mailgun rails - How to define mailgun_settings per ActionMailer - ruby-on-rails

Question

I am using mailgun-ruby to send emails in my rails app.
I have activated a number of domains on my Mailgun account and for each ActionMailer I wish to choose a specific domain to send emails from.
The gem's documentation only explains a global way of setting mailgun_settings:
config.action_mailer.delivery_method = :mailgun
config.action_mailer.mailgun_settings = {
api_key: 'api-myapikey',
domain: 'mydomain.com'
}
Any suggestion how this can be done per ActionMailer?

Answer 1

I came up with a self crafted design for this:
class ApplicationMailer < ActionMailer::Base
before_action do
#layout = 'mailer'
#from = 'default#domain.com'
#to = 'default_to#domain.com'
#subject = 'Default Subject'
#domain = 'default.domain.com'
#params = {}
end
after_action do
ac = ActionController::Base.new()
mg = Mailgun::Client.new 'key-xxxxxxxxx'
message_params = {
from: #from,
to: #to,
subject: #subject,
text: ac.render_to_string("#{self.class.to_s.underscore}/#{action_name}.text", layout: #layout, locals: #params),
html: ac.render_to_string("#{self.class.to_s.underscore}/#{action_name}.html", layout: #layout, locals: #params)
}
mg.send_message #domain, message_params
end
end
class UserMailer < ApplicationMailer
before_action do
#from = 'Domain <updates#domain.com>'
#domain = 'updates.domain.com'
end
def test
#to = "yourself#gmail.com"
#subject = "Test"
#params = {}
end
end
Customize user_mailer/test.txt.erb and user_mailer/test.html.erb and send the email:
UserMailer.test