Pull request 1899: nextapi-pidfile-webaddr

Squashed commit of the following:

commit 73b97b638016dd3992376c2cd7d11b2e85b2c3a4
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Thu Jun 29 18:43:05 2023 +0300

    next: use maybe; sync conf

commit 99e18b8fbfad11343a1e66f746085d54be7aafea
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Thu Jun 29 18:13:13 2023 +0300

    next: add local frontend, pidfile, webaddr

internal/next/AdGuardHome.example.yaml

@@ -23,4 +23,5 @@ http:
   secure_addresses: []
   timeout: 5s
   force_https: true
-verbose: true
+log:
+  verbose: true

internal/next/cmd/cmd.go

@@ -16,7 +16,7 @@ import (
 )
 
 // Main is the entry point of AdGuard Home.
-func Main(frontend fs.FS) {
+func Main(embeddedFrontend fs.FS) {
 	start := time.Now()
 
 	cmdName := os.Args[0]
@@ -37,7 +37,17 @@ func Main(frontend fs.FS) {
 		check(err)
 	}
 
-	confMgr, err := newConfigMgr(opts.confFile, frontend, start)
+	frontend, err := frontendFromOpts(opts, embeddedFrontend)
+	check(err)
+
+	confMgrConf := &configmgr.Config{
+		Frontend: frontend,
+		WebAddr:  opts.webAddr,
+		Start:    start,
+		FileName: opts.confFile,
+	}
+
+	confMgr, err := newConfigMgr(confMgrConf)
 	check(err)
 
 	web := confMgr.Web()
@@ -49,9 +59,8 @@ func Main(frontend fs.FS) {
 	check(err)
 
 	sigHdlr := newSignalHandler(
-		opts.confFile,
+		confMgrConf,
-		frontend,
+		opts.pidFile,
-		start,
 		web,
 		dns,
 	)
@@ -71,11 +80,11 @@ func ctxWithDefaultTimeout() (ctx context.Context, cancel context.CancelFunc) {
 
 // newConfigMgr returns a new configuration manager using defaultTimeout as the
 // context timeout.
-func newConfigMgr(confFile string, frontend fs.FS, start time.Time) (m *configmgr.Manager, err error) {
+func newConfigMgr(c *configmgr.Config) (m *configmgr.Manager, err error) {
 	ctx, cancel := ctxWithDefaultTimeout()
 	defer cancel()
 
-	return configmgr.New(ctx, confFile, frontend, start)
+	return configmgr.New(ctx, c)
 }
 
 // check is a simple error-checking helper.  It must only be used within Main.

internal/next/cmd/opt.go

@@ -1,15 +1,18 @@
 package cmd
 
 import (
+	"encoding"
 	"flag"
 	"fmt"
 	"io"
+	"io/fs"
 	"net/netip"
 	"os"
 	"strings"
 
 	"github.com/AdguardTeam/AdGuardHome/internal/next/configmgr"
 	"github.com/AdguardTeam/AdGuardHome/internal/version"
+	"github.com/AdguardTeam/golibs/log"
 	"golang.org/x/exp/slices"
 )
 
@@ -26,8 +29,6 @@ type options struct {
 	logFile string
 
 	// pidFile is the path to the file where to store the PID.
-	//
-	// TODO(a.garipov): Use.
 	pidFile string
 
 	// serviceAction is the service control action to perform:
@@ -50,10 +51,8 @@ type options struct {
 	// other configuration is read, so all relative paths are relative to it.
 	workDir string
 
-	// webAddrs contains the addresses on which to serve the web UI.
+	// webAddr contains the address on which to serve the web UI.
-	//
+	webAddr netip.AddrPort
-	// TODO(a.garipov): Use.
-	webAddrs []netip.AddrPort
 
