> Mail services are usually made far more complicated than they should be, and I understand there are a lot of desired features...
That was my impression of the whole thing, too. I've long had an exim configuration I could decorate my walls with, without understanding what most of it did or if it was secure.
Recently, I got so fed up I began writing my own mail server suite. It's still pretty basic and in development, but it does have some of the features you mention, namely
> SMTP
> POP3
> WebMail (though rudimentary)
> WebAdmin
> Multi-Domain support
In the pipeline, but not yet ready
> IMAP
> Plugins
Some of the goals of the project are to have a mail processing suite with a clear interface between the modules, as well as easy extensibility and configuration.
Me and some people I've talked into testing it already run some instances, and so far it has proved pretty stable.
Caveat: The backend is an SQLite database, so if your use-case is serving a lot of clients, there might be some lock contention.
If you separate each account's folders/inbox into a separate sqlite database, with the accounts/configuration in another, it probably wouldn't be to bad at even moderate scale.
But for < 100 users one sqlite db would probably be sufficient. (on a relatively fast drive/ssd)
That's actually exactly what you can already do with cmail ;)
Each user can optionally be assigned a "user database", storing only the mails in her own inbox (which also allows users to have direct control over their own mail database).
If this is not used, mail is stored in the master database.
As you said, most normal deployments should not run into those limits, but its worth keeping them in mind.
Why not use Maildir, or really any other standard scalable mail storage format? The most annoying thing in the universe is trying to export mail from one client to another with incompatible formats. Well, okay, maybe Vogon poetry is worse, but e-mail is a close second.
SQLite has a pretty great C API making it really easy to programmatically store, modify and retrieve data, which made it my first choice for runtime configuration data.
Adding another storage backend for the mail data would have meant a lot more code paths to support.
SQLite also has a lot of tools surrounding and supporting it (I particularly like SQLiteStudio) which allows querying/modifying/analyzing your mails with a huge number of programs, and using SQL - something I've found really useful!
With a sufficiently sane schema (which I hope we've achieved), transforming from the database format to any other format becomes really easy!
Also, since cmail is not really being developed with the intent to have people access their mail with a shell account (the main reason being that cmail users should not have to map to system users), supporting access formats on the server side is less of a priority - preferred access is via POP (already available) and IMAP (once it's done). The user database feature allows cmail users that ARE system users to control their own database.
An exporter to convert to/from Maildir is a planned feature :)
Hear-hear. Aside from a big directory of ascii text files, I can't think of a more future proof method of storage. So sqlite has that going for it, in addition to the extension API - which is awesome. I recently had to write some integration software for Kronos and some no name security system, as I was already storing the data in sqlite I decided to handle the Kronos business logic with a loadable extension - it was a pretty pleasant experience. Actually, I'm pretty sure there is an extension out there that allows you to use a directory of CSV files for table storage...
I've been thinking of using one of their schemas as a base for doing something similiar for an email client/interactive mail archive type thing (think: hyperkitty/pipermail).
Also notmuch has done some work for mapping email to xapian for search/tagging/indexing -- could also be a good source of inspiration I think.
I was aware of dbmail, but did not peruse the source in-depth, in part because it does not in itself implement SMTP.
Archiveopteryx I did not know, but thanks for the tip!
Using their databases as the basis for new tools has the obvious benefits of cross-compatibility, though there's always the drawback of database cruft that accumulates by virtue of differences in implementation or project goals.
That was my impression of the whole thing, too. I've long had an exim configuration I could decorate my walls with, without understanding what most of it did or if it was secure.
Recently, I got so fed up I began writing my own mail server suite. It's still pretty basic and in development, but it does have some of the features you mention, namely
> SMTP
> POP3
> WebMail (though rudimentary)
> WebAdmin
> Multi-Domain support
In the pipeline, but not yet ready
> IMAP
> Plugins
Some of the goals of the project are to have a mail processing suite with a clear interface between the modules, as well as easy extensibility and configuration.
Me and some people I've talked into testing it already run some instances, and so far it has proved pretty stable.
Caveat: The backend is an SQLite database, so if your use-case is serving a lot of clients, there might be some lock contention.
If you're interested, check out https://github.com/cmail-mta / http://cmail.rocks/