docs: def periodic_ops(self):
          """Run periodic operations on the the data store.
          
          Operations like making sure collections are capped and indexes are set up.
          """
  
          # Only run every 30 seconds
          if (time.time() - self.last_ops_run) < 30:
              return
  
          try:
  
              # Reset last ops run
              self.last_ops_run = time.time()
              print 'Running Periodic Ops'
  
              # Get all the collections in the workbench database
              all_c = self.database.collection_names()
  
              # Remove collections that we don't want to cap
              try:
                  all_c.remove('system.indexes')
                  all_c.remove('fs.chunks')
                  all_c.remove('fs.files')
                  all_c.remove('info')
                  all_c.remove('tags')
                  all_c.remove(self.sample_collection)
              except ValueError:
                  print 'Catching a benign exception thats expected...'
  
              # Convert collections to capped if desired
              if self.worker_cap:
                  size = self.worker_cap * pow(1024, 2)  # MegaBytes per collection
                  for collection in all_c:
                      self.database.command('convertToCapped', collection, size=size)
  
              # Loop through all collections ensuring they have an index on MD5s
              for collection in all_c:
                  self.database[collection].ensure_index('md5')
  
              # Add required indexes for samples collection
              self.database[self.sample_collection].create_index('import_time')
  
              # Create an index on tags
              self.database['tags'].create_index('tags')
  
      
          # Mongo may throw an autoreconnect exception so catch it and just return
          # the autoreconnect means that some operations didn't get executed but
          # because this method gets called every 30 seconds no biggy...
          except pymongo.errors.AutoReconnect as e:
              print 'Warning: MongoDB raised an AutoReconnect...' % e
              return
          except Exception as e:
              print 'Critical: MongoDB raised an exception' % e
              return