diffi command to inspect changes on image filesystem

[ashwinphatak]

Closes #12641

Signed-off-by: Ashwin Phatak ashwinpphatak@gmail.com

[ashwinphatak]

#12641

[tcurdt]

Hm. Since the change type does not have a size attribute - how could we get the size of the change.
I guess best would be to add it to the struct so we don't have to change the driver protocol.

https://github.com/docker/docker/blob/master/daemon/graphdriver/driver.go#L115

But adding it to the driver doesn't seem to be so easy

https://github.com/docker/docker/blob/master/daemon/graphdriver/aufs/aufs.go#L352

unless we could use this here too for size:

https://github.com/docker/docker/blob/master/daemon/graphdriver/aufs/aufs.go#L328

[ashwinphatak]

Do we need the size diff at the level of each change, or only the layer?

DiffSize() should work for layers https://github.com/docker/docker/blob/master/daemon/graphdriver/driver.go#L123

[tcurdt]

I am personally after the size diff of each change. The user story is to track down changes that enlarge images.

[cpuguy83]

@ashwinphatak can you add closes #12641 to the main/first comment?

[ashwinphatak]

@cpuguy83 done

[tiborvass]

@ashwinphatak my personal opinion is that I don't want to add another command just for diffing images. But we should also probably not overload diff like we did with inspect that is a hybrid between image_inspect and container_inspect.

I do welcome the feature, but not in this form. Would prefer to close the PR and continue discussion on the issue.

[ashwinphatak]

Closing the issue as this feature needs more discussion around requirements. See #12641

[tiborvass]

Thanks for your understanding !