grafana/pkg/services/grafana-apiserver/service.go

package grafanaapiserver

import (
	"context"
	"fmt"
	"net/http"
	"net/http/httptest"
	"path"
	"runtime/debug"
	"strconv"
	"strings"

	"github.com/go-logr/logr"
	"github.com/grafana/dskit/services"
	"golang.org/x/mod/semver"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"k8s.io/apimachinery/pkg/runtime/serializer"
	"k8s.io/apiserver/pkg/endpoints/responsewriter"
	genericapiserver "k8s.io/apiserver/pkg/server"
	"k8s.io/apiserver/pkg/server/options"
	clientrest "k8s.io/client-go/rest"
	"k8s.io/client-go/tools/clientcmd"
	"k8s.io/component-base/logs"
	"k8s.io/klog/v2"

	"github.com/grafana/grafana/pkg/services/grafana-apiserver/auth/authorizer"
	"github.com/grafana/grafana/pkg/services/grafana-apiserver/utils"
	"github.com/grafana/grafana/pkg/services/org"

	"github.com/grafana/grafana/pkg/api/routing"
	"github.com/grafana/grafana/pkg/infra/appcontext"
	"github.com/grafana/grafana/pkg/infra/db"
	"github.com/grafana/grafana/pkg/infra/tracing"
	"github.com/grafana/grafana/pkg/middleware"
	"github.com/grafana/grafana/pkg/modules"
	"github.com/grafana/grafana/pkg/registry"
	contextmodel "github.com/grafana/grafana/pkg/services/contexthandler/model"
	"github.com/grafana/grafana/pkg/services/featuremgmt"
	entitystorage "github.com/grafana/grafana/pkg/services/grafana-apiserver/storage/entity"
	filestorage "github.com/grafana/grafana/pkg/services/grafana-apiserver/storage/file"
	"github.com/grafana/grafana/pkg/services/store/entity"
	"github.com/grafana/grafana/pkg/services/store/entity/db/dbimpl"
	"github.com/grafana/grafana/pkg/services/store/entity/sqlstash"
	"github.com/grafana/grafana/pkg/setting"
)

type StorageType string

const (
	StorageTypeFile        StorageType = "file"
	StorageTypeEtcd        StorageType = "etcd"
	StorageTypeLegacy      StorageType = "legacy"
	StorageTypeUnified     StorageType = "unified"
	StorageTypeUnifiedGrpc StorageType = "unified-grpc"
)

var (
	_ Service                    = (*service)(nil)
	_ RestConfigProvider         = (*service)(nil)
	_ registry.BackgroundService = (*service)(nil)
	_ registry.CanBeDisabled     = (*service)(nil)

	Scheme = runtime.NewScheme()
	Codecs = serializer.NewCodecFactory(Scheme)

	unversionedVersion = schema.GroupVersion{Group: "", Version: "v1"}
	unversionedTypes   = []runtime.Object{
		&metav1.Status{},
		&metav1.WatchEvent{},
		&metav1.APIVersions{},
		&metav1.APIGroupList{},
		&metav1.APIGroup{},
		&metav1.APIResourceList{},
	}
)

func init() {
	// we need to add the options to empty v1
	metav1.AddToGroupVersion(Scheme, schema.GroupVersion{Group: "", Version: "v1"})
	Scheme.AddUnversionedTypes(unversionedVersion, unversionedTypes...)
}

type Service interface {
	services.NamedService
	registry.BackgroundService
	registry.CanBeDisabled
}

type APIRegistrar interface {
	RegisterAPI(builder APIGroupBuilder)
}

type RestConfigProvider interface {
	GetRestConfig() *clientrest.Config
}

type DirectRestConfigProvider interface {
	// GetDirectRestConfig returns a k8s client configuration that will use the same
	// logged logged in user as the current request context.  This is useful when
	// creating clients that map legacy API handlers to k8s backed services
	GetDirectRestConfig(c *contextmodel.ReqContext) *clientrest.Config
}

type service struct {
	*services.BasicService

	config     *config
	restConfig *clientrest.Config

	cfg      *setting.Cfg
	features featuremgmt.FeatureToggles

	stopCh    chan struct{}
	stoppedCh chan error

	db       db.DB
	rr       routing.RouteRegister
	handler  http.Handler
	builders []APIGroupBuilder

	tracing *tracing.TracingService

	authorizer *authorizer.GrafanaAuthorizer
}

func ProvideService(
	cfg *setting.Cfg,
	features featuremgmt.FeatureToggles,
	rr routing.RouteRegister,
	orgService org.Service,
	tracing *tracing.TracingService,
	db db.DB,
) (*service, error) {
	s := &service{
		config:     newConfig(cfg, features),
		cfg:        cfg,
		features:   features,
		rr:         rr,
		stopCh:     make(chan struct{}),
		builders:   []APIGroupBuilder{},
		authorizer: authorizer.NewGrafanaAuthorizer(cfg, orgService),
		tracing:    tracing,
		db:         db, // For Unified storage
	}

