* lib/resolv.rb: make timeout configurable for DNS query.

patch by Eric Wong.  [ruby-core:38533] [Feature #5100]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@33504 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Sat Oct 22 17:43:33 2011  Tanaka Akira  <akr@fsij.org>
+
+	* lib/resolv.rb: make timeout configurable for DNS query.
+	  patch by Eric Wong.  [ruby-core:38533] [Feature #5100]
+
 Sat Oct 22 02:07:48 2011  Naohisa Goto  <ngotogenome@gmail.com>
 
 	* numeric.c (rb_infinity, rb_nan): use union to prevent bus error

lib/resolv.rb

@@ -336,6 +336,21 @@ class Resolv
       @initialized = nil
     end
 
+    # Sets the resolver timeouts.  This may be a single positive number
+    # or an array of positive numbers representing timeouts in seconds.
+    # If an array is specified, a DNS request will retry and wait for
+    # each successive interval in the array until a successful response
+    # is received.  Specifying +nil+ reverts to the default timeouts:
+    # [ 5, second = 5 * 2 / nameserver_count, 2 * second, 4 * second ]
+    #
+    # Example:
+    #
+    #   dns.timeouts = 3
+    #
+    def timeouts=(values)
+      @config.timeouts = values
+    end
+
     def lazy_initialize # :nodoc:
       @mutex.synchronize {
         unless @initialized
@@ -851,6 +866,20 @@ class Resolv
         @mutex = Mutex.new
         @config_info = config_info
         @initialized = nil
+        @timeouts = nil
+      end
+
+      def timeouts=(values)
+        if values
+          values = Array(values)
+          values.each do |t|
+            Numeric === t or raise ArgumentError, "#{t.inspect} is not numeric"
+            t > 0.0 or raise Argument, "timeout=#{t} must be postive"
+          end
+          @timeouts = values
+        else
+          @timeouts = nil
+        end
       end
 
       def Config.parse_resolv_conf(filename)
@@ -1013,7 +1042,7 @@ class Resolv
 
       def resolv(name)
         candidates = generate_candidates(name)
-        timeouts = generate_timeouts
+        timeouts = @timeouts || generate_timeouts
         begin
           candidates.each {|candidate|
             begin

test/resolv/test_dns.rb

@@ -105,6 +105,30 @@ class TestResolvDNS < Test::Unit::TestCase
     }
   end
 
+  def test_query_ipv4_address_timeout
+    with_udp('127.0.0.1', 0) {|u|
+      _, port , _, host = u.addr
+      start = nil
+      rv = Resolv::DNS.open(:nameserver_port => [[host, port]]) {|dns|
+        dns.timeouts = 0.1
+        start = Time.now
+        dns.getresources("foo.example.org", Resolv::DNS::Resource::IN::A)
+      }
+      diff = Time.now - start
+      assert rv.empty?, "unexpected: #{rv.inspect} (expected empty)"
+      assert_in_delta 0.1, diff, 0.05
+
+      rv = Resolv::DNS.open(:nameserver_port => [[host, port]]) {|dns|
+        dns.timeouts = [ 0.1, 0.2 ]
+        start = Time.now
+        dns.getresources("foo.example.org", Resolv::DNS::Resource::IN::A)
+      }
+      diff = Time.now - start
+      assert rv.empty?, "unexpected: #{rv.inspect} (expected empty)"
+      assert_in_delta 0.3, diff, 0.05
+    }
+  end
+
   def test_no_server
     u = UDPSocket.new
     u.bind("127.0.0.1", 0)