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/grpc_nbi_api_handler.go b/ro_core/core/grpc_nbi_api_handler.go
new file mode 100644
index 0000000..5727983
--- /dev/null
+++ b/ro_core/core/grpc_nbi_api_handler.go
@@ -0,0 +1,254 @@
+/*
+ * 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"
+	"errors"
+	"github.com/golang/protobuf/ptypes/empty"
+	da "github.com/opencord/voltha-go/common/core/northbound/grpc"
+	"github.com/opencord/voltha-go/common/log"
+	"github.com/opencord/voltha-go/protos/common"
+	"github.com/opencord/voltha-go/protos/voltha"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/status"
+)
+
+type APIHandler struct {
+	commonMgr        *ModelProxyManager
+	deviceMgr        *DeviceManager
+	logicalDeviceMgr *LogicalDeviceManager
+	da.DefaultAPIHandler
+}
+
+func NewAPIHandler(generalMgr *ModelProxyManager, deviceMgr *DeviceManager, lDeviceMgr *LogicalDeviceManager) *APIHandler {
+	handler := &APIHandler{
+		commonMgr:        generalMgr,
+		deviceMgr:        deviceMgr,
+		logicalDeviceMgr: lDeviceMgr,
+	}
+	return handler
+}
+
+// isTestMode is a helper function to determine a function is invoked for testing only
+func isTestMode(ctx context.Context) bool {
+	md, _ := metadata.FromIncomingContext(ctx)
+	_, exist := md[common.TestModeKeys_api_test.String()]
+	return exist
+}
+
+// waitForNilResponseOnSuccess is a helper function to wait for a response on channel ch where an nil
+// response is expected in a successful scenario
+func waitForNilResponseOnSuccess(ctx context.Context, ch chan interface{}) (*empty.Empty, error) {
+	select {
+	case res := <-ch:
+		if res == nil {
+			return new(empty.Empty), nil
+		} else if err, ok := res.(error); ok {
+			return new(empty.Empty), err
+		} else {
+			log.Warnw("unexpected-return-type", log.Fields{"result": res})
+			err = status.Errorf(codes.Internal, "%s", res)
+			return new(empty.Empty), err
+		}
+	case <-ctx.Done():
+		log.Debug("client-timeout")
+		return nil, ctx.Err()
+	}
+}
+
+// GetVoltha returns the contents of all components (i.e. devices, logical_devices, ...)
+func (handler *APIHandler) GetVoltha(ctx context.Context, empty *empty.Empty) (*voltha.Voltha, error) {
+	log.Debug("GetVoltha")
+	return handler.commonMgr.GetVoltha(ctx)
+}
+
+// ListCoreInstances returns details on the running core containers
+func (handler *APIHandler) ListCoreInstances(ctx context.Context, empty *empty.Empty) (*voltha.CoreInstances, error) {
+	log.Debug("ListCoreInstances")
+	return handler.commonMgr.ListCoreInstances(ctx)
+}
+
+// GetCoreInstance returns the details of a specific core container
+func (handler *APIHandler) GetCoreInstance(ctx context.Context, id *voltha.ID) (*voltha.CoreInstance, error) {
+	log.Debugw("GetCoreInstance", log.Fields{"id": id})
+	return handler.commonMgr.GetCoreInstance(ctx, id.Id)
+}
+
+// ListAdapters returns the contents of all adapters known to the system
+func (handler *APIHandler) ListAdapters(ctx context.Context, empty *empty.Empty) (*voltha.Adapters, error) {
+	log.Debug("ListDevices")
+	return handler.commonMgr.ListAdapters(ctx)
+}
+
+// GetDevice returns the details a specific device
+func (handler *APIHandler) GetDevice(ctx context.Context, id *voltha.ID) (*voltha.Device, error) {
+	log.Debugw("GetDevice-request", log.Fields{"id": id})
+	return handler.deviceMgr.GetDevice(id.Id)
+}
+
+// ListDevices returns the contents of all devices known to the system
+func (handler *APIHandler) ListDevices(ctx context.Context, empty *empty.Empty) (*voltha.Devices, error) {
+	log.Debug("ListDevices")
