Get rid of nil filters for nsmgr

pkg/networkservice/chains/nsmgr/fd_chains.go

@@ -21,19 +21,22 @@ package nsmgr
 import (
 	"github.com/networkservicemesh/api/pkg/api/networkservice"
 	"github.com/networkservicemesh/api/pkg/api/registry"
+
+	"github.com/networkservicemesh/sdk/pkg/networkservice/common/null"
+	null_registry "github.com/networkservicemesh/sdk/pkg/registry/common/null"
 )
 
 // newRecvFD - construct a recvfd server
 func newRecvFD() networkservice.NetworkServiceServer {
-	return nil
+	return null.NewServer()
 }
 
 // newSendFDClient - construct a sendfd server
 func newSendFDClient() networkservice.NetworkServiceClient {
-	return nil
+	return null.NewClient()
 }
 
 // newRecvFDEndpointRegistry - construct a registry server
 func newRecvFDEndpointRegistry() registry.NetworkServiceEndpointRegistryServer {
-	return nil
+	return null_registry.NewNetworkServiceEndpointRegistryServer()
 }

pkg/networkservice/chains/nsmgr/server.go

@@ -107,74 +107,38 @@ func NewServer(ctx context.Context, nsmRegistration *registryapi.NetworkServiceE
 		nsmRegistration.Name,
 		authzServer,
 		tokenGenerator,
-		nilFilter(
-			discover.NewServer(nsClient, nseClient),
-			roundrobin.NewServer(),
-			localbypass.NewServer(&localbypassRegistryServer),
-			excludedprefixes.NewServer(ctx),
-			newRecvFD(), // Receive any files passed
-			interpose.NewServer(nsmRegistration.Name, &interposeRegistry),
-			filtermechanisms.NewServer(&urlsRegistryServer),
-			connect.NewServer(
-				ctx,
-				client.NewClientFactory(nsmRegistration.Name,
-					addressof.NetworkServiceClient(
-						adapters.NewServerToClient(rv)),
-					tokenGenerator,
-					nilClientFilter(
-						newSendFDClient(), // Send passed files.
-					)...,
-				),
-				clientDialOptions...),
-		)...,
+		discover.NewServer(nsClient, nseClient),
+		roundrobin.NewServer(),
+		localbypass.NewServer(&localbypassRegistryServer),
+		excludedprefixes.NewServer(ctx),
+		newRecvFD(), // Receive any files passed
+		interpose.NewServer(nsmRegistration.Name, &interposeRegistry),
+		filtermechanisms.NewServer(&urlsRegistryServer),
+		connect.NewServer(
+			ctx,
+			client.NewClientFactory(nsmRegistration.Name,
+				addressof.NetworkServiceClient(
+					adapters.NewServerToClient(rv)),
+				tokenGenerator,
+				newSendFDClient(), // Send passed files.
+			),
+			clientDialOptions...),
 	)
 
 	nsChain := chain_registry.NewNetworkServiceRegistryServer(nsRegistry)
 	nseChain := chain_registry.NewNetworkServiceEndpointRegistryServer(
-		nilEndpointFilter(
-			newRecvFDEndpointRegistry(), // Allow to receive a passed files
-			urlsRegistryServer,
-			interposeRegistry,         // Store cross connect NSEs
-			localbypassRegistryServer, // Store endpoint Id to EndpointURL for local access.
-			seturl.NewNetworkServiceEndpointRegistryServer(nsmRegistration.Url), // Remember endpoint URL
-			nseRegistry, // Register NSE inside Remote registry with ID assigned
-		)...,
+		newRecvFDEndpointRegistry(), // Allow to receive a passed files
+		urlsRegistryServer,
+		interposeRegistry,         // Store cross connect NSEs
+		localbypassRegistryServer, // Store endpoint Id to EndpointURL for local access.
+		seturl.NewNetworkServiceEndpointRegistryServer(nsmRegistration.Url), // Remember endpoint URL
+		nseRegistry, // Register NSE inside Remote registry with ID assigned
 	)
 	rv.Registry = registry.NewServer(nsChain, nseChain)
 
