[full-ci] enhancement: use reva client pool selectors (#6452)

* enhancement: use reva client pool selectors

register mock service to registry and pass tests

* enhancement: bump reva

* Fix a couple of linter issues

---------

Co-authored-by: Ralf Haferkamp <rhaferkamp@owncloud.com>

services/graph/pkg/identity/cs3.go

@@ -5,12 +5,12 @@ import (
 	"net/url"
 
 	"github.com/CiscoM31/godata"
+	gateway "github.com/cs3org/go-cs3apis/cs3/gateway/v1beta1"
 	cs3group "github.com/cs3org/go-cs3apis/cs3/identity/group/v1beta1"
 	cs3user "github.com/cs3org/go-cs3apis/cs3/identity/user/v1beta1"
 	cs3rpc "github.com/cs3org/go-cs3apis/cs3/rpc/v1beta1"
 	"github.com/cs3org/reva/v2/pkg/rgrpc/todo/pool"
 	libregraph "github.com/owncloud/libre-graph-api-go"
-
 	"github.com/owncloud/ocis/v2/ocis-pkg/log"
 	"github.com/owncloud/ocis/v2/ocis-pkg/shared"
 	"github.com/owncloud/ocis/v2/services/graph/pkg/service/v0/errorcode"
@@ -21,8 +21,9 @@ var (
 )
 
 type CS3 struct {
-	Config *shared.Reva
-	Logger *log.Logger
+	Config          *shared.Reva
+	Logger          *log.Logger
+	GatewaySelector pool.Selectable[gateway.GatewayAPIClient]
 }
 
 // CreateUser implements the Backend Interface. It's currently not supported for the CS3 backend
@@ -44,13 +45,13 @@ func (i *CS3) UpdateUser(ctx context.Context, nameOrID string, user libregraph.U
 func (i *CS3) GetUser(ctx context.Context, userID string, _ *godata.GoDataRequest) (*libregraph.User, error) {
 	logger := i.Logger.SubloggerWithRequestID(ctx)
 	logger.Debug().Str("backend", "cs3").Msg("GetUser")
-	client, err := pool.GetGatewayServiceClient(i.Config.Address, i.Config.GetRevaOptions()...)
+	gatewayClient, err := i.GatewaySelector.Next()
 	if err != nil {
-		logger.Error().Str("backend", "cs3").Err(err).Msg("could not get client")
+		logger.Error().Str("backend", "cs3").Err(err).Msg("could not get gatewayClient")
 		return nil, errorcode.New(errorcode.ServiceNotAvailable, err.Error())
 	}
 
-	res, err := client.GetUserByClaim(ctx, &cs3user.GetUserByClaimRequest{
+	res, err := gatewayClient.GetUserByClaim(ctx, &cs3user.GetUserByClaimRequest{
 		Claim: "userid", // FIXME add consts to reva
 		Value: userID,
 	})
@@ -73,9 +74,9 @@ func (i *CS3) GetUser(ctx context.Context, userID string, _ *godata.GoDataReques
 func (i *CS3) GetUsers(ctx context.Context, oreq *godata.GoDataRequest) ([]*libregraph.User, error) {
 	logger := i.Logger.SubloggerWithRequestID(ctx)
 	logger.Debug().Str("backend", "cs3").Msg("GetUsers")
-	client, err := pool.GetGatewayServiceClient(i.Config.Address, i.Config.GetRevaOptions()...)
+	gatewayClient, err := i.GatewaySelector.Next()
 	if err != nil {
-		logger.Error().Str("backend", "cs3").Err(err).Msg("could not get client")
+		logger.Error().Str("backend", "cs3").Err(err).Msg("could not get gatewayClient")
 		return nil, errorcode.New(errorcode.ServiceNotAvailable, err.Error())
 	}
 
@@ -84,7 +85,7 @@ func (i *CS3) GetUsers(ctx context.Context, oreq *godata.GoDataRequest) ([]*libr
 		return nil, err
 	}
 
-	res, err := client.FindUsers(ctx, &cs3user.FindUsersRequest{
+	res, err := gatewayClient.FindUsers(ctx, &cs3user.FindUsersRequest{
 		// FIXME presence match is currently not implemented, an empty search currently leads to
 		// Unwilling To Perform": Search Error: error parsing filter: (&(objectclass=posixAccount)(|(cn=*)(displayname=*)(mail=*))), error: Present filter match for cn not implemented
 		Filter: search,
@@ -114,9 +115,9 @@ func (i *CS3) GetUsers(ctx context.Context, oreq *godata.GoDataRequest) ([]*libr
 func (i *CS3) GetGroups(ctx context.Context, queryParam url.Values) ([]*libregraph.Group, error) {
 	logger := i.Logger.SubloggerWithRequestID(ctx)
 	logger.Debug().Str("backend", "cs3").Msg("GetGroups")
-	client, err := pool.GetGatewayServiceClient(i.Config.Address, i.Config.GetRevaOptions()...)
+	gatewayClient, err := i.GatewaySelector.Next()
 	if err != nil {
-		logger.Error().Str("backend", "cs3").Err(err).Msg("could not get client")
+		logger.Error().Str("backend", "cs3").Err(err).Msg("could not get gatewayClient")
 		return nil, errorcode.New(errorcode.ServiceNotAvailable, err.Error())
 	}
 
@@ -125,7 +126,7 @@ func (i *CS3) GetGroups(ctx context.Context, queryParam url.Values) ([]*libregra
 		search = queryParam.Get("$search")
 	}
 
-	res, err := client.FindGroups(ctx, &cs3group.FindGroupsRequest{
+	res, err := gatewayClient.FindGroups(ctx, &cs3group.FindGroupsRequest{
 		// FIXME presence match is currently not implemented, an empty search currently leads to
 		// Unwilling To Perform": Search Error: error parsing filter: (&(objectclass=posixAccount)(|(cn=*)(displayname=*)(mail=*))), error: Present filter match for cn not implemented
 		Filter: search,
@@ -161,13 +162,13 @@ func (i *CS3) CreateGroup(ctx context.Context, group libregraph.Group) (*libregr
 func (i *CS3) GetGroup(ctx context.Context, groupID string, queryParam url.Values) (*libregraph.Group, error) {
 	logger := i.Logger.SubloggerWithRequestID(ctx)
 	logger.Debug().Str("backend", "cs3").Msg("GetGroup")
-	client, err := pool.GetGatewayServiceClient(i.Config.Address, i.Config.GetRevaOptions()...)
+	gatewayClient, err := i.GatewaySelector.Next()
 	if err != nil {
-		logger.Error().Str("backend", "cs3").Err(err).Msg("could not get client")
+		logger.Error().Str("backend", "cs3").Err(err).Msg("could not get gatewayClient")
 		return nil, errorcode.New(errorcode.ServiceNotAvailable, err.Error())
 	}
 
-	res, err := client.GetGroupByClaim(ctx, &cs3group.GetGroupByClaimRequest{
+	res, err := gatewayClient.GetGroupByClaim(ctx, &cs3group.GetGroupByClaimRequest{
 		Claim: "groupid", // FIXME add consts to reva
 		Value: groupID,
 	})

services/graph/pkg/server/http/server.go

@@ -17,6 +17,7 @@ import (
 	ociscrypto "github.com/owncloud/ocis/v2/ocis-pkg/crypto"
 	"github.com/owncloud/ocis/v2/ocis-pkg/keycloak"
 	"github.com/owncloud/ocis/v2/ocis-pkg/middleware"
+	"github.com/owncloud/ocis/v2/ocis-pkg/registry"
 	"github.com/owncloud/ocis/v2/ocis-pkg/service/grpc"
 	"github.com/owncloud/ocis/v2/ocis-pkg/service/http"
 	"github.com/owncloud/ocis/v2/ocis-pkg/version"
@@ -114,7 +115,7 @@ func Server(opts ...Option) (http.Service, error) {
 	// how do we secure the api?
 	var requireAdminMiddleware func(stdhttp.Handler) stdhttp.Handler
 	var roleService svc.RoleService
-	var gatewayClient gateway.GatewayAPIClient
+	var gatewaySelector pool.Selectable[gateway.GatewayAPIClient]
 	grpcClient, err := grpc.NewClient(append(grpc.GetClientOptions(options.Config.GRPCClientTLS), grpc.WithTraceProvider(tracing.TraceProvider))...)
 	if err != nil {
 		return http.Service{}, err
@@ -126,9 +127,9 @@ func Server(opts ...Option) (http.Service, error) {
 				account.JWTSecret(options.Config.TokenManager.JWTSecret),
 			))
 		roleService = settingssvc.NewRoleService("com.owncloud.api.settings", grpcClient)
-		gatewayClient, err = pool.GetGatewayServiceClient(options.Config.Reva.Address, options.Config.Reva.GetRevaOptions()...)
+		gatewaySelector, err = pool.GatewaySelector(options.Config.Reva.Address, append(options.Config.Reva.GetRevaOptions(), pool.WithRegistry(registry.GetRegistry()))...)
 		if err != nil {
-			return http.Service{}, errors.Wrap(err, "could not initialize gateway client")
+			return http.Service{}, errors.Wrap(err, "could not initialize gateway selector")
 		}
 	} else {
 		middlewares = append(middlewares, graphMiddleware.Token(options.Config.HTTP.APIToken))
@@ -159,7 +160,7 @@ func Server(opts ...Option) (http.Service, error) {
 		svc.EventsPublisher(publisher),
 		svc.WithRoleService(roleService),
 		svc.WithRequireAdminMiddleware(requireAdminMiddleware),
-		svc.WithGatewayClient(gatewayClient),
+		svc.WithGatewaySelector(gatewaySelector),
 		svc.WithSearchService(searchsvc.NewSearchProviderService("com.owncloud.api.search", grpcClient)),
 		svc.KeycloakClient(keyCloakClient),
 		svc.EventHistoryClient(hClient),

