Refactor pkg/common, Fixes #11599

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

stringid/README.md

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

stringid/stringid.go

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+package stringid
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+	"io"
+	"strconv"
+)
+
+// TruncateID returns a shorthand version of a string identifier for convenience.
+// A collision with other shorthands is very unlikely, but possible.
+// In case of a collision a lookup with TruncIndex.Get() will fail, and the caller
+// will need to use a langer prefix, or the full-length Id.
+func TruncateID(id string) string {
+	shortLen := 12
+	if len(id) < shortLen {
+		shortLen = len(id)
+	}
+	return id[:shortLen]
+}
+
+// GenerateRandomID returns an unique id
+func GenerateRandomID() string {
+	for {
+		id := make([]byte, 32)
+		if _, err := io.ReadFull(rand.Reader, id); err != nil {
+			panic(err) // This shouldn't happen
+		}
+		value := hex.EncodeToString(id)
+		// if we try to parse the truncated for as an int and we don't have
+		// an error then the value is all numberic and causes issues when
+		// used as a hostname. ref #3869
+		if _, err := strconv.ParseInt(TruncateID(value), 10, 64); err == nil {
+			continue
+		}
+		return value
+	}
+}

stringid/stringid_test.go

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+package stringid
+
+import "testing"
+
+func TestGenerateRandomID(t *testing.T) {
+	id := GenerateRandomID()
+
+	if len(id) != 64 {
+		t.Fatalf("Id returned is incorrect: %s", id)
+	}
+}
+
+func TestShortenId(t *testing.T) {
+	id := GenerateRandomID()
+	truncID := TruncateID(id)
+	if len(truncID) != 12 {
+		t.Fatalf("Id returned is incorrect: truncate on %s returned %s", id, truncID)
+	}
+}
+
+func TestShortenIdEmpty(t *testing.T) {
+	id := ""
+	truncID := TruncateID(id)
+	if len(truncID) > len(id) {
+		t.Fatalf("Id returned is incorrect: truncate on %s returned %s", id, truncID)
+	}
+}
+
+func TestShortenIdInvalid(t *testing.T) {
+	id := "1234"
+	truncID := TruncateID(id)
+	if len(truncID) != len(id) {
+		t.Fatalf("Id returned is incorrect: truncate on %s returned %s", id, truncID)
+	}
+}