54 lines
1.8 KiB
Ruby
54 lines
1.8 KiB
Ruby
# A Mail delivery method that randomly balances the actual delivery between different
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# methods.
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#
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# Usage:
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#
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# ```ruby
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# ActionMailer::Base.add_delivery_method :balancer, BalancerDeliveryMethod
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# config.action_mailer.balancer_settings = {
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# smtp: 25,
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# sendmail: 75
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# }
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# config.action_mailer.delivery_method = :balancer
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# ```
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#
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# Be sure to restart your server when you modify this file.
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class BalancerDeliveryMethod
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FORCE_DELIVERY_METHOD_HEADER = 'X-deliver-with'
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# Allows configuring the random number generator used for selecting a delivery method,
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# mostly for testing purposes.
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mattr_accessor :random, default: Random.new
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def initialize(settings)
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@delivery_methods = settings
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end
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def deliver!(mail)
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balanced_delivery_method = delivery_method(mail)
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ApplicationMailer.wrap_delivery_behavior(mail, balanced_delivery_method)
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# Because we don't want to invoke observers or interceptors twice,
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# we can't call again `mail.deliver` here to send the email with balanced method
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# (it was first called before by deliver_now in ActiveJob or application code, which leads us here).
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#
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# Instead, we directly deliver the email from the handler (set by the wrapper above)
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# like Mail::Message.deliver does.
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#
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# See https://github.com/mikel/mail/blob/199a76bed3fc518508b46135691914a1cfd8bff8/lib/mail/message.rb#L250
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mail.delivery_handler.deliver_mail(mail) { mail.send :do_delivery }
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end
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private
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def force_delivery_method?(mail)
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@delivery_methods.keys.map(&:to_s).include?(mail[FORCE_DELIVERY_METHOD_HEADER]&.value)
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end
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def delivery_method(mail)
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return mail[FORCE_DELIVERY_METHOD_HEADER].value.to_sym if force_delivery_method?(mail)
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@delivery_methods
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.flat_map { |delivery_method, weight| [delivery_method] * weight }
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.sample(random: self.class.random)
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end
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end
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