services/graph/pkg/service/v0/application_test.go

@@ -7,13 +7,13 @@ import (
 	"net/http"
 	"net/http/httptest"
 
+	gateway "github.com/cs3org/go-cs3apis/cs3/gateway/v1beta1"
+	"github.com/cs3org/reva/v2/pkg/rgrpc/todo/pool"
+	cs3mocks "github.com/cs3org/reva/v2/tests/cs3mocks/mocks"
 	"github.com/go-chi/chi/v5"
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
 	libregraph "github.com/owncloud/libre-graph-api-go"
-	"github.com/stretchr/testify/mock"
-
-	cs3mocks "github.com/cs3org/reva/v2/tests/cs3mocks/mocks"
 	ogrpc "github.com/owncloud/ocis/v2/ocis-pkg/service/grpc"
 	"github.com/owncloud/ocis/v2/ocis-pkg/shared"
 	settingsmsg "github.com/owncloud/ocis/v2/protogen/gen/ocis/messages/settings/v0"
@@ -23,6 +23,8 @@ import (
 	"github.com/owncloud/ocis/v2/services/graph/pkg/config/defaults"
 	identitymocks "github.com/owncloud/ocis/v2/services/graph/pkg/identity/mocks"
 	service "github.com/owncloud/ocis/v2/services/graph/pkg/service/v0"
+	"github.com/stretchr/testify/mock"
+	"google.golang.org/grpc"
 )
 
 type applicationList struct {
@@ -35,6 +37,7 @@ var _ = Describe("Applications", func() {
 		ctx             context.Context
 		cfg             *config.Config
 		gatewayClient   *cs3mocks.GatewayAPIClient
+		gatewaySelector pool.Selectable[gateway.GatewayAPIClient]
 		eventsPublisher mocks.Publisher
 		roleService     *mocks.RoleService
 		identityBackend *identitymocks.Backend
@@ -47,7 +50,16 @@ var _ = Describe("Applications", func() {
 
 		identityBackend = &identitymocks.Backend{}
 		roleService = &mocks.RoleService{}
+
+		pool.RemoveSelector("GatewaySelector" + "com.owncloud.api.gateway")
 		gatewayClient = &cs3mocks.GatewayAPIClient{}
+		gatewaySelector = pool.GetSelector[gateway.GatewayAPIClient](
+			"GatewaySelector",
+			"com.owncloud.api.gateway",
+			func(cc *grpc.ClientConn) gateway.GatewayAPIClient {
+				return gatewayClient
+			},
+		)
 
 		rr = httptest.NewRecorder()
 		ctx = context.Background()
@@ -62,7 +74,7 @@ var _ = Describe("Applications", func() {
 		_ = ogrpc.Configure(ogrpc.GetClientOptions(cfg.GRPCClientTLS)...)
 		svc, _ = service.NewService(
 			service.Config(cfg),
-			service.WithGatewayClient(gatewayClient),
+			service.WithGatewaySelector(gatewaySelector),
 			service.EventsPublisher(&eventsPublisher),
 			service.WithIdentityBackend(identityBackend),
 			service.WithRoleService(roleService),

services/graph/pkg/service/v0/approleassignments_test.go

@@ -8,15 +8,15 @@ import (
 	"net/http"
 	"net/http/httptest"
 
+	gateway "github.com/cs3org/go-cs3apis/cs3/gateway/v1beta1"
 	userv1beta1 "github.com/cs3org/go-cs3apis/cs3/identity/user/v1beta1"
 	revactx "github.com/cs3org/reva/v2/pkg/ctx"
+	"github.com/cs3org/reva/v2/pkg/rgrpc/todo/pool"
 	cs3mocks "github.com/cs3org/reva/v2/tests/cs3mocks/mocks"
 	"github.com/go-chi/chi/v5"
 	"github.com/golang/protobuf/ptypes/empty"
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
-	"github.com/stretchr/testify/mock"
-
 	libregraph "github.com/owncloud/libre-graph-api-go"
 	ogrpc "github.com/owncloud/ocis/v2/ocis-pkg/service/grpc"
 	"github.com/owncloud/ocis/v2/ocis-pkg/shared"
@@ -27,6 +27,8 @@ import (
 	"github.com/owncloud/ocis/v2/services/graph/pkg/config/defaults"
 	identitymocks "github.com/owncloud/ocis/v2/services/graph/pkg/identity/mocks"
 	service "github.com/owncloud/ocis/v2/services/graph/pkg/service/v0"
+	"github.com/stretchr/testify/mock"
+	"google.golang.org/grpc"
 )
 
 type assignmentList struct {
@@ -39,6 +41,7 @@ var _ = Describe("AppRoleAssignments", func() {
 		ctx             context.Context
 		cfg             *config.Config
 		gatewayClient   *cs3mocks.GatewayAPIClient
+		gatewaySelector pool.Selectable[gateway.GatewayAPIClient]
 		eventsPublisher mocks.Publisher
 		roleService     *mocks.RoleService
 		identityBackend *identitymocks.Backend
@@ -57,7 +60,16 @@ var _ = Describe("AppRoleAssignments", func() {
 
 		identityBackend = &identitymocks.Backend{}
 		roleService = &mocks.RoleService{}
+
+		pool.RemoveSelector("GatewaySelector" + "com.owncloud.api.gateway")
 		gatewayClient = &cs3mocks.GatewayAPIClient{}
+		gatewaySelector = pool.GetSelector[gateway.GatewayAPIClient](
+			"GatewaySelector",
+			"com.owncloud.api.gateway",
+			func(cc *grpc.ClientConn) gateway.GatewayAPIClient {
+				return gatewayClient
+			},
+		)
 
 		rr = httptest.NewRecorder()
 		ctx = context.Background()
@@ -72,7 +84,7 @@ var _ = Describe("AppRoleAssignments", func() {
 		_ = ogrpc.Configure(ogrpc.GetClientOptions(cfg.GRPCClientTLS)...)
 		svc, _ = service.NewService(
 			service.Config(cfg),
-			service.WithGatewayClient(gatewayClient),
+			service.WithGatewaySelector(gatewaySelector),
 			service.EventsPublisher(&eventsPublisher),
 			service.WithIdentityBackend(identityBackend),
 			service.WithRoleService(roleService),

services/graph/pkg/service/v0/driveitems.go

@@ -25,9 +25,14 @@ func (g Graph) GetRootDriveChildren(w http.ResponseWriter, r *http.Request) {
 	g.logger.Info().Msg("Calling GetRootDriveChildren")
 	ctx := r.Context()
 
-	client := g.GetGatewayClient()
+	gatewayClient, err := g.gatewaySelector.Next()
+	if err != nil {
+		g.logger.Error().Err(err).Msg("could not select next gateway client")
+		errorcode.ServiceNotAvailable.Render(w, r, http.StatusInternalServerError, "could not select next gateway client, aborting")
+		return
+	}
 
-	res, err := client.GetHome(ctx, &storageprovider.GetHomeRequest{})
+	res, err := gatewayClient.GetHome(ctx, &storageprovider.GetHomeRequest{})
 	switch {
 	case err != nil:
 		g.logger.Error().Err(err).Msg("error sending get home grpc request")
@@ -43,7 +48,7 @@ func (g Graph) GetRootDriveChildren(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	lRes, err := client.ListContainer(ctx, &storageprovider.ListContainerRequest{
+	lRes, err := gatewayClient.ListContainer(ctx, &storageprovider.ListContainerRequest{
 		Ref: &storageprovider.Reference{
 			Path: res.Path,
 		},
@@ -80,9 +85,12 @@ func (g Graph) GetRootDriveChildren(w http.ResponseWriter, r *http.Request) {
 }
 
 func (g Graph) getDriveItem(ctx context.Context, ref storageprovider.Reference) (*libregraph.DriveItem, error) {
-	client := g.GetGatewayClient()
+	gatewayClient, err := g.gatewaySelector.Next()
+	if err != nil {
+		return nil, err
+	}
 
