Comment 1 for bug 1423622

I added a very crude version of this for experimenting into http://bazaar.launchpad.net/~snappy-dev/ubuntu-system-image/ppa-upload/revision/305

Its essentially:
<thing>:json_data

Right now:
ERROR:json.dumps(error_string)
PROGRESS:json.dumps({"now": now, "total":total})
SPINNER:{}

Its this strange mix between "string:json_data" because of idiosyncrasies in the golang json parser, it likes to know a struct that it can unpack the json into (and because the payload of the types is different golang is a bit unhappy). This is not the final format, I think I will just fight the json parser a bit more (and unpack only the type and then unpack into the right type). But I wanted something to experiment with in the image. Happy to hear your opinions too, does not have to be json, but my initial "type:string" is too simple as errors are multi-line of course.