nicobot/Dockerfile-alpine

# This image is based on Alpine linux to get a minimum memory footprint
# Some say that alpine should not be used for Python (https://pythonspeed.com/articles/alpine-docker-python/),
# however given some additional work, overall it may be better in the end (https://nickjanetakis.com/blog/the-3-biggest-wins-when-using-alpine-as-a-base-docker-image)


#################
# STAGE 1
#################

FROM python:3-alpine AS builder

# python:3-alpine misses gcc, ffi.h, ...
#
# GCC part :
# https://number1.co.za/alpine-python-docker-base-image-problem-with-gcc/
# https://wiki.alpinelinux.org/wiki/How_to_get_regular_stuff_working
#
# Python cryptography part :
# https://stackoverflow.com/questions/35736598/cannot-pip-install-cryptography-in-docker-alpine-linux-3-3-with-openssl-1-0-2g
# https://github.com/pyca/cryptography/blob/1340c00/docs/installation.rst#building-cryptography-on-linux

# Required to build
RUN apk add --no-cache build-base gcc abuild binutils cmake \
            libressl-dev musl-dev libffi-dev

COPY requirements-runtime.txt .
RUN pip install --no-cache-dir --user -r requirements-runtime.txt
# The 'qr' command is used in the process to link the machine with a Signal account
RUN pip install --no-cache-dir --user qrcode
# It could be packaged (RUN python setup.py sdist bdist_wheel) to possibly
# improve size and speed ; probably as a multistage build
# And update the version from git using setuptools-scm
# But it requires a bit of work
#RUN python setup.py sdist bdist_wheel

# Signal installation
ENV SIGNAL_VERSION=0.6.7
RUN wget "https://github.com/AsamK/signal-cli/releases/download/v${SIGNAL_VERSION}/signal-cli-${SIGNAL_VERSION}.tar.gz"
RUN tar xf "signal-cli-${SIGNAL_VERSION}.tar.gz" -C /opt
RUN mv "/opt/signal-cli-${SIGNAL_VERSION}" /opt/signal-cli



#################
# STAGE 2
#################

FROM python:3-alpine

WORKDIR /usr/src/app

# Required at runtime
# libressl-dev : seems required for python to locate modules, or for omemo ?
# openjdk : requirement for signal-cli
# A Java 8+ runtime seems to be required for 0.6, 0.7 requires JRE 11 (which is 50MB bigger...)
# For an even smaller JRE image, see maybe https://github.com/rhuss/docker-java-jolokia/blob/master/base/alpine/jre/8/Dockerfile
# or https://hub.docker.com/r/azul/zulu-openjdk-alpine/dockerfile
# bash is to use extended syntax in entrypoint.sh (in particular tee >(...))
RUN apk add --no-cache libressl-dev
RUN apk add --no-cache bash openjdk8-jre

# All Python files, including nicobot's
COPY --from=builder /root/.local /root/.local/
# https://www.docker.com/blog/containerized-python-development-part-1/
ENV PATH=/root/.local/bin:$PATH
#COPY --from=builder /root/.cache /root/.cache/
#COPY --from=builder /usr/local/lib /usr/local/lib/

# signal-cli files
COPY --from=builder /opt/signal-cli /opt/signal-cli
ENV PATH=/opt/signal-cli/bin:$PATH

# TODO How to do it with one COPY ?
# Or it could be COPY . . with a proper .dockerignore
# Or build the context as a preliminary step
COPY nicobot nicobot/

# This script allows packaging several bots in the same image
# (to be clean they could be in separate images but they're so close that it's a lot easier to package and does not waste space by duplicating images)
# Otherwise the ENTRYPOINT should simply be [ "python"]
# Made a a separate COPY because it's a docker-specific layer
# (other layers don't need to be re-built if this one changes)
COPY docker-entrypoint.sh .
ENTRYPOINT [ "./docker-entrypoint.sh" ]