Share files between host system and docker container using specific UID

Question

I\'m trying to share files within a Docker guest using the volume sharing. In order to get the same UID, and therefore interoperability with those files, I would like to cr

Answer 1

The environment is not shared, you could use -e, --env options to set env variables in container.

I usually use this approach when I want to have the same owner of the mapped volume: I check uid & gid of directory in container and then create a corresponding user. Here my script (setuser.sh) which creates a user for a directory:

#!/bin/bash

setuser() {
  if [ -z "$1" ]; then
    echo "Usage: $0 "
    return
  fi
  CURRENT_UID=`id -u`
  DEST_UID=`stat -c "%u" $1`
  if [ $CURRENT_UID = $DEST_UID ]; then
    return
  fi
  DEST_GID=`stat -c "%g" $1`
  if [ -e /home/$DEST_UID ]; then
    return
  fi
  groupadd -g $DEST_GID $DEST_GID
  useradd -u $DEST_UID -g $DEST_GID $DEST_UID
  mkdir -p /home/$DEST_UID
  chown $DEST_UID:$DEST_GID /home/$DEST_UID
}
setuser $1

And this is the wrapper script which runs commands as the user, where the directory with permissions is specified either as $USER_DIR or in /etc/user_dir

#!/bin/bash
if [ -z "$USER_DIR" ]; then
  if [ -e /etc/user_dir ]; then
    export USER_DIR=`head -n 1 /etc/user_dir`
  fi
fi
if [ -n "$USER_DIR" ]; then
  if [ ! -d "$USER_DIR" ]; then
    echo "Please mount $USER_DIR before running this script"
    exit 1
  fi
  . `dirname $BASH_SOURCE`/setuser.sh $USER_DIR
fi
if [ -n "$USER_DIR" ]; then
  cd $USER_DIR
fi
if [ -e /etc/user_script ]; then
  . /etc/user_script
fi
if [ $CURRENT_UID = $DEST_UID ]; then
  "$@"
else
  su $DEST_UID -p -c "$@"
fi

P.S. Alleo suggested different approach: to map users and groups files into container and to specify uid and gid. So your container does not depend on built-in users/groups you could use it without additional scripts.