VOL-1596 Add Support for handling multicast groups in OpenOLT Adapter.
VOL-1595 Add Support for handling multicast flows in OpenOLT Adapter.

Depends voltha-protos from the patch below:
https://gerrit.opencord.org/#/c/16690/

Change-Id: I1cc9900bd6400bb31aed11beda674138838a21d2
diff --git a/vendor/github.com/opencord/voltha-lib-go/v3/pkg/kafka/kafka_inter_container_library.go b/vendor/github.com/opencord/voltha-lib-go/v3/pkg/kafka/kafka_inter_container_library.go
new file mode 100644
index 0000000..042e121
--- /dev/null
+++ b/vendor/github.com/opencord/voltha-lib-go/v3/pkg/kafka/kafka_inter_container_library.go
@@ -0,0 +1,841 @@
+/*
+ * 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 kafka
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"reflect"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/golang/protobuf/proto"
+	"github.com/golang/protobuf/ptypes"
+	"github.com/golang/protobuf/ptypes/any"
+	"github.com/google/uuid"
+	"github.com/opencord/voltha-lib-go/v3/pkg/log"
+	ic "github.com/opencord/voltha-protos/v3/go/inter_container"
+)
+
+const (
+	DefaultMaxRetries     = 3
+	DefaultRequestTimeout = 10000 // 10000 milliseconds - to handle a wider latency range
+)
+
+const (
+	TransactionKey = "transactionID"
+	FromTopic      = "fromTopic"
+)
+
+var ErrorTransactionNotAcquired = errors.New("transaction-not-acquired")
+var ErrorTransactionInvalidId = errors.New("transaction-invalid-id")
+
+// requestHandlerChannel represents an interface associated with a channel.  Whenever, an event is
+// obtained from that channel, this interface is invoked.   This is used to handle
+// async requests into the Core via the kafka messaging bus
+type requestHandlerChannel struct {
+	requesthandlerInterface interface{}
+	ch                      <-chan *ic.InterContainerMessage
+}
+
+// transactionChannel represents a combination of a topic and a channel onto which a response received
+// on the kafka bus will be sent to
+type transactionChannel struct {
+	topic *Topic
+	ch    chan *ic.InterContainerMessage
+}
+
+// InterContainerProxy represents the messaging proxy
+type InterContainerProxy struct {
+	kafkaHost                      string
+	kafkaPort                      int
+	DefaultTopic                   *Topic
+	defaultRequestHandlerInterface interface{}
+	deviceDiscoveryTopic           *Topic
+	kafkaClient                    Client
+	doneCh                         chan int
+
+	// This map is used to map a topic to an interface and channel.   When a request is received
+	// on that channel (registered to the topic) then that interface is invoked.
+	topicToRequestHandlerChannelMap   map[string]*requestHandlerChannel
+	lockTopicRequestHandlerChannelMap sync.RWMutex
+
+	// This map is used to map a channel to a response topic.   This channel handles all responses on that
+	// channel for that topic and forward them to the appropriate consumers channel, using the
+	// transactionIdToChannelMap.
+	topicToResponseChannelMap   map[string]<-chan *ic.InterContainerMessage
+	lockTopicResponseChannelMap sync.RWMutex
+
+	// This map is used to map a transaction to a consumers channel.  This is used whenever a request has been
+	// sent out and we are waiting for a response.