 	// checkConfig, if true, instructs AdGuard Home to check the configuration
 	// file, optionally print an error message to stdout, and exit with a
@@ -103,7 +102,7 @@ const (
 	pidFileIdx
 	serviceActionIdx
 	workDirIdx
-	webAddrsIdx
+	webAddrIdx
 	checkConfigIdx
 	disableUpdateIdx
 	glinetModeIdx
@@ -172,10 +171,9 @@ var commandLineOptions = []*commandLineOption{
 		valueType: "path",
 	},
 
-	webAddrsIdx: {
+	webAddrIdx: {
-		defaultValue: []netip.AddrPort(nil),
+		defaultValue: netip.AddrPort{},
-		description: `Address(es) to serve the web UI on, in the host:port format.  ` +
+		description:  `Address to serve the web UI on, in the host:port format.`,
-			`Can be used multiple times.`,
 		long:         "web-addr",
 		short:        "",
 		valueType:    "host:port",
@@ -258,7 +256,7 @@ func parseOptions(cmdName string, args []string) (opts *options, err error) {
 		pidFileIdx:       &opts.pidFile,
 		serviceActionIdx: &opts.serviceAction,
 		workDirIdx:       &opts.workDir,
-		webAddrsIdx:      &opts.webAddrs,
+		webAddrIdx:       &opts.webAddr,
 		checkConfigIdx:   &opts.checkConfig,
 		disableUpdateIdx: &opts.disableUpdate,
 		glinetModeIdx:    &opts.glinetMode,
@@ -291,23 +289,16 @@ func addOption(flags *flag.FlagSet, fieldPtr any, o *commandLineOption) {
 		if o.short != "" {
 			flags.StringVar(fieldPtr, o.short, o.defaultValue.(string), o.description)
 		}
-	case *[]netip.AddrPort:
-		flags.Func(o.long, o.description, func(s string) (err error) {
-			addr, err := netip.ParseAddrPort(s)
-			if err != nil {
-				// Don't wrap the error, because it's informative enough as is.
-				return err
-			}
-
-			*fieldPtr = append(*fieldPtr, addr)
-
-			return nil
-		})
 	case *bool:
 		flags.BoolVar(fieldPtr, o.long, o.defaultValue.(bool), o.description)
 		if o.short != "" {
 			flags.BoolVar(fieldPtr, o.short, o.defaultValue.(bool), o.description)
 		}
+	case encoding.TextUnmarshaler:
+		flags.TextVar(fieldPtr, o.long, o.defaultValue.(encoding.TextMarshaler), o.description)
+		if o.short != "" {
+			flags.TextVar(fieldPtr, o.short, o.defaultValue.(encoding.TextMarshaler), o.description)
+		}
 	default:
 		panic(fmt.Errorf("unexpected field pointer type %T", fieldPtr))
 	}
@@ -380,13 +371,13 @@ func processOptions(
 ) (exitCode int, needExit bool) {
 	if parseErr != nil {
 		// Assume that usage has already been printed.
-		return 2, true
+		return statusArgumentError, true
 	}
 
 	if opts.help {
 		usage(cmdName, os.Stdout)
 
-		return 0, true
+		return statusSuccess, true
 	}
 
 	if opts.version {
@@ -396,7 +387,7 @@ func processOptions(
 			fmt.Printf("AdGuard Home %s\n", version.Version())
 		}
 
-		return 0, true
+		return statusSuccess, true
 	}
 
 	if opts.checkConfig {
@@ -404,11 +395,24 @@ func processOptions(
 		if err != nil {
 			_, _ = io.WriteString(os.Stdout, err.Error()+"\n")
 
-			return 1, true
+			return statusError, true
 		}
 
-		return 0, true
+		return statusSuccess, true
 	}
 
 	return 0, false
 }
+
+// frontendFromOpts returns the frontend to use based on the options.
+func frontendFromOpts(opts *options, embeddedFrontend fs.FS) (frontend fs.FS, err error) {
+	const frontendSubdir = "build/static"
+
+	if opts.localFrontend {
+		log.Info("warning: using local frontend files")
+
+		return os.DirFS(frontendSubdir), nil
+	}
+
+	return fs.Sub(embeddedFrontend, frontendSubdir)
+}

internal/next/cmd/signal.go

@@ -1,29 +1,27 @@
 package cmd
 
 import (
-	"io/fs"
 	"os"
-	"time"
+	"strconv"
 
