Dockerfile

FROM python:3.8

# ...

ADD entrypoint.sh /usr/local/bin
ENTRYPOINT ["bash"]
CMD ["-l"]

entrypoint.sh

#! /bin/bash

set -e

USER_NAME=${USER_NAME:-user}
USER_ID=${USER_ID:-1000}
GROUP_NAME=${GROUP_NAME:-${USER_NAME}}
GROUP_ID=${GROUP_ID:-${USER_ID}}

if [[ -d /home/${USER_NAME} ]]; then
  USER_OPTS=-M
else
  USER_OPTS=-m
fi
useradd ${USER_OPTS} -s /bin/bash -u ${USER_ID} ${USER_NAME}

if [[ "${DOCKER_GID}" != "" ]]; then
  groupadd -g ${DOCKER_GID} docker
  usermod -aG ${DOCKER_GID} ${USER_NAME}
fi

if (( $# )); then
  exec runuser -u ${USER_NAME} -- "$@"
else
  exec runuser -u ${USER_NAME} -- bash -l
fi

run.sh

#! /bin/bash

set -e

BASE_DIR=${PWD}/$(dirname "$0")

USER_NAME=$(id -un)
USER_ID=$(id -u)
DOCKER_GID=$(getent group docker | cut -d: -f3)

docker run \
  --rm -it \
  --name=run \
  --entrypoint entrypoint.sh \
  --network host \
  --workdir /src \
  -e USER_NAME=${USER_NAME} \
  -e USER_ID=${USER_ID} \
  -e DOCKER_GID=${DOCKER_GID} \
  -v "${HOME}:/home/${USER_NAME}" \
  -v "${BASE_DIR}":/src \
  -v /var/run/docker.sock:/var/run/docker.sock \
  "$@"