My docker image build seems to be taking a longer than usual time when running building an image. I noticed this happens to Rails applications a lot. My go app is way faster (~ 2 minutes while Rails takes about ~20 minutes!).
docker images are built using docker, inside the official docker:dind container. Drone has no control over how long it takes for an image to build. This is determined by docker (running inside docker:dind) and a variety of factors related to your host machine (memory, network, iops, etc).
One possible reason is the docker:dind does not have access to the docker build cache. It always seems to start a fresh docker build… Is there a way to configure it to use the host docker or utilize a private cache?