grafana/pkg/api/http_server.go

package api

import (
	"context"
	"crypto/tls"
	"errors"
	"fmt"
	"net"
	"net/http"
	"os"
	"path"
	"path/filepath"
	"strings"
	"sync"

	"github.com/grafana/grafana/pkg/middleware/csrf"

	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promhttp"

	"github.com/grafana/grafana/pkg/api/avatar"
	"github.com/grafana/grafana/pkg/api/routing"
	httpstatic "github.com/grafana/grafana/pkg/api/static"
	"github.com/grafana/grafana/pkg/components/simplejson"
	"github.com/grafana/grafana/pkg/framework/coremodel"
	"github.com/grafana/grafana/pkg/infra/localcache"
	"github.com/grafana/grafana/pkg/infra/log"
	"github.com/grafana/grafana/pkg/infra/remotecache"
	"github.com/grafana/grafana/pkg/infra/tracing"
	loginpkg "github.com/grafana/grafana/pkg/login"
	"github.com/grafana/grafana/pkg/login/social"
	"github.com/grafana/grafana/pkg/middleware"
	"github.com/grafana/grafana/pkg/models"
	"github.com/grafana/grafana/pkg/plugins"
	"github.com/grafana/grafana/pkg/plugins/plugincontext"
	"github.com/grafana/grafana/pkg/services/accesscontrol"
	"github.com/grafana/grafana/pkg/services/alerting"
	"github.com/grafana/grafana/pkg/services/cleanup"
	"github.com/grafana/grafana/pkg/services/comments"
	"github.com/grafana/grafana/pkg/services/contexthandler"
	"github.com/grafana/grafana/pkg/services/dashboards"
	"github.com/grafana/grafana/pkg/services/dashboardsnapshots"
	dashver "github.com/grafana/grafana/pkg/services/dashboardversion"
	"github.com/grafana/grafana/pkg/services/datasourceproxy"
	"github.com/grafana/grafana/pkg/services/datasources"
	"github.com/grafana/grafana/pkg/services/datasources/permissions"
	"github.com/grafana/grafana/pkg/services/encryption"
	"github.com/grafana/grafana/pkg/services/export"
	"github.com/grafana/grafana/pkg/services/featuremgmt"
	"github.com/grafana/grafana/pkg/services/hooks"
	"github.com/grafana/grafana/pkg/services/ldap"
	"github.com/grafana/grafana/pkg/services/libraryelements"
	"github.com/grafana/grafana/pkg/services/librarypanels"
	"github.com/grafana/grafana/pkg/services/live"
	"github.com/grafana/grafana/pkg/services/live/pushhttp"
	"github.com/grafana/grafana/pkg/services/login"
	"github.com/grafana/grafana/pkg/services/ngalert"
	"github.com/grafana/grafana/pkg/services/notifications"
	"github.com/grafana/grafana/pkg/services/plugindashboards"
	pluginSettings "github.com/grafana/grafana/pkg/services/pluginsettings/service"
	pref "github.com/grafana/grafana/pkg/services/preference"
	"github.com/grafana/grafana/pkg/services/provisioning"
	"github.com/grafana/grafana/pkg/services/query"
	"github.com/grafana/grafana/pkg/services/queryhistory"
	"github.com/grafana/grafana/pkg/services/quota"
	"github.com/grafana/grafana/pkg/services/rendering"
	"github.com/grafana/grafana/pkg/services/search"
	"github.com/grafana/grafana/pkg/services/searchusers"
	"github.com/grafana/grafana/pkg/services/secrets"
	"github.com/grafana/grafana/pkg/services/serviceaccounts"
	"github.com/grafana/grafana/pkg/services/shorturls"
	"github.com/grafana/grafana/pkg/services/sqlstore"
	"github.com/grafana/grafana/pkg/services/star"
	"github.com/grafana/grafana/pkg/services/store"
	"github.com/grafana/grafana/pkg/services/teamguardian"
	"github.com/grafana/grafana/pkg/services/thumbs"
	"github.com/grafana/grafana/pkg/services/updatechecker"
	"github.com/grafana/grafana/pkg/setting"
	"github.com/grafana/grafana/pkg/web"
)

type HTTPServer struct {
	log              log.Logger
	web              *web.Mux
	context          context.Context
	httpSrv          *http.Server
	middlewares      []web.Handler
	namedMiddlewares []routing.RegisterNamedMiddleware

