GRPC Server: Add gRPC server service (#47849)

Co-authored-by: Todd Treece <todd.treece@grafana.com>
Co-authored-by: Ryan McKinley <ryantxu@gmail.com>

pkg/services/grpcserver/service.go

@@ -0,0 +1,98 @@
+package grpcserver
+
+import (
+	"context"
+	"fmt"
+	"net"
+
+	"github.com/grafana/grafana-plugin-sdk-go/backend"
+	"github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/registry"
+	"github.com/grafana/grafana/pkg/services/apikey"
+	"github.com/grafana/grafana/pkg/services/featuremgmt"
+	"github.com/grafana/grafana/pkg/services/user"
+	"github.com/grafana/grafana/pkg/setting"
+	grpcAuth "github.com/grpc-ecosystem/go-grpc-middleware/auth"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/reflection"
+)
+
+type Provider interface {
+	registry.BackgroundService
+	GetServer() *grpc.Server
+}
+
+type GPRCServerService struct {
+	cfg    *setting.Cfg
+	logger log.Logger
+	server *grpc.Server
+}
+
+func ProvideService(cfg *setting.Cfg, apiKey apikey.Service, userService user.Service) (Provider, error) {
+	s := &GPRCServerService{
+		cfg:    cfg,
+		logger: log.New("grpc-server"),
+	}
+
+	var opts []grpc.ServerOption
+
+	// Default auth is admin token check, but this can be overridden by
+	// services which implement ServiceAuthFuncOverride interface.
+	// See https://github.com/grpc-ecosystem/go-grpc-middleware/blob/master/auth/auth.go#L30.
+	authenticator := newAuthenticator(apiKey, userService)
+	opts = append(opts, []grpc.ServerOption{
+		grpc.StreamInterceptor(grpcAuth.StreamServerInterceptor(authenticator.authenticate)),
+		grpc.UnaryInterceptor(grpcAuth.UnaryServerInterceptor(authenticator.authenticate)),
+	}...)
+
+	if s.cfg.GRPCServerTLSConfig != nil {
+		opts = append(opts, grpc.Creds(credentials.NewTLS(cfg.GRPCServerTLSConfig)))
+	}
+
+	grpcServer := grpc.NewServer(opts...)
+	reflection.Register(grpcServer)
+	s.server = grpcServer
+	return s, nil
+}
+
+func (s *GPRCServerService) Run(ctx context.Context) error {
+	s.logger.Info("Running GRPC server", "address", s.cfg.GRPCServerAddress, "network", s.cfg.GRPCServerNetwork, "tls", s.cfg.GRPCServerTLSConfig != nil)
+
+	listener, err := net.Listen(s.cfg.GRPCServerNetwork, s.cfg.GRPCServerAddress)
+	if err != nil {
+		return fmt.Errorf("GRPC server: failed to listen: %w", err)
+	}
+
+	serveErr := make(chan error, 1)
+	go func() {
+		s.logger.Info("GRPC server: starting")
+		err := s.server.Serve(listener)
+		if err != nil {
+			backend.Logger.Error("GRPC server: failed to serve", "err", err)
+			serveErr <- err
+		}
+	}()
+
+	select {
+	case err := <-serveErr:
+		backend.Logger.Error("GRPC server: failed to serve", "err", err)
+		return err
+	case <-ctx.Done():
+	}
+	s.logger.Warn("GRPC server: shutting down")
+	s.server.Stop()
+	return ctx.Err()
+}
+
+func (s *GPRCServerService) IsDisabled() bool {
+	if s.cfg == nil {
+		return true
+	}
+	return !s.cfg.IsFeatureToggleEnabled(featuremgmt.FlagGrpcServer)
+}
+
+func (s *GPRCServerService) GetServer() *grpc.Server {
+	return s.server
+}