class Puppet::HTTP::DNS

   # File lib/puppet/http/dns.rb
27 def initialize(resolver = Resolv::DNS.new)
28   @resolver = resolver
29 
30   # Stores DNS records per service, along with their TTL
31   # and the time at which they were resolved, for cache
32   # eviction.
33   @record_cache = {}
34 end

   # File lib/puppet/http/dns.rb
43 def each_srv_record(domain, service_name = :puppet, &block)
44   if (domain.nil? or domain.empty?)
45     Puppet.debug "Domain not known; skipping SRV lookup"
46     return
47   end
48 
49   Puppet.debug "Searching for SRV records for domain: #{domain}"
50 
51   case service_name
52     when :puppet then service = '_x-puppet'
53     when :file   then service = '_x-puppet-fileserver'
54     else              service = "_x-puppet-#{service_name}"
55   end
56   record_name = "#{service}._tcp.#{domain}"
57 
58   if @record_cache.has_key?(service_name) && !expired?(service_name)
59     records = @record_cache[service_name].records
60     Puppet.debug "Using cached record for #{record_name}"
61   else
62     records = @resolver.getresources(record_name, Resolv::DNS::Resource::IN::SRV)
63     if records.size > 0
64       @record_cache[service_name] = CacheEntry.new(records)
65     end
66     Puppet.debug "Found #{records.size} SRV records for: #{record_name}"
67   end
68 
69   if records.size == 0 && service_name != :puppet
70     # Try the generic :puppet service if no SRV records were found
71     # for the specific service.
72     each_srv_record(domain, :puppet, &block)
73   else
74     each_priority(records) do |recs|
75       while next_rr = recs.delete(find_weighted_server(recs)) #rubocop:disable Lint/AssignmentInCondition
76         Puppet.debug "Yielding next server of #{next_rr.target}:#{next_rr.port}"
77         yield next_rr.target.to_s, next_rr.port
78       end
79     end
80   end
81 end

    # File lib/puppet/http/dns.rb
128 def expired?(service_name)
129   entry = @record_cache[service_name]
130   if entry
131     return Time.now > (entry.resolution_time + entry.ttl)
132   else
133     return true
134   end
135 end

    # File lib/puppet/http/dns.rb
 88 def find_weighted_server(records)
 89   return nil if records.nil? || records.empty?
 90   return records.first if records.size == 1
 91 
 92   # Calculate the sum of all weights in the list of resource records,
 93   # This is used to then select hosts until the weight exceeds what
 94   # random number we selected.  For example, if we have weights of 1 8 and 3:
 95   #
 96   # |-|--------|---|
 97   #        ^
 98   # We generate a random number 5, and iterate through the records, adding
 99   # the current record's weight to the accumulator until the weight of the
100   # current record plus previous records is greater than the random number.
101   total_weight = records.inject(0) { |sum,record|
102     sum + weight(record)
103   }
104   current_weight = 0
105   chosen_weight  = 1 + Kernel.rand(total_weight)
106 
107   records.each do |record|
108     current_weight += weight(record)
109     return record if current_weight >= chosen_weight
110   end
111 end

    # File lib/puppet/http/dns.rb
120 def ttl(service_name)
121   return @record_cache[service_name].ttl
122 end

    # File lib/puppet/http/dns.rb
113 def weight(record)
114   record.weight == 0 ? 1 : record.weight * 10
115 end

    # File lib/puppet/http/dns.rb
148 def each_priority(records)
149   pri_hash = records.inject({}) do |groups, element|
150     groups[element.priority] ||= []
151     groups[element.priority] << element
152     groups
153   end
154 
155   pri_hash.keys.sort.each do |key|
156     yield pri_hash[key]
157   end
158 end