	PluginContextProvider        *plugincontext.Provider
	RouteRegister                routing.RouteRegister
	RenderService                rendering.Service
	Cfg                          *setting.Cfg
	Features                     *featuremgmt.FeatureManager
	SettingsProvider             setting.Provider
	HooksService                 *hooks.HooksService
	CacheService                 *localcache.CacheService
	DataSourceCache              datasources.CacheService
	AuthTokenService             models.UserTokenService
	QuotaService                 *quota.QuotaService
	RemoteCacheService           *remotecache.RemoteCache
	ProvisioningService          provisioning.ProvisioningService
	Login                        login.Service
	License                      models.Licensing
	AccessControl                accesscontrol.AccessControl
	DataProxy                    *datasourceproxy.DataSourceProxyService
	PluginRequestValidator       models.PluginRequestValidator
	pluginClient                 plugins.Client
	pluginStore                  plugins.Store
	pluginDashboardService       plugindashboards.Service
	pluginStaticRouteResolver    plugins.StaticRouteResolver
	pluginErrorResolver          plugins.ErrorResolver
	SearchService                search.Service
	ShortURLService              shorturls.Service
	QueryHistoryService          queryhistory.Service
	Live                         *live.GrafanaLive
	LivePushGateway              *pushhttp.Gateway
	ThumbService                 thumbs.Service
	ExportService                export.ExportService
	StorageService               store.HTTPStorageService
	ContextHandler               *contexthandler.ContextHandler
	SQLStore                     sqlstore.Store
	AlertEngine                  *alerting.AlertEngine
	AlertNG                      *ngalert.AlertNG
	LibraryPanelService          librarypanels.Service
	LibraryElementService        libraryelements.Service
	SocialService                social.Service
	Listener                     net.Listener
	EncryptionService            encryption.Internal
	SecretsService               secrets.Service
	DataSourcesService           datasources.DataSourceService
	cleanUpService               *cleanup.CleanUpService
	tracer                       tracing.Tracer
	grafanaUpdateChecker         *updatechecker.GrafanaService
	pluginsUpdateChecker         *updatechecker.PluginsService
	searchUsersService           searchusers.Service
	ldapGroups                   ldap.Groups
	teamGuardian                 teamguardian.TeamGuardian
	queryDataService             *query.Service
	serviceAccountsService       serviceaccounts.Service
	authInfoService              login.AuthInfoService
	authenticator                loginpkg.Authenticator
	teamPermissionsService       accesscontrol.TeamPermissionsService
	NotificationService          *notifications.NotificationService
	dashboardService             dashboards.DashboardService
	dashboardProvisioningService dashboards.DashboardProvisioningService
	folderService                dashboards.FolderService
	DatasourcePermissionsService permissions.DatasourcePermissionsService
	commentsService              *comments.Service
	AlertNotificationService     *alerting.AlertNotificationService
	DashboardsnapshotsService    *dashboardsnapshots.Service
	PluginSettings               *pluginSettings.Service
	AvatarCacheServer            *avatar.AvatarCacheServer
	preferenceService            pref.Service
	Csrf                         csrf.Service
	entityEventsService          store.EntityEventsService
	folderPermissionsService     accesscontrol.FolderPermissionsService
	dashboardPermissionsService  accesscontrol.DashboardPermissionsService
	dashboardVersionService      dashver.Service
	starService                  star.Service
	CoremodelRegistry            *coremodel.Registry
}

