docker

Overall Docker Setup for Coq's CI.

This directory provides Docker images to be used by Coq's CI. The images do support Docker autobuild on hub.docker.com and Gitlab's private registry.

The Gitlab CI will build a Docker image unless the CI environment variable SKIP_DOCKER is set to true. This image will be stored in the Gitlab container registry under the name given by the CACHEKEY variable from the Gitlab CI configuration file.

SKIP_DOCKER is set to "true" in https://gitlab.com/coq/coq to avoid running a lengthy redundant job. For efficiency, users should enable that setting in forked repositories after the initial Docker build in the fork succeeds.

The steps to generate a new Docker image are:

• Update the CACHEKEY variable in .gitlab-ci.yml with the date and md5.
• Submit the change in a PR. coqbot will detect that the Dockerfile has changed and will trigger a pipeline build with SKIP_DOCKER set to false. This will run a docker-boot process, and once completed, a new Docker image will be available in the container registry, with the name set in CACHEKEY.
• Any pipeline with the same CACHEKEY will now automatically reuse that image without rebuilding it from scratch.

Manual Building

You can also manually build and push any image:

• Build the image docker build -t base:$VERSION .

To upload/push to your hub:

• Create a https://hub.docker.com account.
• Login into your space docker login --username=$USER
• Push the image:
  • docker tag base:$VERSION $USER/base:$VERSION
  • docker push $USER/base:$VERSION

Debugging / Misc

To open a shell inside an image do docker run -ti --entrypoint /bin/bash <imageID>

Each RUN command creates an "layer", thus a Docker build is incremental and it always help to put things updated more often at the end.

Possible Improvements:

• Use ARG for customizing versions, centralize variable setup;