 	"github.com/AdguardTeam/AdGuardHome/internal/aghos"
 	"github.com/AdguardTeam/AdGuardHome/internal/next/agh"
+	"github.com/AdguardTeam/AdGuardHome/internal/next/configmgr"
 	"github.com/AdguardTeam/golibs/log"
+	"github.com/google/renameio/maybe"
 )
 
 // signalHandler processes incoming signals and shuts services down.
 type signalHandler struct {
+	// confMgrConf contains the configuration parameters for the configuration
+	// manager.
+	confMgrConf *configmgr.Config
+
 	// signal is the channel to which OS signals are sent.
 	signal chan os.Signal
 
-	// confFile is the path to the configuration file.
+	// pidFile is the path to the file where to store the PID, if any.
-	confFile string
+	pidFile string
-
-	// frontend is the filesystem with the frontend and other statically
-	// compiled files.
-	frontend fs.FS
-
-	// start is the time at which AdGuard Home has been started.
-	start time.Time
 
 	// services are the services that are shut down before application exiting.
 	services []agh.Service
@@ -33,6 +31,8 @@ type signalHandler struct {
 func (h *signalHandler) handle() {
 	defer log.OnPanic("signalHandler.handle")
 
+	h.writePID()
+
 	for sig := range h.signal {
 		log.Info("sighdlr: received signal %q", sig)
 
@@ -40,6 +40,8 @@ func (h *signalHandler) handle() {
 			h.reconfigure()
 		} else if aghos.IsShutdownSignal(sig) {
 			status := h.shutdown()
+			h.removePID()
+
 			log.Info("sighdlr: exiting with status %d", status)
 
 			os.Exit(status)
@@ -62,7 +64,7 @@ func (h *signalHandler) reconfigure() {
 	// reconfigured without the full shutdown, and the error handling is
 	// currently not the best.
 
-	confMgr, err := newConfigMgr(h.confFile, h.frontend, h.start)
+	confMgr, err := newConfigMgr(h.confMgrConf)
 	check(err)
 
 	web := confMgr.Web()
@@ -85,6 +87,7 @@ func (h *signalHandler) reconfigure() {
 const (
 	statusSuccess       = 0
 	statusError         = 1
+	statusArgumentError = 2
 )
 
 // shutdown gracefully shuts down all services.
@@ -108,16 +111,14 @@ func (h *signalHandler) shutdown() (status int) {
 
 // newSignalHandler returns a new signalHandler that shuts down svcs.
 func newSignalHandler(
-	confFile string,
+	confMgrConf *configmgr.Config,
-	frontend fs.FS,
+	pidFile string,
-	start time.Time,
 	svcs ...agh.Service,
 ) (h *signalHandler) {
 	h = &signalHandler{
+		confMgrConf: confMgrConf,
 		signal:      make(chan os.Signal, 1),
-		confFile: confFile,
+		pidFile:     pidFile,
-		frontend: frontend,
-		start:    start,
 		services:    svcs,
 	}
 
@@ -126,3 +127,41 @@ func newSignalHandler(
 
 	return h
 }
+
+// writePID writes the PID to the file, if needed.  Any errors are reported to
+// log.
+func (h *signalHandler) writePID() {
+	if h.pidFile == "" {
+		return
+	}
+
+	// Use 8, since most PIDs will fit.
+	data := make([]byte, 0, 8)
+	data = strconv.AppendInt(data, int64(os.Getpid()), 10)
+	data = append(data, '\n')
+
+	err := maybe.WriteFile(h.pidFile, data, 0o644)
+	if err != nil {
+		log.Error("sighdlr: writing pidfile: %s", err)
+
+		return
+	}
+
+	log.Debug("sighdlr: wrote pid to %q", h.pidFile)
+}
+
+// removePID removes the PID file, if any.
+func (h *signalHandler) removePID() {
+	if h.pidFile == "" {
+		return
+	}
+
+	err := os.Remove(h.pidFile)
+	if err != nil {
+		log.Error("sighdlr: removing pidfile: %s", err)
+
+		return
+	}
+
+	log.Debug("sighdlr: removed pid at %q", h.pidFile)
+}