+	transactionIdToChannelMap     map[string]*transactionChannel
+	lockTransactionIdToChannelMap sync.RWMutex
+}
+
+type InterContainerProxyOption func(*InterContainerProxy)
+
+func InterContainerHost(host string) InterContainerProxyOption {
+	return func(args *InterContainerProxy) {
+		args.kafkaHost = host
+	}
+}
+
+func InterContainerPort(port int) InterContainerProxyOption {
+	return func(args *InterContainerProxy) {
+		args.kafkaPort = port
+	}
+}
+
+func DefaultTopic(topic *Topic) InterContainerProxyOption {
+	return func(args *InterContainerProxy) {
+		args.DefaultTopic = topic
+	}
+}
+
+func DeviceDiscoveryTopic(topic *Topic) InterContainerProxyOption {
+	return func(args *InterContainerProxy) {
+		args.deviceDiscoveryTopic = topic
+	}
+}
+
+func RequestHandlerInterface(handler interface{}) InterContainerProxyOption {
+	return func(args *InterContainerProxy) {
+		args.defaultRequestHandlerInterface = handler
+	}
+}
+
+func MsgClient(client Client) InterContainerProxyOption {
+	return func(args *InterContainerProxy) {
+		args.kafkaClient = client
+	}
+}
+
+func NewInterContainerProxy(opts ...InterContainerProxyOption) (*InterContainerProxy, error) {
+	proxy := &InterContainerProxy{
+		kafkaHost: DefaultKafkaHost,
+		kafkaPort: DefaultKafkaPort,
+	}
+
+	for _, option := range opts {
+		option(proxy)
+	}
+
+	// Create the locks for all the maps
+	proxy.lockTopicRequestHandlerChannelMap = sync.RWMutex{}
+	proxy.lockTransactionIdToChannelMap = sync.RWMutex{}
+	proxy.lockTopicResponseChannelMap = sync.RWMutex{}
+
+	return proxy, nil
+}
+
+func (kp *InterContainerProxy) Start() error {
+	logger.Info("Starting-Proxy")
+
+	// Kafka MsgClient should already have been created.  If not, output fatal error
+	if kp.kafkaClient == nil {
+		logger.Fatal("kafka-client-not-set")
+	}
+
+	// Create the Done channel
+	kp.doneCh = make(chan int, 1)
+
+	// Start the kafka client
+	if err := kp.kafkaClient.Start(); err != nil {
+		logger.Errorw("Cannot-create-kafka-proxy", log.Fields{"error": err})
+		return err
+	}
+
+	// Create the topic to response channel map
+	kp.topicToResponseChannelMap = make(map[string]<-chan *ic.InterContainerMessage)
+	//
+	// Create the transactionId to Channel Map
+	kp.transactionIdToChannelMap = make(map[string]*transactionChannel)
+
+	// Create the topic to request channel map
+	kp.topicToRequestHandlerChannelMap = make(map[string]*requestHandlerChannel)
+
+	return nil
+}
+
+func (kp *InterContainerProxy) Stop() {
+	logger.Info("stopping-intercontainer-proxy")
+	kp.doneCh <- 1
+	// TODO : Perform cleanup
+	kp.kafkaClient.Stop()
+	//kp.deleteAllTopicRequestHandlerChannelMap()
+	//kp.deleteAllTopicResponseChannelMap()
+	//kp.deleteAllTransactionIdToChannelMap()
+}
+
+// DeviceDiscovered publish the discovered device onto the kafka messaging bus
+func (kp *InterContainerProxy) DeviceDiscovered(deviceId string, deviceType string, parentId string, publisher string) error {
+	logger.Debugw("sending-device-discovery-msg", log.Fields{"deviceId": deviceId})
+	//	Simple validation
+	if deviceId == "" || deviceType == "" {
+		logger.Errorw("invalid-parameters", log.Fields{"id": deviceId, "type": deviceType})
+		return errors.New("invalid-parameters")
+	}
+	//	Create the device discovery message
+	header := &ic.Header{
+		Id:        uuid.New().String(),
+		Type:      ic.MessageType_DEVICE_DISCOVERED,
+		FromTopic: kp.DefaultTopic.Name,
+		ToTopic:   kp.deviceDiscoveryTopic.Name,
+		Timestamp: time.Now().UnixNano(),
+	}
+	body := &ic.DeviceDiscovered{
+		Id:         deviceId,
+		DeviceType: deviceType,
+		ParentId:   parentId,
+		Publisher:  publisher,
+	}
+
+	var marshalledData *any.Any
+	var err error
+	if marshalledData, err = ptypes.MarshalAny(body); err != nil {
+		logger.Errorw("cannot-marshal-request", log.Fields{"error": err})
+		return err
+	}
+	msg := &ic.InterContainerMessage{
+		Header: header,
+		Body:   marshalledData,
+	}
+
+	// Send the message
+	if err := kp.kafkaClient.Send(msg, kp.deviceDiscoveryTopic); err != nil {
+		logger.Errorw("cannot-send-device-discovery-message", log.Fields{"error": err})
+		return err
+	}
+	return nil
+}
+
+// InvokeRPC is used to send a request to a given topic
+func (kp *InterContainerProxy) InvokeRPC(ctx context.Context, rpc string, toTopic *Topic, replyToTopic *Topic,
+	waitForResponse bool, key string, kvArgs ...*KVArg) (bool, *any.Any) {
+
+	//	If a replyToTopic is provided then we use it, otherwise just use the  default toTopic.  The replyToTopic is
+	// typically the device ID.
+	responseTopic := replyToTopic
+	if responseTopic == nil {
+		responseTopic = kp.DefaultTopic
+	}
+
+	// Encode the request
+	protoRequest, err := encodeRequest(rpc, toTopic, responseTopic, key, kvArgs...)
