'unset' environment variables

General
4

dockerfile

FROM alpine:latest
RUN apk update && apk upgrade \
  && apk add --update --no-cache mariadb \
  && rm -f /var/cache/apk/*
COPY inc/run.sh /usr/bin/run.sh
RUN chmod +x /usr/bin/run.sh
VOLUME ["/var/lib/mysql", "/run/mysqld"]
EXPOSE 3306/tcp
CMD ["/usr/bin/supervisord", "-c", "/etc/supervisord.conf"]

supervisord.conf

...snip
[program:mariadb]
command=/usr/bin/run.sh
...snap

run.sh

#!/bin/bash

if [ "$(ls -A /var/lib/mysql/)" ]; then
  echo "[i] MySQL directory already present, skipping creation"
else
  echo "[i] MySQL data directory not found, creating initial DBs"
  mysql_install_db --user=mysql --skip-name-resolve > /dev/null

  if [ "$MYSQL_ROOT_PASSWORD" = "" ]; then
    MYSQL_ROOT_PASSWORD=<db_rootpass>
    echo "[i] MySQL root Password: $MYSQL_ROOT_PASSWORD"
  fi

  MYSQL_DATABASE=${MYSQL_DATABASE:-""}
  MYSQL_USER=${MYSQL_USER:-""}
  MYSQL_PASSWORD=${MYSQL_PASSWORD:-""}

  if [ ! -d "/run/mysqld" ]; then
    mkdir -p /run/mysqld
  fi

  tfile=`mktemp`
  if [ ! -f "$tfile" ]; then
      return 1
  fi

  cat << EOF > $tfile
USE mysql;
FLUSH PRIVILEGES;
GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY "$MYSQL_ROOT_PASSWORD" WITH GRANT OPTION;
GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' IDENTIFIED BY "$MYSQL_ROOT_PASSWORD" WITH GRANT OPTION;
DELETE FROM user WHERE user='';
DELETE FROM user WHERE password='';
EOF

  if [ $MYSQL_DATABASE != "" ]; then
    echo "[i] Creating database: $MYSQL_DATABASE"
    echo "CREATE DATABASE IF NOT EXISTS $MYSQL_DATABASE CHARACTER SET utf8 COLLATE utf8_general_ci;" >> $tfile
    if [ $MYSQL_USER != "" ]; then
      echo "[i] Creating user: $MYSQL_USER with password $MYSQL_PASSWORD"
      echo "GRANT ALL ON $MYSQL_DATABASE.* to '$MYSQL_USER'@'%' IDENTIFIED BY '$MYSQL_PASSWORD';" >> $tfile
      echo "GRANT ALL ON $MYSQL_DATABASE.* to '$MYSQL_USER'@'localhost' IDENTIFIED BY '$MYSQL_PASSWORD';" >> $tfile
    fi
  fi
  /usr/bin/mysqld --user=root --bootstrap --verbose=0 < $tfile
  rm -f $tfile
fi

exec /usr/bin/mysqld --user=root --console

docker-compose.yml

...snip
mariadb:
  container_name: mariadb
  image: <image>
  volumes:
    - ./data/db/:/var/lib/mysql/
  environment:
    MYSQL_ROOT_PASSWORD: <db_rootpass>
    MYSQL_DATABASE: <db_name>
    MYSQL_USER: <db_user>
    MYSQL_PASSWORD: <db_userpass>
...snap

Simple ‘unset’-script

#!/bin/bash
unset -v MYSQL_ROOT_PASSWORD
unset -v MYSQL_DATABASE
unset -v MYSQL_USER
unset -v MYSQL_PASSWORD

I launched this ‘unset’-script via supervisord with all three method (one at a time)

[program:unset]
command=/usr/bin/unset.sh

[program:unset]
command=source /usr/bin/unset.sh

[program:unset]
command=/bin/bash -c 'source /usr/bin/unset.sh'

That’s it :slight_smile: