Support of '--prefix' option

anonuuid.go

@@ -23,6 +23,9 @@ type AnonUUID struct {
 
 	// Random flag will generate random fake UUIDs
 	Random bool
+
+	// Prefix will be the beginning of all the generated UUIDs
+	Prefix string
 }
 
 // Sanitize takes a string as input and return sanitized string
@@ -39,6 +42,13 @@ func (a *AnonUUID) Sanitize(input string) string {
 func (a *AnonUUID) FakeUUID(realUUID string) string {
 	if _, ok := a.cache[realUUID]; !ok {
 
+		if a.Prefix != "" {
+			matched, err := regexp.MatchString("^[a-z0-9]+$", a.Prefix)
+			if err != nil || !matched {
+				a.Prefix = "invalidprefix"
+			}
+		}
+
 		var fakeUUID string
 		var err error
 		if a.Hexspeak {
@@ -54,6 +64,13 @@ func (a *AnonUUID) FakeUUID(realUUID string) string {
 			log.Fatalf("Test")
 		}
 
+		if a.Prefix != "" {
+			fakeUUID, err = PrefixUUID(a.Prefix, fakeUUID)
+			if err != nil {
+				panic(err)
+			}
+		}
+
 		// FIXME: check for duplicates and retry
 
 		a.cache[realUUID] = fakeUUID
@@ -74,6 +91,16 @@ func init() {
 	rand.Seed(time.Now().UTC().UnixNano())
 }
 
+// PrefixUUID returns a prefixed UUID
+func PrefixUUID(prefix string, uuid string) (string, error) {
+	uuidLetters := uuid[:8] + uuid[9:13] + uuid[14:18] + uuid[19:23] + uuid[24:36]
+	prefixedUUID, err := FormatUUID(prefix + uuidLetters)
+	if err != nil {
+		return "", err
+	}
+	return prefixedUUID, nil
+}
+
 // FormatUUID takes a string in input and return an UUID formatted string by repeating the string and placing dashes if necessary
 func FormatUUID(part string) (string, error) {
 	if len(part) < 32 {

cmd/anonuuid/main.go

@@ -28,6 +28,10 @@ func main() {
 			Name:  "random, r",
 			Usage: "Generate random fake UUIDs",
 		},
+		cli.StringFlag{
+			Name:  "prefix, p",
+			Usage: "Prefix generated UUIDs",
+		},
 	}
 
 	app.Action = action
@@ -41,6 +45,7 @@ func action(c *cli.Context) {
 
 	anonuuid.Hexspeak = c.Bool("hexspeak")
 	anonuuid.Random = c.Bool("random")
+	anonuuid.Prefix = c.String("prefix")
 
 	for scanner.Scan() {
 		line := scanner.Text()