Fork and promote one Heroku app's Postgres Database to another app.

fork_db.sh

#!/bin/sh

set -e

app=${1}
staging_app=staging-${app}
db_type=${2:-crane}

old_db=`heroku config -a ${staging_app} | grep ^HEROKU_POSTGRESQL | cut -d : -f 1 | sed s/_URL//`
heroku addons:add heroku-postgresql:${db_type} --fork `heroku config -a ${app} | grep ^DATABASE_URL | cut -d : -f 2-5` -a ${staging_app}

# Fork and promote new db for staging
new_db=`heroku config -a ${staging_app} | grep ^HEROKU_POSTGRESQL | grep -v ${old_db} | cut -d : -f 1 | sed s/_URL//`
heroku pg:wait -a ${staging_app}
heroku pg:promote ${new_db} -a ${staging_app}

# Remove the old staging db
if [ ! -z "${old_db}" ]l; then
  heroku addons:remove ${old_db} -a ${staging_app} --confirm ${staging_app}
fi

set +e