Add version package to later use as configuration package

Author: MatteoPologruto

Diff for: globals/globals.go

@@ -0,0 +1,13 @@
+package globals
+
+import (
+	"os"
+	"path/filepath"
+
+	"github.com/arduino/arduinoOTA/version"
+)
+
+var (
+	// VersionInfo contains all info injected during build
+	VersionInfo = version.NewInfo(filepath.Base(os.Args[0]))
+)

Diff for: main.go

@@ -15,10 +15,9 @@ import (
 	"strconv"
 	"strings"
 	"time"
-)
 
-// AppVersion is the application version.
-const AppVersion = "1.3.0"
+	"github.com/arduino/arduinoOTA/globals"
+)
 
 var compileInfo string
 
@@ -45,7 +44,7 @@ func main() {
 	flag.Parse()
 
 	if *version {
-		fmt.Println(AppVersion + compileInfo)
+		fmt.Println(globals.VersionInfo.String() + compileInfo)
 		os.Exit(0)
 	}
 

Diff for: version/version.go

@@ -0,0 +1,39 @@
+package version
+
+import "fmt"
+
+var (
+	defaultVersionString = "0.0.0-git"
+	versionString        = ""
+	commit               = ""
+	date                 = ""
+)
+
+// Info is a struct that contains information about the application
+type Info struct {
+	Application   string `json:"Application"`
+	VersionString string `json:"VersionString"`
+	Commit        string `json:"Commit"`
+	Date          string `json:"Date"`
+}
+
+// NewInfo returns a pointer to an updated Info struct
+func NewInfo(application string) *Info {
+	return &Info{
+		Application:   application,
+		VersionString: versionString,
+		Commit:        commit,
+		Date:          date,
+	}
+}
+
+func (i *Info) String() string {
+	return fmt.Sprintf("%[1]s Version: %[2]s Commit: %[3]s Date: %[4]s", i.Application, i.VersionString, i.Commit, i.Date)
+}
+
+//nolint:gochecknoinits
+func init() {
+	if versionString == "" {
+		versionString = defaultVersionString
+	}
+}