type ServerOptions struct {
	Listener net.Listener
}

func ProvideHTTPServer(opts ServerOptions, cfg *setting.Cfg, routeRegister routing.RouteRegister,
	renderService rendering.Service, licensing models.Licensing, hooksService *hooks.HooksService,
	cacheService *localcache.CacheService, sqlStore *sqlstore.SQLStore, alertEngine *alerting.AlertEngine,
	pluginRequestValidator models.PluginRequestValidator, pluginStaticRouteResolver plugins.StaticRouteResolver,
	pluginDashboardService plugindashboards.Service, pluginStore plugins.Store, pluginClient plugins.Client,
	pluginErrorResolver plugins.ErrorResolver, settingsProvider setting.Provider,
	dataSourceCache datasources.CacheService, userTokenService models.UserTokenService,
	cleanUpService *cleanup.CleanUpService, shortURLService shorturls.Service, queryHistoryService queryhistory.Service,
	thumbService thumbs.Service, remoteCache *remotecache.RemoteCache, provisioningService provisioning.ProvisioningService,
	loginService login.Service, authenticator loginpkg.Authenticator, accessControl accesscontrol.AccessControl,
	dataSourceProxy *datasourceproxy.DataSourceProxyService, searchService *search.SearchService,
	live *live.GrafanaLive, livePushGateway *pushhttp.Gateway, plugCtxProvider *plugincontext.Provider,
	contextHandler *contexthandler.ContextHandler, features *featuremgmt.FeatureManager,
	alertNG *ngalert.AlertNG, libraryPanelService librarypanels.Service, libraryElementService libraryelements.Service,
	quotaService *quota.QuotaService, socialService social.Service, tracer tracing.Tracer, exportService export.ExportService,
	encryptionService encryption.Internal, grafanaUpdateChecker *updatechecker.GrafanaService,
	pluginsUpdateChecker *updatechecker.PluginsService, searchUsersService searchusers.Service,
	dataSourcesService datasources.DataSourceService, secretsService secrets.Service, queryDataService *query.Service,
	ldapGroups ldap.Groups, teamGuardian teamguardian.TeamGuardian, serviceaccountsService serviceaccounts.Service,
	authInfoService login.AuthInfoService, storageService store.HTTPStorageService,
	notificationService *notifications.NotificationService, dashboardService dashboards.DashboardService,
	dashboardProvisioningService dashboards.DashboardProvisioningService, folderService dashboards.FolderService,
	datasourcePermissionsService permissions.DatasourcePermissionsService, alertNotificationService *alerting.AlertNotificationService,
	dashboardsnapshotsService *dashboardsnapshots.Service, commentsService *comments.Service, pluginSettings *pluginSettings.Service,
	avatarCacheServer *avatar.AvatarCacheServer, preferenceService pref.Service, entityEventsService store.EntityEventsService,
	teamsPermissionsService accesscontrol.TeamPermissionsService, folderPermissionsService accesscontrol.FolderPermissionsService,
	dashboardPermissionsService accesscontrol.DashboardPermissionsService, dashboardVersionService dashver.Service,
	starService star.Service, coremodelRegistry *coremodel.Registry, csrfService csrf.Service,
) (*HTTPServer, error) {
	web.Env = cfg.Env
	m := web.New()

