Entrypoint example with waiter for port

docker-entrypoint.sh

#!/bin/bash

set -e

cp config/local.tpl config/local.yml

export DB_TCP="/dev/tcp/${DB_1_PORT_3306_TCP_ADDR}/${DB_1_PORT_3306_TCP_PORT}"

# See http://tldp.org/LDP/abs/html/devref1.html for description of this syntax.
while ! exec 6<>${DB_TCP}; do
    echo "$(date) - still trying to connect to mysql at ${DB_TCP}"
    sleep 1
done

bundle exec rake db:migrate

exec "$@"