ENHANCMENT: save compressed subuser images

[peter1000]

Before starting with subuser a couple of days ago I looked into saving compressed docker images to file.

Because I like to be as much as possible internet independent (or if one uses subuser with a slower connection on a mobile ect.. or download limit) I will add the option to save subuser program images to file.

build once transfer and install multiple times.

[timthelion]

This is a good idea. I think, going off the example of git, we could call it subuser bundle...

[peter1000]

Not sure if that would be the best for what I had in mind.

Anyway, I implemented the first part of it to save to file: but will only send a pullrequest after the make image is merged.

at the moment I live in Southamerica so I do not want to be always dependent on the internet even though it works mostly fine

So my idea would be:

Additional folder: savedCompressedProgramImages

subuser save-compressed-image firefox saves to 'subuser/savedCompressedProgramImages/firefox.tar.xz

The compression is quite ok: the new libubuntu_precise has 172.2 MB and compresses to a saved one of 36 MB

This I already finished

[peter1000]

The second part I will do is a simple: command: install-compressed-image

the third part would be to integrate it into the normal subuser install procedure
maybe with an option like

subuser install firefox --allow-saveimage or something like that

Than it should first check if for any required dependency a saved image is available: this should work from top->bottom of dependencies because if a saved image for x11 is ready we do not need the lower dependent once

Just an idea?

[peter1000]

maybe the list argument could also have an option
subuser list savedimage

[peter1000]

the example: firefox_libx11_libubuntu_precise 373.2 MB compressed to 92 MB

Anyway if we want we could add a compression level option: xz uses default level 6 of 9

[peter1000]

compression level 9 did reduce a test image another 10+%

libubuntu_precise compression6.tar.xz 36.2MB
libubuntu_precise compression9.tar.xz 31.9MB

[timthelion]

I will work on going over all your comments tomorrow. It's 1 am here, and I want to think this through properly...

[peter1000]

see explanation: 47e3647#commitcomment-5405340

[timthelion]

It just occured to me, that putting the image-id into the filename won't work on Windows due to the 255 character long path restriction.

[timthelion]

I think that we shouldn't worry about that though. Some advanced features may not be supported on outdated operating systems ;)

[peter1000]

Do you want an image file and a extra jsonlike

firefox-image.tar.xz
firefox-image.json

firefox-image.json has the output of inspect

[timthelion]

That would be fine. But don't put the program name in the name of the files. It is simpler to progam if the names are standard.

[peter1000]

hi,
in the next couple of days I want have time for this.