Add version to the Service struct

.run/Run Vertex.run.xml

@@ -2,6 +2,9 @@
   <configuration default="false" name="Run Vertex" type="GoApplicationRunConfiguration" factoryName="Go Application">
     <module name="Vertex" />
     <working_directory value="$PROJECT_DIR$" />
+    <envs>
+      <env name="DEBUG" value="1" />
+    </envs>
     <kind value="PACKAGE" />
     <package value="github.com/vertex-center/vertex" />
     <directory value="$PROJECT_DIR$" />

types/service.go

@@ -1,12 +1,30 @@
 package types
 
-import "errors"
+import (
+	"errors"
+
+	"github.com/vertex-center/vertex/pkg/log"
+	"github.com/vertex-center/vlog"
+)
 
 const (
 	URLKindClient = "client"
 )
 
+var (
+	ErrServiceNotFound = errors.New("the service was not found")
+)
+
+type Version int
+
+type ServiceVersioning struct {
+	// Version is the version of the service format used.
+	Version Version `yaml:"version" json:"version"`
+}
+
 type Service struct {
+	ServiceVersioning
+
 	// ID is the identifier of the service. It must be unique.
 	ID string `yaml:"id" json:"id"`
 
@@ -41,6 +59,33 @@ type Service struct {
 	Methods ServiceMethods `yaml:"methods" json:"methods"`
 }
 
+type ServiceV1 Service
+
+func (s *Service) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	var versioning ServiceVersioning
+	err := unmarshal(&versioning)
+	if err != nil {
+		return err
+	}
+	s.ServiceVersioning = versioning
+
+	log.Debug("reading service", vlog.Int("version", int(versioning.Version)))
+
+	switch versioning.Version {
+	case 0, 1:
+		var service ServiceV1
+		err := unmarshal(&service)
+		if err != nil {
+			return err
+		}
+		*s = Service(service)
+	default:
+		return errors.New("service version not supported")
+	}
+
+	return nil
+}
+
 type DatabaseEnvironment struct {
 	// DisplayName is a readable name for the user.
 	DisplayName string `yaml:"display_name" json:"display_name"`
@@ -187,10 +232,6 @@ type URL struct {
 	Kind string `yaml:"kind" json:"kind"`
 }
 
-var (
-	ErrServiceNotFound = errors.New("the service was not found")
-)
-
 type ServiceAdapterPort interface {
 	// Get a service with its id. Returns ErrServiceNotFound if
 	// the service was not found.