Pull request: websvc-config-manager

Merge in DNS/adguard-home from websvc-config-manager to master

Squashed commit of the following:

commit 2143b47c6528030dfe059172888fddf9061e42da
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Tue Oct 4 14:50:47 2022 +0300

    next: add config manager

internal/next/websvc/dns.go

@@ -0,0 +1,84 @@
+package websvc
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/netip"
+	"time"
+
+	"github.com/AdguardTeam/AdGuardHome/internal/next/dnssvc"
+)
+
+// DNS Settings Handlers
+
+// ReqPatchSettingsDNS describes the request to the PATCH /api/v1/settings/dns
+// HTTP API.
+type ReqPatchSettingsDNS struct {
+	// TODO(a.garipov): Add more as we go.
+
+	Addresses        []netip.AddrPort `json:"addresses"`
+	BootstrapServers []string         `json:"bootstrap_servers"`
+	UpstreamServers  []string         `json:"upstream_servers"`
+	UpstreamTimeout  JSONDuration     `json:"upstream_timeout"`
+}
+
+// HTTPAPIDNSSettings are the DNS settings as used by the HTTP API.  See the
+// DnsSettings object in the OpenAPI specification.
+type HTTPAPIDNSSettings struct {
+	// TODO(a.garipov): Add more as we go.
+
+	Addresses        []netip.AddrPort `json:"addresses"`
+	BootstrapServers []string         `json:"bootstrap_servers"`
+	UpstreamServers  []string         `json:"upstream_servers"`
+	UpstreamTimeout  JSONDuration     `json:"upstream_timeout"`
+}
+
+// handlePatchSettingsDNS is the handler for the PATCH /api/v1/settings/dns HTTP
+// API.
+func (svc *Service) handlePatchSettingsDNS(w http.ResponseWriter, r *http.Request) {
+	req := &ReqPatchSettingsDNS{
+		Addresses:        []netip.AddrPort{},
+		BootstrapServers: []string{},
+		UpstreamServers:  []string{},
+	}
+
+	// TODO(a.garipov): Validate nulls and proper JSON patch.
+
+	err := json.NewDecoder(r.Body).Decode(&req)
+	if err != nil {
+		writeJSONErrorResponse(w, r, fmt.Errorf("decoding: %w", err))
+
+		return
+	}
+
+	newConf := &dnssvc.Config{
+		Addresses:        req.Addresses,
+		BootstrapServers: req.BootstrapServers,
+		UpstreamServers:  req.UpstreamServers,
+		UpstreamTimeout:  time.Duration(req.UpstreamTimeout),
+	}
+
+	ctx := r.Context()
+	err = svc.confMgr.UpdateDNS(ctx, newConf)
+	if err != nil {
+		writeJSONErrorResponse(w, r, fmt.Errorf("updating: %w", err))
+
+		return
+	}
+
+	newSvc := svc.confMgr.DNS()
+	err = newSvc.Start()
+	if err != nil {
+		writeJSONErrorResponse(w, r, fmt.Errorf("starting new service: %w", err))
+
+		return
+	}
+
+	writeJSONOKResponse(w, r, &HTTPAPIDNSSettings{
+		Addresses:        newConf.Addresses,
+		BootstrapServers: newConf.BootstrapServers,
+		UpstreamServers:  newConf.UpstreamServers,
+		UpstreamTimeout:  JSONDuration(newConf.UpstreamTimeout),
+	})
+}

internal/next/websvc/dns_test.go

@@ -0,0 +1,68 @@
+package websvc_test
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/netip"
+	"net/url"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/AdguardTeam/AdGuardHome/internal/aghtest"
+	"github.com/AdguardTeam/AdGuardHome/internal/next/dnssvc"
+	"github.com/AdguardTeam/AdGuardHome/internal/next/websvc"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestService_HandlePatchSettingsDNS(t *testing.T) {
+	wantDNS := &websvc.HTTPAPIDNSSettings{
+		Addresses:        []netip.AddrPort{netip.MustParseAddrPort("127.0.1.1:53")},
+		BootstrapServers: []string{"1.0.0.1"},
+		UpstreamServers:  []string{"1.1.1.1"},
+		UpstreamTimeout:  websvc.JSONDuration(2 * time.Second),
+	}
+
+	// TODO(a.garipov): Use [atomic.Bool] in Go 1.19.
+	var numStarted uint64
+	confMgr := newConfigManager()
+	confMgr.onDNS = func() (s websvc.ServiceWithConfig[*dnssvc.Config]) {
+		return &aghtest.ServiceWithConfig[*dnssvc.Config]{
+			OnStart: func() (err error) {
+				atomic.AddUint64(&numStarted, 1)
+
+				return nil
+			},
+			OnShutdown: func(_ context.Context) (err error) { panic("not implemented") },
+			OnConfig:   func() (c *dnssvc.Config) { panic("not implemented") },
+		}
+	}
+	confMgr.onUpdateDNS = func(ctx context.Context, c *dnssvc.Config) (err error) {
+		return nil
+	}
+
+	_, addr := newTestServer(t, confMgr)
+	u := &url.URL{
+		Scheme: "http",
+		Host:   addr.String(),
+		Path:   websvc.PathV1SettingsDNS,
+	}
+
+	req := jobj{
+		"addresses":         wantDNS.Addresses,
+		"bootstrap_servers": wantDNS.BootstrapServers,
+		"upstream_servers":  wantDNS.UpstreamServers,
+		"upstream_timeout":  wantDNS.UpstreamTimeout,
+	}
+
+	respBody := httpPatch(t, u, req, http.StatusOK)
+	resp := &websvc.HTTPAPIDNSSettings{}
+	err := json.Unmarshal(respBody, resp)
+	require.NoError(t, err)
+
+	assert.Equal(t, uint64(1), numStarted)
+	assert.Equal(t, wantDNS, resp)
+	assert.Equal(t, wantDNS, resp)
+}

