Don't use layer cache, but do use mount-cache when using docker+buildkit

Question

When using buildkit, using the docker cli frontend, I sometimes do not want to use layer-cache, but do want to rely on the newer mount-cache type.

RUN --mount=type=cache,target=...

However running docker build --no-cache seemingly disables both.

Is there a way to choose such that only mount-cache is used during a rebuild ?

to force a package manager to update to its latest state, but in this case, with all the packages which have not changed still in the mount cache. — hbogert, Apr 07 '20 at 08:13
This is also useful to measure time saving when implementing caching. — Konrad Höffner, Apr 22 '22 at 11:19

score 1 · Answer 1 · answered Jul 18 '22 at 11:06

1

You can hack around it by starting the Dockerfile with a layer that will always change, invalidating all following cached layers.

An ARG with always-changing values will do. E.g:

FROM whatever
ARG CACHE_EPOCH
# ... etc

docker build --pull --build-arg CACHE_EPOCH=$(date +%s)

answered Jul 18 '22 at 11:06

N1ngu

On windows: `--build-arg CACHE_EPOCH="%time%"` – Antoine Dahan May 21 '23 at 17:52

1 Answers1