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/config/config.go b/ro_core/config/config.go
new file mode 100644
index 0000000..b7906f2
--- /dev/null
+++ b/ro_core/config/config.go
@@ -0,0 +1,147 @@
+/*
+ * 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 config
+
+import (
+	"flag"
+	"fmt"
+	"github.com/opencord/voltha-go/common/log"
+	"os"
+)
+
+// RO Core service default constants
+const (
+	ConsulStoreName               = "consul"
+	EtcdStoreName                 = "etcd"
+	default_InstanceID            = "rocore001"
+	default_GrpcPort              = 50057
+	default_GrpcHost              = ""
+	default_KVStoreType           = EtcdStoreName
+	default_KVStoreTimeout        = 5 //in seconds
+	default_KVStoreHost           = "127.0.0.1"
+	default_KVStorePort           = 2379 // Consul = 8500; Etcd = 2379
+	default_KVTxnKeyDelTime       = 60
+	default_LogLevel              = 0
+	default_Banner                = false
+	default_CoreTopic             = "rocore"
+	default_ROCoreEndpoint        = "rocore"
+	default_ROCoreKey             = "pki/voltha.key"
+	default_ROCoreCert            = "pki/voltha.crt"
+	default_ROCoreCA              = "pki/voltha-CA.pem"
+	default_Affinity_Router_Topic = "affinityRouter"
+)
+
+// ROCoreFlags represents the set of configurations used by the read-only core service
+type ROCoreFlags struct {
+	// Command line parameters
+	InstanceID          string
+	ROCoreEndpoint      string
+	GrpcHost            string
+	GrpcPort            int
+	KVStoreType         string
+	KVStoreTimeout      int // in seconds
+	KVStoreHost         string
+	KVStorePort         int
+	KVTxnKeyDelTime     int
+	CoreTopic           string
+	LogLevel            int
+	Banner              bool
+	ROCoreKey           string
+	ROCoreCert          string
+	ROCoreCA            string
+	AffinityRouterTopic string
+}
+
+func init() {
+	log.AddPackage(log.JSON, log.WarnLevel, nil)
+}
+
+// NewROCoreFlags returns a new ROCore config
+func NewROCoreFlags() *ROCoreFlags {
+	var roCoreFlag = ROCoreFlags{ // Default values
+		InstanceID:          default_InstanceID,
+		ROCoreEndpoint:      default_ROCoreEndpoint,
+		GrpcHost:            default_GrpcHost,
+		GrpcPort:            default_GrpcPort,
+		KVStoreType:         default_KVStoreType,
+		KVStoreTimeout:      default_KVStoreTimeout,
+		KVStoreHost:         default_KVStoreHost,
+		KVStorePort:         default_KVStorePort,
+		KVTxnKeyDelTime:     default_KVTxnKeyDelTime,
+		CoreTopic:           default_CoreTopic,
+		LogLevel:            default_LogLevel,
+		Banner:              default_Banner,
+		ROCoreKey:           default_ROCoreKey,
+		ROCoreCert:          default_ROCoreCert,
+		ROCoreCA:            default_ROCoreCA,
+		AffinityRouterTopic: default_Affinity_Router_Topic,
+	}
+	return &roCoreFlag
+}
+
+// ParseCommandArguments parses the arguments when running read-only core service
+func (cf *ROCoreFlags) ParseCommandArguments() {
+
+	var help string
+
+	help = fmt.Sprintf("RO core endpoint address")
+	flag.StringVar(&(cf.ROCoreEndpoint), "vcore-endpoint", default_ROCoreEndpoint, help)
+
+	help = fmt.Sprintf("GRPC server - host")
+	flag.StringVar(&(cf.GrpcHost), "grpc_host", default_GrpcHost, help)
+
+	help = fmt.Sprintf("GRPC server - port")
+	flag.IntVar(&(cf.GrpcPort), "grpc_port", default_GrpcPort, help)
+
+	help = fmt.Sprintf("RO Core topic")
+	flag.StringVar(&(cf.CoreTopic), "ro_core_topic", default_CoreTopic, help)
+
+	help = fmt.Sprintf("Affinity Router topic")
+	flag.StringVar(&(cf.AffinityRouterTopic), "affinity_router_topic", default_Affinity_Router_Topic, help)
+
+	help = fmt.Sprintf("KV store type")
+	flag.StringVar(&(cf.KVStoreType), "kv_store_type", default_KVStoreType, help)
+
+	help = fmt.Sprintf("The default timeout when making a kv store request")
+	flag.IntVar(&(cf.KVStoreTimeout), "kv_store_request_timeout", default_KVStoreTimeout, help)
+
+	help = fmt.Sprintf("KV store host")
+	flag.StringVar(&(cf.KVStoreHost), "kv_store_host", default_KVStoreHost, help)
+
+	help = fmt.Sprintf("KV store port")
+	flag.IntVar(&(cf.KVStorePort), "kv_store_port", default_KVStorePort, help)
+
+	help = fmt.Sprintf("The time to wait before deleting a completed transaction key")
+	flag.IntVar(&(cf.KVTxnKeyDelTime), "kv_txn_delete_time", default_KVTxnKeyDelTime, help)
+
+	help = fmt.Sprintf("Log level")
+	flag.IntVar(&(cf.LogLevel), "log_level", default_LogLevel, help)
+
+	help = fmt.Sprintf("Show startup banner log lines")
+	flag.BoolVar(&cf.Banner, "banner", default_Banner, help)
+
+	flag.Parse()
+
+	containerName := getContainerInfo()
+	if len(containerName) > 0 {
+		cf.InstanceID = containerName
+	}
+
+}
+
+func getContainerInfo() string {
+	return os.Getenv("HOSTNAME")
+}