+	if err != nil {
+		logger.Warnw("cannot-format-request", log.Fields{"rpc": rpc, "error": err})
+		return false, nil
+	}
+
+	// Subscribe for response, if needed, before sending request
+	var ch <-chan *ic.InterContainerMessage
+	if waitForResponse {
+		var err error
+		if ch, err = kp.subscribeForResponse(*responseTopic, protoRequest.Header.Id); err != nil {
+			logger.Errorw("failed-to-subscribe-for-response", log.Fields{"error": err, "toTopic": toTopic.Name})
+		}
+	}
+
+	// Send request - if the topic is formatted with a device Id then we will send the request using a
+	// specific key, hence ensuring a single partition is used to publish the request.  This ensures that the
+	// subscriber on that topic will receive the request in the order it was sent.  The key used is the deviceId.
+	//key := GetDeviceIdFromTopic(*toTopic)
+	logger.Debugw("sending-msg", log.Fields{"rpc": rpc, "toTopic": toTopic, "replyTopic": responseTopic, "key": key, "xId": protoRequest.Header.Id})
+	go kp.kafkaClient.Send(protoRequest, toTopic, key)
+
+	if waitForResponse {
+		// Create a child context based on the parent context, if any
+		var cancel context.CancelFunc
+		childCtx := context.Background()
+		if ctx == nil {
+			ctx, cancel = context.WithTimeout(context.Background(), DefaultRequestTimeout*time.Millisecond)
+		} else {
+			childCtx, cancel = context.WithTimeout(ctx, DefaultRequestTimeout*time.Millisecond)
+		}
+		defer cancel()
+
+		// Wait for response as well as timeout or cancellation
+		// Remove the subscription for a response on return
+		defer kp.unSubscribeForResponse(protoRequest.Header.Id)
+		select {
+		case msg, ok := <-ch:
+			if !ok {
+				logger.Warnw("channel-closed", log.Fields{"rpc": rpc, "replyTopic": replyToTopic.Name})
+				protoError := &ic.Error{Reason: "channel-closed"}
+				var marshalledArg *any.Any
+				if marshalledArg, err = ptypes.MarshalAny(protoError); err != nil {
+					return false, nil // Should never happen
+				}
+				return false, marshalledArg
+			}
+			logger.Debugw("received-response", log.Fields{"rpc": rpc, "msgHeader": msg.Header})
+			var responseBody *ic.InterContainerResponseBody
+			var err error
+			if responseBody, err = decodeResponse(msg); err != nil {
+				logger.Errorw("decode-response-error", log.Fields{"error": err})
+			}
+			return responseBody.Success, responseBody.Result
+		case <-ctx.Done():
+			logger.Debugw("context-cancelled", log.Fields{"rpc": rpc, "ctx": ctx.Err()})
+			//	 pack the error as proto any type
+			protoError := &ic.Error{Reason: ctx.Err().Error()}
+			var marshalledArg *any.Any
+			if marshalledArg, err = ptypes.MarshalAny(protoError); err != nil {
+				return false, nil // Should never happen
+			}
+			return false, marshalledArg
+		case <-childCtx.Done():
+			logger.Debugw("context-cancelled", log.Fields{"rpc": rpc, "ctx": childCtx.Err()})
+			//	 pack the error as proto any type
+			protoError := &ic.Error{Reason: childCtx.Err().Error()}
+			var marshalledArg *any.Any
+			if marshalledArg, err = ptypes.MarshalAny(protoError); err != nil {
+				return false, nil // Should never happen
+			}
+			return false, marshalledArg
+		case <-kp.doneCh:
+			logger.Infow("received-exit-signal", log.Fields{"toTopic": toTopic.Name, "rpc": rpc})
+			return true, nil
+		}
+	}
+	return true, nil
+}
+
+// SubscribeWithRequestHandlerInterface allows a caller to assign a target object to be invoked automatically
+// when a message is received on a given topic
+func (kp *InterContainerProxy) SubscribeWithRequestHandlerInterface(topic Topic, handler interface{}) error {
+
+	// Subscribe to receive messages for that topic
+	var ch <-chan *ic.InterContainerMessage
+	var err error
+	if ch, err = kp.kafkaClient.Subscribe(&topic); err != nil {
+		//if ch, err = kp.Subscribe(topic); err != nil {
+		logger.Errorw("failed-to-subscribe", log.Fields{"error": err, "topic": topic.Name})
+		return err
+	}
+
+	kp.defaultRequestHandlerInterface = handler
+	kp.addToTopicRequestHandlerChannelMap(topic.Name, &requestHandlerChannel{requesthandlerInterface: handler, ch: ch})
+	// Launch a go routine to receive and process kafka messages
+	go kp.waitForMessages(ch, topic, handler)
+
+	return nil
+}
+
+// SubscribeWithDefaultRequestHandler allows a caller to add a topic to an existing target object to be invoked automatically
+// when a message is received on a given topic.  So far there is only 1 target registered per microservice
+func (kp *InterContainerProxy) SubscribeWithDefaultRequestHandler(topic Topic, initialOffset int64) error {
+	// Subscribe to receive messages for that topic
+	var ch <-chan *ic.InterContainerMessage
+	var err error
+	if ch, err = kp.kafkaClient.Subscribe(&topic, &KVArg{Key: Offset, Value: initialOffset}); err != nil {
+		logger.Errorw("failed-to-subscribe", log.Fields{"error": err, "topic": topic.Name})
+		return err
+	}
+	kp.addToTopicRequestHandlerChannelMap(topic.Name, &requestHandlerChannel{requesthandlerInterface: kp.defaultRequestHandlerInterface, ch: ch})
+
+	// Launch a go routine to receive and process kafka messages
+	go kp.waitForMessages(ch, topic, kp.defaultRequestHandlerInterface)
+
+	return nil
+}
+
+func (kp *InterContainerProxy) UnSubscribeFromRequestHandler(topic Topic) error {
+	return kp.deleteFromTopicRequestHandlerChannelMap(topic.Name)
+}
+
+// setupTopicResponseChannelMap sets up single consumers channel that will act as a broadcast channel for all
+// responses from that topic.
