Allow running the specs of external huginn agent gems

[dsander]

Only created to reference it from the Huginn PR, I think we should keep the discussion there and continue here after we agree to pursue this approach.

[cantino]

I'll try this out myself shortly!

[TildeWill]

Rather than providing paths to look for agents, could we structure this such that Agents "register" themselves as they're loaded? Something like:

class MyAgent < HuginnAgent
  add_self_to_registry
  ...
end

class HuginnAgent
  cattr_accessor :agent_types
  agent_types = []
  def self.add_self_to_registry
    agent_types |= [self]
  end
  ...
end

Or, per huginn/huginn#1526 just call HuginnAgent.descendants

[dsander]

The Agents need to inherit from Agent (the AR base model), so to allow this kind of registration HuginnAgent would need to be a subclass of Agent which is not defined yet when the gem is loaded into Huginn. Maybe I am missing something but due to the load order I think that would require us to monkey patch (predefine) the Agent class before its defined in Huginn.
What I like about the approach that @cantino took is that the Agent code does not need any changes to be move into a gem.

[cantino]

Agreed that it's nice how little code change was needed. Agents definitely should stay subclasses of Agent for now, I think. All of our AR code assumes this. It'd be okay to add an (optional?) registration call made at the class level when an Agent is defined, though. Or just a class method that sets a class variable indicating the group or something @TildeWill?

[dsander]

Can we get this merged? I know this PR introduces a lot of new code, but most of it is for the agent gem generator. The only code path that is run by Huginn is this method which doesn't do anything when the ADDITIONAL_GEMS .env variable is not configured, so it will definitely not break existing installations.

[cantino]

I'm traveling, but will try to look at it tonight.

[cantino]

Yes, looks good to me @dsander! I haven't manually tested it, but it all makes sense. Go ahead and merge.

[dsander]

@cantino Thanks! Now we only need to push the new version to rubygems to merge the Huginn side of this :)

[cantino]

@dsander, I just pushed v0.4.0 to RubyGems.

I tried to add you on RubyGems as an owner and it said that it couldn't find your mail@ email. Is there a different one I should use?

[dsander]

@cantino Awesome! It should be git (at) dsander.de

[cantino]

Added you!