66 lines
1.6 KiB
Ruby
66 lines
1.6 KiB
Ruby
# frozen_string_literal: true
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require "resolv"
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module DiscourseAi
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module Utils
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module DnsSrv
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def self.lookup(domain)
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Discourse
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.cache
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.fetch("dns_srv_lookup:#{domain}", expires_in: 5.minutes) do
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resources = dns_srv_lookup_for_domain(domain)
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server_election(resources)
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end
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end
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private
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def self.dns_srv_lookup_for_domain(domain)
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resolver = Resolv::DNS.new
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resources = resolver.getresources(domain, Resolv::DNS::Resource::IN::SRV)
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end
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def self.select_server(resources)
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priority = resources.group_by(&:priority).keys.min
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priority_resources = resources.select { |r| r.priority == priority }
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total_weight = priority_resources.map(&:weight).sum
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random_weight = rand(total_weight)
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priority_resources.each do |resource|
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random_weight -= resource.weight
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return resource if random_weight < 0
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end
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end
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def self.server_available?(server)
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begin
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conn = Faraday.new { |f| f.adapter FinalDestination::FaradayAdapter }
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conn.head("https://#{server.target}:#{server.port}")
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true
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rescue StandardError
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false
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end
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end
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def self.server_election(resources)
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return nil if resources.empty?
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return resources.first if resources.length == 1
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candidate = select_server(resources)
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if server_available?(candidate)
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candidate
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else
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server_election(resources - [candidate])
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end
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end
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end
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end
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end
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