all: add --local-frontend, upd docker

CHANGELOG.md

@@ -13,6 +13,11 @@ and this project adheres to
 ## [v0.107.0] - 2021-06-28 (APPROX.)
 -->
 
+### Added
+
+- New flag `--local-frontend` to serve dinamically changeable frontend files
+  from disk as opposed to the ones that were compiled into the binary.
+
 ### Deprecated
 
 <!--

bamboo-specs/test.yaml

@@ -5,7 +5,7 @@
   'key': 'AHBRTSPECS'
   'name': 'AdGuard Home - Build and run tests'
 'variables':
-  'dockerGo': 'adguard/golang-ubuntu:3.0'
+  'dockerGo': 'adguard/golang-ubuntu:3.1'
 
 'stages':
 - 'Tests':

internal/home/home.go

@@ -227,15 +227,23 @@ func setupConfig(args options) {
 	}
 }
 
-func initWeb(clientBuildFS fs.FS) (web *Web, err error) {
-	clientFS, err := fs.Sub(clientBuildFS, "build/static")
-	if err != nil {
-		return nil, fmt.Errorf("getting embedded client subdir: %w", err)
-	}
+func initWeb(args options, clientBuildFS fs.FS) (web *Web, err error) {
+	var clientFS, clientBetaFS fs.FS
+	if args.localFrontend {
+		log.Info("warning: using local frontend files")
 
-	clientBetaFS, err := fs.Sub(clientBuildFS, "build2/static")
-	if err != nil {
-		return nil, fmt.Errorf("getting embedded beta client subdir: %w", err)
+		clientFS = os.DirFS("build/static")
+		clientBetaFS = os.DirFS("build2/static")
+	} else {
+		clientFS, err = fs.Sub(clientBuildFS, "build/static")
+		if err != nil {
+			return nil, fmt.Errorf("getting embedded client subdir: %w", err)
+		}
+
+		clientBetaFS, err = fs.Sub(clientBuildFS, "build2/static")
+		if err != nil {
+			return nil, fmt.Errorf("getting embedded beta client subdir: %w", err)
+		}
 	}
 
 	webConf := webConfig{
@@ -345,7 +353,7 @@ func run(args options, clientBuildFS fs.FS) {
 		log.Fatalf("Can't initialize TLS module")
 	}
 
-	Context.web, err = initWeb(clientBuildFS)
+	Context.web, err = initWeb(args, clientBuildFS)
 	if err != nil {
 		log.Fatal(err)
 	}

internal/home/options.go

@@ -36,6 +36,10 @@ type options struct {
 	// noEtcHosts flag should be provided when /etc/hosts file shouldn't be
 	// used.
 	noEtcHosts bool
+
+	// localFrontend forces AdGuard Home to use the frontend files from disk
+	// rather than the ones that have been compiled into the binary.
+	localFrontend bool
 }
 
 // functions used for their side-effects
@@ -234,6 +238,16 @@ var noEtcHostsArg = arg{
 	serialize:       func(o options) []string { return boolSliceOrNil(o.noEtcHosts) },
 }
 
+var localFrontendArg = arg{
+	description:     "Use local frontend directories.",
+	longName:        "local-frontend",
+	shortName:       "",
+	updateWithValue: nil,
+	updateNoValue:   func(o options) (options, error) { o.localFrontend = true; return o, nil },
+	effect:          nil,
+	serialize:       func(o options) []string { return boolSliceOrNil(o.localFrontend) },
+}
+
 func init() {
 	args = []arg{
 		configArg,
@@ -247,6 +261,7 @@ func init() {
 		noCheckUpdateArg,
 		disableMemoryOptimizationArg,
 		noEtcHostsArg,
+		localFrontendArg,
 		verboseArg,
 		glinetArg,
 		versionArg,