+func (kp *InterContainerProxy) setupTopicResponseChannelMap(topic string, arg <-chan *ic.InterContainerMessage) {
+	kp.lockTopicResponseChannelMap.Lock()
+	defer kp.lockTopicResponseChannelMap.Unlock()
+	if _, exist := kp.topicToResponseChannelMap[topic]; !exist {
+		kp.topicToResponseChannelMap[topic] = arg
+	}
+}
+
+func (kp *InterContainerProxy) isTopicSubscribedForResponse(topic string) bool {
+	kp.lockTopicResponseChannelMap.RLock()
+	defer kp.lockTopicResponseChannelMap.RUnlock()
+	_, exist := kp.topicToResponseChannelMap[topic]
+	return exist
+}
+
+func (kp *InterContainerProxy) deleteFromTopicResponseChannelMap(topic string) error {
+	kp.lockTopicResponseChannelMap.Lock()
+	defer kp.lockTopicResponseChannelMap.Unlock()
+	if _, exist := kp.topicToResponseChannelMap[topic]; exist {
+		// Unsubscribe to this topic first - this will close the subscribed channel
+		var err error
+		if err = kp.kafkaClient.UnSubscribe(&Topic{Name: topic}, kp.topicToResponseChannelMap[topic]); err != nil {
+			logger.Errorw("unsubscribing-error", log.Fields{"topic": topic})
+		}
+		delete(kp.topicToResponseChannelMap, topic)
+		return err
+	} else {
+		return errors.New(fmt.Sprintf("%s-Topic-not-found", topic))
+	}
+}
+
+func (kp *InterContainerProxy) deleteAllTopicResponseChannelMap() error {
+	kp.lockTopicResponseChannelMap.Lock()
+	defer kp.lockTopicResponseChannelMap.Unlock()
+	var err error
+	for topic, _ := range kp.topicToResponseChannelMap {
+		// Unsubscribe to this topic first - this will close the subscribed channel
+		if err = kp.kafkaClient.UnSubscribe(&Topic{Name: topic}, kp.topicToResponseChannelMap[topic]); err != nil {
+			logger.Errorw("unsubscribing-error", log.Fields{"topic": topic, "error": err})
+		}
+		delete(kp.topicToResponseChannelMap, topic)
+	}
+	return err
+}
+
+func (kp *InterContainerProxy) addToTopicRequestHandlerChannelMap(topic string, arg *requestHandlerChannel) {
+	kp.lockTopicRequestHandlerChannelMap.Lock()
+	defer kp.lockTopicRequestHandlerChannelMap.Unlock()
+	if _, exist := kp.topicToRequestHandlerChannelMap[topic]; !exist {
+		kp.topicToRequestHandlerChannelMap[topic] = arg
+	}
+}
+
+func (kp *InterContainerProxy) deleteFromTopicRequestHandlerChannelMap(topic string) error {
+	kp.lockTopicRequestHandlerChannelMap.Lock()
+	defer kp.lockTopicRequestHandlerChannelMap.Unlock()
+	if _, exist := kp.topicToRequestHandlerChannelMap[topic]; exist {
+		// Close the kafka client client first by unsubscribing to this topic
+		kp.kafkaClient.UnSubscribe(&Topic{Name: topic}, kp.topicToRequestHandlerChannelMap[topic].ch)
+		delete(kp.topicToRequestHandlerChannelMap, topic)
+		return nil
+	} else {
+		return errors.New(fmt.Sprintf("%s-Topic-not-found", topic))
+	}
+}
+
+func (kp *InterContainerProxy) deleteAllTopicRequestHandlerChannelMap() error {
+	kp.lockTopicRequestHandlerChannelMap.Lock()
+	defer kp.lockTopicRequestHandlerChannelMap.Unlock()
+	var err error
+	for topic, _ := range kp.topicToRequestHandlerChannelMap {
+		// Close the kafka client client first by unsubscribing to this topic
+		if err = kp.kafkaClient.UnSubscribe(&Topic{Name: topic}, kp.topicToRequestHandlerChannelMap[topic].ch); err != nil {
+			logger.Errorw("unsubscribing-error", log.Fields{"topic": topic, "error": err})
+		}
+		delete(kp.topicToRequestHandlerChannelMap, topic)
+	}
+	return err
+}
+
+func (kp *InterContainerProxy) addToTransactionIdToChannelMap(id string, topic *Topic, arg chan *ic.InterContainerMessage) {
+	kp.lockTransactionIdToChannelMap.Lock()
+	defer kp.lockTransactionIdToChannelMap.Unlock()
+	if _, exist := kp.transactionIdToChannelMap[id]; !exist {
+		kp.transactionIdToChannelMap[id] = &transactionChannel{topic: topic, ch: arg}
+	}
+}
+
+func (kp *InterContainerProxy) deleteFromTransactionIdToChannelMap(id string) {