	hs := &HTTPServer{
		Cfg:                          cfg,
		RouteRegister:                routeRegister,
		RenderService:                renderService,
		License:                      licensing,
		HooksService:                 hooksService,
		CacheService:                 cacheService,
		SQLStore:                     sqlStore,
		AlertEngine:                  alertEngine,
		PluginRequestValidator:       pluginRequestValidator,
		pluginClient:                 pluginClient,
		pluginStore:                  pluginStore,
		pluginStaticRouteResolver:    pluginStaticRouteResolver,
		pluginDashboardService:       pluginDashboardService,
		pluginErrorResolver:          pluginErrorResolver,
		grafanaUpdateChecker:         grafanaUpdateChecker,
		pluginsUpdateChecker:         pluginsUpdateChecker,
		SettingsProvider:             settingsProvider,
		DataSourceCache:              dataSourceCache,
		AuthTokenService:             userTokenService,
		cleanUpService:               cleanUpService,
		ShortURLService:              shortURLService,
		QueryHistoryService:          queryHistoryService,
		Features:                     features,
		ThumbService:                 thumbService,
		StorageService:               storageService,
		RemoteCacheService:           remoteCache,
		ProvisioningService:          provisioningService,
		Login:                        loginService,
		AccessControl:                accessControl,
		DataProxy:                    dataSourceProxy,
		SearchService:                searchService,
		ExportService:                exportService,
		Live:                         live,
		LivePushGateway:              livePushGateway,
		PluginContextProvider:        plugCtxProvider,
		ContextHandler:               contextHandler,
		AlertNG:                      alertNG,
		LibraryPanelService:          libraryPanelService,
		LibraryElementService:        libraryElementService,
		QuotaService:                 quotaService,
		tracer:                       tracer,
		log:                          log.New("http.server"),
		web:                          m,
		Listener:                     opts.Listener,
		SocialService:                socialService,
		EncryptionService:            encryptionService,
		SecretsService:               secretsService,
		DataSourcesService:           dataSourcesService,
		searchUsersService:           searchUsersService,
		ldapGroups:                   ldapGroups,
		teamGuardian:                 teamGuardian,
		queryDataService:             queryDataService,
		serviceAccountsService:       serviceaccountsService,
		authInfoService:              authInfoService,
		authenticator:                authenticator,
		NotificationService:          notificationService,
		dashboardService:             dashboardService,
		dashboardProvisioningService: dashboardProvisioningService,
		folderService:                folderService,
		DatasourcePermissionsService: datasourcePermissionsService,
		commentsService:              commentsService,
		teamPermissionsService:       teamsPermissionsService,
		AlertNotificationService:     alertNotificationService,
		DashboardsnapshotsService:    dashboardsnapshotsService,
		PluginSettings:               pluginSettings,
		AvatarCacheServer:            avatarCacheServer,
		preferenceService:            preferenceService,
		Csrf:                         csrfService,
		entityEventsService:          entityEventsService,
		folderPermissionsService:     folderPermissionsService,
		dashboardPermissionsService:  dashboardPermissionsService,
		dashboardVersionService:      dashboardVersionService,
		starService:                  starService,
		CoremodelRegistry:            coremodelRegistry,
	}
	if hs.Listener != nil {
		hs.log.Debug("Using provided listener")
	}
	hs.registerRoutes()

	// Register access control scope resolver for annotations
	hs.AccessControl.RegisterScopeAttributeResolver(AnnotationTypeScopeResolver())

	if err := hs.declareFixedRoles(); err != nil {
		return nil, err
	}
	return hs, nil
}

func (hs *HTTPServer) AddMiddleware(middleware web.Handler) {
	hs.middlewares = append(hs.middlewares, middleware)
}

func (hs *HTTPServer) AddNamedMiddleware(middleware routing.RegisterNamedMiddleware) {
	hs.namedMiddlewares = append(hs.namedMiddlewares, middleware)
}

func (hs *HTTPServer) Run(ctx context.Context) error {
	hs.context = ctx

	hs.applyRoutes()

	// Remove any square brackets enclosing IPv6 addresses, a format we support for backwards compatibility
	host := strings.TrimSuffix(strings.TrimPrefix(hs.Cfg.HTTPAddr, "["), "]")
	hs.httpSrv = &http.Server{
		Addr:        net.JoinHostPort(host, hs.Cfg.HTTPPort),
		Handler:     hs.web,
		ReadTimeout: hs.Cfg.ReadTimeout,
	}
	switch hs.Cfg.Protocol {
	case setting.HTTP2Scheme:
		if err := hs.configureHttp2(); err != nil {
			return err
		}
	case setting.HTTPSScheme:
		if err := hs.configureHttps(); err != nil {
			return err
		}
	default:
	}

	listener, err := hs.getListener()
	if err != nil {
		return err
	}

	hs.log.Info("HTTP Server Listen", "address", listener.Addr().String(), "protocol",
		hs.Cfg.Protocol, "subUrl", hs.Cfg.AppSubURL, "socket", hs.Cfg.SocketPath)

	var wg sync.WaitGroup
	wg.Add(1)

