Admittedly I have been very annoyed with Dreamhost since they announced that users would no longer be able to use procmail.
How to get procmail Back
After reading the most recent entry I realized that it is possible to still use both procmail and spamassassin. However, this solution is not elegant.
Currently Dreamhost has a rudimentary Mail Filter system that is accessible by all mail users. This system is due to be upgraded soon. Dreamhost also allows regular shell users to access and run procmail as well as spamassassin. In fact, shell users can install their own custom install of spamassassin. Lastly, shell users can also receive email, although there is no imap or pop service for this mail.
Using the above features it is possible to run a spamassassin setup that seems identical to the end user. It works by forwarding your email all over the place. First, your email is received by a mail account, this mail account has access to the rudimentary keyword filter. The mail filter looks for an X-Scanned header to see if this email has already run through the procmail system. Second, if the message has not been run through the procmail system it is forwarded to a user shell account. Third, the user shell account receives the email and runs it through procmail and spamassassin. During the process the procmail script adds the X-Scanned header, the procmail script can also add an X-Sort header if necessary. Fourth, the last recipe in the procmail script forwards the email back to the mail account. Finally, the mail account filters the email again, this time seeing the X-Scanned header and places it in your inbox.
As noted, the setup requires a mail account and a shell account. Also this scheme receives your email 3 times in order to accomplish the process:
1. The Mail Account receives incoming email
2. The Shell Account receives the mail forwarded from the Mail Account
3. The Mail Account receives the mail after it has be processed by the Shell account.
To me this seems to put more strain on the servers than was on them before using the old setup. But if this is what they prefer than so be it.
This is obviously less than ideal, and will likely slow down the delivery of mail slightly, but in the end you will still be able to process email using spamassassin and procmail.
We still have to wait for Dreamhost to update the keyword filter. Currently you would have to alter the subject or the body in order to process your mail. As I said earlier, I would imagine that Dreamhost will update the filter very soon.
There is one upside to this system. Using this method you could create a single shell account to handle all of your spamassassin work, including work for any user whether on your domain or not. This would allow you to tweak global SA settings for all users.
This would be accomplished by setting procmail to forward the email back to which ever mail account sent it the email in the first place. Theoretically you could filter and process any mail account this way, even accounts that are not hosted by dreamhost, as long as they can filter by message headers. A feature that most cPanel accounts have accessible to them.