 	return rv
 }
 
-func nilClientFilter(clients ...networkservice.NetworkServiceClient) []networkservice.NetworkServiceClient {
-	result := []networkservice.NetworkServiceClient{}
-	for _, s := range clients {
-		if s != nil {
-			result = append(result, s)
-		}
-	}
-	return result
-}
-
-func nilEndpointFilter(servers ...registryapi.NetworkServiceEndpointRegistryServer) []registryapi.NetworkServiceEndpointRegistryServer {
-	result := []registryapi.NetworkServiceEndpointRegistryServer{}
-	for _, s := range servers {
-		if s != nil {
-			result = append(result, s)
-		}
-	}
-	return result
-}
-
-func nilFilter(servers ...networkservice.NetworkServiceServer) []networkservice.NetworkServiceServer {
-	result := []networkservice.NetworkServiceServer{}
-	for _, s := range servers {
-		if s != nil {
-			result = append(result, s)
-		}
-	}
-	return result
-}
-
 func newRemoteNSServer(cc grpc.ClientConnInterface) registryapi.NetworkServiceRegistryServer {
 	if cc != nil {
 		return adapter_registry.NetworkServiceClientToServer(

pkg/networkservice/common/mechanisms/checkmechanism/check_client_sets_mechanism_preferences.go

@@ -26,10 +26,10 @@ import (
 	"google.golang.org/grpc"
 
 	"github.com/networkservicemesh/sdk/pkg/networkservice/common/mechanisms"
+	"github.com/networkservicemesh/sdk/pkg/networkservice/common/null"
 	"github.com/networkservicemesh/sdk/pkg/networkservice/core/adapters"
 	"github.com/networkservicemesh/sdk/pkg/networkservice/core/chain"
 	"github.com/networkservicemesh/sdk/pkg/networkservice/utils/checks/checkrequest"
-	"github.com/networkservicemesh/sdk/pkg/networkservice/utils/null"
 )
 
 type checkClientSetsMechanismPreferences struct {

pkg/networkservice/common/mechanisms/checkmechanism/check_context.go

@@ -23,11 +23,11 @@ import (
 	"github.com/networkservicemesh/api/pkg/api/networkservice"
 
 	"github.com/networkservicemesh/sdk/pkg/networkservice/common/mechanisms"
+	"github.com/networkservicemesh/sdk/pkg/networkservice/common/null"
 	"github.com/networkservicemesh/sdk/pkg/networkservice/core/adapters"
 	"github.com/networkservicemesh/sdk/pkg/networkservice/core/chain"
 	"github.com/networkservicemesh/sdk/pkg/networkservice/utils/checks/checkcontext"
 	"github.com/networkservicemesh/sdk/pkg/networkservice/utils/checks/checkcontextonreturn"
-	"github.com/networkservicemesh/sdk/pkg/networkservice/utils/null"
 )
 
 // CheckClientContextOnReturn - returns a NetworkServiceClient that will check the state of the context.Context

pkg/networkservice/common/mechanisms/server_test.go

@@ -41,9 +41,9 @@ import (
 	"gonum.org/v1/gonum/stat/combin"
 
 	"github.com/networkservicemesh/sdk/pkg/networkservice/common/mechanisms"
+	"github.com/networkservicemesh/sdk/pkg/networkservice/common/null"
 	"github.com/networkservicemesh/sdk/pkg/networkservice/core/chain"
 	"github.com/networkservicemesh/sdk/pkg/networkservice/utils/inject/injecterror"
-	"github.com/networkservicemesh/sdk/pkg/networkservice/utils/null"
 )
 
 type unsupportedMechanismServer struct{}

pkg/networkservice/utils/null/client.go → pkg/networkservice/common/null/client.go

@@ -1,5 +1,7 @@
 // Copyright (c) 2020 Cisco and/or its affiliates.
 //
+// Copyright (c) 2020 Doc.ai and/or its affiliates.
+//
 // SPDX-License-Identifier: Apache-2.0
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -15,7 +17,8 @@
 // limitations under the License.
 
