annotate contrib/packaging/docker/ubuntu.template @ 38457:11eda1f1b6e7

packaging: consistently create build user in Dockerfiles

Previously, dockerlib.sh appended some commands to create a
"build" user in each Docker image. The resulting Docker images
could be inconsistent depending on the execution environment
and base image.

With this change, we explicitly create our custom user and
group as the first action in each Dockerfile. The user always
has user:group 1000:1000 and all built images are consistent.

We also create a home directory for the user under /build.
This directory is currently ignored.

As part of this, we stop setting the DBUILDUSER variable in
dockerlib.sh and instead set it in the respective scripts that
call it. This is in preparation for further refactoring of
dockerlib.sh.

Differential Revision: https://phab.mercurial-scm.org/D3758

FROM ubuntu:__CODENAME__

RUN groupadd -g 1000 build && \
    useradd -u 1000 -g 1000 -s /bin/bash -d /build -m build

RUN apt-get update && apt-get install -y \
  build-essential \
  debhelper \
  devscripts \
  dh-python \
  less \
  python \
  python-all-dev \
  python-docutils \
  unzip \
  zip