K8SPSMDB-1593: Refactor user annotation key generation

pkg/controller/perconaservermongodb/custom_users.go

@@ -105,7 +105,7 @@ func handleUsers(ctx context.Context, cr *api.PerconaServerMongoDB, mongoCli mon
 			continue
 		}
 
-		annotationKey := fmt.Sprintf("percona.com/%s-%s-hash", cr.Name, user.Name)
+		annotationKey := buildAnnotationKey(cr.Name, user.Name)
 
 		if userInfo == nil && !user.IsExternalDB() {
 			err = createUser(ctx, client, mongoCli, &user, sec, annotationKey, userSecretPassKey)
@@ -422,6 +422,22 @@ func createUser(
 	return nil
 }
 
+// buildAnnotationKey creates a Kubernetes annotation key for tracking user password hashes.
+// Kubernetes annotation keys have a limit of 63 characters for the name part.
+// Format: "percona.com/<name>" where it must be less than or equal to 63 characters.
+// We need to keep the "-hash" suffix (5 chars), so we have 58 chars for the prefix.
+func buildAnnotationKey(crName, userName string) string {
+	annotationKeyBase := fmt.Sprintf("percona.com/%s-%s", crName, userName)
+	const hashSuffix = "-hash"
+	const maxAnnotationNameLength = 63
+	const maxPrefixLength = maxAnnotationNameLength - len(hashSuffix)
+
+	if len(annotationKeyBase) > maxPrefixLength {
+		annotationKeyBase = annotationKeyBase[:maxPrefixLength]
+	}
+	return fmt.Sprintf("%s%s", annotationKeyBase, hashSuffix)
+}
+
 // getCustomUserSecret gets secret by name defined by `user.PasswordSecretRef.Name` or returns a secret
 // with newly generated password if name matches defaultName
 func getCustomUserSecret(ctx context.Context, cl client.Client, cr *api.PerconaServerMongoDB, user *api.User, passKey string) (*corev1.Secret, error) {

pkg/controller/perconaservermongodb/custom_users_test.go

@@ -2,6 +2,7 @@ package perconaservermongodb
 
 import (
 	"context"
+	"strings"
 	"testing"
 
 	"github.com/pkg/errors"
@@ -411,3 +412,98 @@ func TestGetCustomUserSecret(t *testing.T) {
 		})
 	}
 }
+
+func TestBuildAnnotationKey(t *testing.T) {
+	tests := []struct {
+		name      string
+		crName    string
+		userName  string
+		want      string
+		wantLen   int
+		maxLength int
+	}{
+		{
+			name:      "short names within limit",
+			crName:    "my-cluster",
+			userName:  "user1",
+			want:      "percona.com/my-cluster-user1-hash",
+			wantLen:   33,
+			maxLength: 63,
+		},
+		{
+			name:      "exactly at limit",
+			crName:    "a",
+			userName:  strings.Repeat("x", 44), // 1 + 5 + 44 + 13 (percona.com/-) = 63, will not be truncated
+			want:      "percona.com/a-" + strings.Repeat("x", 44) + "-hash",
+			wantLen:   63,
+			maxLength: 63,
+		},
+		{
+			name:      "exceeds limit - truncates but keeps hash suffix",
+			crName:    "very-long-cluster-name-that-exceeds",
+			userName:  "very-long-user-name-that-also-exceeds",
+			want:      "percona.com/very-long-cluster-name-that-exceeds-very-long--hash",
+			wantLen:   63,
+			maxLength: 63,
+		},
+		{
+			name:      "very long cluster name",
+			crName:    strings.Repeat("a", 100),
+			userName:  "user",
+			want:      "percona.com/" + strings.Repeat("a", 46) + "-hash",
+			wantLen:   63,
+			maxLength: 63,
+		},
+		{
+			name:      "very long user name",
+			crName:    "cluster",
+			userName:  strings.Repeat("b", 100),
+			want:      "percona.com/cluster-" + strings.Repeat("b", 38) + "-hash",
+			wantLen:   63,
+			maxLength: 63,
+		},
+		{
+			name:      "both names very long",
+			crName:    strings.Repeat("c", 50),
+			userName:  strings.Repeat("d", 50),
+			want:      "percona.com/" + strings.Repeat("c", 46) + "-hash",
+			wantLen:   63,
+			maxLength: 63,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := buildAnnotationKey(tt.crName, tt.userName)
+
+			// Extract the name part (after "percona.com/")
+			prefix := "percona.com/"
+			if !strings.HasPrefix(got, prefix) {
+				t.Errorf("buildAnnotationKey() = %v, should start with %v", got, prefix)
+			}
+
+			namePart := got[len(prefix):]
+			gotLen := len(got)
+
+			// Verify the annotation key name part is within Kubernetes limit
+			if len(namePart) > tt.maxLength {
+				t.Errorf("buildAnnotationKey() name part length = %v, should be <= %v. Got: %v", len(namePart), tt.maxLength, got)
+			}
+
+			// Verify it ends with "-hash"
+			if !strings.HasSuffix(got, "-hash") {
+				t.Errorf("buildAnnotationKey() = %v, should end with '-hash'", got)
+			}
+
+			// Verify exact match for non-truncated cases
+			if gotLen <= tt.maxLength && tt.want != "" {
+				assert.Equal(t, tt.want, got, "buildAnnotationKey() = %v, want %v", got, tt.want)
+			}
+
+			// Verify length matches expected for all cases
+			if tt.wantLen > 0 {
+				assert.Equal(t, tt.wantLen, gotLen, "buildAnnotationKey() length = %v, want %v", gotLen, tt.wantLen)
+			}
+		})
+	}
+}