Question

Using the ruby mongodb driver, is there a way I can create a connection object in the configure block that can be accessed in the route methods so that I don’t have to recreate the connection on each request?

Answer 1

Set a global variable in a configuration block:

configure do
  $mongo = Mongo::Connection.new
end

or stick it in settings:

configure do
  set :mongo, Mongo::Connection.new
end

get '/' do
  # the connection is available through settings.mongo
end

I must say that I find neither of these very elegant.

When developing in may look as if the connection is created on every request, but start your server in production and you will see that it behaves differently (for example, thin -e production).

Also, if your app will run under Passenger, you need to do this:

 configure do
   if defined?(PhusionPassenger)
     PhusionPassenger.on_event(:starting_worker_process) do |forked|
       if forked
         # *** reconnect to the database here! ***
       end
     end
   end
 end

What it does is that it reconnects to the database after Passenger forks, so that child processes have their own connection. Not doing this will give you really strange errors.