ubuntu-device-flash lacks offline system image generation

[John McAleely]

Currently ubuntu-device-flash feeds data to a device script 'system-image-updater' to assemble a viable 'system-image' system partition for a phone (and it does other stuff this bug doesn't care about, like wiping userdata).

As input to the factory image process, the 'system' filesystem is needed to be output from ubuntu-device-flash without an attached device.

so, I think it would be useful if it were possible to say:

ubuntu-device-flash [--revision N] touch [--channel ubuntu-touch/stable] --device [mako|flo|whatever-is-in-the-channel] [--developer-mode] [--password X] --output-image path/to/system-image.tar.xz

Where system-image.tar.xz contains the contents of:

ubuntu-XXX.tar.xz
custom-YYY.tar.xz
device-ZZZ.tar.xz
version-AAA-tar.xz

plus any manipulations implied by the optional arguments so that this file can be input to a factory image creation tool for the device. It is assumed that these will be placed onto a suitable filesystem hosted in a single storage partition.

The optional --developer-mode arguments are so that devices can be fed into an OEM CI system that flashes the devices as they would be in the factory, but still requires test access to the system.

[John McAleely (john.mcaleely)]

reading the implenmentaion, --developer mode might be tough to support. In which case I'd be happy to drop that requirement, since we can depend ubuntu-device-flash flashing for all the CI systems we currently interact with.

[John McAleely (john.mcaleely)]

I'd be happy if the tool produced the output of make_ext4s instead of just files in a tarball, but I understand that there are android devices & factory flash tools which depend on particular versions of make_ext4s, so I'm not sure I see a clean way to support that.