internal/next/websvc/http.go

@@ -0,0 +1,109 @@
+package websvc
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/netip"
+	"time"
+
+	"github.com/AdguardTeam/golibs/log"
+)
+
+// HTTP Settings Handlers
+
+// ReqPatchSettingsHTTP describes the request to the PATCH /api/v1/settings/http
+// HTTP API.
+type ReqPatchSettingsHTTP struct {
+	// TODO(a.garipov): Add more as we go.
+	//
+	// TODO(a.garipov): Add wait time.
+
+	Addresses       []netip.AddrPort `json:"addresses"`
+	SecureAddresses []netip.AddrPort `json:"secure_addresses"`
+	Timeout         JSONDuration     `json:"timeout"`
+}
+
+// HTTPAPIHTTPSettings are the HTTP settings as used by the HTTP API.  See the
+// HttpSettings object in the OpenAPI specification.
+type HTTPAPIHTTPSettings struct {
+	// TODO(a.garipov): Add more as we go.
+
+	Addresses       []netip.AddrPort `json:"addresses"`
+	SecureAddresses []netip.AddrPort `json:"secure_addresses"`
+	Timeout         JSONDuration     `json:"timeout"`
+	ForceHTTPS      bool             `json:"force_https"`
+}
+
+// handlePatchSettingsHTTP is the handler for the PATCH /api/v1/settings/http
+// HTTP API.
+func (svc *Service) handlePatchSettingsHTTP(w http.ResponseWriter, r *http.Request) {
+	req := &ReqPatchSettingsHTTP{}
+
+	// TODO(a.garipov): Validate nulls and proper JSON patch.
+
+	err := json.NewDecoder(r.Body).Decode(&req)
+	if err != nil {
+		writeJSONErrorResponse(w, r, fmt.Errorf("decoding: %w", err))
+
+		return
+	}
+
+	newConf := &Config{
+		ConfigManager:   svc.confMgr,
+		TLS:             svc.tls,
+		Addresses:       req.Addresses,
+		SecureAddresses: req.SecureAddresses,
+		Timeout:         time.Duration(req.Timeout),
+		ForceHTTPS:      svc.forceHTTPS,
+	}
+
+	writeJSONOKResponse(w, r, &HTTPAPIHTTPSettings{
+		Addresses:       newConf.Addresses,
+		SecureAddresses: newConf.SecureAddresses,
+		Timeout:         JSONDuration(newConf.Timeout),
+		ForceHTTPS:      newConf.ForceHTTPS,
+	})
+
+	cancelUpd := func() {}
+	updCtx := context.Background()
+
+	ctx := r.Context()
+	if deadline, ok := ctx.Deadline(); ok {
+		updCtx, cancelUpd = context.WithDeadline(updCtx, deadline)
+	}
+
+	// Launch the new HTTP service in a separate goroutine to let this handler
+	// finish and thus, this server to shutdown.
+	go func() {
+		defer cancelUpd()
+
+		updErr := svc.confMgr.UpdateWeb(updCtx, newConf)
+		if updErr != nil {
+			writeJSONErrorResponse(w, r, fmt.Errorf("updating: %w", updErr))
+
+			return
+		}
+
+		// TODO(a.garipov): Consider better ways to do this.
+		const maxUpdDur = 10 * time.Second
+		updStart := time.Now()
+		var newSvc ServiceWithConfig[*Config]
+		for newSvc = svc.confMgr.Web(); newSvc == svc; {
+			if time.Since(updStart) >= maxUpdDur {
+				log.Error("websvc: failed to update svc after %s", maxUpdDur)
+
+				return
+			}
+
+			log.Debug("websvc: waiting for new websvc to be configured")
+			time.Sleep(1 * time.Second)
+		}
+
+		updErr = newSvc.Start()
+		if updErr != nil {
+			log.Error("websvc: new svc failed to start with error: %s", updErr)
+		}
+	}()
+}

internal/next/websvc/http_test.go

@@ -0,0 +1,62 @@
+package websvc_test
+
+import (
+	"context"
+	"crypto/tls"
+	"encoding/json"
+	"net/http"
+	"net/netip"
+	"net/url"
+	"testing"
+	"time"
+
+	"github.com/AdguardTeam/AdGuardHome/internal/next/websvc"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestService_HandlePatchSettingsHTTP(t *testing.T) {
+	wantWeb := &websvc.HTTPAPIHTTPSettings{
+		Addresses:       []netip.AddrPort{netip.MustParseAddrPort("127.0.1.1:80")},
+		SecureAddresses: []netip.AddrPort{netip.MustParseAddrPort("127.0.1.1:443")},
+		Timeout:         websvc.JSONDuration(10 * time.Second),
+		ForceHTTPS:      false,
+	}
+
+	confMgr := newConfigManager()
+	confMgr.onWeb = func() (s websvc.ServiceWithConfig[*websvc.Config]) {
+		return websvc.New(&websvc.Config{
+			TLS: &tls.Config{
+				Certificates: []tls.Certificate{{}},
+			},
+			Addresses:       []netip.AddrPort{netip.MustParseAddrPort("127.0.0.1:80")},
+			SecureAddresses: []netip.AddrPort{netip.MustParseAddrPort("127.0.0.1:443")},
+			Timeout:         5 * time.Second,
+			ForceHTTPS:      true,
+		})
+	}
+	confMgr.onUpdateWeb = func(ctx context.Context, c *websvc.Config) (err error) {
+		return nil
+	}
+
+	_, addr := newTestServer(t, confMgr)
+	u := &url.URL{
+		Scheme: "http",
+		Host:   addr.String(),
+		Path:   websvc.PathV1SettingsHTTP,
+	}
+
+	req := jobj{
+		"addresses":        wantWeb.Addresses,
+		"secure_addresses": wantWeb.SecureAddresses,
+		"timeout":          wantWeb.Timeout,
+		"force_https":      wantWeb.ForceHTTPS,
+	}
+
+	respBody := httpPatch(t, u, req, http.StatusOK)
+	resp := &websvc.HTTPAPIHTTPSettings{}
+	err := json.Unmarshal(respBody, resp)
+	require.NoError(t, err)
+
+	assert.Equal(t, wantWeb, resp)
+}

