Gitlab-runner exec docker: local cache?

I’m using the following command to run a job locally to test it before I push:

gitlab-runner exec docker --cache-dir=/tmp/gitlab-cache specs

When I run in this manner I get the following output (and no cache capabilities):

ERROR: Could not create cache adapter
error=cache factory not found: factory for cache adapter "" was not registered

Is there a way to configure (globally?) my gitlab-runner exec to allow for a local caching so I can leverage cache: in my .gitlab-ci.yml to test builds locally?

Thanks in advance.

I realize I can specify s3 or google cloud, but then I have to pass around credentials, etc. and I’d prefer to just leverage the local /tmp directory for a cache.