+	kp.lockTransactionIdToChannelMap.Lock()
+	defer kp.lockTransactionIdToChannelMap.Unlock()
+	if transChannel, exist := kp.transactionIdToChannelMap[id]; exist {
+		// Close the channel first
+		close(transChannel.ch)
+		delete(kp.transactionIdToChannelMap, id)
+	}
+}
+
+func (kp *InterContainerProxy) deleteTopicTransactionIdToChannelMap(id string) {
+	kp.lockTransactionIdToChannelMap.Lock()
+	defer kp.lockTransactionIdToChannelMap.Unlock()
+	for key, value := range kp.transactionIdToChannelMap {
+		if value.topic.Name == id {
+			close(value.ch)
+			delete(kp.transactionIdToChannelMap, key)
+		}
+	}
+}
+
+func (kp *InterContainerProxy) deleteAllTransactionIdToChannelMap() {
+	kp.lockTransactionIdToChannelMap.Lock()
+	defer kp.lockTransactionIdToChannelMap.Unlock()
+	for key, value := range kp.transactionIdToChannelMap {
+		close(value.ch)
+		delete(kp.transactionIdToChannelMap, key)
+	}
+}
+
+func (kp *InterContainerProxy) DeleteTopic(topic Topic) error {
+	// If we have any consumers on that topic we need to close them
+	if err := kp.deleteFromTopicResponseChannelMap(topic.Name); err != nil {
+		logger.Errorw("delete-from-topic-responsechannelmap-failed", log.Fields{"error": err})
+	}
+	if err := kp.deleteFromTopicRequestHandlerChannelMap(topic.Name); err != nil {
+		logger.Errorw("delete-from-topic-requesthandlerchannelmap-failed", log.Fields{"error": err})
+	}
+	kp.deleteTopicTransactionIdToChannelMap(topic.Name)
+
+	return kp.kafkaClient.DeleteTopic(&topic)
+}
+
+func encodeReturnedValue(returnedVal interface{}) (*any.Any, error) {
+	// Encode the response argument - needs to be a proto message
+	if returnedVal == nil {
+		return nil, nil
+	}
+	protoValue, ok := returnedVal.(proto.Message)
+	if !ok {
+		logger.Warnw("response-value-not-proto-message", log.Fields{"error": ok, "returnVal": returnedVal})
+		err := errors.New("response-value-not-proto-message")
+		return nil, err
+	}
+
+	// Marshal the returned value, if any
+	var marshalledReturnedVal *any.Any
+	var err error
+	if marshalledReturnedVal, err = ptypes.MarshalAny(protoValue); err != nil {
+		logger.Warnw("cannot-marshal-returned-val", log.Fields{"error": err})
+		return nil, err
+	}
+	return marshalledReturnedVal, nil
+}
+
+func encodeDefaultFailedResponse(request *ic.InterContainerMessage) *ic.InterContainerMessage {
+	responseHeader := &ic.Header{
+		Id:        request.Header.Id,
+		Type:      ic.MessageType_RESPONSE,
+		FromTopic: request.Header.ToTopic,
+		ToTopic:   request.Header.FromTopic,
+		Timestamp: time.Now().Unix(),
+	}
+	responseBody := &ic.InterContainerResponseBody{
+		Success: false,
+		Result:  nil,
+	}
+	var marshalledResponseBody *any.Any
+	var err error
+	// Error should never happen here
+	if marshalledResponseBody, err = ptypes.MarshalAny(responseBody); err != nil {
+		logger.Warnw("cannot-marshal-failed-response-body", log.Fields{"error": err})
+	}
+
+	return &ic.InterContainerMessage{
+		Header: responseHeader,
+		Body:   marshalledResponseBody,
+	}
+
+}
+
+//formatRequest formats a request to send over kafka and returns an InterContainerMessage message on success
+//or an error on failure
+func encodeResponse(request *ic.InterContainerMessage, success bool, returnedValues ...interface{}) (*ic.InterContainerMessage, error) {
+	//logger.Debugw("encodeResponse", log.Fields{"success": success, "returnedValues": returnedValues})
+	responseHeader := &ic.Header{
+		Id:        request.Header.Id,
+		Type:      ic.MessageType_RESPONSE,
+		FromTopic: request.Header.ToTopic,
+		ToTopic:   request.Header.FromTopic,
+		KeyTopic:  request.Header.KeyTopic,
+		Timestamp: time.Now().UnixNano(),
+	}
+
+	// Go over all returned values
+	var marshalledReturnedVal *any.Any
+	var err error
+	for _, returnVal := range returnedValues {