internal/next/websvc/json.go

@@ -0,0 +1,143 @@
+package websvc
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/AdguardTeam/AdGuardHome/internal/aghhttp"
+	"github.com/AdguardTeam/golibs/log"
+)
+
+// JSON Utilities
+
+// nsecPerMsec is the number of nanoseconds in a millisecond.
+const nsecPerMsec = float64(time.Millisecond / time.Nanosecond)
+
+// JSONDuration is a time.Duration that can be decoded from JSON and encoded
+// into JSON according to our API conventions.
+type JSONDuration time.Duration
+
+// type check
+var _ json.Marshaler = JSONDuration(0)
+
+// MarshalJSON implements the json.Marshaler interface for JSONDuration.  err is
+// always nil.
+func (d JSONDuration) MarshalJSON() (b []byte, err error) {
+	msec := float64(time.Duration(d)) / nsecPerMsec
+	b = strconv.AppendFloat(nil, msec, 'f', -1, 64)
+
+	return b, nil
+}
+
+// type check
+var _ json.Unmarshaler = (*JSONDuration)(nil)
+
+// UnmarshalJSON implements the json.Marshaler interface for *JSONDuration.
+func (d *JSONDuration) UnmarshalJSON(b []byte) (err error) {
+	if d == nil {
+		return fmt.Errorf("json duration is nil")
+	}
+
+	msec, err := strconv.ParseFloat(string(b), 64)
+	if err != nil {
+		return fmt.Errorf("parsing json time: %w", err)
+	}
+
+	*d = JSONDuration(int64(msec * nsecPerMsec))
+
+	return nil
+}
+
+// JSONTime is a time.Time that can be decoded from JSON and encoded into JSON
+// according to our API conventions.
+type JSONTime time.Time
+
+// type check
+var _ json.Marshaler = JSONTime{}
+
+// MarshalJSON implements the json.Marshaler interface for JSONTime.  err is
+// always nil.
+func (t JSONTime) MarshalJSON() (b []byte, err error) {
+	msec := float64(time.Time(t).UnixNano()) / nsecPerMsec
+	b = strconv.AppendFloat(nil, msec, 'f', -1, 64)
+
+	return b, nil
+}
+
+// type check
+var _ json.Unmarshaler = (*JSONTime)(nil)
+
+// UnmarshalJSON implements the json.Marshaler interface for *JSONTime.
+func (t *JSONTime) UnmarshalJSON(b []byte) (err error) {
+	if t == nil {
+		return fmt.Errorf("json time is nil")
+	}
+
+	msec, err := strconv.ParseFloat(string(b), 64)
+	if err != nil {
+		return fmt.Errorf("parsing json time: %w", err)
+	}
+
+	*t = JSONTime(time.Unix(0, int64(msec*nsecPerMsec)).UTC())
+
+	return nil
+}
+
+// writeJSONOKResponse writes headers with the code 200 OK, encodes v into w,
+// and logs any errors it encounters.  r is used to get additional information
+// from the request.
+func writeJSONOKResponse(w http.ResponseWriter, r *http.Request, v any) {
+	writeJSONResponse(w, r, v, http.StatusOK)
+}
+
+// writeJSONResponse writes headers with code, encodes v into w, and logs any
+// errors it encounters.  r is used to get additional information from the
+// request.
+func writeJSONResponse(w http.ResponseWriter, r *http.Request, v any, code int) {
+	// TODO(a.garipov): Put some of these to a middleware.
+	h := w.Header()
+	h.Set(aghhttp.HdrNameContentType, aghhttp.HdrValApplicationJSON)
+	h.Set(aghhttp.HdrNameServer, aghhttp.UserAgent())
+
+	w.WriteHeader(code)
+
+	err := json.NewEncoder(w).Encode(v)
+	if err != nil {
+		log.Error("websvc: writing resp to %s %s: %s", r.Method, r.URL.Path, err)
+	}
+}
+
+// ErrorCode is the error code as used by the HTTP API.  See the ErrorCode
+// definition in the OpenAPI specification.
+type ErrorCode string
+
+// ErrorCode constants.
+//
+// TODO(a.garipov): Expand and document codes.
+const (
+	// ErrorCodeTMP000 is the temporary error code used for all errors.
+	ErrorCodeTMP000 = ""
+)
+
+// HTTPAPIErrorResp is the error response as used by the HTTP API.  See the
+// BadRequestResp, InternalServerErrorResp, and similar objects in the OpenAPI
+// specification.
+type HTTPAPIErrorResp struct {
+	Code ErrorCode `json:"code"`
+	Msg  string    `json:"msg"`
+}
+
+// writeJSONErrorResponse encodes err as a JSON error into w, and logs any
+// errors it encounters.  r is used to get additional information from the
+// request.
+func writeJSONErrorResponse(w http.ResponseWriter, r *http.Request, err error) {
+	log.Error("websvc: %s %s: %s", r.Method, r.URL.Path, err)
+
+	writeJSONResponse(w, r, &HTTPAPIErrorResp{
+		Code: ErrorCodeTMP000,
+		Msg:  err.Error(),
+	}, http.StatusUnprocessableEntity)
+}

