Debian packaging via dh_virtualenv (#4285)

docker/Dockerfile-dhvirtualenv

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+# A dockerfile which builds a docker image for building a debian package for
+# synapse. The distro to build for is passed as a docker build var.
+#
+# The default entrypoint expects the synapse source to be mounted as a
+# (read-only) volume at /synapse/source, and an output directory at /debs.
+#
+# A pair of environment variables (TARGET_USERID and TARGET_GROUPID) can be
+# passed to the docker container; if these are set, the build script will chown
+# the build products accordingly, to avoid ending up with things owned by root
+# in the host filesystem.
+
+# Get the distro we want to pull from as a dynamic build variable
+ARG distro=""
+FROM ${distro}
+
+# Install the build dependencies
+RUN apt-get update -qq -o Acquire::Languages=none \
+    && env DEBIAN_FRONTEND=noninteractive apt-get install \
+        -yqq --no-install-recommends -o Dpkg::Options::=--force-unsafe-io \
+        build-essential \
+        debhelper \
+        devscripts \
+        dh-systemd \
+        dh-virtualenv \
+        equivs \
+        lsb-release \
+        python3-dev \
+        python3-pip \
+        python3-setuptools \
+        python3-venv \
+        sqlite3 \
+        wget
+
+WORKDIR /synapse/source
+ENTRYPOINT ["bash","/synapse/source/docker/build_debian.sh"]

docker/build_debian.sh

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+#!/bin/bash
+
+# The script to build the Debian package, as ran inside the Docker image.
+
+set -ex
+
+DIST=`lsb_release -c -s`
+
+# We need to build a newer dh_virtualenv on older OSes like Xenial.
+if [ "$DIST" = 'xenial' ]; then
+    mkdir -p /tmp/dhvenv
+    cd /tmp/dhvenv
+    wget https://github.com/spotify/dh-virtualenv/archive/1.1.tar.gz
+    tar xvf 1.1.tar.gz
+    cd dh-virtualenv-1.1/
+    env DEBIAN_FRONTEND=noninteractive mk-build-deps -ri -t "apt-get -yqq --no-install-recommends -o Dpkg::Options::=--force-unsafe-io"
+    dpkg-buildpackage -us -uc -b
+    cd /tmp/dhvenv
+    apt-get install -yqq ./dh-virtualenv_1.1-1_all.deb
+fi
+
+
+# we get a read-only copy of the source: make a writeable copy
+cp -aT /synapse/source /synapse/build
+cd /synapse/build
+
+# add an entry to the changelog for this distribution
+dch -M -l "+$DIST" "build for $DIST"
+dch -M -r "" --force-distribution --distribution "$DIST"
+
+dpkg-buildpackage -us -uc
+
+ls -l ..
+
+# copy the build results out, setting perms if necessary
+shopt -s nullglob
+for i in ../*.deb ../*.dsc ../*.tar.xz ../*.changes ../*.buildinfo; do
+    [ -z "$TARGET_USERID" ] || chown "$TARGET_USERID" "$i"
+    [ -z "$TARGET_GROUPID" ] || chgrp "$TARGET_GROUPID" "$i"
+    mv "$i" /debs
+done

docker/build_debian_packages.sh

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+#!/bin/bash
+
+# Build the Debian packages using Docker images.
+#
+# This script builds the Docker images and then executes them sequentially, each
+# one building a Debian package for the targeted operating system. It is
+# designed to be a "single command" to produce all the images.
+#
+# By default, builds for all known distributions, but a list of distributions
+# can be passed on the commandline for debugging.
+
+set -ex
+
+cd `dirname $0`
+
+if [ $# -lt 1 ]; then
+    DISTS=(debian:stretch debian:sid ubuntu:xenial ubuntu:bionic ubuntu:cosmic)
+else
+    DISTS=("$@")
+fi
+
+# Make the dir where the debs will live.
+#
+# Note that we deliberately put this outside the source tree, otherwise we tend
+# to get source packages which are full of debs. (We could hack around that
+# with more magic in the build_debian.sh script, but that doesn't solve the
+# problem for natively-run dpkg-buildpakage).
+
+mkdir -p ../../debs
+
+# Build each OS image;
+for i in "${DISTS[@]}"; do
+    TAG=$(echo ${i} | cut -d ":" -f 2)
+    docker build --tag dh-venv-builder:${TAG} --build-arg distro=${i} -f Dockerfile-dhvirtualenv .
+    docker run -it --rm --volume=$(pwd)/../\:/synapse/source:ro --volume=$(pwd)/../../debs:/debs \
+           -e TARGET_USERID=$(id -u) \
+           -e TARGET_GROUPID=$(id -g) \
+           dh-venv-builder:${TAG}
+done