+		if marshalledReturnedVal, err = encodeReturnedValue(returnVal); err != nil {
+			logger.Warnw("cannot-marshal-response-body", log.Fields{"error": err})
+		}
+		break // for now we support only 1 returned value - (excluding the error)
+	}
+
+	responseBody := &ic.InterContainerResponseBody{
+		Success: success,
+		Result:  marshalledReturnedVal,
+	}
+
+	// Marshal the response body
+	var marshalledResponseBody *any.Any
+	if marshalledResponseBody, err = ptypes.MarshalAny(responseBody); err != nil {
+		logger.Warnw("cannot-marshal-response-body", log.Fields{"error": err})
+		return nil, err
+	}
+
+	return &ic.InterContainerMessage{
+		Header: responseHeader,
+		Body:   marshalledResponseBody,
+	}, nil
+}
+
+func CallFuncByName(myClass interface{}, funcName string, params ...interface{}) (out []reflect.Value, err error) {
+	myClassValue := reflect.ValueOf(myClass)
+	// Capitalize the first letter in the funcName to workaround the first capital letters required to
+	// invoke a function from a different package
+	funcName = strings.Title(funcName)
+	m := myClassValue.MethodByName(funcName)
+	if !m.IsValid() {
+		return make([]reflect.Value, 0), fmt.Errorf("method-not-found \"%s\"", funcName)
+	}
+	in := make([]reflect.Value, len(params))
+	for i, param := range params {
+		in[i] = reflect.ValueOf(param)
+	}
+	out = m.Call(in)
+	return
+}
+
+func (kp *InterContainerProxy) addTransactionId(transactionId string, currentArgs []*ic.Argument) []*ic.Argument {
+	arg := &KVArg{
+		Key:   TransactionKey,
+		Value: &ic.StrType{Val: transactionId},
+	}
+
+	var marshalledArg *any.Any
+	var err error
+	if marshalledArg, err = ptypes.MarshalAny(&ic.StrType{Val: transactionId}); err != nil {
+		logger.Warnw("cannot-add-transactionId", log.Fields{"error": err})
+		return currentArgs
+	}
+	protoArg := &ic.Argument{
+		Key:   arg.Key,
+		Value: marshalledArg,
+	}
+	return append(currentArgs, protoArg)
+}
+
+func (kp *InterContainerProxy) addFromTopic(fromTopic string, currentArgs []*ic.Argument) []*ic.Argument {
+	var marshalledArg *any.Any
+	var err error
+	if marshalledArg, err = ptypes.MarshalAny(&ic.StrType{Val: fromTopic}); err != nil {
+		logger.Warnw("cannot-add-transactionId", log.Fields{"error": err})
+		return currentArgs
+	}
+	protoArg := &ic.Argument{
+		Key:   FromTopic,
+		Value: marshalledArg,
+	}
+	return append(currentArgs, protoArg)
+}
+
+func (kp *InterContainerProxy) handleMessage(msg *ic.InterContainerMessage, targetInterface interface{}) {
+
+	// First extract the header to know whether this is a request - responses are handled by a different handler
+	if msg.Header.Type == ic.MessageType_REQUEST {
+		var out []reflect.Value
+		var err error
+
+		// Get the request body
+		requestBody := &ic.InterContainerRequestBody{}
+		if err = ptypes.UnmarshalAny(msg.Body, requestBody); err != nil {
+			logger.Warnw("cannot-unmarshal-request", log.Fields{"error": err})
+		} else {
+			logger.Debugw("received-request", log.Fields{"rpc": requestBody.Rpc, "header": msg.Header})
+			// let the callee unpack the arguments as its the only one that knows the real proto type
+			// Augment the requestBody with the message Id as it will be used in scenarios where cores
+			// are set in pairs and competing
+			requestBody.Args = kp.addTransactionId(msg.Header.Id, requestBody.Args)
+
+			// Augment the requestBody with the From topic name as it will be used in scenarios where a container
+			// needs to send an unsollicited message to the currently requested container
+			requestBody.Args = kp.addFromTopic(msg.Header.FromTopic, requestBody.Args)
+
+			out, err = CallFuncByName(targetInterface, requestBody.Rpc, requestBody.Args)
+			if err != nil {
+				logger.Warn(err)
+			}
+		}
+		// Response required?