internal/next/websvc/json_test.go

@@ -0,0 +1,114 @@
+package websvc_test
+
+import (
+	"encoding/json"
+	"testing"
+	"time"
+
+	"github.com/AdguardTeam/AdGuardHome/internal/next/websvc"
+	"github.com/AdguardTeam/golibs/testutil"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// testJSONTime is the JSON time for tests.
+var testJSONTime = websvc.JSONTime(time.Unix(1_234_567_890, 123_456_000).UTC())
+
+// testJSONTimeStr is the string with the JSON encoding of testJSONTime.
+const testJSONTimeStr = "1234567890123.456"
+
+func TestJSONTime_MarshalJSON(t *testing.T) {
+	testCases := []struct {
+		name       string
+		wantErrMsg string
+		in         websvc.JSONTime
+		want       []byte
+	}{{
+		name:       "unix_zero",
+		wantErrMsg: "",
+		in:         websvc.JSONTime(time.Unix(0, 0)),
+		want:       []byte("0"),
+	}, {
+		name:       "empty",
+		wantErrMsg: "",
+		in:         websvc.JSONTime{},
+		want:       []byte("-6795364578871.345"),
+	}, {
+		name:       "time",
+		wantErrMsg: "",
+		in:         testJSONTime,
+		want:       []byte(testJSONTimeStr),
+	}}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			got, err := tc.in.MarshalJSON()
+			testutil.AssertErrorMsg(t, tc.wantErrMsg, err)
+
+			assert.Equal(t, tc.want, got)
+		})
+	}
+
+	t.Run("json", func(t *testing.T) {
+		in := &struct {
+			A websvc.JSONTime
+		}{
+			A: testJSONTime,
+		}
+
+		got, err := json.Marshal(in)
+		require.NoError(t, err)
+
+		assert.Equal(t, []byte(`{"A":`+testJSONTimeStr+`}`), got)
+	})
+}
+
+func TestJSONTime_UnmarshalJSON(t *testing.T) {
+	testCases := []struct {
+		name       string
+		wantErrMsg string
+		want       websvc.JSONTime
+		data       []byte
+	}{{
+		name:       "time",
+		wantErrMsg: "",
+		want:       testJSONTime,
+		data:       []byte(testJSONTimeStr),
+	}, {
+		name: "bad",
+		wantErrMsg: `parsing json time: strconv.ParseFloat: parsing "{}": ` +
+			`invalid syntax`,
+		want: websvc.JSONTime{},
+		data: []byte(`{}`),
+	}}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			var got websvc.JSONTime
+			err := got.UnmarshalJSON(tc.data)
+			testutil.AssertErrorMsg(t, tc.wantErrMsg, err)
+
+			assert.Equal(t, tc.want, got)
+		})
+	}
+
+	t.Run("nil", func(t *testing.T) {
+		err := (*websvc.JSONTime)(nil).UnmarshalJSON([]byte("0"))
+		require.Error(t, err)
+
+		msg := err.Error()
+		assert.Equal(t, "json time is nil", msg)
+	})
+
+	t.Run("json", func(t *testing.T) {
+		want := testJSONTime
+		var got struct {
+			A websvc.JSONTime
+		}
+
+		err := json.Unmarshal([]byte(`{"A":`+testJSONTimeStr+`}`), &got)
+		require.NoError(t, err)
+
+		assert.Equal(t, want, got.A)
+	})
+}

internal/next/websvc/middleware.go

@@ -0,0 +1,16 @@
+package websvc
+
+import "net/http"
+
+// Middlewares
+
+// jsonMw sets the content type of the response to application/json.
+func jsonMw(h http.Handler) (wrapped http.HandlerFunc) {
+	f := func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+
+		h.ServeHTTP(w, r)
+	}
+
+	return http.HandlerFunc(f)
+}

internal/next/websvc/path.go

@@ -0,0 +1,11 @@
+package websvc
+
+// Path constants
+const (
+	PathHealthCheck = "/health-check"
+
+	PathV1SettingsAll  = "/api/v1/settings/all"
+	PathV1SettingsDNS  = "/api/v1/settings/dns"
+	PathV1SettingsHTTP = "/api/v1/settings/http"
+	PathV1SystemInfo   = "/api/v1/system/info"
+)

internal/next/websvc/settings.go

@@ -0,0 +1,42 @@
+package websvc
+
+import (
+	"net/http"
+)
+
+// All Settings Handlers
+
+// RespGetV1SettingsAll describes the response of the GET /api/v1/settings/all
+// HTTP API.
+type RespGetV1SettingsAll struct {
+	// TODO(a.garipov): Add more as we go.
+
+	DNS  *HTTPAPIDNSSettings  `json:"dns"`
+	HTTP *HTTPAPIHTTPSettings `json:"http"`
+}
+
+// handleGetSettingsAll is the handler for the GET /api/v1/settings/all HTTP
+// API.
+func (svc *Service) handleGetSettingsAll(w http.ResponseWriter, r *http.Request) {
+	dnsSvc := svc.confMgr.DNS()
+	dnsConf := dnsSvc.Config()
+
+	webSvc := svc.confMgr.Web()
+	httpConf := webSvc.Config()
+
+	// TODO(a.garipov): Add all currently supported parameters.
+	writeJSONOKResponse(w, r, &RespGetV1SettingsAll{
+		DNS: &HTTPAPIDNSSettings{
+			Addresses:        dnsConf.Addresses,
+			BootstrapServers: dnsConf.BootstrapServers,
+			UpstreamServers:  dnsConf.UpstreamServers,
+			UpstreamTimeout:  JSONDuration(dnsConf.UpstreamTimeout),
+		},
+		HTTP: &HTTPAPIHTTPSettings{
+			Addresses:       httpConf.Addresses,
+			SecureAddresses: httpConf.SecureAddresses,
+			Timeout:         JSONDuration(httpConf.Timeout),
+			ForceHTTPS:      httpConf.ForceHTTPS,
+		},
+	})
+}