+	return handler.deviceMgr.ListDevices()
+}
+
+// ListDeviceIds returns the list of device ids managed by a voltha core
+func (handler *APIHandler) ListDeviceIds(ctx context.Context, empty *empty.Empty) (*voltha.IDs, error) {
+	log.Debug("ListDeviceIDs")
+	if isTestMode(ctx) {
+		out := &voltha.IDs{Items: make([]*voltha.ID, 0)}
+		return out, nil
+	}
+	return handler.deviceMgr.ListDeviceIds()
+}
+
+// ListDevicePorts returns the ports details for a specific device entry
+func (handler *APIHandler) ListDevicePorts(ctx context.Context, id *voltha.ID) (*voltha.Ports, error) {
+	log.Debugw("ListDevicePorts", log.Fields{"deviceid": id})
+	return handler.deviceMgr.ListDevicePorts(ctx, id.Id)
+}
+
+// ListDevicePmConfigs returns the PM config details for a specific device entry
+func (handler *APIHandler) ListDevicePmConfigs(ctx context.Context, id *voltha.ID) (*voltha.PmConfigs, error) {
+	log.Debugw("ListDevicePmConfigs", log.Fields{"deviceid": id})
+	return handler.deviceMgr.ListDevicePmConfigs(ctx, id.Id)
+}
+
+// ListDeviceFlows returns the flow details for a specific device entry
+func (handler *APIHandler) ListDeviceFlows(ctx context.Context, id *voltha.ID) (*voltha.Flows, error) {
+	log.Debugw("ListDeviceFlows", log.Fields{"deviceid": id})
+	return handler.deviceMgr.ListDeviceFlows(ctx, id.Id)
+}
+
+// ListDeviceFlowGroups returns the flow group details for a specific device entry
+func (handler *APIHandler) ListDeviceFlowGroups(ctx context.Context, id *voltha.ID) (*voltha.FlowGroups, error) {
+	log.Debugw("ListDeviceFlowGroups", log.Fields{"deviceid": id})
+	return handler.deviceMgr.ListDeviceFlowGroups(ctx, id.Id)
+}
+
+// ListDeviceTypes returns all the device types known to the system
+func (handler *APIHandler) ListDeviceTypes(ctx context.Context, empty *empty.Empty) (*voltha.DeviceTypes, error) {
+	log.Debug("ListDeviceTypes")
+	return handler.commonMgr.ListDeviceTypes(ctx)
+}
+
+// GetDeviceType returns the device type for a specific device entry
+func (handler *APIHandler) GetDeviceType(ctx context.Context, id *voltha.ID) (*voltha.DeviceType, error) {
+	log.Debugw("GetDeviceType", log.Fields{"typeid": id})
+	return handler.commonMgr.GetDeviceType(ctx, id.Id)
+}
+
+// ListDeviceGroups returns all the device groups known to the system
+func (handler *APIHandler) ListDeviceGroups(ctx context.Context, empty *empty.Empty) (*voltha.DeviceGroups, error) {
+	log.Debug("ListDeviceGroups")
+	return handler.commonMgr.ListDeviceGroups(ctx)
+}
+
+// GetDeviceGroup returns a specific device group entry
+func (handler *APIHandler) GetDeviceGroup(ctx context.Context, id *voltha.ID) (*voltha.DeviceGroup, error) {
+	log.Debugw("GetDeviceGroup", log.Fields{"groupid": id})
+	return handler.commonMgr.GetDeviceGroup(ctx, id.Id)
+}
+
+// GetImageDownloadStatus returns the download status for a specific image entry
+func (handler *APIHandler) GetImageDownloadStatus(ctx context.Context, img *voltha.ImageDownload) (*voltha.ImageDownload, error) {
+	log.Debugw("GetImageDownloadStatus", log.Fields{"deviceid": img.GetId(), "imagename": img.GetName()})
+	return handler.deviceMgr.GetImageDownloadStatus(ctx, img.GetId(), img.GetName())
+}
+
+// GetImageDownload return the download details for a specific image entry
+func (handler *APIHandler) GetImageDownload(ctx context.Context, img *voltha.ImageDownload) (*voltha.ImageDownload, error) {
+	log.Debugw("GetImageDownload", log.Fields{"deviceid": img.GetId(), "imagename": img.GetName()})
+	return handler.deviceMgr.GetImageDownload(ctx, img.GetId(), img.GetName())
+}
+
