[gitlab] [circleci] Use a Custom Docker Image as base CI setup.

We provide a custom `Dockerfile` for Coq's CI system, based on
`ubuntu:bionic`. The image includes the required set of packages and
OPAM switches.

This greatly simplifies the Gitlab and Circle scripts, at the cost of
having to push a Docker build for them to depend on.

Travis is not included in this PR as it requires significant more
refactoring due to lack of native Docker support.

This is work in progress but ready, a build hook is used so the image
is properly tagged in the Docker autobuilder.

We need to improve the autobuilder setup but this last point requires
some design on how to trigger it.

Fixes #7383

3 files changed, 118 insertions, 0 deletions

diff --git a/dev/ci/docker/README.md b/dev/ci/docker/README.md
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+## 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`
+
+Autobuild is the preferred build method [see below]; if you are a
+member of the `coqci` organization, the automated build will push the
+image to the `coqci/name:$VERSION` tag using a Docker hub hook.
+
+## Updating the Image and Syncronization with CI files
+
+Unfortunately, at this point some manual synchronization is needed
+between the `Dockerfile` and `.gitlab-ci.yml`. In particular, the
+checklist is:
+
+- check the name and version of the image setup in `hooks/post_push`
+  have to match.
+- check `COMPILER` variables do match.
+
+Once you are sure the variables are right, then proceed to trigger an
+autobuild or do a manual build, et voilà !
+
+## Docker Autobuilding.
+
+We provide basic support for auto-building, see:
+
+https://docs.docker.com/docker-cloud/builds/advanced/
+
+If you are member of the `coqci` Docker organization, trigger an
+autobuild in your account and the image will be pushed to it as we
+set the proper tag in `hooks/post_push`.
+
+We still need to figure out how properly setup a more automated,
+organization-wide auto-building process.
+
+## Manual Building
+
+You can also manually build and push any image:
+
+- Build the image `docker build -t base:$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`
+
+Now your docker image is ready to be used. To upload to `coqci`:
+- `docker tag base:$VERSION coqci/base:$VERSION`
+- `docker push coqci/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;
+- Learn more about Docker registry for GITLAB https://gitlab.com/coq/coq/container_registry .
diff --git a/dev/ci/docker/bionic_coq/Dockerfile b/dev/ci/docker/bionic_coq/Dockerfile
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+FROM ubuntu:bionic
+LABEL maintainer="e@x80.org"
+
+ENV DEBIAN_FRONTEND="noninteractive"
+
+RUN apt-get update -qq && apt-get install -y -qq m4 wget time gcc-multilib opam \
+        libgtk2.0-dev libgtksourceview2.0-dev \
+        texlive-latex-extra texlive-fonts-recommended hevea \
+        python3-sphinx python3-pexpect python3-sphinx-rtd-theme python3-bs4 python3-sphinxcontrib.bibtex python3-pip
+
+RUN pip3 install antlr4-python3-runtime
+
+# Basic OPAM setup
+ENV NJOBS="2" \
+    OPAMROOT=/root/.opamcache \
+    OPAMROOTISOK="true"
+
+ENV COMPILER="4.02.3" \
+    BASE_OPAM="num ocamlfind jbuilder"
+
+RUN opam init -a -y -j $NJOBS --compiler="$COMPILER" default https://opam.ocaml.org && eval $(opam config env) && opam update
+
+# Setup of the base switch
+ENV CAMLP5_VER="6.14" \
+    COQIDE_OPAM="lablgtk.2.18.5 conf-gtksourceview.2" \
+    CI_OPAM="menhir elpi ocamlgraph"
+
+RUN opam switch -y -j $NJOBS "$COMPILER" && eval $(opam config env) && \
+    opam install -j $NJOBS $BASE_OPAM camlp5.$CAMLP5_VER $COQIDE_OPAM $CI_OPAM
+
+# base+32bit switch
+RUN opam switch -y -j $NJOBS "${COMPILER}+32bit" && eval $(opam config env) && \
+    opam install -j $NJOBS $BASE_OPAM camlp5.$CAMLP5_VER
+
+# BE switch
+ENV COMPILER_BE="4.06.1" \
+    CAMLP5_VER_BE="7.05" \
+    COQIDE_OPAM_BE="lablgtk.2.18.6 conf-gtksourceview.2"
+
+RUN opam switch -y -j $NJOBS $COMPILER_BE && eval $(opam config env) && \
+    opam install -j $NJOBS $BASE_OPAM camlp5.$CAMLP5_VER_BE $COQIDE_OPAM_BE
+
+# BE+flambda switch
+RUN opam switch -y -j $NJOBS "${COMPILER_BE}+flambda" && eval $(opam config env) && \
+    opam install -j $NJOBS $BASE_OPAM camlp5.$CAMLP5_VER_BE $COQIDE_OPAM_BE
diff --git a/dev/ci/docker/bionic_coq/hooks/post_push b/dev/ci/docker/bionic_coq/hooks/post_push
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+#!/usr/bin/env bash
+
+COQCI_VERSION=V2018-05-05
+docker tag $IMAGE_NAME $DOCKER_REPO:$COQCI_VERSION
+docker push $DOCKER_REPO:$COQCI_VERSION
+
+docker tag $IMAGE_NAME coqci/base:$COQCI_VERSION
+docker push coqci/base:$COQCI_VERSION