postfix-formula/postfix/files/virtual_mailbox_maps.cf

{%- if 'mysql' in salt['pillar.get']('postfix:config:virtual_mailbox_maps', '') %}
{%- set config = salt['pillar.get']('postfix:mysql:virtual_mailbox_maps', {}) -%}
{%- for key,value in salt['pillar.get']('postfix:vmail').items() %}
{{ key }} = {{ value }}
{%- endfor %}
query = SELECT {{ config.select_field|default('1') }} FROM {{ config.table|default('virtual_users') }} WHERE {{ config.where_field|default('email') }}='%s'
{%- else %}
{% set config = salt['pillar.get']('postfix:vmail', {}) -%}
{% macro set_parameter(parameter, default=None) -%}
{% set value = config.get(parameter, default) -%}
{% if value is not none -%}
{{ parameter }} = {{ value }}
{% endif -%}
{% endmacro -%}

{# Accept arbitrary parameters -#}
{% for parameter in config -%}
{{ set_parameter(parameter) }}
{% endfor -%}

{{ set_parameter('table', 'mailbox') }}
{{ set_parameter('select_field', 'maildir') }}
{{ set_parameter('where_field', 'username') }}
{%- endif %}