Clarifies that glob pattern should be enclosed in quotes

This is to avoid the shell expanding the glob pattern before
it arrives to Go land.

This commit also does some code cleaning.

Author: c4milo

main.go

@@ -22,14 +22,16 @@ import (
 )
 
 var (
-	GithubToken       string
-	GithubUser        string
-	GithubRepo        string
-	GithubAPIEndpoint string
-	Version           string
-	Debug             bool
+	githubToken       string
+	githubUser        string
+	githubRepo        string
+	githubAPIEndpoint string
+	// Version gets initialized in compilation time.
+	Version string
+	debug   bool
 )
 
+// Release represents a Github Release.
 type Release struct {
 	UploadURL  string `json:"upload_url,omitempty"`
 	TagName    string `json:"tag_name"`
@@ -45,28 +47,29 @@ var verFlag bool
 func init() {
 	log.SetFlags(0)
 
-	Debug, _ = strconv.ParseBool(os.Getenv("DEBUG"))
+	debug, _ = strconv.ParseBool(os.Getenv("DEBUG"))
 
-	GithubToken = os.Getenv("GITHUB_TOKEN")
-	GithubUser = os.Getenv("GITHUB_USER")
-	GithubRepo = os.Getenv("GITHUB_REPO")
-	GithubAPIEndpoint = os.Getenv("GITHUB_API")
+	githubToken = os.Getenv("GITHUB_TOKEN")
+	githubUser = os.Getenv("GITHUB_USER")
+	githubRepo = os.Getenv("GITHUB_REPO")
+	githubAPIEndpoint = os.Getenv("GITHUB_API")
 
 	flag.BoolVar(&verFlag, "version", false, "-version")
 	flag.Parse()
 }
 
-var usage string = `Github command line release tool.
+var usage = `Github command line release tool.
 
 Usage:
-	github-release <user/repo> <tag> <branch> <description> <files>
+	github-release <user/repo> <tag> <branch> <description> "<files>"
 
 Parameters:
 	<user/repo>: Github user and repository
 	<tag>: Used to created the release. It is also used as the release's name
 	<branch>: Reference from where to create the provided <tag>, if it does not exist
 	<description>: The release description
-	<files>: Glob pattern describing the list of files to include in the release
+	<files>: Glob pattern describing the list of files to include in the release.
+			Make sure you enclose it in quotes to avoid the shell expanding the glob pattern.
 
 Options:
 	-version: Displays version
@@ -80,7 +83,7 @@ Environment variables:
 
 Before using this tool make sure you set the environment variable GITHUB_TOKEN
 with a valid Github token and correct authorization scopes to allow you to create releases
-in your project. For more information about creating Github tokens please read the 
+in your project. For more information about creating Github tokens please read the
 official Github documentation at https://help.github.com/articles/creating-an-access-token-for-command-line-use/
 
 Author: https://github.com/c4milo
@@ -103,16 +106,16 @@ func main() {
 		log.Fatal(usage)
 	}
 
-	if GithubToken == "" {
+	if githubToken == "" {
 		log.Fatal(`Error: GITHUB_TOKEN environment variable is not set.
 Please refer to https://help.github.com/articles/creating-an-access-token-for-command-line-use/ for more help\n`)
 	}
 
-	GithubUser = userRepo[0]
-	GithubRepo = userRepo[1]
-	GithubAPIEndpoint = fmt.Sprintf("https://api.github.com/repos/%s/%s", GithubUser, GithubRepo)
+	githubUser = userRepo[0]
+	githubRepo = userRepo[1]
+	githubAPIEndpoint = fmt.Sprintf("https://api.github.com/repos/%s/%s", githubUser, githubRepo)
 
-	if Debug {
+	if debug {
 		log.Println("Glob pattern received: ")
 		log.Println(os.Args[5])
 	}
@@ -122,7 +125,7 @@ Please refer to https://help.github.com/articles/creating-an-access-token-for-co
 		log.Fatalf("Error: Invalid glob pattern: %s\n", os.Args[5])
 	}
 
-	if Debug {
+	if debug {
 		log.Println("Expanded glob pattern: ")
 		log.Printf("%v\n", filepaths)
 	}
@@ -156,16 +159,16 @@ func uploadFile(uploadURL, path string) {
 		log.Printf("Error: %s\n", err.Error())
 	}
 
-	if Debug {
+	if debug {
 		log.Println("========= UPLOAD RESPONSE ===========")
 		log.Println(string(body[:]))
 	}
 }
 
-// Creates a Github Release, attaching the given files as release assets
-// If a release already exist, up in Github, this function will attempt to attach the given files to it
+// CreateRelease creates a Github Release, attaching the given files as release assets
+// If a release already exist, up in Github, this function will attempt to attach the given files to it.
 func CreateRelease(tag, branch, desc string, filepaths []string) {
-	endpoint := fmt.Sprintf("%s/releases", GithubAPIEndpoint)
+	endpoint := fmt.Sprintf("%s/releases", githubAPIEndpoint)
 
 	release := Release{
 		TagName:    tag,
@@ -224,12 +227,12 @@ func doRequest(method, url, contentType string, reqBody io.Reader, bodySize int6
 		return nil, err
 	}
 
-	req.Header.Set("Authorization", fmt.Sprintf("token %s", GithubToken))
+	req.Header.Set("Authorization", fmt.Sprintf("token %s", githubToken))
 	req.Header.Set("Content-type", contentType)
 	req.Header.Set("Accept", "application/vnd.github.v3+json")
 	req.ContentLength = bodySize
 
-	if Debug {
+	if debug {
 		log.Println("================ REQUEST DUMP ==================")
 		dump, err := httputil.DumpRequestOut(req, true)
 		if err != nil {
@@ -240,7 +243,7 @@ func doRequest(method, url, contentType string, reqBody io.Reader, bodySize int6
 
 	resp, err := http.DefaultClient.Do(req)
 
-	if Debug {
+	if debug {
 		log.Println("================ RESPONSE DUMP ==================")
 		dump, err := httputil.DumpResponse(resp, true)
 		if err != nil {