-	res, err := client.Stat(ctx, &storageprovider.StatRequest{Ref: &ref})
+	res, err := gatewayClient.Stat(ctx, &storageprovider.StatRequest{Ref: &ref})
 	if err != nil {
 		return nil, err
 	}
@@ -94,12 +102,15 @@ func (g Graph) getDriveItem(ctx context.Context, ref storageprovider.Reference)
 }
 
 func (g Graph) getRemoteItem(ctx context.Context, root *storageprovider.ResourceId, baseURL *url.URL) (*libregraph.RemoteItem, error) {
-	client := g.GetGatewayClient()
+	gatewayClient, err := g.gatewaySelector.Next()
+	if err != nil {
+		return nil, err
+	}
 
 	ref := &storageprovider.Reference{
 		ResourceId: root,
 	}
-	res, err := client.Stat(ctx, &storageprovider.StatRequest{Ref: ref})
+	res, err := gatewayClient.Stat(ctx, &storageprovider.StatRequest{Ref: ref})
 	if err != nil {
 		return nil, err
 	}
@@ -204,8 +215,12 @@ func cs3ResourceToRemoteItem(res *storageprovider.ResourceInfo) (*libregraph.Rem
 }
 
 func (g Graph) getPathForResource(ctx context.Context, id storageprovider.ResourceId) (string, error) {
-	client := g.GetGatewayClient()
-	res, err := client.GetPath(ctx, &storageprovider.GetPathRequest{ResourceId: &id})
+	gatewayClient, err := g.gatewaySelector.Next()
+	if err != nil {
+		return "", err
+	}
+
+	res, err := gatewayClient.GetPath(ctx, &storageprovider.GetPathRequest{ResourceId: &id})
 	if err != nil {
 		return "", err
 	}

services/graph/pkg/service/v0/driveitems_test.go

@@ -8,14 +8,14 @@ import (
 	"net/http/httptest"
 	"time"
 
+	gateway "github.com/cs3org/go-cs3apis/cs3/gateway/v1beta1"
 	provider "github.com/cs3org/go-cs3apis/cs3/storage/provider/v1beta1"
 	"github.com/cs3org/reva/v2/pkg/rgrpc/status"
+	"github.com/cs3org/reva/v2/pkg/rgrpc/todo/pool"
 	"github.com/cs3org/reva/v2/pkg/utils"
 	cs3mocks "github.com/cs3org/reva/v2/tests/cs3mocks/mocks"
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
-	"github.com/stretchr/testify/mock"
-
 	libregraph "github.com/owncloud/libre-graph-api-go"
 	ogrpc "github.com/owncloud/ocis/v2/ocis-pkg/service/grpc"
 	"github.com/owncloud/ocis/v2/ocis-pkg/shared"
@@ -24,6 +24,8 @@ import (
 	"github.com/owncloud/ocis/v2/services/graph/pkg/config/defaults"
 	identitymocks "github.com/owncloud/ocis/v2/services/graph/pkg/identity/mocks"
 	service "github.com/owncloud/ocis/v2/services/graph/pkg/service/v0"
+	"github.com/stretchr/testify/mock"
+	"google.golang.org/grpc"
 )
 
 type itemsList struct {
@@ -36,6 +38,7 @@ var _ = Describe("Driveitems", func() {
 		ctx             context.Context
 		cfg             *config.Config
 		gatewayClient   *cs3mocks.GatewayAPIClient
+		gatewaySelector pool.Selectable[gateway.GatewayAPIClient]
 		eventsPublisher mocks.Publisher
 		identityBackend *identitymocks.Backend
 
@@ -49,8 +52,17 @@ var _ = Describe("Driveitems", func() {
 
 		rr = httptest.NewRecorder()
 
-		identityBackend = &identitymocks.Backend{}
+		pool.RemoveSelector("GatewaySelector" + "com.owncloud.api.gateway")
 		gatewayClient = &cs3mocks.GatewayAPIClient{}
+		gatewaySelector = pool.GetSelector[gateway.GatewayAPIClient](
+			"GatewaySelector",
+			"com.owncloud.api.gateway",
+			func(cc *grpc.ClientConn) gateway.GatewayAPIClient {
+				return gatewayClient
+			},
+		)
+
+		identityBackend = &identitymocks.Backend{}
 		newGroup = libregraph.NewGroup()
 		newGroup.SetMembersodataBind([]string{"/users/user1"})
 		newGroup.SetId("group1")
@@ -67,7 +79,7 @@ var _ = Describe("Driveitems", func() {
 		_ = ogrpc.Configure(ogrpc.GetClientOptions(cfg.GRPCClientTLS)...)
 		svc, _ = service.NewService(
 			service.Config(cfg),
-			service.WithGatewayClient(gatewayClient),
+			service.WithGatewaySelector(gatewaySelector),
 			service.EventsPublisher(&eventsPublisher),
 			service.WithIdentityBackend(identityBackend),
 		)

services/graph/pkg/service/v0/drives.go

@@ -261,7 +261,13 @@ func (g Graph) CreateDrive(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	client := g.GetGatewayClient()
+	gatewayClient, err := g.gatewaySelector.Next()
+	if err != nil {
+		logger.Error().Err(err).Msg("could not select next gateway client")
+		errorcode.ServiceNotAvailable.Render(w, r, http.StatusInternalServerError, "could not select next gateway client, aborting")
+		return
+	}
+
 	drive := libregraph.Drive{}
 	if err := StrictJSONUnmarshal(r.Body, &drive); err != nil {
 		logger.Debug().Err(err).Interface("body", r.Body).Msg("could not create drive: invalid body schema definition")
@@ -306,7 +312,7 @@ func (g Graph) CreateDrive(w http.ResponseWriter, r *http.Request) {
 		csr.Owner = us
 	}
 
-	resp, err := client.CreateStorageSpace(r.Context(), &csr)
+	resp, err := gatewayClient.CreateStorageSpace(r.Context(), &csr)
 	if err != nil {
 		logger.Error().Err(err).Msg("could not create drive: transport error")
 		errorcode.GeneralException.Render(w, r, http.StatusInternalServerError, err.Error())
@@ -374,7 +380,12 @@ func (g Graph) UpdateDrive(w http.ResponseWriter, r *http.Request) {
 	}
 	root := &rid
 
-	client := g.GetGatewayClient()
+	gatewayClient, err := g.gatewaySelector.Next()
+	if err != nil {
+		g.logger.Error().Err(err).Msg("could not select next gateway client")
+		errorcode.ServiceNotAvailable.Render(w, r, http.StatusInternalServerError, "could not select next gateway client, aborting")
+		return
+	}
 
 	updateSpaceRequest := &storageprovider.UpdateStorageSpaceRequest{
 		// Prepare the object to apply the diff from. The properties on StorageSpace will overwrite
@@ -459,7 +470,7 @@ func (g Graph) UpdateDrive(w http.ResponseWriter, r *http.Request) {
 	}
 
 	logger.Debug().Interface("payload", updateSpaceRequest).Msg("calling update space on backend")
-	resp, err := client.UpdateStorageSpace(r.Context(), updateSpaceRequest)
+	resp, err := gatewayClient.UpdateStorageSpace(r.Context(), updateSpaceRequest)
 	if err != nil {
 		logger.Error().Err(err).Msg("could not update drive: transport error")
 		errorcode.GeneralException.Render(w, r, http.StatusInternalServerError, "transport error")
@@ -581,7 +592,10 @@ func (g Graph) formatDrives(ctx context.Context, baseURL *url.URL, storageSpaces
 
 // ListStorageSpacesWithFilters List Storage Spaces using filters
 func (g Graph) ListStorageSpacesWithFilters(ctx context.Context, filters []*storageprovider.ListStorageSpacesRequest_Filter, unrestricted bool) (*storageprovider.ListStorageSpacesResponse, error) {
-	client := g.GetGatewayClient()
+	gatewayClient, err := g.gatewaySelector.Next()
+	if err != nil {
+		return nil, err
+	}
 
 	grpcClient, err := grpc.NewClient(append(grpc.GetClientOptions(g.config.GRPCClientTLS), grpc.WithTraceProvider(gtracing.TraceProvider))...)
 	if err != nil {
@@ -615,7 +629,7 @@ func (g Graph) ListStorageSpacesWithFilters(ctx context.Context, filters []*stor
 		}},
 		Filters: filters,
 	}
-	res, err := client.ListStorageSpaces(ctx, lReq)
+	res, err := gatewayClient.ListStorageSpaces(ctx, lReq)
 	return res, err
 }
 
