Mailman list archive link preservation

Humankind has been carefully storing past knowledge for a very long time.

At the end of July, Debian 10 (Buster) reached end-of-life, and with it, all mainstream support for Python 2. The Python Software Foundation actually ended support for Python 2 on 1st January 2020, but it’s remained in Debian until now because a small number of important packages depend on it.

One of those packages is Mailman 2, a widely-used mailing list manager.  For various reasons, many projects using Mailman 2 have resisted upgrading to its successor, Mailman 3.  With Debian 10 reaching end-of-life, we’re seeing renewed interest in this migration.

One of the barriers to migrating to Mailman 3 is that the upgrade breaks links to messages in the mailing list archives.  There are links all over the internet to messages in Mailman 2 list archives, and for many projects, breaking these links would be a significant loss.

We’ve recently done some Mailman 2 to 3 migrations, and as part of this, we developed our own solution to preserving archive URLs.  We created a script that trawls Mailman 2 archives and creates a map of old URLs in the Mailman 2 archives to the corresponding URL in the Mailman 3 archives.  This can be used by Apache’s mod_rewrite to generate redirects for the old URLs.   The map can be converted to a DBM file for more efficient lookups.  This is important for archives containing many thousands of URLs.

We’ve made the mailman-archive-mapper script freely available on GitHub.

We offer mailman as a managed application.