Adds Resque integration

[ryplo]

Overview

Adds the Resque integration, using the built-in hooks. To create a Job that is traced during the execution, just extend our base class:

require 'ddtrace'
require 'ddtrace/contrib/resque/resque_job'

# patch Resque
Datadog::Monkey.patch_module(:resque)

class MyJob
  # extend MyJob with integration hooks
  extend Datadog::Contrib::Resque::ResqueJob
   
  def self.perform(*args)
    # do_something
  end
end

[palazzem]

why can't we use simply follow rubocop suggestion?

[ryplo]

I initially thought that was needed to call for the base class. I've changed it!

[palazzem]

we should not do this in the around_perform, because it means making this calls before each execution. set_service_info call must be done only once per initialization, so it would be great if we can find another hook or class initialization to send the service metadata.

[palazzem]

the service must be set according to the pin, since users may change the service name later.

[palazzem]

👍

[palazzem]

we attach the Pin to the base class, but we don't provide a clean way to change the service name. Can you write here an example of how I change the service name from the main app? Let's say I have Rails + Resque, how do I change the service name from resque to my-app-at-resque from a Rails initializer?

[palazzem]

can we add a test where we change the service name using the Pin?

[palazzem]

Wonderful work @ryplo ! thank you!