	// This will be used when running as a dskit service
	s.BasicService = services.NewBasicService(s.start, s.running, nil).WithName(modules.GrafanaAPIServer)

	// TODO: this is very hacky
	// We need to register the routes in ProvideService to make sure
	// the routes are registered before the Grafana HTTP server starts.
	proxyHandler := func(k8sRoute routing.RouteRegister) {
		handler := func(c *contextmodel.ReqContext) {
			if s.handler == nil {
				c.Resp.WriteHeader(404)
				_, _ = c.Resp.Write([]byte("Not found"))
				return
			}

			req := c.Req
			if req.URL.Path == "" {
				req.URL.Path = "/"
			}

			// TODO: add support for the existing MetricsEndpointBasicAuth config option
			if req.URL.Path == "/apiserver-metrics" {
				req.URL.Path = "/metrics"
			}

			resp := responsewriter.WrapForHTTP1Or2(c.Resp)
			s.handler.ServeHTTP(resp, req)
		}
		k8sRoute.Any("/", middleware.ReqSignedIn, handler)
		k8sRoute.Any("/*", middleware.ReqSignedIn, handler)
	}

	s.rr.Group("/apis", proxyHandler)
	s.rr.Group("/apiserver-metrics", proxyHandler)
	s.rr.Group("/openapi", proxyHandler)

	return s, nil
}

func (s *service) GetRestConfig() *clientrest.Config {
	return s.restConfig
}

func (s *service) IsDisabled() bool {
	return !s.config.enabled
}

// Run is an adapter for the BackgroundService interface.
func (s *service) Run(ctx context.Context) error {
	if err := s.start(ctx); err != nil {
		return err
	}
	return s.running(ctx)
}

func (s *service) RegisterAPI(builder APIGroupBuilder) {
	s.builders = append(s.builders, builder)
}

func (s *service) start(ctx context.Context) error {
	logger := logr.New(newLogAdapter(s.config.logLevel))
	klog.SetLoggerWithOptions(logger, klog.ContextualLogger(true))
	if _, err := logs.GlogSetter(strconv.Itoa(s.config.logLevel)); err != nil {
		logger.Error(err, "failed to set log level")
	}

	// Get the list of groups the server will support
	builders := s.builders

	groupVersions := make([]schema.GroupVersion, 0, len(builders))
	// Install schemas
	for _, b := range builders {
		groupVersions = append(groupVersions, b.GetGroupVersion())
		if err := b.InstallSchema(Scheme); err != nil {
			return err
		}

		// Optionally register a custom authorizer
		auth := b.GetAuthorizer()
		if auth != nil {
			s.authorizer.Register(b.GetGroupVersion(), auth)
		}
	}

	o := options.NewRecommendedOptions("/registry/grafana.app", Codecs.LegacyCodec(groupVersions...))
	o.SecureServing.BindAddress = s.config.ip
	o.SecureServing.BindPort = s.config.port
	o.Authentication.RemoteKubeConfigFileOptional = true
	o.Authorization.RemoteKubeConfigFileOptional = true

	o.Admission = nil
	o.CoreAPI = nil

	serverConfig := genericapiserver.NewRecommendedConfig(Codecs)
	serverConfig.ExternalAddress = s.config.host

	if s.config.devMode {
		// SecureServingOptions is used when the apiserver needs it's own listener.
		// this is not needed in production, but it's useful for development kubectl access.
		if err := o.SecureServing.ApplyTo(&serverConfig.SecureServing, &serverConfig.LoopbackClientConfig); err != nil {
			return err
		}
		// AuthenticationOptions is needed to authenticate requests from kubectl in dev mode.
		if err := o.Authentication.ApplyTo(&serverConfig.Authentication, serverConfig.SecureServing, serverConfig.OpenAPIConfig); err != nil {
			return err
		}
	} else {
		// In production mode, override ExternalAddress and LoopbackClientConfig.
		// In dev mode we want to use the loopback client config
		// and address provided by SecureServingOptions.
		serverConfig.ExternalAddress = s.config.host
		serverConfig.LoopbackClientConfig = &clientrest.Config{
			Host: s.config.apiURL,
			TLSClientConfig: clientrest.TLSClientConfig{
				Insecure: true,
			},
		}
	}

	switch s.config.storageType {
	case StorageTypeEtcd:
		o.Etcd.StorageConfig.Transport.ServerList = s.config.etcdServers
		if err := o.Etcd.Validate(); len(err) > 0 {
			return err[0]
		}
		if err := o.Etcd.ApplyTo(&serverConfig.Config); err != nil {
			return err
		}

	case StorageTypeUnified:
		if !s.features.IsEnabledGlobally(featuremgmt.FlagUnifiedStorage) {
			return fmt.Errorf("unified storage requires the unifiedStorage feature flag (and app_mode = development)")
		}

		eDB, err := dbimpl.ProvideEntityDB(s.db, s.cfg, s.features)
		if err != nil {
			return err
		}

		store, err := sqlstash.ProvideSQLEntityServer(eDB)
		if err != nil {
			return err
		}

		serverConfig.Config.RESTOptionsGetter = entitystorage.NewRESTOptionsGetter(s.cfg, store, o.Etcd.StorageConfig.Codec)

	case StorageTypeUnifiedGrpc:
		// Create a connection to the gRPC server
		// TODO: support configuring the gRPC server address
		conn, err := grpc.Dial("localhost:10000", grpc.WithTransportCredentials(insecure.NewCredentials()))
		if err != nil {
			return err
		}