internal/next/websvc/settings_test.go

@@ -0,0 +1,74 @@
+package websvc_test
+
+import (
+	"crypto/tls"
+	"encoding/json"
+	"net/http"
+	"net/netip"
+	"net/url"
+	"testing"
+	"time"
+
+	"github.com/AdguardTeam/AdGuardHome/internal/next/dnssvc"
+	"github.com/AdguardTeam/AdGuardHome/internal/next/websvc"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestService_HandleGetSettingsAll(t *testing.T) {
+	// TODO(a.garipov): Add all currently supported parameters.
+
+	wantDNS := &websvc.HTTPAPIDNSSettings{
+		Addresses:        []netip.AddrPort{netip.MustParseAddrPort("127.0.0.1:53")},
+		BootstrapServers: []string{"94.140.14.140", "94.140.14.141"},
+		UpstreamServers:  []string{"94.140.14.14", "1.1.1.1"},
+		UpstreamTimeout:  websvc.JSONDuration(1 * time.Second),
+	}
+
+	wantWeb := &websvc.HTTPAPIHTTPSettings{
+		Addresses:       []netip.AddrPort{netip.MustParseAddrPort("127.0.0.1:80")},
+		SecureAddresses: []netip.AddrPort{netip.MustParseAddrPort("127.0.0.1:443")},
+		Timeout:         websvc.JSONDuration(5 * time.Second),
+		ForceHTTPS:      true,
+	}
+
+	confMgr := newConfigManager()
+	confMgr.onDNS = func() (s websvc.ServiceWithConfig[*dnssvc.Config]) {
+		c, err := dnssvc.New(&dnssvc.Config{
+			Addresses:        wantDNS.Addresses,
+			UpstreamServers:  wantDNS.UpstreamServers,
+			BootstrapServers: wantDNS.BootstrapServers,
+			UpstreamTimeout:  time.Duration(wantDNS.UpstreamTimeout),
+		})
+		require.NoError(t, err)
+
+		return c
+	}
+
+	confMgr.onWeb = func() (s websvc.ServiceWithConfig[*websvc.Config]) {
+		return websvc.New(&websvc.Config{
+			TLS: &tls.Config{
+				Certificates: []tls.Certificate{{}},
+			},
+			Addresses:       wantWeb.Addresses,
+			SecureAddresses: wantWeb.SecureAddresses,
+			Timeout:         time.Duration(wantWeb.Timeout),
+			ForceHTTPS:      true,
+		})
+	}
+
+	_, addr := newTestServer(t, confMgr)
+	u := &url.URL{
+		Scheme: "http",
+		Host:   addr.String(),
+		Path:   websvc.PathV1SettingsAll,
+	}
+
+	body := httpGet(t, u, http.StatusOK)
+	resp := &websvc.RespGetV1SettingsAll{}
+	err := json.Unmarshal(body, resp)
+	require.NoError(t, err)
+
+	assert.Equal(t, wantDNS, resp.DNS)
+	assert.Equal(t, wantWeb, resp.HTTP)
+}

internal/next/websvc/system.go

@@ -0,0 +1,35 @@
+package websvc
+
+import (
+	"net/http"
+	"runtime"
+
+	"github.com/AdguardTeam/AdGuardHome/internal/version"
+)
+
+// System Handlers
+
+// RespGetV1SystemInfo describes the response of the GET /api/v1/system/info
+// HTTP API.
+type RespGetV1SystemInfo struct {
+	Arch       string   `json:"arch"`
+	Channel    string   `json:"channel"`
+	OS         string   `json:"os"`
+	NewVersion string   `json:"new_version,omitempty"`
+	Start      JSONTime `json:"start"`
+	Version    string   `json:"version"`
+}
+
+// handleGetV1SystemInfo is the handler for the GET /api/v1/system/info HTTP
+// API.
+func (svc *Service) handleGetV1SystemInfo(w http.ResponseWriter, r *http.Request) {
+	writeJSONOKResponse(w, r, &RespGetV1SystemInfo{
+		Arch:    runtime.GOARCH,
+		Channel: version.Channel(),
+		OS:      runtime.GOOS,
+		// TODO(a.garipov): Fill this when we have an updater.
+		NewVersion: "",
+		Start:      JSONTime(svc.start),
+		Version:    version.Version(),
+	})
+}

internal/next/websvc/system_test.go

@@ -0,0 +1,37 @@
+package websvc_test
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/url"
+	"runtime"
+	"testing"
+	"time"
+
+	"github.com/AdguardTeam/AdGuardHome/internal/next/websvc"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestService_handleGetV1SystemInfo(t *testing.T) {
+	confMgr := newConfigManager()
+	_, addr := newTestServer(t, confMgr)
+	u := &url.URL{
+		Scheme: "http",
+		Host:   addr.String(),
+		Path:   websvc.PathV1SystemInfo,
+	}
+
+	body := httpGet(t, u, http.StatusOK)
+	resp := &websvc.RespGetV1SystemInfo{}
+	err := json.Unmarshal(body, resp)
+	require.NoError(t, err)
+
+	// TODO(a.garipov): Consider making version.Channel and version.Version
+	// testable and test these better.
+	assert.NotEmpty(t, resp.Channel)
+
+	assert.Equal(t, resp.Arch, runtime.GOARCH)
+	assert.Equal(t, resp.OS, runtime.GOOS)
+	assert.Equal(t, testStart, time.Time(resp.Start))
+}