@@ -858,7 +872,10 @@ func (g Graph) getDriveQuota(ctx context.Context, space *storageprovider.Storage
 	if noQuotaInOpaque {
 		// we have to make a trip to the storage
 		// TODO only if quota property was requested
-		client := g.GetGatewayClient()
+		gatewayClient, err := g.gatewaySelector.Next()
+		if err != nil {
+			return libregraph.Quota{}, err
+		}
 
 		req := &gateway.GetQuotaRequest{
 			Ref: &storageprovider.Reference{
@@ -866,7 +883,8 @@ func (g Graph) getDriveQuota(ctx context.Context, space *storageprovider.Storage
 				Path:       ".",
 			},
 		}
-		res, err := client.GetQuota(ctx, req)
+
+		res, err := gatewayClient.GetQuota(ctx, req)
 		switch {
 		case err != nil:
 			logger.Error().Err(err).Interface("ref", req.Ref).Msg("could not call GetQuota: transport error")
@@ -1041,8 +1059,8 @@ func (g Graph) DeleteDrive(w http.ResponseWriter, r *http.Request) {
 			},
 		}
 	}
-
-	dRes, err := g.gatewayClient.DeleteStorageSpace(r.Context(), &storageprovider.DeleteStorageSpaceRequest{
+	gatewayClient, _ := g.gatewaySelector.Next()
+	dRes, err := gatewayClient.DeleteStorageSpace(r.Context(), &storageprovider.DeleteStorageSpaceRequest{
 		Opaque: opaque,
 		Id: &storageprovider.StorageSpaceId{
 			OpaqueId: storagespace.FormatResourceID(rid),

services/graph/pkg/service/v0/educationclasses_test.go

@@ -9,14 +9,14 @@ import (
 	"net/http"
 	"net/http/httptest"
 
+	gateway "github.com/cs3org/go-cs3apis/cs3/gateway/v1beta1"
 	userv1beta1 "github.com/cs3org/go-cs3apis/cs3/identity/user/v1beta1"
 	revactx "github.com/cs3org/reva/v2/pkg/ctx"
+	"github.com/cs3org/reva/v2/pkg/rgrpc/todo/pool"
 	cs3mocks "github.com/cs3org/reva/v2/tests/cs3mocks/mocks"
 	"github.com/go-chi/chi/v5"
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
-	"github.com/test-go/testify/mock"
-
 	libregraph "github.com/owncloud/libre-graph-api-go"
 	"github.com/owncloud/ocis/v2/ocis-pkg/log"
 	ogrpc "github.com/owncloud/ocis/v2/ocis-pkg/service/grpc"
@@ -27,6 +27,8 @@ import (
 	identitymocks "github.com/owncloud/ocis/v2/services/graph/pkg/identity/mocks"
 	service "github.com/owncloud/ocis/v2/services/graph/pkg/service/v0"
 	"github.com/owncloud/ocis/v2/services/graph/pkg/service/v0/errorcode"
+	"github.com/test-go/testify/mock"
+	"google.golang.org/grpc"
 )
 
 var _ = Describe("EducationClass", func() {
@@ -35,6 +37,7 @@ var _ = Describe("EducationClass", func() {
 		ctx                      context.Context
 		cfg                      *config.Config
 		gatewayClient            *cs3mocks.GatewayAPIClient
+		gatewaySelector          pool.Selectable[gateway.GatewayAPIClient]
 		eventsPublisher          mocks.Publisher
 		identityBackend          *identitymocks.Backend
 		identityEducationBackend *identitymocks.EducationBackend
@@ -52,9 +55,18 @@ var _ = Describe("EducationClass", func() {
 	BeforeEach(func() {
 		eventsPublisher.On("Publish", mock.Anything, mock.Anything, mock.Anything).Return(nil)
 
+		pool.RemoveSelector("GatewaySelector" + "com.owncloud.api.gateway")
+		gatewayClient = &cs3mocks.GatewayAPIClient{}
+		gatewaySelector = pool.GetSelector[gateway.GatewayAPIClient](
+			"GatewaySelector",
+			"com.owncloud.api.gateway",
+			func(cc *grpc.ClientConn) gateway.GatewayAPIClient {
+				return gatewayClient
+			},
+		)
+
 		identityEducationBackend = &identitymocks.EducationBackend{}
 		identityBackend = &identitymocks.Backend{}
-		gatewayClient = &cs3mocks.GatewayAPIClient{}
 		newClass = libregraph.NewEducationClass("math", "course")
 		newClass.SetMembersodataBind([]string{"/users/user1"})
 		newClass.SetId("math")
@@ -71,7 +83,7 @@ var _ = Describe("EducationClass", func() {
 		_ = ogrpc.Configure(ogrpc.GetClientOptions(cfg.GRPCClientTLS)...)
 		svc, _ = service.NewService(
 			service.Config(cfg),
-			service.WithGatewayClient(gatewayClient),
+			service.WithGatewaySelector(gatewaySelector),
 			service.EventsPublisher(&eventsPublisher),
 			service.WithIdentityBackend(identityBackend),
 			service.WithIdentityEducationBackend(identityEducationBackend),
@@ -320,7 +332,7 @@ var _ = Describe("EducationClass", func() {
 				cfg.API.GroupMembersPatchLimit = 21
 				svc, _ = service.NewService(
 					service.Config(cfg),
-					service.WithGatewayClient(gatewayClient),
+					service.WithGatewaySelector(gatewaySelector),
 					service.EventsPublisher(&eventsPublisher),
 					service.WithIdentityBackend(identityBackend),
 					service.WithIdentityEducationBackend(identityEducationBackend),

services/graph/pkg/service/v0/educationschools_test.go

@@ -9,13 +9,16 @@ import (
 	"net/http"
 	"net/http/httptest"
 
+	gateway "github.com/cs3org/go-cs3apis/cs3/gateway/v1beta1"
 	userv1beta1 "github.com/cs3org/go-cs3apis/cs3/identity/user/v1beta1"
 	ctxpkg "github.com/cs3org/reva/v2/pkg/ctx"
+	"github.com/cs3org/reva/v2/pkg/rgrpc/todo/pool"
 	cs3mocks "github.com/cs3org/reva/v2/tests/cs3mocks/mocks"
 	"github.com/go-chi/chi/v5"
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
 	"github.com/test-go/testify/mock"
+	"google.golang.org/grpc"
 
 	libregraph "github.com/owncloud/libre-graph-api-go"
 	ogrpc "github.com/owncloud/ocis/v2/ocis-pkg/service/grpc"
@@ -37,6 +40,7 @@ var _ = Describe("Schools", func() {
 		ctx                      context.Context
 		cfg                      *config.Config
 		gatewayClient            *cs3mocks.GatewayAPIClient
+		gatewaySelector          pool.Selectable[gateway.GatewayAPIClient]
 		identityEducationBackend *identitymocks.EducationBackend
 
 		rr *httptest.ResponseRecorder
@@ -50,8 +54,17 @@ var _ = Describe("Schools", func() {
 	)
 
 	BeforeEach(func() {
-		identityEducationBackend = &identitymocks.EducationBackend{}
+		pool.RemoveSelector("GatewaySelector" + "com.owncloud.api.gateway")
 		gatewayClient = &cs3mocks.GatewayAPIClient{}
+		gatewaySelector = pool.GetSelector[gateway.GatewayAPIClient](
+			"GatewaySelector",
+			"com.owncloud.api.gateway",
+			func(cc *grpc.ClientConn) gateway.GatewayAPIClient {
+				return gatewayClient
+			},
+		)
+
+		identityEducationBackend = &identitymocks.EducationBackend{}
 		newSchool = libregraph.NewEducationSchool()
 		newSchool.SetId("school1")
 
@@ -67,7 +80,7 @@ var _ = Describe("Schools", func() {
 		_ = ogrpc.Configure(ogrpc.GetClientOptions(cfg.GRPCClientTLS)...)
 		svc, _ = service.NewService(
 			service.Config(cfg),
-			service.WithGatewayClient(gatewayClient),
+			service.WithGatewaySelector(gatewaySelector),
 			service.WithIdentityEducationBackend(identityEducationBackend),
 		)
 	})

services/graph/pkg/service/v0/educationuser.go

@@ -239,13 +239,19 @@ func (g Graph) DeleteEducationUser(w http.ResponseWriter, r *http.Request) {
 		e.Executant = currentUser.GetId()
 	}
 
