VOL-1405 : First submission for read-only core

- Most of the logic was copied from the read-write implementation
- Added missing Get/List calls
- Added necessary targets in Makefile
- Added docker and k8s manifests

Amendments:

- Removed more unecessary code.
- Removed refs to kafka
- Adjustements to reflect comments
- Removed refs to kafka in manifests

Change-Id: Ife2ca13d3ae428923825f7c19d42359d60406839
diff --git a/ro_core/core/logical_device_agent.go b/ro_core/core/logical_device_agent.go
new file mode 100644
index 0000000..9cb6655
--- /dev/null
+++ b/ro_core/core/logical_device_agent.go
@@ -0,0 +1,119 @@
+/*
+ * 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 core
+
+import (
+	"context"
+	"github.com/opencord/voltha-go/common/log"
+	"github.com/opencord/voltha-go/db/model"
+	"github.com/opencord/voltha-go/protos/voltha"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+	"sync"
+)
+
+type LogicalDeviceAgent struct {
+	logicalDeviceId   string
+	lastData          *voltha.LogicalDevice
+	rootDeviceId      string
+	deviceMgr         *DeviceManager
+	ldeviceMgr        *LogicalDeviceManager
+	clusterDataProxy  *model.Proxy
+	exitChannel       chan int
+	lockLogicalDevice sync.RWMutex
+}
+
+func newLogicalDeviceAgent(id string, deviceId string, ldeviceMgr *LogicalDeviceManager, deviceMgr *DeviceManager, cdProxy *model.Proxy) *LogicalDeviceAgent {
+	var agent LogicalDeviceAgent
+	agent.exitChannel = make(chan int, 1)
+	agent.logicalDeviceId = id
+	agent.rootDeviceId = deviceId
+	agent.deviceMgr = deviceMgr
+	agent.clusterDataProxy = cdProxy
+	agent.ldeviceMgr = ldeviceMgr
+	agent.lockLogicalDevice = sync.RWMutex{}
+	return &agent
+}
+
+// start creates the logical device and add it to the data model
+func (agent *LogicalDeviceAgent) start(ctx context.Context) error {
+	log.Infow("starting-logical_device-agent", log.Fields{"logicaldeviceId": agent.logicalDeviceId})
+	agent.lockLogicalDevice.Lock()
+	defer agent.lockLogicalDevice.Unlock()
+	log.Info("logical_device-agent-started")
+	return nil
+}
+
+// stop terminates the logical device agent.
+func (agent *LogicalDeviceAgent) stop(ctx context.Context) {
+	log.Info("stopping-logical_device-agent")
+	agent.lockLogicalDevice.Lock()
+	defer agent.lockLogicalDevice.Unlock()
+	//Remove the logical device from the model
+	agent.exitChannel <- 1
+	log.Info("logical_device-agent-stopped")
+}
+
+// GetLogicalDevice locks the logical device model and then retrieves the latest logical device information
+func (agent *LogicalDeviceAgent) GetLogicalDevice() (*voltha.LogicalDevice, error) {
+	log.Debug("GetLogicalDevice")
+	agent.lockLogicalDevice.Lock()
+	defer agent.lockLogicalDevice.Unlock()
+	logicalDevice := agent.clusterDataProxy.Get("/logical_devices/"+agent.logicalDeviceId, 1, false, "")
+	if lDevice, ok := logicalDevice.(*voltha.LogicalDevice); ok {
+		return lDevice, nil
+	}
+	return nil, status.Errorf(codes.NotFound, "logical_device-%s", agent.logicalDeviceId)
+}
+
+func (agent *LogicalDeviceAgent) ListLogicalDevicePorts() (*voltha.LogicalPorts, error) {
+	log.Debug("!!!!!ListLogicalDevicePorts")
+	agent.lockLogicalDevice.Lock()
+	defer agent.lockLogicalDevice.Unlock()
+	logicalDevice := agent.clusterDataProxy.Get("/logical_devices/"+agent.logicalDeviceId, 1, false, "")
+	if lDevice, ok := logicalDevice.(*voltha.LogicalDevice); ok {
+		lPorts := make([]*voltha.LogicalPort, 0)
+		for _, port := range lDevice.Ports {
+			lPorts = append(lPorts, port)
+		}
+		return &voltha.LogicalPorts{Items: lPorts}, nil
+	}
+	return nil, status.Errorf(codes.NotFound, "logical_device-%s", agent.logicalDeviceId)
+}
+
+// listFlows locks the logical device model and then retrieves the latest flow information
+func (agent *LogicalDeviceAgent) ListLogicalDeviceFlows() (*voltha.Flows, error) {
+	log.Debug("listFlows")
+	agent.lockLogicalDevice.Lock()
+	defer agent.lockLogicalDevice.Unlock()
+	logicalDevice := agent.clusterDataProxy.Get("/logical_devices/"+agent.logicalDeviceId+"/flows", 1, false, "")
+	if lDevice, ok := logicalDevice.(*voltha.LogicalDevice); ok {
+		return lDevice.Flows, nil
+	}
+	return nil, status.Errorf(codes.NotFound, "logical_device-%s", agent.logicalDeviceId)
+}
+
+// listFlowGroups locks the logical device model and then retrieves the latest flow groups information
+func (agent *LogicalDeviceAgent) ListLogicalDeviceFlowGroups() (*voltha.FlowGroups, error) {
+	log.Debug("listFlowGroups")
+	agent.lockLogicalDevice.Lock()
+	defer agent.lockLogicalDevice.Unlock()
+	logicalDevice := agent.clusterDataProxy.Get("/logical_devices/"+agent.logicalDeviceId, 1, false, "")
+	if lDevice, ok := logicalDevice.(*voltha.LogicalDevice); ok {
+		return lDevice.FlowGroups, nil
+	}
+	return nil, status.Errorf(codes.NotFound, "logical_device-%s", agent.logicalDeviceId)
+}