Run Python in Docker

rsubr@hanoi:~/tmp/foo$ docker images
REPOSITORY  TAG                                      IMAGE ID       CREATED          SIZE
python      latest197b4deb87ffa3decd9f045926a86cd0   be265f5c35a3   14 minutes ago   931MB

#!/bin/bash

# Filename: /usr/local/bin/python-docker
# Script to run python inside an ephemeral docker container
# pip install python modules if requirements.txt is preset
# for faster container startup, build a local docker image with required python modules
# local docker images will be tagged with a santised version of requirements.txt md5

#  export PYTHONVERSION=intel/oneapi-runtime  # alternate python docker image
#  export GPU_DISABLE=y    # to disable GPU/DRI acceleration
#  export DOCKER_BUILD=y   # build docker image locally for faster container startup

# Python version to run from docker hub, python:latest = 900MB, python:slim = 100MB
X_PYTHON_VERSION="${PYTHONVERSION:-python:slim}"

# Disable GPU by default, need it only for ML workloads
X_GPU_DISABLE="${GPU_DISABLE:-y}"

# By default build local docker containers for faster container startup
X_DOCKER_BUILD="${DOCKER_BUILD:-y}"


# do not continue script on errors
set -euo pipefail

# Get current user details so we can run python with this user id later
X_UID=$(id -u)
X_USERNAME=$(id -un)

# Set docker container name to curr dir or python script name and UUID
FNAME="${PWD}" ; [ "$#" -ne "0" ] && FNAME="$1"
NAME=$(realpath ${FNAME} | sed 's/^.//' | sed 's/[^a-zA-Z0-9_-]/-/g' ).$(</proc/sys/kernel/random/uuid)

# Use GPU if available, set GPU_DISABLE not required
X_DRI=""
[ "${X_GPU_DISABLE}" != "y" ] && [ -d /dev/dri ] && X_DRI="--device=/dev/dri"

# Build and tag docker image locally, run pip install for faster container startup
docker_build() {
  docker_tag=$1

  X_DOCKER_CONTEXT="$(mktemp -d)"
  # Remove temp files on exit
  trap "{ rm -rf ${X_DOCKER_CONTEXT}; }" EXIT

  cp requirements.txt ${X_DOCKER_CONTEXT}

  cat > "${X_DOCKER_CONTEXT}/Dockerfile" << EOF

FROM ${X_PYTHON_VERSION}

COPY requirements.txt /tmp

RUN PIP_DISABLE_PIP_VERSION_CHECK=1 PIP_NO_CACHE_DIR=1 PIP_ROOT_USER_ACTION=ignore pip install -qq -r /tmp/requirements.txt
EOF

  docker build -t "${docker_tag}" "${X_DOCKER_CONTEXT}" > /dev/null

  rm -rf "${X_DOCKER_CONTEXT}"
}

# Build a local docker container with python modules if required
REQUIREMENTS_MD5=""
if [ "${X_DOCKER_BUILD}" == "y" ] && [ -r requirements.txt ]; then

  # sanitise requirements.txt - strip comments, blank lines and sort lines before computing shortened md5
  REQUIREMENTS_MD5=`sed 's/\s*#.*$//;/^\s*$/d' < requirements.txt | sort | md5sum | awk '{print $1}' | cut -c1-8`


  # build local docker image if not already available
  docker image inspect "${X_PYTHON_VERSION}-${REQUIREMENTS_MD5}" > /dev/null 2>&1 || \
    docker_build "${X_PYTHON_VERSION}-${REQUIREMENTS_MD5}"

fi

# Create temporary docker ENTRYPOINT shell script
X_TMPDIR="$(mktemp -d)"
ENTRYPOINT="${X_TMPDIR}/entrypoint.sh"
# Remove temp files on exit
trap "{ rm -rf ${X_TMPDIR}; }" EXIT

cat > "${ENTRYPOINT}" <<EOF
#!/bin/bash

# Alternate entrypoint for python docker image
# Run pip as root, then run python as X_USERNAME

# do not continue script on errors
set -euo pipefail

# Optimize pip for docker usage
export PIP_DISABLE_PIP_VERSION_CHECK=1
export PIP_NO_CACHE_DIR=1
export PIP_ROOT_USER_ACTION=ignore

# pip install modules only if DOCKER_BUILD is not used
[ ! -f /tmp/requirements.txt ] && [ -f requirements.txt ] && pip install -qq -r requirements.txt

# create the current user in the container, and add to video group to access /dev/dri/card0
useradd -u ${X_UID} -U -s /bin/bash -M ${X_USERNAME}
usermod -a -G video ${X_USERNAME}

# run python
exec su -c "python \"\$@\"" ${X_USERNAME}
EOF

chmod 755 ${ENTRYPOINT}

# Run python in docker with all volume mounts and options

docker run -it --rm \
        -v /etc/timezone:/etc/timezone:ro \
        -v /etc/localtime:/etc/localtime:ro \
        -v /data:/data -v /home:/home \
        -v ${X_TMPDIR}:${X_TMPDIR} \
        -w $(pwd) \
        --entrypoint "${ENTRYPOINT}" \
        --name ${NAME} \
        --net=host ${X_DRI} \
        ${X_PYTHON_VERSION}-${REQUIREMENTS_MD5} "$@"

# Use local pip cache
X_INDEX_URL='http://192.168.1.15:5000/index/'
X_TRUSTED_HOST='192.168.1.15'

pip install -qq --index-url=${X_INDEX_URL} --trusted-host ${X_TRUSTED_HOST} -r requirements.txt