SEBA-964 Remove hardcoded hostnames and replace with config system;
Move code to canonical golang directory structure;
Update licensing;
Update README.md

Change-Id: I4b00301eef4e87e81fc731a5af20cf7b7ed68678
diff --git a/internal/pkg/proxy/config.go b/internal/pkg/proxy/config.go
new file mode 100755
index 0000000..9d1b949
--- /dev/null
+++ b/internal/pkg/proxy/config.go
@@ -0,0 +1,167 @@
+/*

+ * 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.

+ */

+

+// Implements global configuration for nem-ondemand-proxy

+package proxy

+

+import (

+	"fmt"

+	flags "github.com/jessevdk/go-flags"

+	"gopkg.in/yaml.v2"

+	"io/ioutil"

+	"log"

+	"os"

+	"path"

+	"path/filepath"

+	"strings"

+	"time"

+)

+

+type OutputType uint8

+

+type GrpcConfigSpec struct {

+	Timeout time.Duration `yaml:"timeout"`

+}

+

+type TlsConfigSpec struct {

+	UseTls bool   `yaml:"useTls"`

+	CACert string `yaml:"caCert"`

+	Cert   string `yaml:"cert"`

+	Key    string `yaml:"key"`

+	Verify string `yaml:"verify"`

+}

+

+type GlobalConfigSpec struct {

+	Server string         `yaml:"server"`

+	Kafka  string         `yaml:"kafka"`

+	Local  string         `yaml:"local"`

+	Tls    TlsConfigSpec  `yaml:"tls"`

+	Grpc   GrpcConfigSpec `yaml:"grpc"`

+}

+

+var (

+	CharReplacer = strings.NewReplacer("\\t", "\t", "\\n", "\n")

+

+	GlobalConfig = GlobalConfigSpec{

+		Server: "voltha-rw-core.voltha:50057",

+		Kafka:  "voltha-kafka.voltha:9092",

+		Local:  "0.0.0.0:50052",

+		Tls: TlsConfigSpec{

+			UseTls: false,

+		},

+		Grpc: GrpcConfigSpec{

+			Timeout: time.Minute * 5,

+		},

+	}

+

+	GlobalCommandOptions = make(map[string]map[string]string)

+

+	GlobalOptions struct {

+		Config string `short:"c" long:"config" env:"PROXYCONFIG" value-name:"FILE" default:"" description:"Location of proxy config file"`

+		Server string `short:"s" long:"server" default:"" value-name:"SERVER:PORT" description:"IP/Host and port of VOLTHA"`

+		Kafka  string `short:"k" long:"kafka" default:"" value-name:"SERVER:PORT" description:"IP/Host and port of Kafka"`

+		Local  string `short:"l" long:"local" default:"" value-name:"SERVER:PORT" description:"IP/Host and port to listen on"`

+

+		// The following are not necessarily implemented yet.

+		Debug   bool   `short:"d" long:"debug" description:"Enable debug mode"`

+		Timeout string `short:"t" long:"timeout" description:"API call timeout duration" value-name:"DURATION" default:""`

+		UseTLS  bool   `long:"tls" description:"Use TLS"`

+		CACert  string `long:"tlscacert" value-name:"CA_CERT_FILE" description:"Trust certs signed only by this CA"`

+		Cert    string `long:"tlscert" value-name:"CERT_FILE" description:"Path to TLS vertificate file"`

+		Key     string `long:"tlskey" value-name:"KEY_FILE" description:"Path to TLS key file"`

+		Verify  bool   `long:"tlsverify" description:"Use TLS and verify the remote"`

+	}

+

+	Debug = log.New(os.Stdout, "DEBUG: ", 0)

+	Info  = log.New(os.Stdout, "INFO: ", 0)

+	Warn  = log.New(os.Stderr, "WARN: ", 0)

+	Error = log.New(os.Stderr, "ERROR: ", 0)

+)

+

+func ParseCommandLine() {

+	parser := flags.NewNamedParser(path.Base(os.Args[0]),

+		flags.HelpFlag|flags.PassDoubleDash|flags.PassAfterNonOption)

+	_, err := parser.AddGroup("Global Options", "", &GlobalOptions)

+	if err != nil {

+		panic(err)

+	}

+

+	_, err = parser.ParseArgs(os.Args[1:])

+	if err != nil {

+		_, ok := err.(*flags.Error)

+		if ok {

+			real := err.(*flags.Error)

+			if real.Type == flags.ErrHelp {

+				os.Stdout.WriteString(err.Error() + "\n")

+				os.Exit(0)

+			}

+		}

+

+		fmt.Fprintf(os.Stderr, "%s: %s\n", os.Args[0], err.Error())

+

+		os.Exit(1)

+	}

+}

+

+func ProcessGlobalOptions() {

+	if len(GlobalOptions.Config) == 0 {

+		home, err := os.UserHomeDir()

+		if err != nil {

+			Warn.Printf("Unable to discover the user's home directory: %s", err)

+			home = "~"

+		}

+		GlobalOptions.Config = filepath.Join(home, ".nem", "config")

+	}

+

+	if info, err := os.Stat(GlobalOptions.Config); err == nil && !info.IsDir() {

+		configFile, err := ioutil.ReadFile(GlobalOptions.Config)

+		if err != nil {

+			Error.Fatalf("Unable to read the configuration file '%s': %s",

+				GlobalOptions.Config, err.Error())

+		}

+		if err = yaml.Unmarshal(configFile, &GlobalConfig); err != nil {

+			Error.Fatalf("Unable to parse the configuration file '%s': %s",

+				GlobalOptions.Config, err.Error())

+		}

+	}

+

+	// Override from command line

+	if GlobalOptions.Server != "" {

+		GlobalConfig.Server = GlobalOptions.Server

+	}

+	if GlobalOptions.Kafka != "" {

+		GlobalConfig.Kafka = GlobalOptions.Kafka

+	}

+	if GlobalOptions.Local != "" {

+		GlobalConfig.Local = GlobalOptions.Local

+	}

+

+	if GlobalOptions.Timeout != "" {

+		timeout, err := time.ParseDuration(GlobalOptions.Timeout)

+		if err != nil {

+			Error.Fatalf("Unable to parse specified timeout duration '%s': %s",

+				GlobalOptions.Timeout, err.Error())

+		}

+		GlobalConfig.Grpc.Timeout = timeout

+	}

+}

+

+func ShowGlobalOptions() {

+	log.Printf("Configuration:")

+	log.Printf("    Voltha gRPC Server: %v", GlobalConfig.Server)

+	log.Printf("    Kafka: %v", GlobalConfig.Kafka)

+	log.Printf("    Listen Address: %v", GlobalConfig.Local)

+}