Make it possible to set authtoken via ENV

main.go

@@ -14,29 +14,95 @@ import (
 
 func main() {
 	// log.SetFlags(log.Lshortfile)
-	flag.Int("port", 4912, "Port to run server/client on.")
-	addr := flag.String("a", "127.0.0.1", "address to connect to.")
-	isServer := flag.Bool("s", false, "Set if running the server.")
+	// flag.Int("port", 4912, "Port to run server/client on.")
+	// addr := flag.String("a", "127.0.0.1", "address to connect to.")
+	isServer := flag.Bool("s", false, "Run netgiv in server mode")
+
+	// client mode flags
 	isList := flag.Bool("l", false, "Set if requesting a list")
-	isSend := flag.Bool("c", false, "Set if sending a file (copy)")
-	isReceive := flag.Bool("p", false, "Set if receiving a file (paste)")
+	isSend := flag.Bool("c", false, "sending stdin to netgiv server (copy)")
+	isReceive := flag.Bool("p", false, "receive file from netgiv server to stdout (paste)")
+	flag.String("address", "", "IP address/hostname of the netgiv server")
+
+	helpConfig := flag.Bool("help-config", false, "Show help on netgiv configuration")
+
+	// common flags
+	flag.String("authtoken", "", "Authentication token")
+	flag.Int("port", 0, "Port")
 
 	flag.Parse()
 
+	viper.AddConfigPath("$HOME/.netgiv/") // call multiple times to add many search paths
+	viper.SetConfigType("yaml")
+
 	viper.SetDefault("port", 4512)
 
+	if err := viper.ReadInConfig(); err != nil {
+		if _, ok := err.(viper.ConfigFileNotFoundError); ok {
+			// no config file maybe that's ok
+			panic(err)
+		} else {
+			// Config file was found but another error was produced
+			log.Fatal(err)
+		}
+	}
+
 	pflag.CommandLine.AddGoFlagSet(flag.CommandLine)
 	pflag.Parse()
 	viper.BindPFlags(pflag.CommandLine)
 
+	viper.SetEnvPrefix("NETGIV")
+	viper.BindEnv("authtoken")
+
+	// pull the various things into local variables
 	port := viper.GetInt("port") // retrieve value from viper
+	authtoken := viper.GetString("authtoken")
+
+	if authtoken == "" {
+		log.Fatal("authtoken must be set")
+	}
+
+	address := viper.GetString("address")
+	if !*isServer && address == "" {
+		log.Fatal("an address must be provided on the command line, or configuration")
+	}
+
+	flag.Usage = func() {
+		fmt.Fprintf(flag.CommandLine.Output(), "Usage of %s:\n", os.Args[0])
+		flag.PrintDefaults()
+		fmt.Printf("\nIf stdin or stdout is a pipe, %s will automatically choose an appropriate\n", os.Args[0])
+		fmt.Printf("copy (-c) or paste (-p) mode\n")
+	}
+
+	if *helpConfig {
+		fmt.Print(
+			`netgiv can be configured by command line parameters (see --help)  but it will
+often be convenient to create a config file. The config file is in yaml format,
+and should be stored in $HOME/.netgiv/config.yaml.
+
+For both client and server, you will want to set the 'authtoken' key (they must
+match). You'll want to also set the 'port' key if you would like to run netgiv 
+on a non-standard port (the default is 4512).
+
+On the client you will probably want to set the 'address' key, so that your client
+knows where to find the netgiv server. This key is ignored when running in server
+mode.
+
+Example:
+
+port: 5412
+authtoken: verysecretvaluehere
+address: 10.1.12.20
+`)
+		os.Exit(1)
+
+	}
 
 	if *isServer {
-
-		log.Printf("Server running on %d\n", port)
-		s := Server{port: port}
+		s := Server{port: port, authToken: authtoken}
 		s.Run()
 	} else {
+
 		if !*isList && !*isSend && !*isReceive {
 			// try to work out the intent based on whether or not stdin/stdout
 			// are ttys
@@ -45,21 +111,18 @@ func main() {
 
 			if stdinTTY && !stdoutTTY {
 				*isReceive = true
-
 			} else if !stdinTTY && stdoutTTY {
 				*isSend = true
 			} else if !stdinTTY && !stdoutTTY {
 				log.Fatal("I can't cope with both stdin and stdout being pipes")
+			} else {
+				flag.Usage()
+				os.Exit(1)
 			}
 
 		}
 
-		if !*isList && !*isSend && !*isReceive {
-			// could default to list?
-			*isList = true
-		}
-
-		c := Client{port: port, address: *addr, list: *isList, send: *isSend, receive: *isReceive}
+		c := Client{port: port, address: address, list: *isList, send: *isSend, receive: *isReceive, authToken: authtoken}
 		err := c.Connect()
 		if err != nil {
 			fmt.Print(err)