internal/next/configmgr/config.go

@@ -14,11 +14,11 @@ import (
 type config struct {
 	DNS  *dnsConfig  `yaml:"dns"`
 	HTTP *httpConfig `yaml:"http"`
+	Log  *logConfig  `yaml:"log"`
 	// TODO(a.garipov): Use.
 	SchemaVersion int `yaml:"schema_version"`
 	// TODO(a.garipov): Use.
 	DebugPprof bool `yaml:"debug_pprof"`
-	Verbose    bool `yaml:"verbose"`
 }
 
 const errNoConf errors.Error = "configuration not found"
@@ -41,6 +41,9 @@ func (c *config) validate() (err error) {
 	}, {
 		validate: c.HTTP.validate,
 		name:     "http",
+	}, {
+		validate: c.Log.validate,
+		name:     "log",
 	}}
 
 	for _, v := range validators {
@@ -54,8 +57,6 @@ func (c *config) validate() (err error) {
 }
 
 // dnsConfig is the on-disk DNS configuration.
-//
-// TODO(a.garipov): Validate.
 type dnsConfig struct {
 	Addresses           []netip.AddrPort  `yaml:"addresses"`
 	BootstrapDNS        []string          `yaml:"bootstrap_dns"`
@@ -82,9 +83,8 @@ func (c *dnsConfig) validate() (err error) {
 }
 
 // httpConfig is the on-disk web API configuration.
-//
-// TODO(a.garipov): Validate.
 type httpConfig struct {
+	// TODO(a.garipov): Document the configuration change.
 	Addresses       []netip.AddrPort  `yaml:"addresses"`
 	SecureAddresses []netip.AddrPort  `yaml:"secure_addresses"`
 	Timeout         timeutil.Duration `yaml:"timeout"`
@@ -104,3 +104,20 @@ func (c *httpConfig) validate() (err error) {
 		return nil
 	}
 }
+
+// logConfig is the on-disk web API configuration.
+type logConfig struct {
+	// TODO(a.garipov): Use.
+	Verbose bool `yaml:"verbose"`
+}
+
+// validate returns an error if the HTTP configuration structure is invalid.
+//
+// TODO(a.garipov): Add more validations.
+func (c *logConfig) validate() (err error) {
+	if c == nil {
+		return errNoConf
+	}
+
+	return nil
+}

internal/next/configmgr/configmgr.go

@@ -8,6 +8,7 @@ import (
 	"context"
 	"fmt"
 	"io/fs"
+	"net/netip"
 	"os"
 	"sync"
 	"time"
@@ -27,6 +28,8 @@ import (
 
 // Manager handles full and partial changes in the configuration, persisting
 // them to disk if necessary.
+//
+// TODO(a.garipov): Support missing configs and default values.
 type Manager struct {
 	// updMu makes sure that at most one reconfiguration is performed at a time.
 	// updMu protects all fields below.
@@ -58,16 +61,27 @@ func Validate(fileName string) (err error) {
 	return conf.validate()
 }
 
