Create DNSContext NetworkServiceServer chain elements

go.mod

@@ -7,6 +7,7 @@ require (
 	github.com/golang/protobuf v1.3.3
 	github.com/google/uuid v1.1.1
 	github.com/grpc-ecosystem/grpc-opentracing v0.0.0-20180507213350-8e809c8a8645
+	github.com/kelseyhightower/envconfig v1.4.0
 	github.com/networkservicemesh/api v0.0.0-20200203181400-b7f0d29ed5cd
 	github.com/open-policy-agent/opa v0.16.1
 	github.com/opentracing/opentracing-go v1.1.0

go.sum

@@ -75,6 +75,8 @@ github.com/jonboulle/clockwork v0.1.0/go.mod h1:Ii8DK3G1RaLaWxj9trq07+26W01tbo22
 github.com/jtolds/gls v4.20.0+incompatible h1:xdiiI2gbIgH/gLH7ADydsJ1uDOEzR8yvV7C0MuV77Wo=
 github.com/jtolds/gls v4.20.0+incompatible/go.mod h1:QJZ7F/aHp+rZTRtaJ1ow/lLfFfVYBRgL+9YlvaHOwJU=
 github.com/julienschmidt/httprouter v1.2.0/go.mod h1:SYymIcj16QtmaHHD7aYtjjsJG7VTCxuUUipMqKk8s4w=
+github.com/kelseyhightower/envconfig v1.4.0 h1:Im6hONhd3pLkfDFsbRgu68RDNkGF1r3dvMUtDTo2cv8=
+github.com/kelseyhightower/envconfig v1.4.0/go.mod h1:cccZRl6mQpaq41TPp5QxidR+Sa3axMbJDNb//FQX6Gg=
 github.com/kisielk/errcheck v1.1.0/go.mod h1:EZBBE59ingxPouuu3KfxchcWSUPOHkagtvWXihfKN4Q=
 github.com/kisielk/errcheck v1.2.0/go.mod h1:/BMXB+zMLi60iA8Vv6Ksmxu/1UDYcXs4uQLJ+jE2L00=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=

pkg/networkservice/connectioncontext/dnscontext/server.go

@@ -0,0 +1,58 @@
+// 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 dnscontext provides a dns context specific chain element. It just adds dns configs into dns context of connection context.
+// It also provides a possibility to use custom dns configs getters for setup users endpoints.
+package dnscontext
+
+import (
+	"context"
+
+	"github.com/golang/protobuf/ptypes/empty"
+	"github.com/networkservicemesh/api/pkg/api/networkservice"
+
+	"github.com/networkservicemesh/sdk/pkg/networkservice/core/next"
+)
+
+// GetDNSConfigsFunc gets dns configs
+type GetDNSConfigsFunc func(conn *networkservice.Connection) []*networkservice.DNSConfig
+
+type dnsContextServer struct {
+	getDNSConfigs GetDNSConfigsFunc
+}
+
+// NewServer creates dns context chain server element.
+func NewServer(getter GetDNSConfigsFunc) networkservice.NetworkServiceServer {
+	return &dnsContextServer{getDNSConfigs: getter}
+}
+
+func (d *dnsContextServer) Request(ctx context.Context, request *networkservice.NetworkServiceRequest) (*networkservice.Connection, error) {
+	if d.getDNSConfigs != nil {
+		request.GetConnection().GetContext().DnsContext = &networkservice.DNSContext{
+			Configs: d.getDNSConfigs(request.GetConnection()),
+		}
+	}
+	return next.Server(ctx).Request(ctx, request)
+}
+
+func (d *dnsContextServer) Close(ctx context.Context, conn *networkservice.Connection) (*empty.Empty, error) {
+	if d.getDNSConfigs != nil {
+		conn.GetContext().DnsContext = &networkservice.DNSContext{
+			Configs: d.getDNSConfigs(conn),
+		}
+	}
+	return next.Server(ctx).Close(ctx, conn)
+}

