A third-party Docker container directory permissions pre-checker.

docker-command-checker.sh

#!/usr/bin/env bash

## date:   2022-10-13
## author: [email protected]
## file:   docker-checker.sh
## desc:   check path permissions before starting the docker image

set -euo pipefail

function error_ln() {
  # usage: error_ln "error message"
  printf "\033[1;32;31m%s\n\033[m" "${1}"
}

function warning_ln() {
  # usage: warning_ln "warning message"
  printf "\033[1;32;33m%s\n\033[m" "${1}"
}

function info_ln() {
  # usage: info_ln "info message"
  printf "\033[1;32;32m%s\n\033[m" "${1}"
}

function debug_ln() {
  # usage: debug_ln "debug message"
  printf "%s\n" "${1}"
}

DOCKER_CMD=()
DOCKER_EXEC=("/usr/bin/docker")
DOCKER_OPTIONS=("$@")

read_only_dirs=()
admin_mail="[email protected]"
report_error=${DOCKER_COMMAND_CHECKER_REPORT_ERROR-true}

while (($#)); do
  case "${1}" in
  -v | --volume)
    host_dir="${2//\:*/}"
    if [ -n "${host_dir}" ]; then
      if ! test -w "${host_dir}"; then
        read_only_dirs+=("${2//\:*/}")
        warning_ln "Warning: Read-only directory on the host: '${host_dir}'"
      fi
    fi
    shift 2
    ;;

  *)
    shift 1
    ;;
  esac
done

if [ ${#read_only_dirs[@]} -gt 0 ]; then
  if ${report_error}; then
    error_ln "Error: Do not mount the read-only directories on the host to the container"
    debug_ln "Try run the command: 'export DOCKER_COMMAND_CHECKER_REPORT_ERROR=false'"
    info_ln "Send mail to ${admin_mail} for more information"
    exit 1
  fi
  warning_ln "Warning: Do not write to the read-only directories on the host in the container"
  info_ln "Send mail to ${admin_mail} for more information"
  printf "Are you sure you want to continue running the command? [Y/n] "
  read -r continue
  if echo "${continue}" | grep -q -E "n|N|no|No|NO"; then exit 0; fi
fi

DOCKER_CMD=(${DOCKER_EXEC[@]+"${DOCKER_EXEC[@]}"} ${DOCKER_OPTIONS[@]+"${DOCKER_OPTIONS[@]}"})
echo ${DOCKER_CMD[@]+"${DOCKER_CMD[@]}"} >"${HOME}"/.docker_command
${DOCKER_CMD[@]+"${DOCKER_CMD[@]}"}

setup-docker-command-checker.sh

#!/usr/bin/env bash

## date:   2022-10-17
## author: [email protected]
## file:   setup-docker-checker.sh
## desc:   setup the docker-command-checker.sh

set -euo pipefail

sudo cp docker-command-checker.sh /usr/local/bin/docker-command-checker.sh
sudo chmod +x /usr/local/bin/docker-command-checker.sh

echo "
alias docker=\"docker-command-checker.sh\"
#unalias docker
" >>"${HOME}"/.bashrc

source "${HOME}"/.bashrc

1. Setup

bash -c "$(curl -fksSL https://gist.githubusercontent.com/duruyao/ea8312f4420c7697f2562e2c6c53acb3/raw/a356b496e7df6e22073372f1b795dff3fdb28ae9/setup-docker-command-checker.sh)" && source ~/.bashrc

2. Usage

$ docker run -it --rm -v /opt:/opt -v $HOME:$HOME -v /var:/var ubuntu:18.04 bash
Warning: Read-only directory on the host: '/opt'
Warning: Read-only directory on the host: '/var'
Error: Do not mount the read-only directories on the host to the container
Try run the command: 'export DOCKER_COMMAND_CHECKER_REPORT_ERROR=false'
Send mail to [email protected] for more information