 // Package null provides simple networkservice chain elements that do nothing by call next and returns what comes
-// back.  This can be very useful in testing.
+// back.
+// This can be very useful in testing or writing os specific code.
 package null
 
 import (

pkg/networkservice/core/adapters/networkservice_test.go

@@ -26,10 +26,10 @@ import (
 	"github.com/stretchr/testify/require"
 	"google.golang.org/grpc"
 
+	"github.com/networkservicemesh/sdk/pkg/networkservice/common/null"
 	"github.com/networkservicemesh/sdk/pkg/networkservice/core/adapters"
 	"github.com/networkservicemesh/sdk/pkg/networkservice/core/next"
 	"github.com/networkservicemesh/sdk/pkg/networkservice/utils/checks/checkcontext"
-	"github.com/networkservicemesh/sdk/pkg/networkservice/utils/null"
 )
 
 type contextKeyType string

pkg/networkservice/utils/checks/checkerror/client_test.go

@@ -26,10 +26,10 @@ import (
 	"github.com/sirupsen/logrus"
 	"github.com/stretchr/testify/assert"
 
+	"github.com/networkservicemesh/sdk/pkg/networkservice/common/null"
 	"github.com/networkservicemesh/sdk/pkg/networkservice/core/chain"
 	"github.com/networkservicemesh/sdk/pkg/networkservice/utils/checks/checkerror"
 	"github.com/networkservicemesh/sdk/pkg/networkservice/utils/inject/injecterror"
-	"github.com/networkservicemesh/sdk/pkg/networkservice/utils/null"
 )
 
 func TestCheckErrorClient_Nil(t *testing.T) {

pkg/networkservice/utils/checks/checkerror/server_test.go

@@ -26,10 +26,10 @@ import (
 	"github.com/sirupsen/logrus"
 	"github.com/stretchr/testify/assert"
 
+	"github.com/networkservicemesh/sdk/pkg/networkservice/common/null"
 	"github.com/networkservicemesh/sdk/pkg/networkservice/core/chain"
 	"github.com/networkservicemesh/sdk/pkg/networkservice/utils/checks/checkerror"
 	"github.com/networkservicemesh/sdk/pkg/networkservice/utils/inject/injecterror"
-	"github.com/networkservicemesh/sdk/pkg/networkservice/utils/null"
 )
 
 func TestCheckErrorServer_Nil(t *testing.T) {

pkg/registry/common/null/doc.go

@@ -0,0 +1,20 @@
+// Copyright (c) 2020 Doc.ai and/or its affiliates.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at:
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package null provides simple registry chain elements that do nothing by call next and returns what comes
+// back.
+// This can be very useful in testing or writing os specific code.
+package null

pkg/registry/common/null/ns_client.go

@@ -0,0 +1,46 @@
+// Copyright (c) 2020 Doc.ai and/or its affiliates.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at:
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package null
+
+import (
+	"context"
+
+	"github.com/golang/protobuf/ptypes/empty"
+	"github.com/networkservicemesh/api/pkg/api/registry"
+	"google.golang.org/grpc"
+
+	"github.com/networkservicemesh/sdk/pkg/registry/core/next"
+)
+
+type nullNSClient struct{}
+
+func (n *nullNSClient) Register(ctx context.Context, in *registry.NetworkService, opts ...grpc.CallOption) (*registry.NetworkService, error) {
+	return next.NetworkServiceRegistryClient(ctx).Register(ctx, in, opts...)
+}
+
+func (n *nullNSClient) Find(ctx context.Context, in *registry.NetworkServiceQuery, opts ...grpc.CallOption) (registry.NetworkServiceRegistry_FindClient, error) {
+	return next.NetworkServiceRegistryClient(ctx).Find(ctx, in, opts...)
+}
+
+func (n *nullNSClient) Unregister(ctx context.Context, in *registry.NetworkService, opts ...grpc.CallOption) (*empty.Empty, error) {
+	return next.NetworkServiceRegistryClient(ctx).Unregister(ctx, in, opts...)
+}
+
+// NewNetworkServiceRegistryClient - returns a new null server that does nothing but call next.NetworkServiceRegistryClient(ctx).
+func NewNetworkServiceRegistryClient() registry.NetworkServiceRegistryClient {
+	return new(nullNSClient)
+}

