Should we need to return JSON as well from the container plugins?

[agonzalezro]

At the moment the container plugin is receiving a JSON and returning a simple string.

Maybe it would be useful for extensibility to return a JSON here as well.

There is a small problem: the plugins are going to be more complex because they need to marshal JSON, but... at the moment they are currently unmarshaling it.

Possible solution: we could accept string responses and json response, this wouldn't break backwards compatibility which is a plus :)