-	if g.gatewayClient != nil {
+	if g.gatewaySelector != nil {
 		logger.Debug().
 			Str("user", user.GetId()).
 			Msg("calling list spaces with user filter to fetch the personal space for deletion")
 		opaque := utils.AppendPlainToOpaque(nil, "unrestricted", "T")
 		f := listStorageSpacesUserFilter(user.GetId())
-		lspr, err := g.gatewayClient.ListStorageSpaces(r.Context(), &storageprovider.ListStorageSpacesRequest{
+		client, err := g.gatewaySelector.Next()
+		if err != nil {
+			logger.Error().Err(err).Msg("could not select next gateway client")
+			errorcode.ServiceNotAvailable.Render(w, r, http.StatusInternalServerError, "could not select next gateway client, aborting")
+			return
+		}
+		lspr, err := client.ListStorageSpaces(r.Context(), &storageprovider.ListStorageSpacesRequest{
 			Opaque:  opaque,
 			Filters: []*storageprovider.ListStorageSpacesRequest_Filter{f},
 		})
@@ -266,7 +272,7 @@ func (g Graph) DeleteEducationUser(w http.ResponseWriter, r *http.Request) {
 			// Deleting a space a two step process (1. disabling/trashing, 2. purging)
 			// Do the "disable/trash" step only if the space is not marked as trashed yet:
 			if _, ok := sp.Opaque.Map["trashed"]; !ok {
-				_, err := g.gatewayClient.DeleteStorageSpace(r.Context(), &storageprovider.DeleteStorageSpaceRequest{
+				_, err := client.DeleteStorageSpace(r.Context(), &storageprovider.DeleteStorageSpaceRequest{
 					Id: &storageprovider.StorageSpaceId{
 						OpaqueId: sp.Id.OpaqueId,
 					},
@@ -278,7 +284,7 @@ func (g Graph) DeleteEducationUser(w http.ResponseWriter, r *http.Request) {
 				}
 			}
 			purgeFlag := utils.AppendPlainToOpaque(nil, "purge", "")
-			_, err := g.gatewayClient.DeleteStorageSpace(r.Context(), &storageprovider.DeleteStorageSpaceRequest{
+			_, err := client.DeleteStorageSpace(r.Context(), &storageprovider.DeleteStorageSpaceRequest{
 				Opaque: purgeFlag,
 				Id: &storageprovider.StorageSpaceId{
 					OpaqueId: sp.Id.OpaqueId,

services/graph/pkg/service/v0/educationuser_test.go

@@ -8,17 +8,17 @@ import (
 	"net/http"
 	"net/http/httptest"
 
+	gateway "github.com/cs3org/go-cs3apis/cs3/gateway/v1beta1"
 	userv1beta1 "github.com/cs3org/go-cs3apis/cs3/identity/user/v1beta1"
 	provider "github.com/cs3org/go-cs3apis/cs3/storage/provider/v1beta1"
 	typesv1beta1 "github.com/cs3org/go-cs3apis/cs3/types/v1beta1"
 	revactx "github.com/cs3org/reva/v2/pkg/ctx"
 	"github.com/cs3org/reva/v2/pkg/rgrpc/status"
+	"github.com/cs3org/reva/v2/pkg/rgrpc/todo/pool"
 	cs3mocks "github.com/cs3org/reva/v2/tests/cs3mocks/mocks"
 	"github.com/go-chi/chi/v5"
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
-	"github.com/stretchr/testify/mock"
-
 	libregraph "github.com/owncloud/libre-graph-api-go"
 	ogrpc "github.com/owncloud/ocis/v2/ocis-pkg/service/grpc"
 	"github.com/owncloud/ocis/v2/ocis-pkg/shared"
@@ -28,6 +28,8 @@ import (
 	"github.com/owncloud/ocis/v2/services/graph/pkg/config/defaults"
 	identitymocks "github.com/owncloud/ocis/v2/services/graph/pkg/identity/mocks"
 	service "github.com/owncloud/ocis/v2/services/graph/pkg/service/v0"
+	"github.com/stretchr/testify/mock"
+	"google.golang.org/grpc"
 )
 
 type educationUserList struct {
@@ -40,6 +42,7 @@ var _ = Describe("EducationUsers", func() {
 		ctx                      context.Context
 		cfg                      *config.Config
 		gatewayClient            *cs3mocks.GatewayAPIClient
+		gatewaySelector          pool.Selectable[gateway.GatewayAPIClient]
 		eventsPublisher          mocks.Publisher
 		roleService              *mocks.RoleService
 		identityEducationBackend *identitymocks.EducationBackend
@@ -56,9 +59,18 @@ var _ = Describe("EducationUsers", func() {
 	BeforeEach(func() {
 		eventsPublisher.On("Publish", mock.Anything, mock.Anything, mock.Anything).Return(nil)
 
+		pool.RemoveSelector("GatewaySelector" + "com.owncloud.api.gateway")
+		gatewayClient = &cs3mocks.GatewayAPIClient{}
+		gatewaySelector = pool.GetSelector[gateway.GatewayAPIClient](
+			"GatewaySelector",
+			"com.owncloud.api.gateway",
+			func(cc *grpc.ClientConn) gateway.GatewayAPIClient {
+				return gatewayClient
+			},
+		)
+
 		identityEducationBackend = &identitymocks.EducationBackend{}
 		roleService = &mocks.RoleService{}
-		gatewayClient = &cs3mocks.GatewayAPIClient{}
 
 		rr = httptest.NewRecorder()
 		ctx = context.Background()
@@ -72,7 +84,7 @@ var _ = Describe("EducationUsers", func() {
 		_ = ogrpc.Configure(ogrpc.GetClientOptions(cfg.GRPCClientTLS)...)
 		svc, _ = service.NewService(
 			service.Config(cfg),
-			service.WithGatewayClient(gatewayClient),
+			service.WithGatewaySelector(gatewaySelector),
 			service.EventsPublisher(&eventsPublisher),
 			service.WithIdentityEducationBackend(identityEducationBackend),
 			service.WithRoleService(roleService),

services/graph/pkg/service/v0/graph.go

@@ -10,6 +10,7 @@ import (
 
 	gateway "github.com/cs3org/go-cs3apis/cs3/gateway/v1beta1"
 	"github.com/cs3org/reva/v2/pkg/events"
+	"github.com/cs3org/reva/v2/pkg/rgrpc/todo/pool"
 	"github.com/go-chi/chi/v5"
 	"github.com/jellydator/ttlcache/v3"
 	libregraph "github.com/owncloud/libre-graph-api-go"
@@ -62,7 +63,7 @@ type Graph struct {
 	logger                   *log.Logger
 	identityBackend          identity.Backend
 	identityEducationBackend identity.EducationBackend
-	gatewayClient            gateway.GatewayAPIClient
+	gatewaySelector          pool.Selectable[gateway.GatewayAPIClient]
 	roleService              RoleService
 	permissionsService       Permissions
 	specialDriveItemsCache   *ttlcache.Cache[string, interface{}]
@@ -86,11 +87,6 @@ func (g Graph) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	g.mux.ServeHTTP(w, r)
 }
 
-// GetGatewayClient returns a gateway client to talk to reva
-func (g Graph) GetGatewayClient() gateway.GatewayAPIClient {
-	return g.gatewayClient
-}
-
 func (g Graph) publishEvent(ev interface{}) {
 	if g.eventsPublisher != nil {
 		if err := events.Publish(g.eventsPublisher, ev); err != nil {

services/graph/pkg/service/v0/graph_suite_test.go

@@ -3,10 +3,24 @@ package svc_test
 import (
 	"testing"
 
+	"github.com/owncloud/ocis/v2/ocis-pkg/registry"
+	mRegistry "go-micro.dev/v4/registry"
+
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
 )
 
