Here is a small snippet of code that I use on applications deployed on Google AppEngine to inform users that the application is in maintenance mode.
It usually happen when the AppEngine team put the datastore in read-only mode for maintenance purpose but other capabilities can be tested as well.
def requires_datastore_write(view): def newview(request, *args, **kwargs): from google.appengine.api import capabilities datastore_write_enabled = capabilities.CapabilitySet('datastore_v3', capabilities=['write']).is_enabled() if datastore_write_enabled: return view(request, *args, **kwargs) else: from django.shortcuts import render_to_response from django.template import RequestContext return render_to_response('maintenance.html', context_instance=RequestContext(request)) return newview
This is a python decorator and you can use it to decorate views that require write access to the datastore. For example:
@requires_datastore_write def update(request): ...
You will need to create a Django template named
maintenance.html
to display a warning to your users. Mine looks like this:
Application Maintenance
The LibraryThing for Facebook application is currently in maintenance mode and some operations are temporarily unavailable. Thanks for trying back later. Sorry for the inconvenience.
They announced it yesterday at the Google Campfire ’09 (