	// handle http shutdown on server context done
	go func() {
		defer wg.Done()

		<-ctx.Done()
		if err := hs.httpSrv.Shutdown(context.Background()); err != nil {
			hs.log.Error("Failed to shutdown server", "error", err)
		}
	}()

	switch hs.Cfg.Protocol {
	case setting.HTTPScheme, setting.SocketScheme:
		if err := hs.httpSrv.Serve(listener); err != nil {
			if errors.Is(err, http.ErrServerClosed) {
				hs.log.Debug("server was shutdown gracefully")
				return nil
			}
			return err
		}
	case setting.HTTP2Scheme, setting.HTTPSScheme:
		if err := hs.httpSrv.ServeTLS(listener, hs.Cfg.CertFile, hs.Cfg.KeyFile); err != nil {
			if errors.Is(err, http.ErrServerClosed) {
				hs.log.Debug("server was shutdown gracefully")
				return nil
			}
			return err
		}
	default:
		panic(fmt.Sprintf("Unhandled protocol %q", hs.Cfg.Protocol))
	}

	wg.Wait()

	return nil
}

func (hs *HTTPServer) getListener() (net.Listener, error) {
	if hs.Listener != nil {
		return hs.Listener, nil
	}

	switch hs.Cfg.Protocol {
	case setting.HTTPScheme, setting.HTTPSScheme, setting.HTTP2Scheme:
		listener, err := net.Listen("tcp", hs.httpSrv.Addr)
		if err != nil {
			return nil, fmt.Errorf("failed to open listener on address %s: %w", hs.httpSrv.Addr, err)
		}
		return listener, nil
	case setting.SocketScheme:
		listener, err := net.ListenUnix("unix", &net.UnixAddr{Name: hs.Cfg.SocketPath, Net: "unix"})
		if err != nil {
			return nil, fmt.Errorf("failed to open listener for socket %s: %w", hs.Cfg.SocketPath, err)
		}

		// Make socket writable by group
		// nolint:gosec
		if err := os.Chmod(hs.Cfg.SocketPath, 0660); err != nil {
			return nil, fmt.Errorf("failed to change socket permissions: %w", err)
		}

		return listener, nil
	default:
		hs.log.Error("Invalid protocol", "protocol", hs.Cfg.Protocol)
		return nil, fmt.Errorf("invalid protocol %q", hs.Cfg.Protocol)
	}
}

func (hs *HTTPServer) configureHttps() error {
	if hs.Cfg.CertFile == "" {
		return fmt.Errorf("cert_file cannot be empty when using HTTPS")
	}

	if hs.Cfg.KeyFile == "" {
		return fmt.Errorf("cert_key cannot be empty when using HTTPS")
	}

	if _, err := os.Stat(hs.Cfg.CertFile); os.IsNotExist(err) {
		return fmt.Errorf(`cannot find SSL cert_file at %q`, hs.Cfg.CertFile)
	}

	if _, err := os.Stat(hs.Cfg.KeyFile); os.IsNotExist(err) {
		return fmt.Errorf(`cannot find SSL key_file at %q`, hs.Cfg.KeyFile)
	}

	tlsCfg := &tls.Config{
		MinVersion: tls.VersionTLS12,
		CipherSuites: []uint16{
			tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
			tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
			tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
			tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
			tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
			tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
			tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
			tls.TLS_RSA_WITH_AES_128_GCM_SHA256,
			tls.TLS_RSA_WITH_AES_256_GCM_SHA384,
			tls.TLS_RSA_WITH_AES_128_CBC_SHA,
			tls.TLS_RSA_WITH_AES_256_CBC_SHA,
		},
	}

	hs.httpSrv.TLSConfig = tlsCfg
	hs.httpSrv.TLSNextProto = make(map[string]func(*http.Server, *tls.Conn, http.Handler))