+func init() {
+	registry.Configure("memory")
+	r := registry.GetRegistry()
+	service := registry.BuildGRPCService("com.owncloud.api.gateway", "", "", "")
+	service.Nodes = []*mRegistry.Node{{
+		Address: "any",
+	}}
+
+	_ = r.Register(service)
+}
+
 func TestGraph(t *testing.T) {
 	RegisterFailHandler(Fail)
 	RunSpecs(t, "Graph Suite")

services/graph/pkg/service/v0/graph_test.go

@@ -16,13 +16,13 @@ import (
 	typesv1beta1 "github.com/cs3org/go-cs3apis/cs3/types/v1beta1"
 	revactx "github.com/cs3org/reva/v2/pkg/ctx"
 	"github.com/cs3org/reva/v2/pkg/rgrpc/status"
+	"github.com/cs3org/reva/v2/pkg/rgrpc/todo/pool"
 	"github.com/cs3org/reva/v2/pkg/utils"
 	cs3mocks "github.com/cs3org/reva/v2/tests/cs3mocks/mocks"
 	"github.com/go-chi/chi/v5"
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
 	libregraph "github.com/owncloud/libre-graph-api-go"
-	ogrpc "github.com/owncloud/ocis/v2/ocis-pkg/service/grpc"
 	"github.com/owncloud/ocis/v2/ocis-pkg/shared"
 	v0 "github.com/owncloud/ocis/v2/protogen/gen/ocis/messages/settings/v0"
 	settingssvc "github.com/owncloud/ocis/v2/protogen/gen/ocis/services/settings/v0"
@@ -40,6 +40,7 @@ var _ = Describe("Graph", func() {
 	var (
 		svc               service.Service
 		gatewayClient     *cs3mocks.GatewayAPIClient
+		gatewaySelector   pool.Selectable[gateway.GatewayAPIClient]
 		eventsPublisher   mocks.Publisher
 		permissionService mocks.Permissions
 		ctx               context.Context
@@ -63,13 +64,21 @@ var _ = Describe("Graph", func() {
 		cfg.Commons = &shared.Commons{}
 		cfg.GRPCClientTLS = &shared.GRPCClientTLS{}
 
-		_ = ogrpc.Configure(ogrpc.GetClientOptions(cfg.GRPCClientTLS)...)
+		pool.RemoveSelector("GatewaySelector" + "com.owncloud.api.gateway")
 		gatewayClient = &cs3mocks.GatewayAPIClient{}
+		gatewaySelector = pool.GetSelector[gateway.GatewayAPIClient](
+			"GatewaySelector",
+			"com.owncloud.api.gateway",
+			func(cc *grpc.ClientConn) gateway.GatewayAPIClient {
+				return gatewayClient
+			},
+		)
+
 		eventsPublisher = mocks.Publisher{}
 		permissionService = mocks.Permissions{}
 		svc, _ = service.NewService(
 			service.Config(cfg),
-			service.WithGatewayClient(gatewayClient),
+			service.WithGatewaySelector(gatewaySelector),
 			service.EventsPublisher(&eventsPublisher),
 			service.PermissionService(&permissionService),
 		)

services/graph/pkg/service/v0/groups_test.go

@@ -9,14 +9,14 @@ import (
 	"net/http"
 	"net/http/httptest"
 
+	gateway "github.com/cs3org/go-cs3apis/cs3/gateway/v1beta1"
 	userv1beta1 "github.com/cs3org/go-cs3apis/cs3/identity/user/v1beta1"
 	revactx "github.com/cs3org/reva/v2/pkg/ctx"
+	"github.com/cs3org/reva/v2/pkg/rgrpc/todo/pool"
 	cs3mocks "github.com/cs3org/reva/v2/tests/cs3mocks/mocks"
 	"github.com/go-chi/chi/v5"
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
-	"github.com/test-go/testify/mock"
-
 	libregraph "github.com/owncloud/libre-graph-api-go"
 	ogrpc "github.com/owncloud/ocis/v2/ocis-pkg/service/grpc"
 	"github.com/owncloud/ocis/v2/ocis-pkg/shared"
@@ -26,6 +26,8 @@ import (
 	identitymocks "github.com/owncloud/ocis/v2/services/graph/pkg/identity/mocks"
 	service "github.com/owncloud/ocis/v2/services/graph/pkg/service/v0"
 	"github.com/owncloud/ocis/v2/services/graph/pkg/service/v0/errorcode"
+	"github.com/test-go/testify/mock"
+	"google.golang.org/grpc"
 )
 
 type groupList struct {
@@ -38,6 +40,7 @@ var _ = Describe("Groups", func() {
 		ctx             context.Context
 		cfg             *config.Config
 		gatewayClient   *cs3mocks.GatewayAPIClient
+		gatewaySelector pool.Selectable[gateway.GatewayAPIClient]
 		eventsPublisher mocks.Publisher
 		identityBackend *identitymocks.Backend
 
@@ -54,8 +57,17 @@ var _ = Describe("Groups", func() {
 	BeforeEach(func() {
 		eventsPublisher.On("Publish", mock.Anything, mock.Anything, mock.Anything).Return(nil)
 
-		identityBackend = &identitymocks.Backend{}
+		pool.RemoveSelector("GatewaySelector" + "com.owncloud.api.gateway")
 		gatewayClient = &cs3mocks.GatewayAPIClient{}
+		gatewaySelector = pool.GetSelector[gateway.GatewayAPIClient](
+			"GatewaySelector",
+			"com.owncloud.api.gateway",
+			func(cc *grpc.ClientConn) gateway.GatewayAPIClient {
+				return gatewayClient
+			},
+		)
+
+		identityBackend = &identitymocks.Backend{}
 		newGroup = libregraph.NewGroup()
 		newGroup.SetMembersodataBind([]string{"/users/user1"})
 		newGroup.SetId("group1")
@@ -72,7 +84,7 @@ var _ = Describe("Groups", func() {
 		_ = ogrpc.Configure(ogrpc.GetClientOptions(cfg.GRPCClientTLS)...)
 		svc, _ = service.NewService(
 			service.Config(cfg),
-			service.WithGatewayClient(gatewayClient),
+			service.WithGatewaySelector(gatewaySelector),
 			service.EventsPublisher(&eventsPublisher),
 			service.WithIdentityBackend(identityBackend),
 		)
@@ -316,7 +328,7 @@ var _ = Describe("Groups", func() {
 				cfg.API.GroupMembersPatchLimit = 21
 				svc, _ = service.NewService(
 					service.Config(cfg),
-					service.WithGatewayClient(gatewayClient),
+					service.WithGatewaySelector(gatewaySelector),
 					service.EventsPublisher(&eventsPublisher),
 					service.WithIdentityBackend(identityBackend),
 				)

services/graph/pkg/service/v0/option.go

@@ -5,6 +5,7 @@ import (
 
 	gateway "github.com/cs3org/go-cs3apis/cs3/gateway/v1beta1"
 	"github.com/cs3org/reva/v2/pkg/events"
+	"github.com/cs3org/reva/v2/pkg/rgrpc/todo/pool"
 	"github.com/owncloud/ocis/v2/ocis-pkg/keycloak"
 	"github.com/owncloud/ocis/v2/ocis-pkg/log"
 	"github.com/owncloud/ocis/v2/ocis-pkg/roles"
@@ -24,7 +25,7 @@ type Options struct {
 	Config                   *config.Config
 	Middleware               []func(http.Handler) http.Handler
 	RequireAdminMiddleware   func(http.Handler) http.Handler
-	GatewayClient            gateway.GatewayAPIClient
+	GatewaySelector          pool.Selectable[gateway.GatewayAPIClient]
 	IdentityBackend          identity.Backend
 	IdentityEducationBackend identity.EducationBackend
 	RoleService              RoleService
@@ -75,10 +76,10 @@ func WithRequireAdminMiddleware(val func(http.Handler) http.Handler) Option {
 	}
 }
 
-// WithGatewayClient provides a function to set the gateway client option.
-func WithGatewayClient(val gateway.GatewayAPIClient) Option {
+// WithGatewaySelector provides a function to set the gateway client option.
+func WithGatewaySelector(val pool.Selectable[gateway.GatewayAPIClient]) Option {
 	return func(o *Options) {
-		o.GatewayClient = val
+		o.GatewaySelector = val
 	}
 }
 

services/graph/pkg/service/v0/password.go

@@ -61,7 +61,12 @@ func (g Graph) ChangeOwnPassword(w http.ResponseWriter, r *http.Request) {
 		ClientId:     u.Username,
 		ClientSecret: currentPw,
 	}
-	authRes, err := g.gatewayClient.Authenticate(r.Context(), authReq)
+	client, err := g.gatewaySelector.Next()
+	if err != nil {
+		errorcode.ServiceNotAvailable.Render(w, r, http.StatusInternalServerError, "could not select next gateway client, aborting")
+		return
+	}
+	authRes, err := client.Authenticate(r.Context(), authReq)
 	if err != nil {
 		errorcode.ServiceNotAvailable.Render(w, r, http.StatusInternalServerError, err.Error())
 		return

services/graph/pkg/service/v0/password_test.go

@@ -12,6 +12,7 @@ import (
 	userv1beta1 "github.com/cs3org/go-cs3apis/cs3/identity/user/v1beta1"
 	revactx "github.com/cs3org/reva/v2/pkg/ctx"
 	"github.com/cs3org/reva/v2/pkg/rgrpc/status"
+	"github.com/cs3org/reva/v2/pkg/rgrpc/todo/pool"
 	cs3mocks "github.com/cs3org/reva/v2/tests/cs3mocks/mocks"
 	"github.com/go-ldap/ldap/v3"
 	. "github.com/onsi/ginkgo/v2"
@@ -25,12 +26,14 @@ import (
 	"github.com/owncloud/ocis/v2/services/graph/pkg/identity"
 	service "github.com/owncloud/ocis/v2/services/graph/pkg/service/v0"
 	"github.com/stretchr/testify/mock"
+	"google.golang.org/grpc"
 )
 
 var _ = Describe("Users changing their own password", func() {
 	var (
 		svc             service.Service
 		gatewayClient   *cs3mocks.GatewayAPIClient
+		gatewaySelector pool.Selectable[gateway.GatewayAPIClient]
 		ldapClient      *mocks.Client
 		ldapConfig      config.LDAP
 		identityBackend identity.Backend
@@ -47,7 +50,16 @@ var _ = Describe("Users changing their own password", func() {
 		cfg.TokenManager.JWTSecret = "loremipsum"
 		cfg.GRPCClientTLS = &shared.GRPCClientTLS{}
 
