Output more information during retrofit-image action

[Joshua Genet]

We've got some low-spec machines where the retrofit-image action can take around 2hrs. We thought the action was hanging due to an error, but it eventually did complete. Some sort of output signifying that this action could take a while would be welcome.

[Frode Nordahl (fnordahl)]

Thank you for the bug, there is opportunity for the action code to relay output from the command during execution as opposed to collecting it and logging it on completion, and we should probably do that at some point.

Also note that the tool benefits from KVM acceleration, so if this is unavailable or disabled on the host it will definitely take longer than it has to.

[Mustafa Kemal Gilor (mustafakemalgilor)]

After giving it a `glance` (pun intended), it seems that the `retrofit-image` action has three major bottlenecks which are desperate for some interactive feedback:

- Original image download
- Retrofitting
- Retrofitted image upload

For the image download & upload steps, it is pretty straightforward to observe the progress with a simple wrapper class via intercepting the read/write filesystem calls and it is possible to have a progress indicator next to the action status (see attachment download.gif).

As for the retrofitting, it is not that simple to report the progress percentage, since it is an external utility with lots of steps and it generates lots of output. At the current state, the output of retrofitting is reported at the end of the execution. This is easy to convert to "log the output as it comes", but observing the activity still needs the log level to be set to DEBUG. To remove this necessity, my first take on the matter is to truncate the output to a pre-determined length and update the status with it (e.g. Retrofitting 'x' -> 'aaaaaaa....'), so the user can easily observe the activity.

Any thoughts?