internal/next/websvc/waitlistener.go

@@ -0,0 +1,31 @@
+package websvc
+
+import (
+	"net"
+	"sync"
+)
+
+// Wait Listener
+
+// waitListener is a wrapper around a listener that also calls wg.Done() on the
+// first call to Accept.  It is useful in situations where it is important to
+// catch the precise moment of the first call to Accept, for example when
+// starting an HTTP server.
+//
+// TODO(a.garipov): Move to aghnet?
+type waitListener struct {
+	net.Listener
+
+	firstAcceptWG   *sync.WaitGroup
+	firstAcceptOnce sync.Once
+}
+
+// type check
+var _ net.Listener = (*waitListener)(nil)
+
+// Accept implements the [net.Listener] interface for *waitListener.
+func (l *waitListener) Accept() (conn net.Conn, err error) {
+	l.firstAcceptOnce.Do(l.firstAcceptWG.Done)
+
+	return l.Listener.Accept()
+}

internal/next/websvc/waitlistener_internal_test.go

@@ -0,0 +1,46 @@
+package websvc
+
+import (
+	"net"
+	"sync"
+	"sync/atomic"
+	"testing"
+
+	"github.com/AdguardTeam/AdGuardHome/internal/aghchan"
+	"github.com/AdguardTeam/AdGuardHome/internal/aghtest"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestWaitListener_Accept(t *testing.T) {
+	// TODO(a.garipov): use atomic.Bool in Go 1.19.
+	var numAcceptCalls uint32
+	var l net.Listener = &aghtest.Listener{
+		OnAccept: func() (conn net.Conn, err error) {
+			atomic.AddUint32(&numAcceptCalls, 1)
+
+			return nil, nil
+		},
+		OnAddr:  func() (addr net.Addr) { panic("not implemented") },
+		OnClose: func() (err error) { panic("not implemented") },
+	}
+
+	wg := &sync.WaitGroup{}
+	wg.Add(1)
+
+	done := make(chan struct{})
+	go aghchan.MustReceive(done, testTimeout)
+
+	go func() {
+		var wrapper net.Listener = &waitListener{
+			Listener:      l,
+			firstAcceptWG: wg,
+		}
+
+		_, _ = wrapper.Accept()
+	}()
+
+	wg.Wait()
+	close(done)
+
+	assert.Equal(t, uint32(1), atomic.LoadUint32(&numAcceptCalls))
+}

