matrix-docker-ansible-deploy/roles/matrix-mailer/templates/env-mailer.j2

{% if matrix_mailer_relay_use %}
SMARTHOST={{ matrix_mailer_relay_host_name }}::{{ matrix_mailer_relay_host_port }}
{% endif %}
{% if matrix_mailer_relay_auth %}
SMTP_USERNAME={{ matrix_mailer_relay_auth_username }}
SMTP_PASSWORD={{ matrix_mailer_relay_auth_password }}
{% endif %}