is a # directory, the entire contents of the directory are copied, # including filesystem metadata. Note: The directory itself is not # copied, just its contents." Order again matters, three files are far # more likely to be cached than the whole project directory COPY certbot /opt/certbot/src/certbot/ COPY acme /opt/certbot/src/acme/ COPY certbot-apache /opt/certbot/src/certbot-apache/ COPY certbot-nginx /opt/certbot/src/certbot-nginx/ COPY letshelp-certbot /opt/certbot/src/letshelp-certbot/ COPY certbot-compatibility-test /opt/certbot/src/certbot-compatibility-test/ COPY tests /opt/certbot/src/tests/ RUN virtualenv --no-site-packages -p python2 /opt/certbot/venv && \ /opt/certbot/venv/bin/pip install -U pip && \ /opt/certbot/venv/bin/pip install -U setuptools && \ /opt/certbot/venv/bin/pip install \ -e /opt/certbot/src/acme \ -e /opt/certbot/src \ -e /opt/certbot/src/certbot-apache \ -e /opt/certbot/src/certbot-nginx \ -e /opt/certbot/src/letshelp-certbot \ -e /opt/certbot/src/certbot-compatibility-test \ -e /opt/certbot/src[dev,docs] # install in editable mode (-e) to save space: it's not possible to # "rm -rf /opt/certbot/src" (it's stays in the underlaying image); # this might also help in debugging: you can "docker run --entrypoint # bash" and investigate, apply patches, etc. ENV PATH /opt/certbot/venv/bin:$PATH