internal/next/websvc/websvc.go

@@ -0,0 +1,316 @@
+// Package websvc contains the AdGuard Home HTTP API service.
+//
+// NOTE: Packages other than cmd must not import this package, as it imports
+// most other packages.
+//
+// TODO(a.garipov): Add tests.
+package websvc
+
+import (
+	"context"
+	"crypto/tls"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/netip"
+	"sync"
+	"time"
+
+	"github.com/AdguardTeam/AdGuardHome/internal/next/agh"
+	"github.com/AdguardTeam/AdGuardHome/internal/next/dnssvc"
+	"github.com/AdguardTeam/golibs/errors"
+	"github.com/AdguardTeam/golibs/log"
+	httptreemux "github.com/dimfeld/httptreemux/v5"
+)
+
+// ServiceWithConfig is an extension of the [agh.Service] interface for services
+// that can return their configuration.
+//
+// TODO(a.garipov): Consider removing this generic interface if we figure out
+// how to make it testable in a better way.
+type ServiceWithConfig[ConfigType any] interface {
+	agh.Service
+
+	Config() (c ConfigType)
+}
+
+// ConfigManager is the configuration manager interface.
+type ConfigManager interface {
+	DNS() (svc ServiceWithConfig[*dnssvc.Config])
+	Web() (svc ServiceWithConfig[*Config])
+
+	UpdateDNS(ctx context.Context, c *dnssvc.Config) (err error)
+	UpdateWeb(ctx context.Context, c *Config) (err error)
+}
+
+// Config is the AdGuard Home web service configuration structure.
+type Config struct {
+	// ConfigManager is used to show information about services as well as
+	// dynamically reconfigure them.
+	ConfigManager ConfigManager
+
+	// TLS is the optional TLS configuration.  If TLS is not nil,
+	// SecureAddresses must not be empty.
+	TLS *tls.Config
+
+	// Start is the time of start of AdGuard Home.
+	Start time.Time
+
+	// Addresses are the addresses on which to serve the plain HTTP API.
+	Addresses []netip.AddrPort
+
+	// SecureAddresses are the addresses on which to serve the HTTPS API.  If
+	// SecureAddresses is not empty, TLS must not be nil.
+	SecureAddresses []netip.AddrPort
+
+	// Timeout is the timeout for all server operations.
+	Timeout time.Duration
+
+	// ForceHTTPS tells if all requests to Addresses should be redirected to a
+	// secure address instead.
+	//
+	// TODO(a.garipov): Use; define rules, which address to redirect to.
+	ForceHTTPS bool
+}
+
+// Service is the AdGuard Home web service.  A nil *Service is a valid
+// [agh.Service] that does nothing.
+type Service struct {
+	confMgr    ConfigManager
+	tls        *tls.Config
+	start      time.Time
+	servers    []*http.Server
+	timeout    time.Duration
+	forceHTTPS bool
+}
+
+// New returns a new properly initialized *Service.  If c is nil, svc is a nil
+// *Service that does nothing.  The fields of c must not be modified after
+// calling New.
+func New(c *Config) (svc *Service) {
+	if c == nil {
+		return nil
+	}
+
+	svc = &Service{
+		confMgr:    c.ConfigManager,
+		tls:        c.TLS,
+		start:      c.Start,
+		timeout:    c.Timeout,
+		forceHTTPS: c.ForceHTTPS,
+	}
+
+	mux := newMux(svc)
+
+	for _, a := range c.Addresses {
+		addr := a.String()
+		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()
+		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
+}
+
+// newMux returns a new HTTP request multiplexor for the AdGuard Home web
+// service.
+func newMux(svc *Service) (mux *httptreemux.ContextMux) {
+	mux = httptreemux.NewContextMux()
+
+	routes := []struct {
+		handler http.HandlerFunc
+		method  string
+		path    string
+		isJSON  bool
+	}{{
+		handler: svc.handleGetHealthCheck,
+		method:  http.MethodGet,
+		path:    PathHealthCheck,
+		isJSON:  false,
+	}, {
+		handler: svc.handleGetSettingsAll,
+		method:  http.MethodGet,
+		path:    PathV1SettingsAll,
+		isJSON:  true,
+	}, {
+		handler: svc.handlePatchSettingsDNS,
+		method:  http.MethodPatch,
+		path:    PathV1SettingsDNS,
+		isJSON:  true,
+	}, {
+		handler: svc.handlePatchSettingsHTTP,
+		method:  http.MethodPatch,
+		path:    PathV1SettingsHTTP,
+		isJSON:  true,
+	}, {
+		handler: svc.handleGetV1SystemInfo,
+		method:  http.MethodGet,
+		path:    PathV1SystemInfo,
+		isJSON:  true,
+	}}
+
+	for _, r := range routes {
+		if r.isJSON {
+			mux.Handle(r.method, r.path, jsonMw(r.handler))
+		} else {
+			mux.Handle(r.method, r.path, r.handler)
+		}
+	}
+
+	return mux
+}
+
+// addrs returns all addresses on which this server serves the HTTP API.  addrs
+// must not be called simultaneously with Start.  If svc was initialized with
+// ":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 {
+		addrPort, err := netip.ParseAddrPort(srv.Addr)
+		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
+		// 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
+}
+
+// handleGetHealthCheck is the handler for the GET /health-check HTTP API.
+func (svc *Service) handleGetHealthCheck(w http.ResponseWriter, _ *http.Request) {
+	_, _ = io.WriteString(w, "OK")
+}
+
+// type check
+var _ agh.Service = (*Service)(nil)
+
+// Start implements the [agh.Service] interface for *Service.  svc may be nil.
+// After Start exits, all HTTP servers have tried to start, possibly failing and
+// writing error messages to the log.
+func (svc *Service) Start() (err error) {
+	if svc == nil {
+		return nil
+	}
+
+	wg := &sync.WaitGroup{}
+	wg.Add(len(svc.servers))
+	for _, srv := range svc.servers {
+		go serve(srv, wg)
+	}
+
+	wg.Wait()
+
+	return nil
+}
+
+// serve starts and runs srv and writes all errors into its log.
+func serve(srv *http.Server, wg *sync.WaitGroup) {
+	addr := srv.Addr
+	defer log.OnPanic(addr)
+
+	var proto string
+	var l net.Listener
+	var err error
+	if srv.TLSConfig == nil {
+		proto = "http"
+		l, err = net.Listen("tcp", addr)
+	} else {
+		proto = "https"
+		l, err = tls.Listen("tcp", addr, srv.TLSConfig)
+	}
+	if err != nil {
+		srv.ErrorLog.Printf("starting srv %s: binding: %s", addr, err)
+	}
+
+	// Update the server's address in case the address had the port zero, which
+	// would mean that a random available port was automatically chosen.
+	srv.Addr = l.Addr().String()
+
+	log.Info("websvc: starting srv %s://%s", proto, srv.Addr)
+
+	l = &waitListener{
+		Listener:      l,
+		firstAcceptWG: wg,
+	}
+
+	err = srv.Serve(l)
+	if err != nil && !errors.Is(err, http.ErrServerClosed) {
+		srv.ErrorLog.Printf("starting srv %s: %s", addr, err)
+	}
+}
+
+// Shutdown implements the [agh.Service] interface for *Service.  svc may be
+// nil.
+func (svc *Service) Shutdown(ctx context.Context) (err error) {
+	if svc == nil {
+		return nil
+	}
+
+	var errs []error
+	for _, srv := range svc.servers {
+		serr := srv.Shutdown(ctx)
+		if serr != nil {
+			errs = append(errs, fmt.Errorf("shutting down srv %s: %w", srv.Addr, serr))
+		}
+	}
+
+	if len(errs) > 0 {
+		return errors.List("shutting down", errs...)
+	}
+
+	return nil
+}
+
+// Config returns the current configuration of the web service.  Config must not
+// be called simultaneously with Start.  If svc was initialized with ":0"
+// addresses, addrs will not return the actual bound ports until Start is
+// finished.
+func (svc *Service) Config() (c *Config) {
+	c = &Config{
+		ConfigManager: svc.confMgr,
+		TLS:           svc.tls,
+		// Leave Addresses and SecureAddresses empty and get the actual
+		// addresses that include the :0 ones later.
+		Start:      svc.start,
+		Timeout:    svc.timeout,
+		ForceHTTPS: svc.forceHTTPS,
+	}
+
+	c.Addresses, c.SecureAddresses = svc.addrs()
+
+	return c
+}

internal/next/websvc/websvc_internal_test.go

@@ -0,0 +1,6 @@
+package websvc
+
+import "time"
+
+// testTimeout is the common timeout for tests.
+const testTimeout = 1 * time.Second