+		pool.RemoveSelector("GatewaySelector" + "com.owncloud.api.gateway")
 		gatewayClient = &cs3mocks.GatewayAPIClient{}
+		gatewaySelector = pool.GetSelector[gateway.GatewayAPIClient](
+			"GatewaySelector",
+			"com.owncloud.api.gateway",
+			func(cc *grpc.ClientConn) gateway.GatewayAPIClient {
+				return gatewayClient
+			},
+		)
+
 		ldapClient = mockedLDAPClient()
 
 		ldapConfig = config.LDAP{
@@ -68,7 +80,7 @@ var _ = Describe("Users changing their own password", func() {
 		eventsPublisher = mocks.Publisher{}
 		svc, _ = service.NewService(
 			service.Config(cfg),
-			service.WithGatewayClient(gatewayClient),
+			service.WithGatewaySelector(gatewaySelector),
 			service.WithIdentityBackend(identityBackend),
 			service.EventsPublisher(&eventsPublisher),
 		)

services/graph/pkg/service/v0/personaldata.go

@@ -10,6 +10,8 @@ import (
 	"path/filepath"
 	"strconv"
 
+	"github.com/owncloud/ocis/v2/services/graph/pkg/service/v0/errorcode"
+
 	gateway "github.com/cs3org/go-cs3apis/cs3/gateway/v1beta1"
 	user "github.com/cs3org/go-cs3apis/cs3/identity/user/v1beta1"
 	rpc "github.com/cs3org/go-cs3apis/cs3/rpc/v1beta1"
@@ -68,8 +70,15 @@ func (g Graph) ExportPersonalData(w http.ResponseWriter, r *http.Request) {
 		Path:       loc,
 	}
 
+	gatewayClient, err := g.gatewaySelector.Next()
+	if err != nil {
+		g.logger.Error().Err(err).Msg("could not select next gateway client")
+		errorcode.ServiceNotAvailable.Render(w, r, http.StatusInternalServerError, "could not select next gateway client, aborting")
+		return
+	}
+
 	// touch file
-	if err := mustTouchFile(ctx, ref, g.GetGatewayClient()); err != nil {
+	if err := mustTouchFile(ctx, ref, gatewayClient); err != nil {
 		g.logger.Error().Err(err).Msg("error touching file")
 		w.WriteHeader(http.StatusInternalServerError)
 		return
@@ -83,8 +92,14 @@ func (g Graph) ExportPersonalData(w http.ResponseWriter, r *http.Request) {
 
 // GatherPersonalData will all gather all personal data of the user and save it to a file in the users personal space
 func (g Graph) GatherPersonalData(usr *user.User, ref *provider.Reference, token string, marsh Marshaller) {
+	gatewayClient, err := g.gatewaySelector.Next()
+	if err != nil {
+		g.logger.Error().Err(err).Msg("could not select next gateway client")
+		return
+	}
+
 	// the context might already be cancelled. We need to impersonate the acting user again
-	ctx, err := utils.ImpersonateUser(usr, g.gatewayClient, g.config.MachineAuthAPIKey)
+	ctx, err := utils.ImpersonateUser(usr, gatewayClient, g.config.MachineAuthAPIKey)
 	if err != nil {
 		g.logger.Error().Err(err).Str("userID", usr.GetId().GetOpaqueId()).Msg("cannot impersonate user")
 	}
@@ -141,13 +156,22 @@ func (g Graph) upload(u *user.User, data []byte, ref *provider.Reference, th str
 		Opaque: utils.AppendPlainToOpaque(nil, "Upload-Length", strconv.FormatUint(uint64(len(data)), 10)),
 	}
 
-	gwc := g.GetGatewayClient()
-	ctx, err := utils.ImpersonateUser(u, gwc, g.config.MachineAuthAPIKey)
+	gatewayClient, err := g.gatewaySelector.Next()
+	if err != nil {
+		g.logger.Error().Err(err).Msg("could not select next gateway client")
+		return err
+	}
+
+	ctx, err := utils.ImpersonateUser(u, gatewayClient, g.config.MachineAuthAPIKey)
+	if err != nil {
+		return err
+	}
+	client, err := g.gatewaySelector.Next()
 	if err != nil {
 		return err
 	}
 	ctx = revactx.ContextSetToken(ctx, th)
-	uRes, err := gwc.InitiateFileUpload(ctx, uReq)
+	uRes, err := client.InitiateFileUpload(ctx, uReq)
 	if err != nil {
 		return err
 	}

services/graph/pkg/service/v0/service.go

@@ -10,6 +10,7 @@ import (
 	"strconv"
 	"time"
 
+	"github.com/cs3org/reva/v2/pkg/rgrpc/todo/pool"
 	"github.com/cs3org/reva/v2/pkg/store"
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/chi/v5/middleware"
@@ -17,6 +18,7 @@ import (
 	"github.com/jellydator/ttlcache/v3"
 	libregraph "github.com/owncloud/libre-graph-api-go"
 	ocisldap "github.com/owncloud/ocis/v2/ocis-pkg/ldap"
+	"github.com/owncloud/ocis/v2/ocis-pkg/registry"
 	"github.com/owncloud/ocis/v2/ocis-pkg/roles"
 	"github.com/owncloud/ocis/v2/ocis-pkg/service/grpc"
 	settingssvc "github.com/owncloud/ocis/v2/protogen/gen/ocis/services/settings/v0"
@@ -144,7 +146,7 @@ func NewService(opts ...Option) (Graph, error) {
 		usersCache:               usersCache,
 		groupsCache:              groupsCache,
 		eventsPublisher:          options.EventsPublisher,
-		gatewayClient:            options.GatewayClient,
+		gatewaySelector:          options.GatewaySelector,
 		searchService:            options.SearchService,
 		identityEducationBackend: options.IdentityEducationBackend,
 		keycloakClient:           options.KeycloakClient,
@@ -316,9 +318,18 @@ func setIdentityBackends(options Options, svc *Graph) error {
 	if options.IdentityBackend == nil {
 		switch options.Config.Identity.Backend {
 		case "cs3":
+			gatewaySelector, err := pool.GatewaySelector(
+				options.Config.Reva.Address,
+				append(options.Config.Reva.GetRevaOptions(), pool.WithRegistry(registry.GetRegistry()))...,
+			)
+			if err != nil {
+				return err
+			}
+
 			svc.identityBackend = &identity.CS3{
-				Config: options.Config.Reva,
-				Logger: &options.Logger,
+				Config:          options.Config.Reva,
+				Logger:          &options.Logger,
+				GatewaySelector: gatewaySelector,
 			}
 		case "ldap":
 			var err error

