Class DRb::DRbServer
In: lib/drb/invokemethod.rb
lib/drb/drb.rb
Parent: Object

Class representing a drb server instance.

A DRbServer must be running in the local process before any incoming dRuby calls can be accepted, or any local objects can be passed as dRuby references to remote processes, even if those local objects are never actually called remotely. You do not need to start a DRbServer in the local process if you are only making outgoing dRuby calls passing marshalled parameters.

Unless multiple servers are being used, the local DRbServer is normally started by calling DRb.start_service.

Methods

Classes and Modules

Module DRb::DRbServer::InvokeMethod18Mixin

Constants

INSECURE_METHOD = [ :__send__   List of insecure methods.

These methods are not callable via dRuby.

Attributes

config  [R]  The configuration of this DRbServer
front  [R]  The front object of the DRbServer.

This object receives remote method calls made on the server‘s URI alone, with an object id.

safe_level  [R] 
thread  [R]  The main thread of this DRbServer.

This is the thread that listens for and accepts connections from clients, not that handles each client‘s request-response session.

uri  [R]  The URI of this DRbServer.

Public Class methods

Set the default value for the :acl option.

See new(). The initial default value is nil.

[Source]

      # File lib/drb/drb.rb, line 1248
1248:     def self.default_acl(acl)
1249:       @@acl = acl
1250:     end

Set the default value for the :argc_limit option.

See new(). The initial default value is 256.

[Source]

      # File lib/drb/drb.rb, line 1234
1234:     def self.default_argc_limit(argc)
1235:       @@argc_limit = argc
1236:     end

Set the default value for the :id_conv option.

See new(). The initial default value is a DRbIdConv instance.

[Source]

      # File lib/drb/drb.rb, line 1255
1255:     def self.default_id_conv(idconv)
1256:       @@idconv = idconv
1257:     end

Set the default value for the :load_limit option.

See new(). The initial default value is 25 MB.

[Source]

      # File lib/drb/drb.rb, line 1241
1241:     def self.default_load_limit(sz)
1242:       @@load_limit = sz
1243:     end

[Source]

      # File lib/drb/drb.rb, line 1259
1259:     def self.default_safe_level(level)
1260:       @@safe_level = level
1261:     end

Create a new DRbServer instance.

uri is the URI to bind to. This is normally of the form ‘druby://<hostname>:<port>’ where <hostname> is a hostname of the local machine. If nil, then the system‘s default hostname will be bound to, on a port selected by the system; these value can be retrieved from the uri attribute. ‘druby:’ specifies the default dRuby transport protocol: another protocol, such as ‘drbunix:’, can be specified instead.

front is the front object for the server, that is, the object to which remote method calls on the server will be passed. If nil, then the server will not accept remote method calls.

If config_or_acl is a hash, it is the configuration to use for this server. The following options are recognised:

:idconv :an id-to-object conversion object. This defaults to an instance of the class DRb::DRbIdConv.
:verbose :if true, all unsuccessful remote calls on objects in the server will be logged to $stdout. false by default.
:tcp_acl :the access control list for this server. See the ACL class from the main dRuby distribution.
:load_limit :the maximum message size in bytes accepted by the server. Defaults to 25 MB (26214400).
:argc_limit :the maximum number of arguments to a remote method accepted by the server. Defaults to 256.

The default values of these options can be modified on a class-wide basis by the class methods default_argc_limit, default_load_limit, default_acl, default_id_conv, and verbose=

If config_or_acl is not a hash, but is not nil, it is assumed to be the access control list for this server. See the :tcp_acl option for more details.

If no other server is currently set as the primary server, this will become the primary server.

The server will immediately start running in its own thread.

[Source]

      # File lib/drb/drb.rb, line 1330
1330:     def initialize(uri=nil, front=nil, config_or_acl=nil)
1331:       if Hash === config_or_acl
1332:         config = config_or_acl.dup
1333:       else
1334:         acl = config_or_acl || @@acl
1335:         config = {
1336:           :tcp_acl => acl
1337:         }
1338:       end
1339: 
1340:       @config = self.class.make_config(config)
1341: 
1342:       @protocol = DRbProtocol.open_server(uri, @config)
1343:       @uri = @protocol.uri
1344: 
1345:       @front = front
1346:       @idconv = @config[:idconv]
1347:       @safe_level = @config[:safe_level]
1348: 
1349:       @grp = ThreadGroup.new
1350:       @thread = run
1351: 
1352:       DRb.regist_server(self)
1353:     end

Get the default value of the :verbose option.

[Source]

      # File lib/drb/drb.rb, line 1271
1271:     def self.verbose
1272:       @@verbose
1273:     end

Set the default value of the :verbose option.

See new(). The initial default value is false.

[Source]

      # File lib/drb/drb.rb, line 1266
1266:     def self.verbose=(on)
1267:       @@verbose = on
1268:     end

Public Instance methods

Is this server alive?