	return nil
}

func (hs *HTTPServer) configureHttp2() error {
	if hs.Cfg.CertFile == "" {
		return fmt.Errorf("cert_file cannot be empty when using HTTP2")
	}

	if hs.Cfg.KeyFile == "" {
		return fmt.Errorf("cert_key cannot be empty when using HTTP2")
	}

	if _, err := os.Stat(hs.Cfg.CertFile); os.IsNotExist(err) {
		return fmt.Errorf(`cannot find SSL cert_file at %q`, hs.Cfg.CertFile)
	}

	if _, err := os.Stat(hs.Cfg.KeyFile); os.IsNotExist(err) {
		return fmt.Errorf(`cannot find SSL key_file at %q`, hs.Cfg.KeyFile)
	}

	tlsCfg := &tls.Config{
		MinVersion: tls.VersionTLS12,
		CipherSuites: []uint16{
			tls.TLS_CHACHA20_POLY1305_SHA256,
			tls.TLS_AES_128_GCM_SHA256,
			tls.TLS_AES_256_GCM_SHA384,
			tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
			tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
			tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
			tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
			tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
			tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
		},
		NextProtos: []string{"h2", "http/1.1"},
	}

	hs.httpSrv.TLSConfig = tlsCfg

	return nil
}

func (hs *HTTPServer) applyRoutes() {
	// start with middlewares & static routes
	hs.addMiddlewaresAndStaticRoutes()
	// then add view routes & api routes
	hs.RouteRegister.Register(hs.web, hs.namedMiddlewares...)
	// then custom app proxy routes
	hs.initAppPluginRoutes(hs.web)
	// lastly not found route
	hs.web.NotFound(middleware.ReqSignedIn, hs.NotFoundHandler)
}

func (hs *HTTPServer) addMiddlewaresAndStaticRoutes() {
	m := hs.web

	m.Use(middleware.RequestTracing(hs.tracer))
	m.Use(middleware.RequestMetrics(hs.Features))

	m.Use(middleware.Logger(hs.Cfg))

	if hs.Cfg.EnableGzip {
		m.UseMiddleware(middleware.Gziper())
	}

	m.Use(middleware.Recovery(hs.Cfg))
	m.UseMiddleware(hs.Csrf.Middleware(hs.log))

	hs.mapStatic(m, hs.Cfg.StaticRootPath, "build", "public/build")
	hs.mapStatic(m, hs.Cfg.StaticRootPath, "", "public", "/public/views/swagger.html")
	hs.mapStatic(m, hs.Cfg.StaticRootPath, "robots.txt", "robots.txt")

	if hs.Cfg.ImageUploadProvider == "local" {
		hs.mapStatic(m, hs.Cfg.ImagesDir, "", "/public/img/attachments")
	}

	m.Use(middleware.AddDefaultResponseHeaders(hs.Cfg))

	if hs.Cfg.ServeFromSubPath && hs.Cfg.AppSubURL != "" {
		m.SetURLPrefix(hs.Cfg.AppSubURL)
	}

	m.UseMiddleware(web.Renderer(filepath.Join(hs.Cfg.StaticRootPath, "views"), "[[", "]]"))

	// These endpoints are used for monitoring the Grafana instance
	// and should not be redirected or rejected.
	m.Use(hs.healthzHandler)
	m.Use(hs.apiHealthHandler)
	m.Use(hs.metricsEndpoint)
	m.Use(hs.pluginMetricsEndpoint)

	m.Use(hs.ContextHandler.Middleware)
	m.Use(middleware.OrgRedirect(hs.Cfg, hs.SQLStore))
	m.Use(accesscontrol.LoadPermissionsMiddleware(hs.AccessControl))

