How to prevent Dockerfile caching git clone

Another workaround:

If you use GitHub (or gitlab or bitbucket too most likely) you can ADD the GitHub API's representation of your repo to a dummy location.

ADD https://api.github.com/repos/$USER/$REPO/git/refs/heads/$BRANCH version.jsonRUN git clone -b $BRANCH https://github.com/$USER/$REPO.git $GIT_HOME/

The API call will return different results when the head changes, invalidating the docker cache.

If you're dealing with private repos you can use github's x-oauth-basic authentication scheme with a personal access token like so:

ADD https://$ACCESS_TOKEN:x-oauth-basic@api.github.com/repos/$USER/$REPO/git/refs/heads/$BRANCH version.json

(thx @captnolimar for a suggested edit to clarify authentication)

Issue 1996 is not yet available, but you have the following workaround:

FROM fooARG CACHE_DATE=2016-01-01RUN git clone ...docker build --build-arg CACHE_DATE=$(date) ....

That would invalidate cache after the ARG CACHE_DATE line for every build.

Or:

ADD http://www.convert-unix-time.com/api?timestamp=now /tmp/bustcacheRUN git pull

That would also invalidate cache after this ADD line.

Similar idea:

Add ARG command to your Dockerfile:

# Dockerfile# add this and below command will run without cacheARG CACHEBUST=1

When you need to rebuild with selected cache, run it with --build-arg option

$ docker build -t your-image --build-arg CACHEBUST=$(date +%s) .

then only layer below ARG command in Dockerfile will rebuild.

I ran into this same issue myself, and I just decided to use the --no-cache option when I build the image, rather than trying to single out the git repo.

docker build --no-cache -t my_image .