[VOL-4291] Rw-core updates for gRPC migration

Change-Id: I8d5a554409115b29318089671ca4e1ab3fa98810
diff --git a/vendor/github.com/opencord/voltha-lib-go/v7/pkg/grpc/server.go b/vendor/github.com/opencord/voltha-lib-go/v7/pkg/grpc/server.go
new file mode 100644
index 0000000..bee418d
--- /dev/null
+++ b/vendor/github.com/opencord/voltha-lib-go/v7/pkg/grpc/server.go
@@ -0,0 +1,180 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+
+ * 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 grpc
+
+import (
+	"context"
+	"net"
+
+	grpc_middleware "github.com/grpc-ecosystem/go-grpc-middleware"
+	grpc_opentracing "github.com/grpc-ecosystem/go-grpc-middleware/tracing/opentracing"
+	"github.com/opencord/voltha-lib-go/v7/pkg/log"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/reflection"
+	"google.golang.org/grpc/status"
+)
+
+/*
+To add a GRPC server to your existing component simply follow these steps:
+
+1. Create a server instance by passing the host and port where it should run and optionally add certificate information
+
+	e.g.
+	s.server = server.NewGrpcServer(s.config.GrpcHost, s.config.GrpcPort, nil, false)
+
+2. Create a function that will register your service with the GRPC server
+
+    e.g.
+	f := func(gs *grpc.Server) {
+		voltha.RegisterVolthaReadOnlyServiceServer(
+			gs,
+			core.NewReadOnlyServiceHandler(s.root),
+		)
+	}
+
+3. Add the service to the server
+
+    e.g.
+	s.server.AddService(f)
+
+4. Start the server
+
+	s.server.Start(ctx)
+*/
+
+// Interface allows probes to be attached to server
+// A probe must support the IsReady() method
+type ReadyProbe interface {
+	IsReady() bool
+}
+
+type GrpcServer struct {
+	gs       *grpc.Server
+	address  string
+	secure   bool
+	services []func(*grpc.Server)
+	probe    ReadyProbe // optional
+
+	*GrpcSecurity
+}
+
+/*
+Instantiate a GRPC server data structure
+*/
+func NewGrpcServer(
+	address string,
+	certs *GrpcSecurity,
+	secure bool,
+	probe ReadyProbe,
+) *GrpcServer {
+	server := &GrpcServer{
+		address:      address,
+		secure:       secure,
+		GrpcSecurity: certs,
+		probe:        probe,
+	}
+	return server
+}
+
+/*
+Start prepares the GRPC server and starts servicing requests
+*/
+func (s *GrpcServer) Start(ctx context.Context) {
+
+	lis, err := net.Listen("tcp", s.address)
+	if err != nil {
+		logger.Fatalf(ctx, "failed to listen: %v", err)
+	}
+
+	// Use Intercepters to automatically inject and publish Open Tracing Spans by this GRPC server
+	serverOptions := []grpc.ServerOption{
+		grpc.StreamInterceptor(grpc_middleware.ChainStreamServer(
+			grpc_opentracing.StreamServerInterceptor(grpc_opentracing.WithTracer(log.ActiveTracerProxy{})),
+		)),
+		grpc.UnaryInterceptor(grpc_middleware.ChainUnaryServer(
+			grpc_opentracing.UnaryServerInterceptor(grpc_opentracing.WithTracer(log.ActiveTracerProxy{})),
+			mkServerInterceptor(s),
+		))}
+
+	if s.secure && s.GrpcSecurity != nil {
+		creds, err := credentials.NewServerTLSFromFile(s.CertFile, s.KeyFile)
+		if err != nil {
+			logger.Fatalf(ctx, "could not load TLS keys: %s", err)
+		}
+
+		serverOptions = append(serverOptions, grpc.Creds(creds))
+		s.gs = grpc.NewServer(serverOptions...)
+	} else {
+		logger.Info(ctx, "starting-insecure-grpc-server")
+		s.gs = grpc.NewServer(serverOptions...)
+	}
+
+	// Register all required services
+	for _, service := range s.services {
+		service(s.gs)
+	}
+	reflection.Register(s.gs)
+
+	if err := s.gs.Serve(lis); err != nil {
+		logger.Fatalf(ctx, "failed to serve: %v\n", err)
+	}
+}
+
+// Make a serverInterceptor for the given GrpcServer
+// This interceptor will check whether there is an attached probe,
+// and if that probe indicates NotReady, then an UNAVAILABLE
+// response will be returned.
+func mkServerInterceptor(s *GrpcServer) func(ctx context.Context,
+	req interface{},
+	info *grpc.UnaryServerInfo,
+	handler grpc.UnaryHandler) (interface{}, error) {
+
+	return func(ctx context.Context,
+		req interface{},
+		info *grpc.UnaryServerInfo,
+		handler grpc.UnaryHandler) (interface{}, error) {
+
+		if (s.probe != nil) && (!s.probe.IsReady()) {
+			logger.Warnf(ctx, "Grpc request received while not ready %v", req)
+			return nil, status.Error(codes.Unavailable, "system is not ready")
+		}
+
+		// Calls the handler
+		h, err := handler(ctx, req)
+
+		return h, err
+	}
+}
+
+/*
+Stop servicing GRPC requests
+*/
+func (s *GrpcServer) Stop() {
+	if s.gs != nil {
+		s.gs.Stop()
+	}
+}
+
+/*
+AddService appends a generic service request function
+*/
+func (s *GrpcServer) AddService(
+	registerFunction func(*grpc.Server),
+) {
+	s.services = append(s.services, registerFunction)
+}