Workaround so you can use `docker run --env-file .env` and read variables with newline escape sequences in them

dockerize-env

#!/bin/bash

# Docker can't pass newlines to containers if there are \n in variables in
# --env-file files. This tool creates a $1.exported file with newlines that
# can be sourced before running your container and a $1.vars for you to pass
# to --env-files so docker passes those variables to the container.

# Usage:
# dockerize-env .env
# This creates: .env.vars and .env.exported
# then you can do: source .env.exported && docker run --env-file .env.vars my_container

# If your .env file contains something like:
# MY_PRIVKEY="-----BEGIN RSA PRIVATE KEY-----\nNIIJKgIBAAKBAgEAsAWzcV2XCTFUj25LkvHIhhgojOERBHWHCQYb7tqs7r3IKfcl\nyhCe5...
# you're going to need something like this

set -o nounset
set -o errexit

echo '' > "$1.vars"
echo '' > "$1.exported"

while read -r in
do
  [[ "$in" =~ ^# ]] && continue
  [ -z "$in" ] && continue
  if [[ "$in" == *"="* ]]
  then
    IFS='=' read -ra LINE <<< "$in"
    echo "${LINE[0]}" >> "$1.vars"
    echo -e "export $in" >> "$1.exported"
  else
    echo "Invalid line:"
    echo $in
    echo "File $1 contained invalid lines. Lines should be of the form:"
    echo "#comment"
    echo "or"
    echo "VAR=VAL"
    echo "Usage: docker-run-envfile .env *docker run arguments*"
    exit 1
  fi
done < "$1"

exit 0