A better wait-for-postgres.sh

wait-for-postgres.sh

#!/bin/bash -e
# wait-for-postgres.sh
# Adapted from https://docs.docker.com/compose/startup-order/

# Expects the necessary PG* variables.

until psql -c '\l'; do
  echo >&2 "$(date +%Y%m%dt%H%M%S) Postgres is unavailable - sleeping"
  sleep 1
done
echo >&2 "$(date +%Y%m%dt%H%M%S) Postgres is up - executing command"

exec ${@}