+		if requestBody.ResponseRequired {
+			// If we already have an error before then just return that
+			var returnError *ic.Error
+			var returnedValues []interface{}
+			var success bool
+			if err != nil {
+				returnError = &ic.Error{Reason: err.Error()}
+				returnedValues = make([]interface{}, 1)
+				returnedValues[0] = returnError
+			} else {
+				returnedValues = make([]interface{}, 0)
+				// Check for errors first
+				lastIndex := len(out) - 1
+				if out[lastIndex].Interface() != nil { // Error
+					if retError, ok := out[lastIndex].Interface().(error); ok {
+						if retError.Error() == ErrorTransactionNotAcquired.Error() {
+							logger.Debugw("Ignoring request", log.Fields{"error": retError, "txId": msg.Header.Id})
+							return // Ignore - process is in competing mode and ignored transaction
+						}
+						returnError = &ic.Error{Reason: retError.Error()}
+						returnedValues = append(returnedValues, returnError)
+					} else { // Should never happen
+						returnError = &ic.Error{Reason: "incorrect-error-returns"}
+						returnedValues = append(returnedValues, returnError)
+					}
+				} else if len(out) == 2 && reflect.ValueOf(out[0].Interface()).IsValid() && reflect.ValueOf(out[0].Interface()).IsNil() {
+					logger.Warnw("Unexpected response of (nil,nil)", log.Fields{"txId": msg.Header.Id})
+					return // Ignore - should not happen
+				} else { // Non-error case
+					success = true
+					for idx, val := range out {
+						//logger.Debugw("returned-api-response-loop", log.Fields{"idx": idx, "val": val.Interface()})
+						if idx != lastIndex {
+							returnedValues = append(returnedValues, val.Interface())
+						}
+					}
+				}
+			}
+
+			var icm *ic.InterContainerMessage
+			if icm, err = encodeResponse(msg, success, returnedValues...); err != nil {
+				logger.Warnw("error-encoding-response-returning-failure-result", log.Fields{"error": err})
+				icm = encodeDefaultFailedResponse(msg)
+			}
+			// To preserve ordering of messages, all messages to a given topic are sent to the same partition
+			// by providing a message key.   The key is encoded in the topic name.  If the deviceId is not
+			// present then the key will be empty, hence all messages for a given topic will be sent to all
+			// partitions.
+			replyTopic := &Topic{Name: msg.Header.FromTopic}
+			key := msg.Header.KeyTopic
+			logger.Debugw("sending-response-to-kafka", log.Fields{"rpc": requestBody.Rpc, "header": icm.Header, "key": key})
+			// TODO: handle error response.
+			go kp.kafkaClient.Send(icm, replyTopic, key)
+		}
+	} else if msg.Header.Type == ic.MessageType_RESPONSE {
+		logger.Debugw("response-received", log.Fields{"msg-header": msg.Header})
+		go kp.dispatchResponse(msg)
+	} else {
+		logger.Warnw("unsupported-message-received", log.Fields{"msg-header": msg.Header})
+	}
+}
+
+func (kp *InterContainerProxy) waitForMessages(ch <-chan *ic.InterContainerMessage, topic Topic, targetInterface interface{}) {
+	//	Wait for messages
+	for msg := range ch {
+		//logger.Debugw("request-received", log.Fields{"msg": msg, "topic": topic.Name, "target": targetInterface})
+		go kp.handleMessage(msg, targetInterface)
+	}
+}
+
+func (kp *InterContainerProxy) dispatchResponse(msg *ic.InterContainerMessage) {
+	kp.lockTransactionIdToChannelMap.RLock()
+	defer kp.lockTransactionIdToChannelMap.RUnlock()
+	if _, exist := kp.transactionIdToChannelMap[msg.Header.Id]; !exist {
+		logger.Debugw("no-waiting-channel", log.Fields{"transaction": msg.Header.Id})
+		return
+	}
+	kp.transactionIdToChannelMap[msg.Header.Id].ch <- msg
+}
+
+// subscribeForResponse allows a caller to subscribe to a given topic when waiting for a response.
