A single version of runas using gosu.

    gid="$(id -g)"

    docker run -v "$PWD:/volume" --user "$uid:$gid" buildimage make

I personally find it a tiresome after the 3rd time I had to rebuild the

I personally find it a tiresome after the 3rd time I had to `sudo chown` the

project because I forgot to specify the uid and gid and it's a (low) barrier

to entry for new users.

of entry for new users.

A better solution

-----------------

    #!/bin/sh

    set -eu

    command -v sudo > /dev/null || { echo "Can't find sudo, exiting."; exit 1; }

    uid="$(stat . --format '%u')"

    gid="$(stat . --format '%g')"

    groupadd --force --non-unique --gid "$gid" builder

    useradd --non-unique --uid "$uid" --gid "$gid" --home-dir "$PWD" --no-create-home --shell /bin/bash builder

    sudo -Eu "#$uid" -g "#$gid" -- "$@"

    [ "$(id -u)" = "0" ] || { echo "Not running as root, continuing as the current user."; eval exec "$@"; }

    command -v stat > /dev/null || { echo "Can't find stat, exiting."; exit 1; }

    command -v gosu > /dev/null || { echo "Can't find gosu, exiting."; exit 1; }

    uid="$(stat . -c '%u')"

    gid="$(stat . -c '%g')"

    eval exec gosu "$uid:$gid" "$@"

The script is also available for `download

<https://www.shore.co.il/blog/static/runas-gnu>`_. The only dependency is

:code:`sudo`. There's also a `version

<https://www.shore.co.il/blog/static/runas-busybox>`_ for images using BusyBox

(like Alpine). You can download and check it to your VCS and incorporate it

into your Dockerfile, or download it via the :code:`ADD` directive, like so:

<https://www.shore.co.il/blog/static/runas>`_. The only dependency is

`gosu <https://github.com/tianon/gosu>`_.  You can download and check it to

your VCS and incorporate it into your Dockerfile, or download it via the

:code:`ADD` directive, like so:

.. code:: shell

    FROM debian:stable

    RUN apt-get update && \

        DEBIAN_FRONTEND=noninteractive apt-get install -y sudo build-essential

    ADD [ "https://www.shore.co.il/blog/static/runas-gnu", "/entrypoint" ]

    ENTRYPOINT [ "/bin/sh", "/entrypoint" ]

    FROM buildpack-deps

    RUN curl -fsSL https://github.com/tianon/gosu/releases/download/1.10/gosu-amd64 -o gosu-amd64 && \

        install -o root -g root -m 755 gosu-amd64 /usr/local/bin/gosu && \

        rm gosu-amd64 && \

        curl -fsSL https://www.shore.co.il/blog/static/runas -o runas && \

        install -o root -g root -m 755 runas /entrypoint && \

        rm runas

    ENTRYPOINT [ "/entrypoint" ]

    VOLUME /volume

    WORKDIR /volume

    ENV HOME /volume

And then finally, to build run

Setting the home directory to the mounted volume will result in some files (like

package managers cache) to be created there, which you may or may not want. And

then finally, to build run

.. code:: shell

runas-gnu

 No newline at end of file

#!/bin/sh

set -eu

[ "$(id -u)" = "0" ] || { echo "Not running as root, continuing as the current user."; eval exec "$@"; }

command -v stat > /dev/null || { echo "Can't find stat, exiting."; exit 1; }

command -v gosu > /dev/null || { echo "Can't find gosu, exiting."; exit 1; }

uid="$(stat . -c '%u')"

gid="$(stat . -c '%g')"

eval exec gosu "$uid:$gid" "$@"

#!/bin/sh

set -eu

command -v sudo > /dev/null || { echo "Can't find sudo, exiting."; exit 1; }

uid="$(stat . -c '%u')"

gid="$(stat . -c '%g')"

addgroup -g "$gid" builder

adduser -h "$PWD" -s /bin/sh -G builder -u "$uid" -H -D builder

sudo -Eu "#$uid" -g "#$gid" -- "$@"

#!/bin/sh

set -eu

command -v sudo > /dev/null || { echo "Can't find sudo, exiting."; exit 1; }

uid="$(stat . --format '%u')"

gid="$(stat . --format '%g')"

groupadd --force --non-unique --gid "$gid" builder

useradd --non-unique --uid "$uid" --gid "$gid" --home-dir "$PWD" --no-create-home --shell /bin/bash builder

sudo -Eu "#$uid" -g "#$gid" -- "$@"