services/graph/pkg/service/v0/tags.go

@@ -66,7 +66,13 @@ func (g Graph) AssignTags(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	sres, err := g.gatewayClient.Stat(ctx, &provider.StatRequest{
+	client, err := g.gatewaySelector.Next()
+	if err != nil {
+		g.logger.Error().Err(err).Msg("error selecting next gateway client")
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+	sres, err := client.Stat(ctx, &provider.StatRequest{
 		Ref: &provider.Reference{ResourceId: &rid},
 	})
 	if err != nil {
@@ -105,7 +111,7 @@ func (g Graph) AssignTags(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	resp, err := g.gatewayClient.SetArbitraryMetadata(ctx, &provider.SetArbitraryMetadataRequest{
+	resp, err := client.SetArbitraryMetadata(ctx, &provider.SetArbitraryMetadataRequest{
 		Ref: &provider.Reference{ResourceId: &rid},
 		ArbitraryMetadata: &provider.ArbitraryMetadata{
 			Metadata: map[string]string{
@@ -155,7 +161,13 @@ func (g Graph) UnassignTags(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	sres, err := g.gatewayClient.Stat(ctx, &provider.StatRequest{
+	client, err := g.gatewaySelector.Next()
+	if err != nil {
+		g.logger.Error().Err(err).Msg("error selecting next gateway client")
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+	sres, err := client.Stat(ctx, &provider.StatRequest{
 		Ref: &provider.Reference{ResourceId: &rid},
 	})
 	if err != nil {
@@ -194,7 +206,7 @@ func (g Graph) UnassignTags(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	resp, err := g.gatewayClient.SetArbitraryMetadata(ctx, &provider.SetArbitraryMetadataRequest{
+	resp, err := client.SetArbitraryMetadata(ctx, &provider.SetArbitraryMetadataRequest{
 		Ref: &provider.Reference{ResourceId: &rid},
 		ArbitraryMetadata: &provider.ArbitraryMetadata{
 			Metadata: map[string]string{

services/graph/pkg/service/v0/users.go

@@ -427,10 +427,18 @@ func (g Graph) GetUser(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 		logger.Debug().Str("id", user.GetId()).Msg("calling list storage spaces with filter")
+
 		// use the unrestricted flag to get all possible spaces
 		// users with the canListAllSpaces permission should see all spaces
+
+		client, err := g.gatewaySelector.Next()
+		if err != nil {
+			logger.Error().Err(err).Msg("error selecting next gateway client")
+			render.Status(r, http.StatusInternalServerError)
+			return
+		}
 		opaque := utils.AppendPlainToOpaque(nil, "unrestricted", "T")
-		lspr, err := g.gatewayClient.ListStorageSpaces(r.Context(), &storageprovider.ListStorageSpacesRequest{
+		lspr, err := client.ListStorageSpaces(r.Context(), &storageprovider.ListStorageSpacesRequest{
 			Opaque:  opaque,
 			Filters: filters,
 		})
@@ -545,13 +553,19 @@ func (g Graph) DeleteUser(w http.ResponseWriter, r *http.Request) {
 		e.Executant = currentUser.GetId()
 	}
 
-	if g.gatewayClient != nil {
+	if g.gatewaySelector != nil {
 		logger.Debug().
 			Str("user", user.GetId()).
 			Msg("calling list spaces with user filter to fetch the personal space for deletion")
 		opaque := utils.AppendPlainToOpaque(nil, "unrestricted", "T")
 		f := listStorageSpacesUserFilter(user.GetId())
-		lspr, err := g.gatewayClient.ListStorageSpaces(r.Context(), &storageprovider.ListStorageSpacesRequest{
+		client, err := g.gatewaySelector.Next()
+		if err != nil {
+			logger.Error().Err(err).Msg("error selecting next gateway client")
+			errorcode.ServiceNotAvailable.Render(w, r, http.StatusInternalServerError, "error selecting next gateway client, aborting")
+			return
+		}
+		lspr, err := client.ListStorageSpaces(r.Context(), &storageprovider.ListStorageSpacesRequest{
 			Opaque:  opaque,
 			Filters: []*storageprovider.ListStorageSpacesRequest_Filter{f},
 		})
@@ -572,7 +586,7 @@ func (g Graph) DeleteUser(w http.ResponseWriter, r *http.Request) {
 			// Deleting a space a two step process (1. disabling/trashing, 2. purging)
 			// Do the "disable/trash" step only if the space is not marked as trashed yet:
 			if _, ok := sp.Opaque.Map["trashed"]; !ok {
-				_, err := g.gatewayClient.DeleteStorageSpace(r.Context(), &storageprovider.DeleteStorageSpaceRequest{
+				_, err := client.DeleteStorageSpace(r.Context(), &storageprovider.DeleteStorageSpaceRequest{
 					Id: &storageprovider.StorageSpaceId{
 						OpaqueId: sp.Id.OpaqueId,
 					},
@@ -584,7 +598,7 @@ func (g Graph) DeleteUser(w http.ResponseWriter, r *http.Request) {
 				}
 			}
 			purgeFlag := utils.AppendPlainToOpaque(nil, "purge", "")
-			_, err := g.gatewayClient.DeleteStorageSpace(r.Context(), &storageprovider.DeleteStorageSpaceRequest{
+			_, err := client.DeleteStorageSpace(r.Context(), &storageprovider.DeleteStorageSpaceRequest{
 				Opaque: purgeFlag,
 				Id: &storageprovider.StorageSpaceId{
 					OpaqueId: sp.Id.OpaqueId,

services/graph/pkg/service/v0/users_test.go

@@ -9,18 +9,17 @@ import (
 	"net/http/httptest"
 	"net/url"
 
+	gateway "github.com/cs3org/go-cs3apis/cs3/gateway/v1beta1"
 	userv1beta1 "github.com/cs3org/go-cs3apis/cs3/identity/user/v1beta1"
 	provider "github.com/cs3org/go-cs3apis/cs3/storage/provider/v1beta1"
 	typesv1beta1 "github.com/cs3org/go-cs3apis/cs3/types/v1beta1"
 	revactx "github.com/cs3org/reva/v2/pkg/ctx"
 	"github.com/cs3org/reva/v2/pkg/rgrpc/status"
+	"github.com/cs3org/reva/v2/pkg/rgrpc/todo/pool"
 	cs3mocks "github.com/cs3org/reva/v2/tests/cs3mocks/mocks"
 	"github.com/go-chi/chi/v5"
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
-	"github.com/stretchr/testify/mock"
-	"go-micro.dev/v4/client"
-
 	libregraph "github.com/owncloud/libre-graph-api-go"
 	ogrpc "github.com/owncloud/ocis/v2/ocis-pkg/service/grpc"
 	"github.com/owncloud/ocis/v2/ocis-pkg/shared"
@@ -31,6 +30,9 @@ import (
 	"github.com/owncloud/ocis/v2/services/graph/pkg/config/defaults"
 	identitymocks "github.com/owncloud/ocis/v2/services/graph/pkg/identity/mocks"
 	service "github.com/owncloud/ocis/v2/services/graph/pkg/service/v0"
+	"github.com/stretchr/testify/mock"
+	"go-micro.dev/v4/client"
+	"google.golang.org/grpc"
 )
 
 type userList struct {
@@ -43,6 +45,7 @@ var _ = Describe("Users", func() {
 		ctx             context.Context
 		cfg             *config.Config
 		gatewayClient   *cs3mocks.GatewayAPIClient
+		gatewaySelector pool.Selectable[gateway.GatewayAPIClient]
 		eventsPublisher mocks.Publisher
 		roleService     *mocks.RoleService
 		identityBackend *identitymocks.Backend
@@ -59,9 +62,18 @@ var _ = Describe("Users", func() {
 	BeforeEach(func() {
 		eventsPublisher.On("Publish", mock.Anything, mock.Anything, mock.Anything).Return(nil)
 
+		pool.RemoveSelector("GatewaySelector" + "com.owncloud.api.gateway")
+		gatewayClient = &cs3mocks.GatewayAPIClient{}
+		gatewaySelector = pool.GetSelector[gateway.GatewayAPIClient](
+			"GatewaySelector",
+			"com.owncloud.api.gateway",
+			func(cc *grpc.ClientConn) gateway.GatewayAPIClient {
+				return gatewayClient
+			},
+		)
+
 		identityBackend = &identitymocks.Backend{}
 		roleService = &mocks.RoleService{}
-		gatewayClient = &cs3mocks.GatewayAPIClient{}
 
 		rr = httptest.NewRecorder()
 		ctx = context.Background()
@@ -76,7 +88,7 @@ var _ = Describe("Users", func() {
 		_ = ogrpc.Configure(ogrpc.GetClientOptions(cfg.GRPCClientTLS)...)
 		svc, _ = service.NewService(
 			service.Config(cfg),
-			service.WithGatewayClient(gatewayClient),
+			service.WithGatewaySelector(gatewaySelector),
 			service.EventsPublisher(&eventsPublisher),
 			service.WithIdentityBackend(identityBackend),
 			service.WithRoleService(roleService),
@@ -681,7 +693,7 @@ var _ = Describe("Users", func() {
 					_ = ogrpc.Configure(ogrpc.GetClientOptions(cfg.GRPCClientTLS)...)
 					localSvc, _ := service.NewService(
 						service.Config(localCfg),
-						service.WithGatewayClient(gatewayClient),
+						service.WithGatewaySelector(gatewaySelector),
 						service.EventsPublisher(&eventsPublisher),
 						service.WithIdentityBackend(identityBackend),
 						service.WithRoleService(roleService),