Pull request 2474: AGDNS-3196-web-port-env

Squashed commit of the following:

commit 0e1ba286f7
Author: Stanislav Chzhen <s.chzhen@adguard.com>
Date:   Tue Sep 9 17:01:50 2025 +0300

    all: imp docs

commit aef2460bdc
Author: Stanislav Chzhen <s.chzhen@adguard.com>
Date:   Tue Sep 9 11:01:13 2025 +0300

    all: web port env

CHANGELOG.md

@@ -18,6 +18,10 @@ See also the [v0.107.66 GitHub milestone][ms-v0.107.66].
 NOTE: Add new changes BELOW THIS COMMENT.
 -->
 
+### Added
+
+- Support for configuring the suggested default HTTP port for the installation wizard via the `ADGUARD_HOME_DEFAULT_WEB_PORT` environment variable (useful for vendors).
+
 ### Security
 
 - Go version has been updated to prevent the possibility of exploiting the Go vulnerabilities fixed in [1.25.1][go-1.25.1].

client/src/install/Setup/Settings.tsx

@@ -375,7 +375,7 @@ export const Settings = ({ handleSubmit, handleFix, validateForm, config, interf
                                         type="number"
                                         data-testid="install_dns_port"
                                         error={fieldState.error?.message}
-                                        placeholder={STANDARD_WEB_PORT.toString()}
+                                        placeholder={STANDARD_DNS_PORT.toString()}
                                         onChange={(e) => {
                                             const { value } = e.target;
                                             field.onChange(toNumber(value));

internal/home/controlinstall.go

@@ -46,7 +46,7 @@ func (web *webAPI) handleInstallGetAddresses(w http.ResponseWriter, r *http.Requ
 	data := getAddrsResponse{
 		Version: version.Version(),
 
-		WebPort: int(defaultPortHTTP),
+		WebPort: int(web.conf.defaultWebPort),
 		DNSPort: int(defaultPortDNS),
 	}
 

internal/home/home.go

@@ -14,6 +14,7 @@ import (
 	"path/filepath"
 	"runtime"
 	"slices"
+	"strconv"
 	"sync"
 	"syscall"
 	"time"
@@ -575,6 +576,8 @@ func initWeb(
 ) (web *webAPI, err error) {
 	logger := baseLogger.With(slogutil.KeyPrefix, "webapi")
 
+	webPort := suggestedWebPort(ctx, logger)
+
 	var clientFS fs.FS
 	if opts.localFrontend {
 		logger.WarnContext(ctx, "using local frontend files")
@@ -606,6 +609,8 @@ func initWeb(
 		ReadHeaderTimeout: readHdrTimeout,
 		WriteTimeout:      writeTimeout,
 
+		defaultWebPort: webPort,
+
 		firstRun:         globalContext.firstRun,
 		disableUpdate:    disableUpdate,
 		runningAsService: opts.runningAsService,
@@ -620,6 +625,37 @@ func initWeb(
 	return web, nil
 }
 
+// suggestedWebPort returns the suggested default HTTP port for the installation
+// wizard, using the port provided via an environment variable.  It falls back
+// to [defaultPortHTTP] on error.
+func suggestedWebPort(ctx context.Context, l *slog.Logger) (p uint16) {
+	const webPortEnv = "ADGUARD_HOME_DEFAULT_WEB_PORT"
+
+	s := os.Getenv(webPortEnv)
+	if s == "" {
+		return defaultPortHTTP
+	}
+
+	v, err := strconv.ParseUint(s, 10, 16)
+	if err == nil && v == 0 {
+		err = errors.ErrOutOfRange
+	}
+
+	if err != nil {
+		l.WarnContext(
+			ctx,
+			"invalid web port; using default",
+			"env", webPortEnv,
+			"val", s,
+			slogutil.KeyError, err,
+		)
+
+		return defaultPortHTTP
+	}
+
+	return uint16(v)
+}
+
 func fatalOnError(err error) {
 	if err != nil {
 		log.Fatal(err)

internal/home/web.go

@@ -80,6 +80,9 @@ type webConfig struct {
 	// appropriate field.
 	WriteTimeout time.Duration
 
+	// defaultWebPort is the suggested default HTTP port for the install wizard.
+	defaultWebPort uint16
+
 	firstRun bool
 
 	// disableUpdate, if true, tells AdGuard Home to not check for updates.