Dockerfile

FROM ubuntu:20.04
LABEL maintainer="David Sn <divad.nnamtdeis@gmail.com>"

ENV DEBIAN_FRONTEND=noninteractive \
    USER=docker \
    USE_CCACHE=1 \
    CCACHE_DIR=/tmp/ccache \
    CCACHE_EXEC=/usr/bin/ccache

# Install required dependencies 
RUN apt-get update && \
    apt-get install --no-install-recommends -y \
        adb autoconf automake axel bc bison build-essential \
        ccache clang cmake expat fastboot flex g++ \
        g++-multilib gawk gcc gcc-multilib git gnupg gperf \
        htop imagemagick lib32ncurses5-dev lib32z1-dev libtinfo5 libc6-dev libcap-dev \
        libexpat1-dev libgmp-dev '^liblz4-.*' '^liblzma.*' libmpc-dev libmpfr-dev libncurses5-dev \
        libsdl1.2-dev libssl-dev libtool libxml2 libxml2-utils '^lzma.*' lzop \
        maven ncftp ncurses-dev patch patchelf pkg-config pngcrush \
        pngquant python2.7 python-all-dev re2c schedtool squashfs-tools subversion \
        texinfo unzip w3m xsltproc zip zlib1g-dev lzip \
        libxml-simple-perl apt-utils \
        libncurses5 curl python-is-python3 sudo ssh rsync && \
    apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*

# Install repo binary (thanks akheel)
RUN curl --create-dirs -L -o /usr/local/bin/repo -O -L https://github.com/akhilnarang/repo/raw/master/repo && \
    chmod a+x /usr/local/bin/repo

# Create seperate build user
RUN groupadd -g 1000 -r ${USER} && \
    useradd -u 1000 --create-home -r -g ${USER} ${USER} && \
    mkdir -p /tmp/ccache /repo && \
    chown -R ${USER}: /tmp/ccache /repo
    
# Allow sudo without password for build user
RUN echo "${USER} ALL=(ALL) NOPASSWD:ALL" > /etc/sudoers.d/90-docker-build && \
    usermod -aG sudo ${USER}

# Setup volumes for persistent data
USER ${USER}
VOLUME ["/tmp/ccache", "/repo"]

# Create gitconfig for build user
RUN git config --global user.name ${USER} && git config --global user.email ${USER}@${HOSTNAME}.local && \
    git config --global color.ui auto

# Work in the build directory, repo is expected to be init'd here
WORKDIR /repo

# This is where the magic happens~
ENTRYPOINT ["/bin/bash"]