wait-for-pg script which can be used as Docker entrypoint

wait-for-pg.sh

#!/usr/bin/env bash
set -e

if [ -z ${DATABASE_HOST+x} ]
then
  echo "$0: Provide DATABASE_HOST environment variable" >&2
  exit 1
fi

attempt=1

until PGPASSWORD="${DATABASE_PASS}" \
  pg_isready \
    -h "${DATABASE_HOST}" \
    -p "${DATABASE_PORT:="5432"}" \
    -U "${DATABASE_USER:="postgres"}"; do
  attempts=$((attempts+1))
  if [ $attempts -eq ${RECONNECT_ATTEMPTS:=3} ]
  then
    echo "$0: Failed to reach the database at ${DATABASE_HOST}" >&2
    exit 1
  fi
  sleep 5
done

exec "$@"