dovecot/rootfs/etc/confd/templates/dovecot-sql.userdb.conf.ext.tmpl

driver = pgsql
connect = host={{ getenv "DB_HOST" }} dbname={{ getenv "DB_NAME" }} user={{ getenv "DB_USER" }} password={{ getenv "DB_PW" }}
user_query = SELECT COUNT(email) as count FROM virtual_users WHERE email = '%n' HAVING COUNT(email) > 0;