+// This method is built to prevent all subscribers to receive all messages as is the case of the Subscribe
+// API. There is one response channel waiting for kafka messages before dispatching the message to the
+// corresponding waiting channel
+func (kp *InterContainerProxy) subscribeForResponse(topic Topic, trnsId string) (chan *ic.InterContainerMessage, error) {
+	logger.Debugw("subscribeForResponse", log.Fields{"topic": topic.Name, "trnsid": trnsId})
+
+	// Create a specific channel for this consumers.  We cannot use the channel from the kafkaclient as it will
+	// broadcast any message for this topic to all channels waiting on it.
+	ch := make(chan *ic.InterContainerMessage)
+	kp.addToTransactionIdToChannelMap(trnsId, &topic, ch)
+
+	return ch, nil
+}
+
+func (kp *InterContainerProxy) unSubscribeForResponse(trnsId string) error {
+	logger.Debugw("unsubscribe-for-response", log.Fields{"trnsId": trnsId})
+	kp.deleteFromTransactionIdToChannelMap(trnsId)
+	return nil
+}
+
+func (kp *InterContainerProxy) EnableLivenessChannel(enable bool) chan bool {
+	return kp.kafkaClient.EnableLivenessChannel(enable)
+}
+
+func (kp *InterContainerProxy) EnableHealthinessChannel(enable bool) chan bool {
+	return kp.kafkaClient.EnableHealthinessChannel(enable)
+}
+
+func (kp *InterContainerProxy) SendLiveness() error {
+	return kp.kafkaClient.SendLiveness()
+}
+
+//formatRequest formats a request to send over kafka and returns an InterContainerMessage message on success
+//or an error on failure
+func encodeRequest(rpc string, toTopic *Topic, replyTopic *Topic, key string, kvArgs ...*KVArg) (*ic.InterContainerMessage, error) {
+	requestHeader := &ic.Header{
+		Id:        uuid.New().String(),
+		Type:      ic.MessageType_REQUEST,
+		FromTopic: replyTopic.Name,
+		ToTopic:   toTopic.Name,
+		KeyTopic:  key,
+		Timestamp: time.Now().UnixNano(),
+	}
+	requestBody := &ic.InterContainerRequestBody{
+		Rpc:              rpc,
+		ResponseRequired: true,
+		ReplyToTopic:     replyTopic.Name,
+	}
+
+	for _, arg := range kvArgs {
+		if arg == nil {
+			// In case the caller sends an array with empty args
+			continue
+		}
+		var marshalledArg *any.Any
+		var err error
+		// ascertain the value interface type is a proto.Message
+		protoValue, ok := arg.Value.(proto.Message)
+		if !ok {
+			logger.Warnw("argument-value-not-proto-message", log.Fields{"error": ok, "Value": arg.Value})
+			err := errors.New("argument-value-not-proto-message")
+			return nil, err
+		}
+		if marshalledArg, err = ptypes.MarshalAny(protoValue); err != nil {
+			logger.Warnw("cannot-marshal-request", log.Fields{"error": err})
+			return nil, err
+		}
+		protoArg := &ic.Argument{
+			Key:   arg.Key,
+			Value: marshalledArg,
+		}
+		requestBody.Args = append(requestBody.Args, protoArg)
+	}
+
+	var marshalledData *any.Any
+	var err error
+	if marshalledData, err = ptypes.MarshalAny(requestBody); err != nil {
+		logger.Warnw("cannot-marshal-request", log.Fields{"error": err})
+		return nil, err
+	}
+	request := &ic.InterContainerMessage{
+		Header: requestHeader,
+		Body:   marshalledData,
+	}
+	return request, nil
+}
+
+func decodeResponse(response *ic.InterContainerMessage) (*ic.InterContainerResponseBody, error) {
+	//	Extract the message body
+	responseBody := ic.InterContainerResponseBody{}
+	if err := ptypes.UnmarshalAny(response.Body, &responseBody); err != nil {
+		logger.Warnw("cannot-unmarshal-response", log.Fields{"error": err})
+		return nil, err
+	}
+	//logger.Debugw("response-decoded-successfully", log.Fields{"response-status": &responseBody.Success})
+
+	return &responseBody, nil
+
+}