Make the config file a required argument

When running in a container we should not attempt to look in the
homedir for a config file. The user should explicitly mount it into the
container and pass it to the program.

README.md

@@ -77,7 +77,7 @@ The `ipv4CheckUrl` and `ipv6CheckUrl` configuration settings are optional. If se
 ./digitalocean-dynamic-ip
 ```
 
-Optionally, you can create the configuration file with any name wherever you want, and pass it as a command line argument:
+Configuration file location must be specified as a positional argument:
 
 ```bash
 #run:

digitalocean-dynamic-ip.go

@@ -13,8 +13,6 @@ import (
 	"net/url"
 	"os"
 	"strconv"
-
-	homedir "github.com/mitchellh/go-homedir"
 )
 
 func checkError(err error) {
@@ -117,16 +115,11 @@ func GetConfig() ClientConfig {
 		log.SetOutput(os.Stdout)
 	}
 
-	configFile := ""
 	if len(flag.Args()) == 0 {
-		var err error
-		configFile, err = homedir.Dir()
-		checkError(err)
-		configFile += "/.digitalocean-dynamic-ip.json"
-	} else {
-		configFile = flag.Args()[0]
+		logError("Missing required argument with config file path.")
 	}
 
+	configFile := flag.Args()[0]
 	log.Printf("Using Config file: %s", configFile)
 
 	getfile, err := ioutil.ReadFile(configFile)
@@ -142,8 +135,6 @@ func usage() {
 		"-h | -help\n\tShow this help message\n"+
 		"-d | -debug\n\tPrint debug messages to standard output\n"+
 		"[config_file]\n\tlocation of the configuration file\n\n"+
-		"If the [config_file] parameter is not passed, then the default\n"+
-		"config location of ~/.digitalocean-dynamic-ip.json will be used.\n\n"+
 		"example usages:\n\t%[1]s -help\n"+
 		"\t%[1]s\n"+
 		"\t%[1]s %[2]s\n"+

go.mod

@@ -1,5 +1,3 @@
 module github.com/anaganisk/digitalocean-dynamic-dns-ip
 
-require github.com/mitchellh/go-homedir v1.1.0
-
 go 1.8

go.sum

@@ -1,2 +0,0 @@
-github.com/mitchellh/go-homedir v1.1.0 h1:lukF9ziXFxDFPkA1vsr5zpc1XuPDn/wFntq5mG+4E0Y=
-github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=