Merge lp://staging/~barry/ubuntu-system-image/lp1423622 into lp://staging/~registry/ubuntu-system-image/client

I'll add NEWS and update the manpage when I merge this into trunk.

Thanks for this work Barry, this looks very nice!

There are two changes I would love to see:
1. progress should be unbuffered (that was wrong in my initial branch, sorry). I.e. instead of print(), could you please use sys.stdout.write() and sys.stdout.flush() ?

2. if a exception happens in main.py (cf. http://bazaar.launchpad.net/~ubuntu-system-image/ubuntu-system-image/client/view/head:/systemimage/main.py#L381) it would be nice to get a json error on stdout. Not sure how well this fits into the new schema, I guess it is ok if I get a non-json error on stderr that I can just display to the user.

On Mar 05, 2015, at 08:05 AM, Michael Vogt wrote:

>1. progress should be unbuffered (that was wrong in my initial branch,
>sorry). I.e. instead of print(), could you please use sys.stdout.write() and
>sys.stdout.flush() ?

Good point, I should have noticed that. I'll fix that asap.

>2. if a exception happens in main.py
>(cf. http://bazaar.launchpad.net/~ubuntu-system-image/ubuntu-system-image/client/view/head:/systemimage/main.py#L381)
>it would be nice to get a json error on stdout. Not sure how well this fits
>into the new schema, I guess it is ok if I get a non-json error on stderr
>that I can just display to the user.

Okay, we chatted on IRC and decided we don't need much here. I've been
meaning to add a simple message to stderr in this case anyway, so that's what
I'll do now.