add exip (mini) cli

README.md

@@ -5,4 +5,3 @@ TODO:
 + Decent Logging;
 + README Documentation;
 + Unit-Tests;
-+ Add a small cmd cli (named `exip`), using standard go code only;

cmd/exip/main.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/glendc/go-external-ip"
+)
+
+// CLI Flags
+var (
+	timeout = flag.Duration("t", time.Second*2, "consensus's voting timeout")
+	verbose = flag.Bool("v", false, "verbose logging")
+)
+
+func main() {
+	// configure the consensus
+	cfg := externalip.DefaultConsensusConfig()
+	if timeout != nil {
+		cfg.WithTimeout(*timeout)
+	}
+
+	// TODO: Add Logging (and use the verbose flag)
+
+	// create the consensus
+	consensus := externalip.DefaultConsensus(
+		externalip.DefaultConsensusConfig().WithTimeout(*timeout))
+
+	// retrieve the external ip
+	ip, err := consensus.ExternalIP()
+
+	// simple error handling
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+
+	// success, simply output the IP in string format
+	fmt.Println(ip.String())
+}
+
+func init() {
+	// Define customized usage output
+	flag.Usage = func() {
+		fmt.Fprint(os.Stderr, "Retrieve your external IP.\n\n")
+		fmt.Fprintf(os.Stderr, "Usage:\n    %s [flags]\n\n", os.Args[0])
+		fmt.Fprintln(os.Stderr, "Flags:")
+		fmt.Fprintf(os.Stderr, "  -h help\n    \tshow this usage message\n")
+		flag.PrintDefaults()
+	}
+
+	// Parse CLI Flags
+	flag.Parse()
+}