Refactor pkg/common, Fixes #11599

Signed-off-by: Antonio Murdaca <me@runcom.ninja>

stringutils/README.md

@@ -0,0 +1 @@
+This package provides helper functions for dealing with strings

stringutils/stringutils.go

@@ -0,0 +1,43 @@
+package stringutils
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+	"io"
+	mathrand "math/rand"
+	"time"
+)
+
+// Generate 32 chars random string
+func GenerateRandomString() string {
+	id := make([]byte, 32)
+
+	if _, err := io.ReadFull(rand.Reader, id); err != nil {
+		panic(err) // This shouldn't happen
+	}
+	return hex.EncodeToString(id)
+}
+
+// Generate alpha only random stirng with length n
+func GenerateRandomAlphaOnlyString(n int) string {
+	// make a really long string
+	letters := []byte("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+	b := make([]byte, n)
+	r := mathrand.New(mathrand.NewSource(time.Now().UTC().UnixNano()))
+	for i := range b {
+		b[i] = letters[r.Intn(len(letters))]
+	}
+	return string(b)
+}
+
+// Generate Ascii random stirng with length n
+func GenerateRandomAsciiString(n int) string {
+	chars := "abcdefghijklmnopqrstuvwxyz" +
+		"ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
+		"~!@#$%^&*()-_+={}[]\\|<,>.?/\"';:` "
+	res := make([]byte, n)
+	for i := 0; i < n; i++ {
+		res[i] = chars[mathrand.Intn(len(chars))]
+	}
+	return string(res)
+}

stringutils/stringutils_test.go

@@ -0,0 +1,25 @@
+package stringutils
+
+import "testing"
+
+func TestRandomString(t *testing.T) {
+	str := GenerateRandomString()
+	if len(str) != 64 {
+		t.Fatalf("Id returned is incorrect: %s", str)
+	}
+}
+
+func TestRandomStringUniqueness(t *testing.T) {
+	repeats := 25
+	set := make(map[string]struct{}, repeats)
+	for i := 0; i < repeats; i = i + 1 {
+		str := GenerateRandomString()
+		if len(str) != 64 {
+			t.Fatalf("Id returned is incorrect: %s", str)
+		}
+		if _, ok := set[str]; ok {
+			t.Fatalf("Random number is repeated")
+		}
+		set[str] = struct{}{}
+	}
+}