Podop is a piece of middleware designed to run between Postfix or Dovecot on one side, any Python implementation of a table lookup protocol on the other side.

It is thus able to forward Postfix maps and Dovecot dicts to the same (or multiple) backends in order to write a single, more flexible backend for a mail distribution.

Examples

• Connect Postfix to a DNS lookup so that every domain that has a proper MX record to your Postfix is actually accepted as a local domain
• Connect both Postfix and Dovecot to an HTTP microservice to run a high availability microservice-based mail service
• Use a single database server running any Python-compatible API for both your Postfix and Dovecot servers

Configure Podop tables

Podop tables are configured through CLI arguments when running the server. You must provide a --name for the table, a --type for the table and a --param that parametrizes the map.

URL table

The URL table will initiate an HTTP GET request for read access and an HTTP POST request for write access to a table. The table is parametrized with a template URL containing § (or {}) for inserting the table key.

--name test --type url --param http://microservice/api/v1/map/tests/§

GET requests should return 200 and a JSON-encoded object that will be passed either to Postfix or Dovecot. They should return 4XX for access issues that will result in lookup miss, and 5XX for backend issues that will result in a temporary failure.

POST requests will contain a JSON-encoded object in the request body, that will be saved in the table.

Postfix usage

In order to access Podop tables from Postfix, you should setup socketmap Postfix maps. For instance, in order to access the test table on a Podop socket at /tmp/podop.socket, use the following setup:

virtual_alias_maps = socketmap:unix:/tmp/podop.socket:test

Multiple maps or identical maps can be configured for various usages.

virtual_alias_maps = socketmap:unix:/tmp/podop.socket:alias
virtual_mailbox_domains = socketmap:unix:/tmp/podop.socket:domain
virtual_mailbox_maps = socketmap:unix:/tmp/podop.socket:alias

In order to simplify the configuration, you can setup a shortcut.

podop = socketmap:unix:/tmp/podop.socket
virtual_alias_maps = ${podop}:alias
virtual_mailbox_domains = ${podop}:domain
virtual_mailbox_maps = ${podop}:alias

Dovecot usage

In order to access Podop tables from Dovecot, you should setup a proxy Dovecot dictionary. For instance, in order to access the test table on a Podop socket at /tmp/podop.socket, use the following setup:

mail_attribute_dict = proxy:/tmp/podop.socket:test

Multiple maps or identical maps can be configured for various usages.

mail_attribute_dict = proxy:/tmp/podop.socket:meta

passdb {
  driver = dict
  args = /etc/dovecot/auth.conf
}

userdb {
  driver = dict
  args = /etc/dovecot/auth.conf
}

# then in auth.conf
uri = proxy:/tmp/podop.socket:auth
iterate_disable = yes
default_pass_scheme = plain
password_key = passdb/%u
user_key = userdb/%u

Contributing

Podop is free software, open to suggestions and contributions. All components are free software and compatible with the MIT license. All the code is placed under the MIT license.