Occasionally I need to take WhisperGifts offline, but still show some parts of the site to users. This has included some system changes that require the site to be non-functional for a little while (such as doing a deployment with a bunch of backwards-incompatible changes, or large database migrations) and for server moves, whilst waiting for DNS changes to propogate.
To do this, I wrote a little library that I could toggle within my Django settings. I've just pulled it out of the WhisperGifts codebase, and django-readonly-site is now available on GitHub. I think it's pretty simple to use.
Install it with pip install django-readonly-site, add readonly to your Django projects' settings.INSTALLED_APPS, and set settings.SITE_READ_ONLY = True. More options are available to keep parts of your site online, see the README for more details.
By keeping parts of your site online (such as the homepage, about us page, and in my case a customers' registry listing) you can provide a transitional experience to users, while the database-intensive and high-integrity parts of the site (such as signup, account management, and checkout) are taken offline with a polite "Sorry, we're temporarily unavailable" message.
Just after I had to quickly move to Rackspace after an outage with my previous web host, Rackspace announced that they now had a public cloud offering in Australia. For performance reasons, I'll be moving from DFW to SYD soon - and I will use django-readonly-site to try and minimise the perceived downtime for my users.
Your thoughts, suggestions, and pull requests are welcome on the GitHub Project Page.