pkg/networkservice/connectioncontext/dnscontext/tests/server_test.go

@@ -0,0 +1,74 @@
+// 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 tests
+
+import (
+	"context"
+	"os"
+	"testing"
+
+	"github.com/networkservicemesh/sdk/pkg/networkservice/connectioncontext/dnscontext"
+
+	"github.com/networkservicemesh/api/pkg/api/networkservice"
+	"github.com/stretchr/testify/require"
+
+	"github.com/networkservicemesh/sdk/pkg/networkservice/core/next"
+)
+
+func TestServerBasic(t *testing.T) {
+	r := &networkservice.NetworkServiceRequest{
+		Connection: &networkservice.Connection{
+			Id:             "0",
+			NetworkService: "icmp",
+			Context: &networkservice.ConnectionContext{
+				IpContext: &networkservice.IPContext{
+					DstIpAddr: "172.16.1.2",
+				},
+			},
+		},
+	}
+	s := next.NewNetworkServiceServer(dnscontext.NewServer(dnscontext.ConfigFromConnection()))
+	resp, err := s.Request(context.Background(), r)
+	require.Nil(t, err)
+	require.NotNil(t, resp.GetContext().GetDnsContext())
+	require.Len(t, resp.Context.DnsContext.Configs[0].SearchDomains, 1)
+	require.Len(t, resp.Context.DnsContext.Configs[0].DnsServerIps, 1)
+	require.Equal(t, resp.Context.DnsContext.Configs[0].SearchDomains[0], r.Connection.NetworkService)
+	require.Equal(t, resp.Context.DnsContext.Configs[0].DnsServerIps[0], r.Connection.Context.IpContext.DstIpAddr)
+}
+
+func TestServerBasicFromEnv(t *testing.T) {
+	r := &networkservice.NetworkServiceRequest{
+		Connection: &networkservice.Connection{
+			Context: &networkservice.ConnectionContext{},
+		},
+	}
+	expectedDomain := "test.domain"
+	expectedIP := "8.8.8.8"
+	err := os.Setenv("DNSCONFIG_DNSSERVERIPS", expectedIP)
+	require.Nil(t, err)
+	err = os.Setenv("DNSCONFIG_SEARCHDOMAINS", expectedDomain)
+	require.Nil(t, err)
+	s := next.NewNetworkServiceServer(dnscontext.NewServer(dnscontext.ConfigFromEnv()))
+	resp, err := s.Request(context.Background(), r)
+	require.Nil(t, err)
+	require.NotNil(t, resp.GetContext().GetDnsContext())
+	require.Len(t, resp.Context.DnsContext.Configs[0].SearchDomains, 1)
+	require.Len(t, resp.Context.DnsContext.Configs[0].DnsServerIps, 1)
+	require.Equal(t, resp.Context.DnsContext.Configs[0].SearchDomains[0], expectedDomain)
+	require.Equal(t, resp.Context.DnsContext.Configs[0].DnsServerIps[0], expectedIP)
+}

pkg/networkservice/connectioncontext/dnscontext/utils.go

@@ -0,0 +1,49 @@
+// 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 dnscontext
+
+import (
+	"github.com/kelseyhightower/envconfig"
+	"github.com/networkservicemesh/api/pkg/api/networkservice"
+	"github.com/sirupsen/logrus"
+)
+
+// ConfigFromEnv returns default getter for DNS configs. Builds config from env variables.
+func ConfigFromEnv() GetDNSConfigsFunc {
+	return func(_ *networkservice.Connection) []*networkservice.DNSConfig {
+		config := &networkservice.DNSConfig{}
+		err := envconfig.Process("DNSCONFIG", config)
+		if err != nil {
+			logrus.Error(err.Error())
+		}
+		return []*networkservice.DNSConfig{config}
+	}
+}
+
+// ConfigFromConnection returns default getter for DNS configs. Builds config from the connection.
+func ConfigFromConnection() GetDNSConfigsFunc {
+	return func(conn *networkservice.Connection) []*networkservice.DNSConfig {
+		domain := conn.GetNetworkService()
+		ip := conn.GetContext().GetIpContext().GetDstIpAddr()
+		return []*networkservice.DNSConfig{
+			{
+				DnsServerIps:  []string{ip},
+				SearchDomains: []string{domain},
+			},
+		}
+	}
+}