{%- macro include_optional(sls_file) %}
    {%- if salt['file.file_exists']('{0}/files/{1}/{2}/init.sls'.format(opts['cachedir'], saltenv, sls_file)) or
           salt['file.file_exists']('{0}/files/{1}/{2}.sls'.format(opts['cachedir'], saltenv, sls_file))
    %}
    - {{ sls_file }}
    {% endif %}
{%- endmacro %}