+// ListImageDownloads returns all image downloads known to the system
+func (handler *APIHandler) ListImageDownloads(ctx context.Context, id *voltha.ID) (*voltha.ImageDownloads, error) {
+	log.Debugw("GetImageDownload", log.Fields{"deviceid": id})
+	return handler.deviceMgr.ListImageDownloads(ctx, id.Id)
+}
+
+// GetImages returns all images for a specific device entry
+func (handler *APIHandler) GetImages(ctx context.Context, id *voltha.ID) (*voltha.Images, error) {
+	log.Debugw("GetImages", log.Fields{"deviceid": id})
+	return handler.deviceMgr.GetImages(ctx, id.Id)
+}
+
+// ListAlarmFilters return all alarm filters known to the system
+func (handler *APIHandler) ListAlarmFilters(ctx context.Context, empty *empty.Empty) (*voltha.AlarmFilters, error) {
+	log.Debug("ListAlarmFilters")
+	return handler.commonMgr.ListAlarmFilters(ctx)
+}
+
+// GetAlarmFilter returns a specific alarm filter entry
+func (handler *APIHandler) GetAlarmFilter(ctx context.Context, id *voltha.ID) (*voltha.AlarmFilter, error) {
+	log.Debugw("GetAlarmFilter", log.Fields{"alarmid": id})
+	return handler.commonMgr.GetAlarmFilter(ctx, id.Id)
+}
+
+//ReconcileDevices is a request to a voltha core to managed a list of devices  based on their IDs
+func (handler *APIHandler) ReconcileDevices(ctx context.Context, ids *voltha.IDs) (*empty.Empty, error) {
+	log.Debug("ReconcileDevices")
+	if isTestMode(ctx) {
+		out := new(empty.Empty)
+		return out, nil
+	}
+	ch := make(chan interface{})
+	defer close(ch)
+	go handler.deviceMgr.ReconcileDevices(ctx, ids, ch)
+	return waitForNilResponseOnSuccess(ctx, ch)
+}
+
+// GetLogicalDevice returns the details for a specific logical device entry
+func (handler *APIHandler) GetLogicalDevice(ctx context.Context, id *voltha.ID) (*voltha.LogicalDevice, error) {
+	log.Debugw("GetLogicalDevice-request", log.Fields{"id": id})
+	return handler.logicalDeviceMgr.getLogicalDevice(id.Id)
+}
+
+// ListLogicalDevices returns all logical devices known to the system
+func (handler *APIHandler) ListLogicalDevices(ctx context.Context, empty *empty.Empty) (*voltha.LogicalDevices, error) {
+	log.Debug("ListLogicalDevices")
+	return handler.logicalDeviceMgr.listLogicalDevices()
+}
+
+// ListLogicalDevicePorts returns port details for a specific logical device entry
+func (handler *APIHandler) ListLogicalDevicePorts(ctx context.Context, id *voltha.ID) (*voltha.LogicalPorts, error) {
+	log.Debugw("ListLogicalDevicePorts", log.Fields{"logicaldeviceid": id})
+	return handler.logicalDeviceMgr.ListLogicalDevicePorts(ctx, id.Id)
+}
+
+// ListLogicalDeviceFlows returns flow details for a specific logical device entry
+func (handler *APIHandler) ListLogicalDeviceFlows(ctx context.Context, id *voltha.ID) (*voltha.Flows, error) {
+	log.Debugw("ListLogicalDeviceFlows", log.Fields{"logicaldeviceid": id})
+	return handler.logicalDeviceMgr.ListLogicalDeviceFlows(ctx, id.Id)
+}
+
+// ListLogicalDeviceFlowGroups returns flow group details for a specific logical device entry
+func (handler *APIHandler) ListLogicalDeviceFlowGroups(ctx context.Context, id *voltha.ID) (*voltha.FlowGroups, error) {
+	log.Debugw("ListLogicalDeviceFlows", log.Fields{"logicaldeviceid": id})
+	return handler.logicalDeviceMgr.ListLogicalDeviceFlowGroups(ctx, id.Id)
+}
+
+func (handler *APIHandler) SelfTest(ctx context.Context, id *voltha.ID) (*voltha.SelfTestResponse, error) {
+	log.Debugw("SelfTest-request", log.Fields{"id": id})
+	if isTestMode(ctx) {
+		resp := &voltha.SelfTestResponse{Result: voltha.SelfTestResponse_SUCCESS}
+		return resp, nil
+	}
+	return nil, errors.New("UnImplemented")
+}