[METAL-1881] Remove naive mysql idenitifer limits (#33)

Co-authored-by: Damian Peckett <damian.peckett@kloeckner.com>

Author: dpeckett

pkg/controller/database/databaseHelper.go

@@ -133,6 +133,13 @@ func parseDatabaseSecretData(dbcr *kciv1alpha1.Database, data map[string][]byte)
 }
 
 func generateDatabaseSecretData(dbcr *kciv1alpha1.Database) (map[string][]byte, error) {
+	const (
+		// https://dev.mysql.com/doc/refman/5.7/en/identifier-length.html
+		mysqlDBNameLengthLimit = 63
+		// https://dev.mysql.com/doc/refman/5.7/en/replication-features-user-names.html
+		mysqlUserLengthLimit = 32
+	)
+
 	engine, err := dbcr.GetEngineType()
 	if err != nil {
 		return nil, err
@@ -151,8 +158,8 @@ func generateDatabaseSecretData(dbcr *kciv1alpha1.Database) (map[string][]byte,
 		return data, nil
 	case "mysql":
 		data := map[string][]byte{
-			"DB":       []byte(stringShortner(dbName)),
-			"USER":     []byte(stringShortner(dbUser)),
+			"DB":       []byte(kci.StringSanitize(dbName, mysqlDBNameLengthLimit)),
+			"USER":     []byte(kci.StringSanitize(dbUser, mysqlUserLengthLimit)),
 			"PASSWORD": []byte(dbPassword)}
 		return data, nil
 	default:

pkg/controller/database/helper.go

@@ -1,11 +1,8 @@
 package database
 
 import (
-	"crypto/md5"
-	"fmt"
 	kciv1alpha1 "github.com/kloeckner-i/db-operator/pkg/apis/kci/v1alpha1"
 	"github.com/kloeckner-i/db-operator/pkg/utils/kci"
-	"io"
 )
 
 func isSpecChanged(dbcr *kciv1alpha1.Database) bool {
@@ -26,13 +23,6 @@ func addSpecChecksum(dbcr *kciv1alpha1.Database) {
 	dbcr.ObjectMeta.SetAnnotations(annotations)
 }
 
-func stringShortner(s string) string {
-	h := md5.New()
-	io.WriteString(h, s)
-	str := fmt.Sprintf("%x", h.Sum(nil))
-	return str[0:16]
-}
-
 func containsString(slice []string, s string) bool {
 	for _, item := range slice {
 		if item == s {

pkg/controller/database/helper_test.go

@@ -82,9 +82,3 @@ func TestIsSpecChanged(t *testing.T) {
 	change := isSpecChanged(db)
 	assert.Equal(t, change, true, "expected true")
 }
-
-func TestStringShortner(t *testing.T) {
-	assert.Equal(t, "e08ba29f56785332", stringShortner("short_string"))
-	assert.Equal(t, "8f54fbbc6fefae00", stringShortner("short_string_longer"))
-	assert.Equal(t, "f32225e6124f2fab", stringShortner("short_string_to_long_to_see_all_chars_in_result"))
-}

pkg/controller/database/monitoring/database.go

@@ -5,8 +5,8 @@ import (
 
 	kciv1alpha1 "github.com/kloeckner-i/db-operator/pkg/apis/kci/v1alpha1"
 
-	v1 "k8s.io/api/core/v1"
 	v1apps "k8s.io/api/apps/v1"
+	v1 "k8s.io/api/core/v1"
 )
 
 // Deployment builds kubernetes deployment object

pkg/controller/database/monitoring/test.go

@@ -7,8 +7,8 @@ import (
 
 	"bou.ke/monkey"
 	"github.com/stretchr/testify/assert"
-	v1 "k8s.io/api/core/v1"
 	v1apps "k8s.io/api/apps/v1"
+	v1 "k8s.io/api/core/v1"
 )
 
 func testPGDeployment(t *testing.T) {

pkg/utils/kci/database.go

@@ -0,0 +1,31 @@
+package kci
+
+import (
+	"crypto/sha256"
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+// StringSanitize sanitizes and truncates a string to a fixed length using a hash function.
+// useful for restricting the length and content of user supplied database identifiers.
+func StringSanitize(s string, limit int) string {
+	// use lowercase exclusively for identifiers.
+	// https://dev.mysql.com/doc/refman/5.7/en/identifier-case-sensitivity.html
+	s = strings.ToLower(s)
+
+	// Strip out any unsupported characters.
+	// https://dev.mysql.com/doc/refman/5.7/en/identifiers.html
+	unsupportedChars := regexp.MustCompile(`[^0-9a-zA-Z$_]`)
+	s = unsupportedChars.ReplaceAllString(s, "_")
+
+	if len(s) <= limit {
+		return s
+	}
+
+	if limit <= 9 {
+		return fmt.Sprintf("%x", sha256.New().Sum([]byte(s)))[:limit]
+	}
+
+	return fmt.Sprintf("%s_%x", s[:limit-9], sha256.New().Sum([]byte(s))[:4])
+}

pkg/utils/kci/database_test.go

@@ -0,0 +1,23 @@
+package kci
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestStringSanitize(t *testing.T) {
+	// Handles very short limits
+	src := "HelloWorld"
+	actual := StringSanitize(src, 6)
+	assert.Equal(t, "68656c", actual)
+
+	// Sanitizes successfully
+	src = "Hello**World$"
+	actual = StringSanitize(src, 32)
+	assert.Equal(t, "hello__world$", actual)
+
+	// Truncates very long values
+	src = "The quick brown fox jumps over the lazy dog"
+	actual = StringSanitize(src, 32)
+	assert.Equal(t, "the_quick_brown_fox_jum_7468655f", actual)
+}