This tool synchronises IMAP mailboxes for mail server migration. Written originally to migrate from Zimbra to Dovecot, this tool may contain idiosyncrasies of these servers.

Contrary to most sync tools out there, this one does not require the knowledge of the users' password, only of a master user for both sides. This allows unattended migrations.

This script requires python 3.4 or above. Lower-versioned will have problems with unicode/bytes/string coercion.

This script has been built for my personal migration and is almost certainly not suitable for yours. It may be a good starting point to writing your own sync tool, or may evolve in something more flexible.

This is released in the public domain.

A lot is left to do but the first one will be testing. I am planning to write a test harness that comprises a dovecot and a UW server, but nothing really exists there yet.

Functionality is limited by the requirements I had at the time. Interesting things to add would be reliable two-ways synchronisation, including deleted messages, faster resync, auto batch size detection, performance statistics, the capability to treat several mailboxes instead of just two, multiprocessing, ...

The api is all over the place at the moment, and will need a serious overhaul before this becomes flexible enough to do a lot more than what my initial need was. Similarly the code structure is messy, needs reorganising big time.

Imaplib is cool but has a little too close-to-the-metal api for my liking. I need to choose to either replace imaplib functionality where relevant (there are a couple of places where I need to 'cheat' to get imaplib to do what I want it to) and/or write a higher level api to it.

The UIDValidity responses' role is not well understood for instance. It is simply ignored for now. My migrations being rather atomic, it's not a huge deal, but I'm pretty sure it can break in interesting ways, possibly loosing data.

A lot more doc is required.

consider concurrent access to mailboxes. What happens when someones deletes/updates a message mid-flight?

• no passwords on the cli
• input and data validation need a lot more robustness

The usage is returned by calling the script with the -h argument.

usage: syncimap.py [-h]
               source_user source_master_user source_master_password
               source_server destination_user destination_master_user
               destination_master_password destination_server

positional arguments:
  source_user
  source_master_user
  source_master_password
  source_server
  destination_user
  destination_master_user
  destination_master_password
  destination_server

optional arguments:
  -h, --help            show this help message and exit