Enable support for build --cache-from

[martinberanek]

Is this a BUG REPORT or FEATURE REQUEST?:

FEATURE REQUEST

Description

Introduce new cacheFrom parametr that (if specified) firstly pulls specified image and than use docker build --cache-from. This can significantly speed up image build and reduce space consumption in docker registry.

[pbillen]

+1

I believe you explicitly need to do docker pull in advance (unless you already have the latest in your local registry) or --cache-from has no effect. That is, I believe that --cache-from only considers the local registry.

So ideally, to do everything via Maven, we also need a pull mojo? Or another flag on top of --cache-from to denote that we want a pull first? I would say that the mojo is preferred, as the second option introduces some custom flag which is not possible via the regular Docker CLI/API.

[pbillen]

Also, we must allow that the pull could fail. This happens if the image was never pushed before.

I believe the general flow of usage of --cache-from is:

docker pull <image> || true
docker build --cache-from <image> --tag <image> .
docker push <image>

[martinberanek]

I have created pull request for this feature. Can anybody review/merge it?

[davidxia]

Added in #217

[seanwang-okta]

is this working? i'm using this in a project but it still doesn't use the image pulled as a cache @martinberanek