SMTP and XMPP deployment/workflow

I'm developing a website that incorporates an XMPP bot and a custom SMTP server (mainly these services process commands and reply). I'd like to set up a system where I can develop locally, push changes to a staging server, and finally to a production system. (Essentially I'm developing on the live server currently.)

I'm using python, and I'm reading a bit about fabric, but I'm running into a mental block.

I am using sqlalchemy-migrate to manage database versions and have the basic DNS stuff set up for the host. Additionally, I have a library that I'm currently working on that these two services both use (in my global site-packages directory). I deploy this egg after I change anything. This would ideally also be deployable, but only available to the correct version. Wo开发者_JAVA百科uld I need two versions, stage-lib and live-lib? Is this possible with python eggs?

Would I need another host to act as a staging server for these services? Or is there a way to tell DNS that something@staging.myhost.com goes to a different port than 25?

I have a fabfile right now that has a bunch of methods like stage_smtp, stage_xmpp, live_smtp, live_xmpp.

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Partial answer: DNS has no way to tell you to connect to a non-standard SMTP port, even with SRV records. (XMPP does.)

So, for sending email, you'll have to do something like:

import smtplib
server = smtplib.SMTP('localhost:2525')
server.sendmail(fromaddr, toaddrs, msg)
server.quit()