feat: add FillEntityID function

go.mod

@@ -5,6 +5,7 @@ go 1.19
 replace github.com/imdario/mergo v0.3.12 => github.com/Kong/mergo v0.3.13
 
 require (
+	github.com/gofrs/uuid v4.4.0+incompatible
 	github.com/google/go-cmp v0.5.9
 	github.com/google/go-querystring v1.1.0
 	github.com/google/uuid v1.3.0

go.sum

@@ -25,6 +25,8 @@ github.com/go-openapi/jsonreference v0.20.0/go.mod h1:Ag74Ico3lPc+zR+qjn4XBUmXym
 github.com/go-openapi/swag v0.19.5/go.mod h1:POnQmlKehdgb5mhVOsnJFsivZCEZ/vjK9gh66Z9tfKk=
 github.com/go-openapi/swag v0.19.14 h1:gm3vOOXfiuw5i9p5N9xJvfjvuofpyvLA9Wr6QfK5Fng=
 github.com/go-openapi/swag v0.19.14/go.mod h1:QYRuS/SOXUCsnplDa677K7+DxSOj6IPNl/eQntq43wQ=
+github.com/gofrs/uuid v4.4.0+incompatible h1:3qXRTX8/NbyulANqlc0lchS1gqAVxRgsuW1YrTJupqA=
+github.com/gofrs/uuid v4.4.0+incompatible/go.mod h1:b2aQJv3Z4Fp6yNu3cdSllBxTCLRxnplIgP/c0N/04lM=
 github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
 github.com/golang/mock v1.1.1/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=

kong/ids.go

@@ -0,0 +1,68 @@
+package kong
+
+import (
+	"fmt"
+
+	"github.com/gofrs/uuid"
+)
+
+// IDFillableEntitiesT is a type constraint for entities that can be filled with an ID.
+type IDFillableEntitiesT interface {
+	Service | Route
+}
+
+// FillEntityID fills the ID of an entity. It is a no-op if the entity already has an ID.
+// ID is generated in a deterministic way using UUIDv5. The UUIDv5 namespace is different for each entity type.
+// The name used to generate the UUIDv5 is:
+// - for Service: Service.Name
+// - for Route:   Route.Name
+func FillEntityID[T IDFillableEntitiesT](entity *T) error {
+	switch e := any(entity).(type) {
+	case *Service:
+		return fillIDForService(e)
+	case *Route:
+		return fillIDForRoute(e)
+	default:
+		return fmt.Errorf("unsupported entity: '%T'", entity)
+	}
+}
+
+// The following variables are UUIDv5 namespaces used to generate IDs for entities, one per each entity type.
+var (
+	serviceIDsNamespace = uuid.Must(uuid.FromString("497d0cb2-5630-40a7-9858-8f210e6295f4"))
+	routeIDsNamespace   = uuid.Must(uuid.FromString("6324c31d-0568-480f-8d8c-a5c1f4c8eb6c"))
+)
+
+func fillIDForService(svc *Service) error {
+	if svc == nil {
+		return fmt.Errorf("service is nil")
+	}
+	if svc.ID != nil {
+		// ID already set, do nothing.
+		return nil
+	}
+	if svc.Name == nil || *svc.Name == "" {
+		return fmt.Errorf("service name is required")
+	}
+
+	id := uuid.NewV5(serviceIDsNamespace, *svc.Name)
+	svc.ID = String(id.String())
+	return nil
+}
+
+func fillIDForRoute(route *Route) error {
+	if route == nil {
+		return fmt.Errorf("route is nil")
+	}
+	if route.ID != nil {
+		// ID already set, do nothing.
+		return nil
+	}
+	if route.Name == nil || *route.Name == "" {
+		return fmt.Errorf("route name is required")
+	}
+
+	id := uuid.NewV5(routeIDsNamespace, *route.Name)
+	route.ID = String(id.String())
+	return nil
+}

kong/ids_test.go

@@ -0,0 +1,111 @@
+package kong_test
+
+import (
+	"testing"
+
+	"github.com/kong/go-kong/kong"
+	"github.com/stretchr/testify/require"
+)
+
+type fillEntityIDTestCase[T kong.IDFillableEntitiesT] struct {
+	name   string
+	entity *T
+
+	assertEntity func(t *testing.T, entity *T)
+	expectErr    bool
+}
+
+func (tc fillEntityIDTestCase[T]) run(t *testing.T) {
+	t.Run(tc.name, func(t *testing.T) {
+		err := kong.FillEntityID(tc.entity)
+		if tc.expectErr {
+			require.Error(t, err)
+			return
+		}
+		require.NoError(t, err)
+		tc.assertEntity(t, tc.entity)
+	})
+}
+
+func TestFillEntityID(t *testing.T) {
+	t.Run("Service", func(t *testing.T) {
+		testCases := []fillEntityIDTestCase[kong.Service]{
+			{
+				name:      "service nil pointer",
+				entity:    (*kong.Service)(nil),
+				expectErr: true,
+			},
+			{
+				name:   "service with nil name",
+				entity: &kong.Service{},
+				assertEntity: func(t *testing.T, svc *kong.Service) {
+					require.Nil(t, svc.ID, "ID should not be set when name is nil")
+				},
+				expectErr: true,
+			},
+			{
+				name:   "service with empty name",
+				entity: &kong.Service{Name: kong.String("")},
+				assertEntity: func(t *testing.T, svc *kong.Service) {
+					require.Nil(t, svc.ID, "ID should not be set when name is empty")
+				},
+				expectErr: true,
+			},
+			{
+				name: "service with name",
+				entity: &kong.Service{
+					Name: kong.String("some.service.name"),
+				},
+				assertEntity: func(t *testing.T, svc *kong.Service) {
+					require.NotNil(t, svc.ID)
+					const expectedID = "14a84f13-96ef-5628-b300-8bcd5a509f9b"
+					require.Equal(t, expectedID, *svc.ID, "ID should be deterministic")
+				},
+			},
+		}
+		for _, tc := range testCases {
+			tc.run(t)
+		}
+	})
+
+	t.Run("Route", func(t *testing.T) {
+		testCases := []fillEntityIDTestCase[kong.Route]{
+			{
+				name:      "route nil pointer",
+				entity:    (*kong.Route)(nil),
+				expectErr: true,
+			},
+			{
+				name:   "route with nil name",
+				entity: &kong.Route{},
+				assertEntity: func(t *testing.T, route *kong.Route) {
+					require.Nil(t, route.ID, "ID should not be set when name is nil")
+				},
+				expectErr: true,
+			},
+			{
+				name:   "route with empty name",
+				entity: &kong.Route{Name: kong.String("")},
+				assertEntity: func(t *testing.T, route *kong.Route) {
+					require.Nil(t, route.ID, "ID should not be set when name is empty")
+				},
+				expectErr: true,
+			},
+			{
+				name: "route with name",
+				entity: &kong.Route{
+					Name: kong.String("some.service.name"),
+				},
+				assertEntity: func(t *testing.T, route *kong.Route) {
+					require.NotNil(t, route.ID)
+
+					const expectedID = "9279da23-17de-5cca-b1da-a60d7cec6802"
+					require.Equal(t, expectedID, *route.ID, "ID should be deterministic")
+				},
+			},
+		}
+		for _, tc := range testCases {
+			tc.run(t)
+		}
+	})
+}