-deploy")
 	upCmd.Flags().AddFlagSet(upFlagset)
 
 	build, _, _ := faasCmd.Find([]string{"build"})
@@ -64,20 +70,80 @@ func preRunUp(cmd *cobra.Command, args []string) error {
 }
 
 func upHandler(cmd *cobra.Command, args []string) error {
-	if err := runBuild(cmd, args); err != nil {
-		return err
-	}
-	fmt.Println()
-	if !skipPush {
-		if err := runPush(cmd, args); err != nil {
+	if !watch {
+		if err := runBuild(cmd, args); err != nil {
 			return err
 		}
-		fmt.Println()
-	}
-	if !skipDeploy {
-		if err := runDeploy(cmd, args); err != nil {
+
+		if !skipPush {
+			if err := runPush(cmd, args); err != nil {
+				return err
+			}
+		}
+
+		if !skipDeploy {
+			if err := runDeploy(cmd, args); err != nil {
+				return err
+			}
+		}
+	} else {
+		watcher, err := fsnotify.NewWatcher()
+		if err != nil {
+			return err
+		}
+		defer watcher.Close()
+
+		err = filepath.Walk("./", func(path string, info os.FileInfo, err error) error {
+			if err != nil {
+				return err
+			}
+			if info.IsDir() {
+				return watcher.Add(path)
+			}
+			return nil
+		})
+
+		if err != nil {
 			return err
 		}
+
+		debounceTimer := time.NewTimer(0 * time.Second)
+		defer debounceTimer.Stop()
+
+		for {
+			select {
+			case event, ok := <-watcher.Events:
+				if !ok {
+					return fmt.Errorf("watcher's Events channel is closed")
+				}
+
+				if event.Op == fsnotify.Write {
+					debounceTimer.Reset(5 * time.Second)
+				}
+
+			case err, ok := <-watcher.Errors:
+				if !ok {
+					return fmt.Errorf("watcher's Errors channel is closed")
+				}
+				return err
+
+			case <-debounceTimer.C:
+				if err := runBuild(cmd, args); err != nil {
+					return err
+				}
+
+				if !skipPush {
+					if err := runPush(cmd, args); err != nil {
+						return err
+					}
+				}
+
+				if err := runDeploy(cmd, args); err != nil {
+					return err
+				}
+			}
+		}
 	}
+
 	return nil
 }

go.mod

@@ -25,56 +25,34 @@ require (
 )
 
 require (
+	github.com/fsnotify/fsnotify v1.6.0
 	github.com/google/go-containerregistry v0.13.0
 	github.com/mitchellh/go-wordwrap v1.0.1
 )
 
 require (
 	github.com/Azure/go-ansiterm v0.0.0-20210617225240-d185dfc1b5a1 // indirect
-	github.com/Masterminds/semver v1.5.0 // indirect
 	github.com/VividCortex/ewma v1.2.0 // indirect
-	github.com/beorn7/perks v1.0.1 // indirect
-	github.com/cespare/xxhash/v2 v2.1.2 // indirect
 	github.com/cheggaaa/pb/v3 v3.1.0 // indirect
 	github.com/containerd/stargz-snapshotter/estargz v0.12.1 // indirect
 	github.com/docker/cli v20.10.20+incompatible // indirect
 	github.com/docker/distribution v2.8.1+incompatible // indirect
 	github.com/docker/docker-credential-helpers v0.7.0 // indirect
-	github.com/docker/go-units v0.5.0 // indirect
 	github.com/fatih/color v1.13.0 // indirect
-	github.com/gogo/protobuf v1.3.2 // indirect
-	github.com/golang/protobuf v1.5.2 // indirect
-	github.com/gorilla/mux v1.8.0 // indirect
 	github.com/inconshreveable/mousetrap v1.0.1 // indirect
 	github.com/klauspost/compress v1.15.11 // indirect
 	github.com/kr/text v0.2.0 // indirect
 	github.com/mattn/go-colorable v0.1.12 // indirect
 	github.com/mattn/go-isatty v0.0.14 // indirect
 	github.com/mattn/go-runewidth v0.0.13 // indirect
-	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
 	github.com/moby/term v0.0.0-20220808134915-39b0c02b01ae // indirect
-	github.com/nats-io/nats.go v1.22.1 // indirect
-	github.com/nats-io/nkeys v0.3.0 // indirect
-	github.com/nats-io/nuid v1.0.1 // indirect
-	github.com/nats-io/stan.go v0.10.4 // indirect
 	github.com/olekukonko/tablewriter v0.0.5 // indirect
 	github.com/opencontainers/go-digest v1.0.0 // indirect
 	github.com/opencontainers/image-spec v1.1.0-rc2 // indirect
-	github.com/openfaas/nats-queue-worker v0.0.0-20230117214128-3615ccb286cc // indirect
-	github.com/otiai10/copy v1.9.0 // indirect
-	github.com/prometheus/client_golang v1.13.0 // indirect
-	github.com/prometheus/client_model v0.2.0 // indirect
-	github.com/prometheus/common v0.37.0 // indirect
-	github.com/prometheus/procfs v0.8.0 // indirect
 	github.com/rivo/uniseg v0.2.0 // indirect
 	github.com/rogpeppe/go-internal v1.9.0 // indirect
-	github.com/sethvargo/go-password v0.2.0 // indirect
 	github.com/sirupsen/logrus v1.9.0 // indirect
 	github.com/vbatts/tar-split v0.11.2 // indirect
-	golang.org/x/crypto v0.6.0 // indirect
-	golang.org/x/mod v0.8.0 // indirect
 	golang.org/x/sync v0.1.0 // indirect
 	golang.org/x/sys v0.5.0 // indirect
-	google.golang.org/protobuf v1.28.1 // indirect
-	gopkg.in/yaml.v2 v2.4.0 // indirect
 )