	// needs to be after context handler
	if hs.Cfg.EnforceDomain {
		m.Use(middleware.ValidateHostHeader(hs.Cfg))
	}

	m.Use(middleware.HandleNoCacheHeader)
	m.UseMiddleware(middleware.AddCSPHeader(hs.Cfg, hs.log))

	for _, mw := range hs.middlewares {
		m.Use(mw)
	}
}

func (hs *HTTPServer) metricsEndpoint(ctx *web.Context) {
	if !hs.Cfg.MetricsEndpointEnabled {
		return
	}

	if ctx.Req.Method != http.MethodGet || ctx.Req.URL.Path != "/metrics" {
		return
	}

	if hs.metricsEndpointBasicAuthEnabled() && !BasicAuthenticatedRequest(ctx.Req, hs.Cfg.MetricsEndpointBasicAuthUsername, hs.Cfg.MetricsEndpointBasicAuthPassword) {
		ctx.Resp.WriteHeader(http.StatusUnauthorized)
		return
	}

	promhttp.
		HandlerFor(prometheus.DefaultGatherer, promhttp.HandlerOpts{EnableOpenMetrics: true}).
		ServeHTTP(ctx.Resp, ctx.Req)
}

// healthzHandler always return 200 - Ok if Grafana's web server is running
func (hs *HTTPServer) healthzHandler(ctx *web.Context) {
	notHeadOrGet := ctx.Req.Method != http.MethodGet && ctx.Req.Method != http.MethodHead
	if notHeadOrGet || ctx.Req.URL.Path != "/healthz" {
		return
	}

	ctx.Resp.WriteHeader(200)
	_, err := ctx.Resp.Write([]byte("Ok"))
	if err != nil {
		hs.log.Error("could not write to response", "err", err)
	}
}

// apiHealthHandler will return ok if Grafana's web server is running and it
// can access the database. If the database cannot be accessed it will return
// http status code 503.
func (hs *HTTPServer) apiHealthHandler(ctx *web.Context) {
	notHeadOrGet := ctx.Req.Method != http.MethodGet && ctx.Req.Method != http.MethodHead
	if notHeadOrGet || ctx.Req.URL.Path != "/api/health" {
		return
	}

	data := simplejson.New()
	data.Set("database", "ok")
	if !hs.Cfg.AnonymousHideVersion {
		data.Set("version", hs.Cfg.BuildVersion)
		data.Set("commit", hs.Cfg.BuildCommit)
	}

	if !hs.databaseHealthy(ctx.Req.Context()) {
		data.Set("database", "failing")
		ctx.Resp.Header().Set("Content-Type", "application/json; charset=UTF-8")
		ctx.Resp.WriteHeader(503)
	} else {
		ctx.Resp.Header().Set("Content-Type", "application/json; charset=UTF-8")
		ctx.Resp.WriteHeader(200)
	}

	dataBytes, err := data.EncodePretty()
	if err != nil {
		hs.log.Error("Failed to encode data", "err", err)
		return
	}

	if _, err := ctx.Resp.Write(dataBytes); err != nil {
		hs.log.Error("Failed to write to response", "err", err)
	}
}

func (hs *HTTPServer) mapStatic(m *web.Mux, rootDir string, dir string, prefix string, exclude ...string) {
	headers := func(c *web.Context) {
		c.Resp.Header().Set("Cache-Control", "public, max-age=3600")
	}

	if prefix == "public/build" {
		headers = func(c *web.Context) {
			c.Resp.Header().Set("Cache-Control", "public, max-age=31536000")
		}
	}

	if hs.Cfg.Env == setting.Dev {
		headers = func(c *web.Context) {
			c.Resp.Header().Set("Cache-Control", "max-age=0, must-revalidate, no-cache")
		}
	}

	m.Use(httpstatic.Static(
		path.Join(rootDir, dir),
		httpstatic.StaticOptions{
			SkipLogging: true,
			Prefix:      prefix,
			AddHeaders:  headers,
			Exclude:     exclude,
		},
	))
}

func (hs *HTTPServer) metricsEndpointBasicAuthEnabled() bool {
	return hs.Cfg.MetricsEndpointBasicAuthUsername != "" && hs.Cfg.MetricsEndpointBasicAuthPassword != ""
}