main

 1# frozen_string_literal: true
 2
 3module Net
 4  module Hippie
 5    # Thread-safe DNS resolution cache with TTL.
 6    class DnsCache
 7      def initialize(timeout: 5, ttl: 300, logger: nil)
 8        @timeout = timeout
 9        @ttl = ttl
10        @logger = logger
11        @cache = {}
12        @monitor = Monitor.new
13      end
14
15      def resolve(hostname)
16        cached = get(hostname)
17        return cached if cached
18
19        ip = Net::Hippie.resolve(hostname, timeout: @timeout)
20        set(hostname, ip)
21        ip
22      rescue Timeout::Error, Resolv::ResolvError => error
23        @logger&.warn("[Hippie] DNS resolution failed for #{hostname}: #{error.message}")
24        nil
25      end
26
27      def clear
28        @monitor.synchronize { @cache.clear }
29      end
30
31      private
32
33      def get(hostname)
34        @monitor.synchronize do
35          entry = @cache[hostname]
36          entry[:ip] if entry && (Time.now - entry[:time]) < @ttl
37        end
38      end
39
40      def set(hostname, ip_addr)
41        @monitor.synchronize { @cache[hostname] = { ip: ip_addr, time: Time.now } }
42      end
43    end
44  end
45end