+// Config contains the configuration parameters for the configuration manager.
+type Config struct {
+	// Frontend is the filesystem with the frontend files.
+	Frontend fs.FS
+
+	// WebAddr is the initial or override address for the Web UI.  It is not
+	// written to the configuration file.
+	WebAddr netip.AddrPort
+
+	// Start is the time of start of AdGuard Home.
+	Start time.Time
+
+	// FileName is the path to the configuration file.
+	FileName string
+}
+
 // New creates a new *Manager that persists changes to the file pointed to by
-// fileName.  It reads the configuration file and populates the service fields.
+// c.FileName.  It reads the configuration file and populates the service
-// start is the startup time of AdGuard Home.
+// fields.  c must not be nil.
-func New(
+func New(ctx context.Context, c *Config) (m *Manager, err error) {
-	ctx context.Context,
+	conf, err := read(c.FileName)
-	fileName string,
-	frontend fs.FS,
-	start time.Time,
-) (m *Manager, err error) {
-	conf, err := read(fileName)
 	if err != nil {
 		// Don't wrap the error, because it's informative enough as is.
 		return nil, err
@@ -81,10 +95,10 @@ func New(
 	m = &Manager{
 		updMu:    &sync.RWMutex{},
 		current:  conf,
-		fileName: fileName,
+		fileName: c.FileName,
 	}
 
-	err = m.assemble(ctx, conf, frontend, start)
+	err = m.assemble(ctx, conf, c.Frontend, c.WebAddr, c.Start)
 	if err != nil {
 		return nil, fmt.Errorf("creating config manager: %w", err)
 	}
@@ -119,6 +133,7 @@ func (m *Manager) assemble(
 	ctx context.Context,
 	conf *config,
 	frontend fs.FS,
+	webAddr netip.AddrPort,
 	start time.Time,
 ) (err error) {
 	dnsConf := &dnssvc.Config{
@@ -143,6 +158,7 @@ func (m *Manager) assemble(
 		Start:           start,
 		Addresses:       conf.HTTP.Addresses,
 		SecureAddresses: conf.HTTP.SecureAddresses,
+		OverrideAddress: webAddr,
 		Timeout:         conf.HTTP.Timeout.Duration,
 		ForceHTTPS:      conf.HTTP.ForceHTTPS,
 	}
@@ -162,7 +178,7 @@ func (m *Manager) write() (err error) {
 		return fmt.Errorf("encoding: %w", err)
 	}
 
-	err = maybe.WriteFile(m.fileName, b, 0o755)
+	err = maybe.WriteFile(m.fileName, b, 0o644)
 	if err != nil {
 		return fmt.Errorf("writing: %w", err)
 	}

internal/next/websvc/websvc.go

@@ -51,6 +51,10 @@ type Config struct {
 	// Start is the time of start of AdGuard Home.
 	Start time.Time
 
+	// OverrideAddress is the initial or override address for the HTTP API.  If
+	// set, it is used instead of [Addresses] and [SecureAddresses].
+	OverrideAddress netip.AddrPort
+
 	// Addresses are the addresses on which to serve the plain HTTP API.
 	Addresses []netip.AddrPort
 
@@ -75,6 +79,7 @@ type Service struct {
 	frontend     fs.FS
 	tls          *tls.Config
 	start        time.Time
+	overrideAddr netip.AddrPort
 	servers      []*http.Server
 	timeout      time.Duration
 	forceHTTPS   bool
@@ -91,54 +96,60 @@ func New(c *Config) (svc *Service, err error) {
 		return nil, nil
 	}
 
-	frontend, err := fs.Sub(c.Frontend, "build/static")
-	if err != nil {
-		return nil, fmt.Errorf("frontend fs: %w", err)
-	}
-
 	svc = &Service{
 		confMgr:      c.ConfigManager,
-		frontend:   frontend,
+		frontend:     c.Frontend,
 		tls:          c.TLS,
 		start:        c.Start,
+		overrideAddr: c.OverrideAddress,
 		timeout:      c.Timeout,
 		forceHTTPS:   c.ForceHTTPS,
 	}
 
 	mux := newMux(svc)
 
