Add APIName constant to generated code (#3445)

Useful to configure telemetry.

codegen/service/service.go

@@ -329,14 +329,17 @@ type Auther interface {
 }
 {{- end }}
 
+// APIName is the name of the API as defined in the design.
+const APIName = {{ printf "%q" .APIName }}
+
+// APIVersion is the version of the API as defined in the design.
+const APIVersion = {{ printf "%q" .APIVersion }}
+
 // ServiceName is the name of the service as defined in the design. This is the
 // same value that is set in the endpoint request contexts under the ServiceKey
 // key.
 const ServiceName = {{ printf "%q" .Name }}
 
-// APIVersion is the version of the API as defined in the design.
-const APIVersion = {{ printf "%q" .APIVersion }}
-
 // MethodNames lists the service method names as defined in the design. These
 // are the same values that are set in the endpoint request contexts under the
 // MethodKey key.

codegen/service/service_data.go

@@ -41,6 +41,8 @@ type (
 		Name string
 		// Description is the service description.
 		Description string
+		// APIName is the name of the API the service belongs to.
+		APIName string
 		// APIVersion is the API version.
 		APIVersion string
 		// StructName is the service struct name.
@@ -749,6 +751,7 @@ func (d ServicesData) analyze(service *expr.ServiceExpr) *Data {
 	data := &Data{
 		Name:               service.Name,
 		Description:        desc,
+		APIName:            expr.Root.API.Name,
 		APIVersion:         expr.Root.API.Version,
 		VarName:            varName,
 		PathName:           codegen.SnakeCase(varName),