		// TODO: determine when to close the connection, we cannot defer it here
		// defer conn.Close()

		// Create a client instance
		store := entity.NewEntityStoreClientWrapper(conn)

		serverConfig.Config.RESTOptionsGetter = entitystorage.NewRESTOptionsGetter(s.cfg, store, o.Etcd.StorageConfig.Codec)

	case StorageTypeFile:
		serverConfig.RESTOptionsGetter = filestorage.NewRESTOptionsGetter(s.config.dataPath, o.Etcd.StorageConfig)

	case StorageTypeLegacy:
		// do nothing?
	}

	serverConfig.Authorization.Authorizer = s.authorizer
	serverConfig.TracerProvider = s.tracing.GetTracerProvider()

	// Add OpenAPI specs for each group+version
	err := SetupConfig(serverConfig, builders)
	if err != nil {
		return err
	}

	// support folder selection
	err = entitystorage.RegisterFieldSelectorSupport(Scheme)
	if err != nil {
		return err
	}

	// Create the server
	server, err := serverConfig.Complete().New("grafana-apiserver", genericapiserver.NewEmptyDelegate())
	if err != nil {
		return err
	}

	// Install the API Group+version
	err = InstallAPIs(server, serverConfig.RESTOptionsGetter, builders)
	if err != nil {
		return err
	}

	// Used by the proxy wrapper registered in ProvideService
	s.handler = server.Handler
	s.restConfig = server.LoopbackClientConfig

	prepared := server.PrepareRun()

	// When running in production, do not start a standalone https server
	if !s.config.devMode {
		return nil
	}

	// only write kubeconfig in dev mode
	if err := s.ensureKubeConfig(); err != nil {
		return err
	}

	go func() {
		s.stoppedCh <- prepared.Run(s.stopCh)
	}()
	return nil
}

func (s *service) GetDirectRestConfig(c *contextmodel.ReqContext) *clientrest.Config {
	return &clientrest.Config{
		Transport: &roundTripperFunc{
			fn: func(req *http.Request) (*http.Response, error) {
				ctx := appcontext.WithUser(req.Context(), c.SignedInUser)
				w := httptest.NewRecorder()
				s.handler.ServeHTTP(w, req.WithContext(ctx))
				return w.Result(), nil
			},
		},
	}
}

func (s *service) running(ctx context.Context) error {
	// skip waiting for the server in prod mode
	if !s.config.devMode {
		<-ctx.Done()
		return nil
	}

	select {
	case err := <-s.stoppedCh:
		if err != nil {
			return err
		}
	case <-ctx.Done():
		close(s.stopCh)
	}
	return nil
}

func (s *service) ensureKubeConfig() error {
	return clientcmd.WriteToFile(
		utils.FormatKubeConfig(s.restConfig),
		path.Join(s.config.dataPath, "grafana.kubeconfig"),
	)
}

type roundTripperFunc struct {
	fn func(req *http.Request) (*http.Response, error)
}

func (f *roundTripperFunc) RoundTrip(req *http.Request) (*http.Response, error) {
	return f.fn(req)
}

// find the k8s version according to build info
func getK8sApiserverVersion() (string, error) {
	bi, ok := debug.ReadBuildInfo()
	if !ok {
		return "", fmt.Errorf("debug.ReadBuildInfo() failed")
	}

	if len(bi.Deps) == 0 {
		return "v?.?", nil // this is normal while debugging
	}

	for _, dep := range bi.Deps {
		if dep.Path == "k8s.io/apiserver" {
			if !semver.IsValid(dep.Version) {
				return "", fmt.Errorf("invalid semantic version for k8s.io/apiserver")
			}
			// v0 => v1
			majorVersion := strings.TrimPrefix(semver.Major(dep.Version), "v")
			majorInt, err := strconv.Atoi(majorVersion)
			if err != nil {
				return "", fmt.Errorf("could not convert majorVersion to int. majorVersion: %s", majorVersion)
			}
			newMajor := fmt.Sprintf("v%d", majorInt+1)
			return strings.Replace(dep.Version, semver.Major(dep.Version), newMajor, 1), nil
		}
	}

	return "", fmt.Errorf("could not find k8s.io/apiserver in build info")
}