internal/next/websvc/websvc_test.go

@@ -0,0 +1,187 @@
+package websvc_test
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"io"
+	"net/http"
+	"net/netip"
+	"net/url"
+	"testing"
+	"time"
+
+	"github.com/AdguardTeam/AdGuardHome/internal/aghtest"
+	"github.com/AdguardTeam/AdGuardHome/internal/next/dnssvc"
+	"github.com/AdguardTeam/AdGuardHome/internal/next/websvc"
+	"github.com/AdguardTeam/golibs/testutil"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMain(m *testing.M) {
+	aghtest.DiscardLogOutput(m)
+}
+
+// testTimeout is the common timeout for tests.
+const testTimeout = 1 * time.Second
+
+// testStart is the server start value for tests.
+var testStart = time.Date(2022, 1, 1, 0, 0, 0, 0, time.UTC)
+
+// type check
+var _ websvc.ConfigManager = (*configManager)(nil)
+
+// configManager is a [websvc.ConfigManager] for tests.
+type configManager struct {
+	onDNS func() (svc websvc.ServiceWithConfig[*dnssvc.Config])
+	onWeb func() (svc websvc.ServiceWithConfig[*websvc.Config])
+
+	onUpdateDNS func(ctx context.Context, c *dnssvc.Config) (err error)
+	onUpdateWeb func(ctx context.Context, c *websvc.Config) (err error)
+}
+
+// DNS implements the [websvc.ConfigManager] interface for *configManager.
+func (m *configManager) DNS() (svc websvc.ServiceWithConfig[*dnssvc.Config]) {
+	return m.onDNS()
+}
+
+// Web implements the [websvc.ConfigManager] interface for *configManager.
+func (m *configManager) Web() (svc websvc.ServiceWithConfig[*websvc.Config]) {
+	return m.onWeb()
+}
+
+// UpdateDNS implements the [websvc.ConfigManager] interface for *configManager.
+func (m *configManager) UpdateDNS(ctx context.Context, c *dnssvc.Config) (err error) {
+	return m.onUpdateDNS(ctx, c)
+}
+
+// UpdateWeb implements the [websvc.ConfigManager] interface for *configManager.
+func (m *configManager) UpdateWeb(ctx context.Context, c *websvc.Config) (err error) {
+	return m.onUpdateWeb(ctx, c)
+}
+
+// newConfigManager returns a *configManager all methods of which panic.
+func newConfigManager() (m *configManager) {
+	return &configManager{
+		onDNS: func() (svc websvc.ServiceWithConfig[*dnssvc.Config]) { panic("not implemented") },
+		onWeb: func() (svc websvc.ServiceWithConfig[*websvc.Config]) { panic("not implemented") },
+		onUpdateDNS: func(_ context.Context, _ *dnssvc.Config) (err error) {
+			panic("not implemented")
+		},
+		onUpdateWeb: func(_ context.Context, _ *websvc.Config) (err error) {
+			panic("not implemented")
+		},
+	}
+}
+
+// newTestServer creates and starts a new web service instance as well as its
+// sole address.  It also registers a cleanup procedure, which shuts the
+// instance down.
+//
+// TODO(a.garipov): Use svc or remove it.
+func newTestServer(
+	t testing.TB,
+	confMgr websvc.ConfigManager,
+) (svc *websvc.Service, addr netip.AddrPort) {
+	t.Helper()
+
+	c := &websvc.Config{
+		ConfigManager:   confMgr,
+		TLS:             nil,
+		Addresses:       []netip.AddrPort{netip.MustParseAddrPort("127.0.0.1:0")},
+		SecureAddresses: nil,
+		Timeout:         testTimeout,
+		Start:           testStart,
+		ForceHTTPS:      false,
+	}
+
+	svc = websvc.New(c)
+
+	err := svc.Start()
+	require.NoError(t, err)
+	t.Cleanup(func() {
+		ctx, cancel := context.WithTimeout(context.Background(), testTimeout)
+		t.Cleanup(cancel)
+
+		err = svc.Shutdown(ctx)
+		require.NoError(t, err)
+	})
+
+	c = svc.Config()
+	require.NotNil(t, c)
+	require.Len(t, c.Addresses, 1)
+
+	return svc, c.Addresses[0]
+}
+
+// jobj is a utility alias for JSON objects.
+type jobj map[string]any
+
+// httpGet is a helper that performs an HTTP GET request and returns the body of
+// the response as well as checks that the status code is correct.
+//
+// TODO(a.garipov): Add helpers for other methods.
+func httpGet(t testing.TB, u *url.URL, wantCode int) (body []byte) {
+	t.Helper()
+
+	req, err := http.NewRequest(http.MethodGet, u.String(), nil)
+	require.NoErrorf(t, err, "creating req")
+
+	httpCli := &http.Client{
+		Timeout: testTimeout,
+	}
+	resp, err := httpCli.Do(req)
+	require.NoErrorf(t, err, "performing req")
+	require.Equal(t, wantCode, resp.StatusCode)
+
+	testutil.CleanupAndRequireSuccess(t, resp.Body.Close)
+
+	body, err = io.ReadAll(resp.Body)
+	require.NoErrorf(t, err, "reading body")
+
+	return body
+}
+
+// httpPatch is a helper that performs an HTTP PATCH request with JSON-encoded
+// reqBody as the request body and returns the body of the response as well as
+// checks that the status code is correct.
+//
+// TODO(a.garipov): Add helpers for other methods.
+func httpPatch(t testing.TB, u *url.URL, reqBody any, wantCode int) (body []byte) {
+	t.Helper()
+
+	b, err := json.Marshal(reqBody)
+	require.NoErrorf(t, err, "marshaling reqBody")
+
+	req, err := http.NewRequest(http.MethodPatch, u.String(), bytes.NewReader(b))
+	require.NoErrorf(t, err, "creating req")
+
+	httpCli := &http.Client{
+		Timeout: testTimeout,
+	}
+	resp, err := httpCli.Do(req)
+	require.NoErrorf(t, err, "performing req")
+	require.Equal(t, wantCode, resp.StatusCode)
+
+	testutil.CleanupAndRequireSuccess(t, resp.Body.Close)
+
+	body, err = io.ReadAll(resp.Body)
+	require.NoErrorf(t, err, "reading body")
+
+	return body
+}
+
+func TestService_Start_getHealthCheck(t *testing.T) {
+	confMgr := newConfigManager()
+	_, addr := newTestServer(t, confMgr)
+	u := &url.URL{
+		Scheme: "http",
+		Host:   addr.String(),
+		Path:   websvc.PathHealthCheck,
+	}
+
+	body := httpGet(t, u, http.StatusOK)
+
+	assert.Equal(t, []byte("OK"), body)
+}