Add a helper to force a connection to secondbase

[hmadison]

Lets you get around situations where you can't change the class inheritance but need to force the model to use secondbase.

cc @nhessler @ashirazi @AEgan @astupka

[ashirazi]

The name "ForceSecondbase" seems uncomfortable to me. Presumably, the usage would be something like:

class Foo < SecondBase::Base
  # my secondbase model
end
class Bar < MySqlModel
  # not a secondbase model, although I still want to use it?
  include ForceSecondbase
end

Even though I can see what will happen here, I am left confused as to the intent. Perhaps it's because we're mixing ActiveRecord and DataMapper paradigms.

[hmadison]

@ashirazi The useage ends up being

class Model < ActiveRecord::Base
extend Secondbase::ForceSecondbase
end

This gets around cases where a gem provides models and you can't edit the base class.

[metaskills]

@ashirazi See here. Specifically "Topic 5: Shared Connection/Pools". http://technology.customink.com/blog/2015/06/22/rails-multi-database-best-practices-roundup/

[ashirazi]

@metaskills yeah, I know what it's doing... I was asking why you would want to declare a model as backed by one DB (inheritance), and then have it use another (extension). Seems like this contradiction would lend itself to a different approach, e.g. different subclasses of AR::Base for each DB (each configured accordingly).

@hmadison If we authored the gem, then perhaps a configurable backing DB would be the better way of doing this. If we don't have control over the gem, then re-opening the models is one way to go.

[metaskills]

I know what it's doing... I was asking why you would want to declare a model as backed by one DB (inheritance), and then have it use another (extension).

The idea is that this is for models that you do not control, likely in other gems. In my article, I used the Delayed::Job ActiveRecord model as an example which is exactly what we need it for. Subclassing is the preferred way, but in cases like ActiveRecord's DB Sessions, Delayed::Job, you simply need to freedom patch.

[nhessler]

LGTM. I can see what @ashirazi is saying about the name of the module, but I can’t think of a better one. I’m on the fence but I’ll lean towards the current name.