Supporting creating applications with a json file (or json-formatted string, or json object)

[vincepii]

The marathon.MarathonApp object can be built by passing all the parameters defining an application.

It would be nice if there was a way to create marathon.MarathonApp with json content directly.

A workaround, given a json object, would be to use marathon.MarathonApp(**myapp_json), but there would still be issues for method parameters using snake-case and json keys using camelCase:

E.g.,

TypeError: __init__() got an unexpected keyword argument 'upgradeStrategy'

[oilbeater]

Try MarathonApp.from_json()

[vincepii]

Thanks, for reference, the following works:

    c = marathon.MarathonClient(uri)
    app = marathon.MarathonApp.from_json(json.loads(json_definition))
    ret = c.create_app(appid, app)