[doc] Clarify how http status is controlled by the template

[drriguz]

Current documentation Currently, the document does not mention how http status will be returned. Obviously, for functions using http.ResponseWriter, we can control by res.WriteHeader(200):

func Handle(ctx context.Context, res http.ResponseWriter, req *http.Request) {

However, for cloudevent users, there's no option for controlling http status directly, instead it should be controlled by err error.

func Handle(ctx context.Context, event cloudevents.Event) (resp *cloudevents.Event, err error) {

Accroding to my understanding, the function should return 5xx if an error is returned by Handle. However, I tested the case but still returned 200.

Suggested changes or additions

• Document how http status is controlled by template
• Return 5xx if error is returned by handler
• Give user an option to specify the http status code if necessary

[drriguz]

It seems that the handler does return 500 if error occurs, however in unit test I got 200.

[drriguz]

Sorry about that, I found it's my mistack. It's working as expected.:p