pkg/registry/common/null/ns_server.go

@@ -0,0 +1,45 @@
+// Copyright (c) 2020 Doc.ai and/or its affiliates.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at:
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package null
+
+import (
+	"context"
+
+	"github.com/golang/protobuf/ptypes/empty"
+	"github.com/networkservicemesh/api/pkg/api/registry"
+
+	"github.com/networkservicemesh/sdk/pkg/registry/core/next"
+)
+
+type nullNSServer struct{}
+
+func (n *nullNSServer) Register(ctx context.Context, service *registry.NetworkService) (*registry.NetworkService, error) {
+	return next.NetworkServiceRegistryServer(ctx).Register(ctx, service)
+}
+
+func (n *nullNSServer) Find(query *registry.NetworkServiceQuery, server registry.NetworkServiceRegistry_FindServer) error {
+	return next.NetworkServiceRegistryServer(server.Context()).Find(query, server)
+}
+
+func (n *nullNSServer) Unregister(ctx context.Context, service *registry.NetworkService) (*empty.Empty, error) {
+	return next.NetworkServiceRegistryServer(ctx).Unregister(ctx, service)
+}
+
+// NewNetworkServiceRegistryServer - returns a new null server that does nothing but call next.NetworkServiceRegistryServer(ctx).
+func NewNetworkServiceRegistryServer() registry.NetworkServiceRegistryServer {
+	return new(nullNSServer)
+}

pkg/registry/common/null/nse_client.go

@@ -0,0 +1,46 @@
+// Copyright (c) 2020 Doc.ai and/or its affiliates.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at:
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package null
+
+import (
+	"context"
+
+	"github.com/golang/protobuf/ptypes/empty"
+	"github.com/networkservicemesh/api/pkg/api/registry"
+	"google.golang.org/grpc"
+
+	"github.com/networkservicemesh/sdk/pkg/registry/core/next"
+)
+
+type nullNSEClient struct{}
+
+func (n *nullNSEClient) Register(ctx context.Context, in *registry.NetworkServiceEndpoint, opts ...grpc.CallOption) (*registry.NetworkServiceEndpoint, error) {
+	return next.NetworkServiceEndpointRegistryClient(ctx).Register(ctx, in, opts...)
+}
+
+func (n *nullNSEClient) Find(ctx context.Context, in *registry.NetworkServiceEndpointQuery, opts ...grpc.CallOption) (registry.NetworkServiceEndpointRegistry_FindClient, error) {
+	return next.NetworkServiceEndpointRegistryClient(ctx).Find(ctx, in, opts...)
+}
+
+func (n *nullNSEClient) Unregister(ctx context.Context, in *registry.NetworkServiceEndpoint, opts ...grpc.CallOption) (*empty.Empty, error) {
+	return next.NetworkServiceEndpointRegistryClient(ctx).Unregister(ctx, in, opts...)
+}
+
+// NewNetworkServiceEndpointRegistryClient - returns a new null client that does nothing but call next.NetworkServiceEndpointRegistryClient(ctx).
+func NewNetworkServiceEndpointRegistryClient() registry.NetworkServiceEndpointRegistryClient {
+	return new(nullNSEClient)
+}