+	if svc.overrideAddr != (netip.AddrPort{}) {
+		svc.servers = []*http.Server{newSrv(svc.overrideAddr, nil, mux, c.Timeout)}
+	} else {
 		for _, a := range c.Addresses {
-		addr := a.String()
+			svc.servers = append(svc.servers, newSrv(a, nil, mux, c.Timeout))
-		errLog := log.StdLog("websvc: plain http: "+addr, log.ERROR)
-		svc.servers = append(svc.servers, &http.Server{
-			Addr:              addr,
-			Handler:           mux,
-			ErrorLog:          errLog,
-			ReadTimeout:       c.Timeout,
-			WriteTimeout:      c.Timeout,
-			IdleTimeout:       c.Timeout,
-			ReadHeaderTimeout: c.Timeout,
-		})
 		}
 
 		for _, a := range c.SecureAddresses {
-		addr := a.String()
+			svc.servers = append(svc.servers, newSrv(a, c.TLS, mux, c.Timeout))
-		errLog := log.StdLog("websvc: https: "+addr, log.ERROR)
+		}
-		svc.servers = append(svc.servers, &http.Server{
-			Addr:              addr,
-			Handler:           mux,
-			TLSConfig:         c.TLS,
-			ErrorLog:          errLog,
-			ReadTimeout:       c.Timeout,
-			WriteTimeout:      c.Timeout,
-			IdleTimeout:       c.Timeout,
-			ReadHeaderTimeout: c.Timeout,
-		})
 	}
 
 	return svc, nil
 }
 
+// newSrv returns a new *http.Server with the given parameters.
+func newSrv(
+	addr netip.AddrPort,
+	tlsConf *tls.Config,
+	h http.Handler,
+	timeout time.Duration,
+) (srv *http.Server) {
+	addrStr := addr.String()
+	srv = &http.Server{
+		Addr:              addrStr,
+		Handler:           h,
+		TLSConfig:         tlsConf,
+		ReadTimeout:       timeout,
+		WriteTimeout:      timeout,
+		IdleTimeout:       timeout,
+		ReadHeaderTimeout: timeout,
+	}
+
+	if tlsConf == nil {
+		srv.ErrorLog = log.StdLog("websvc: plain http: "+addrStr, log.ERROR)
+	} else {
+		srv.ErrorLog = log.StdLog("websvc: https: "+addrStr, log.ERROR)
+	}
+
+	return srv
+}
+
 // newMux returns a new HTTP request multiplexer for the AdGuard Home web
 // service.
 func newMux(svc *Service) (mux *httptreemux.ContextMux) {
@@ -205,23 +216,23 @@ func newMux(svc *Service) (mux *httptreemux.ContextMux) {
 // ":0" addresses, addrs will not return the actual bound ports until Start is
 // finished.
 func (svc *Service) addrs() (addrs, secureAddrs []netip.AddrPort) {
-	for _, srv := range svc.servers {
+	if svc.overrideAddr != (netip.AddrPort{}) {
-		addrPort, err := netip.ParseAddrPort(srv.Addr)
+		return []netip.AddrPort{svc.overrideAddr}, nil
-		if err != nil {
-			// Technically shouldn't happen, since all servers must have a valid
-			// address.
-			panic(fmt.Errorf("websvc: server %q: bad address: %w", srv.Addr, err))
 	}
 
-		// srv.Serve will set TLSConfig to an almost empty value, so, instead of
+	for _, srv := range svc.servers {
-		// relying only on the nilness of TLSConfig, check the length of the
+		// Use MustParseAddrPort, since no errors should technically happen
+		// here, because all servers must have a valid address.
+		addrPort := netip.MustParseAddrPort(srv.Addr)
+
+		// [srv.Serve] will set TLSConfig to an almost empty value, so, instead
+		// of relying only on the nilness of TLSConfig, check the length of the
 		// certificates field as well.
 		if srv.TLSConfig == nil || len(srv.TLSConfig.Certificates) == 0 {
 			addrs = append(addrs, addrPort)
 		} else {
 			secureAddrs = append(secureAddrs, addrPort)
 		}
-
 	}
 
 	return addrs, secureAddrs