[Source]

      # File lib/drb/drb.rb, line 1387
1387:     def alive?
1388:       @thread.alive?
1389:     end

Check that a method is callable via dRuby.

obj is the object we want to invoke the method on. msg_id is the method name, as a Symbol.

If the method is an insecure method (see insecure_method?) a SecurityError is thrown. If the method is private or undefined, a NameError is thrown.

[Source]

      # File lib/drb/drb.rb, line 1470
1470:     def check_insecure_method(obj, msg_id)
1471:       return true if Proc === obj && msg_id == :__drb_yield
1472:       raise(ArgumentError, "#{any_to_s(msg_id)} is not a symbol") unless Symbol == msg_id.class
1473:       raise(SecurityError, "insecure method `#{msg_id}'") if insecure_method?(msg_id)
1474:       
1475:       if obj.private_methods.include?(msg_id.to_s)
1476:         desc = any_to_s(obj)
1477:         raise NoMethodError, "private method `#{msg_id}' called for #{desc}"
1478:       elsif obj.protected_methods.include?(msg_id.to_s)
1479:         desc = any_to_s(obj)
1480:         raise NoMethodError, "protected method `#{msg_id}' called for #{desc}"
1481:       else
1482:         true
1483:       end
1484:     end

Stop this server.

[Source]

      # File lib/drb/drb.rb, line 1392
1392:     def stop_service
1393:       DRb.remove_server(self)
1394:       if  Thread.current['DRb'] && Thread.current['DRb']['server'] == self
1395:         Thread.current['DRb']['stop_service'] = true
1396:       else
1397:         @thread.kill
1398:       end
1399:     end

Convert a local object to a dRuby reference.

[Source]

      # File lib/drb/drb.rb, line 1409
1409:     def to_id(obj)
1410:       return nil if obj.__id__ == front.__id__
1411:       @idconv.to_id(obj)
1412:     end

Convert a dRuby reference to the local object it refers to.

[Source]

      # File lib/drb/drb.rb, line 1402
1402:     def to_obj(ref)
1403:       return front if ref.nil?
1404:       return front[ref.to_s] if DRbURIOption === ref
1405:       @idconv.to_obj(ref)
1406:     end

Get whether the server is in verbose mode.

In verbose mode, failed calls are logged to stdout.

[Source]

      # File lib/drb/drb.rb, line 1384
1384:     def verbose; @config[:verbose]; end

Set whether to operate in verbose mode.

In verbose mode, failed calls are logged to stdout.

[Source]

      # File lib/drb/drb.rb, line 1379
1379:     def verbose=(v); @config[:verbose]=v; end

Private Instance methods

Coerce an object to a string, providing our own representation if to_s is not defined for the object.

[Source]

      # File lib/drb/drb.rb, line 1456
1456:     def any_to_s(obj)
1457:       obj.to_s + ":#{obj.class}"
1458:     rescue
1459:       sprintf("#<%s:0x%lx>", obj.class, obj.__id__)      
1460:     end

Has a method been included in the list of insecure methods?

[Source]

      # File lib/drb/drb.rb, line 1450
1450:     def insecure_method?(msg_id)
1451:       INSECURE_METHOD.include?(msg_id)
1452:     end

[Source]

      # File lib/drb/drb.rb, line 1415
1415:     def kill_sub_thread
1416:       Thread.new do
1417:         grp = ThreadGroup.new
1418:         grp.add(Thread.current)
1419:         list = @grp.list
1420:         while list.size > 0
1421:           list.each do |th|
1422:             th.kill if th.alive?
1423:           end
1424:           list = @grp.list
1425:         end
1426:       end
1427:     end

The main loop performed by a DRbServer‘s internal thread.

Accepts a connection from a client, and starts up its own thread to handle it. This thread loops, receiving requests from the client, invoking them on a local object, and returning responses, until the client closes the connection or a local method call fails.

[Source]

      # File lib/drb/drb.rb, line 1583
1583:     def main_loop
1584:       Thread.start(@protocol.accept) do |client|
1585:         @grp.add Thread.current
1586:         Thread.current['DRb'] = { 'client' => client ,
1587:                                   'server' => self }
1588:         loop do
1589:           begin
1590:             succ = false
1591:             invoke_method = InvokeMethod.new(self, client)
1592:             succ, result = invoke_method.perform
1593:             if !succ && verbose
1594:               p result
1595:               result.backtrace.each do |x|
1596:                 puts x
1597:               end
1598:             end
1599:             client.send_reply(succ, result) rescue nil
1600:           ensure
1601:             client.close unless succ
1602:             if Thread.current['DRb']['stop_service']
1603:               Thread.new { stop_service }
1604:             end
1605:             break unless succ
1606:           end
1607:         end
1608:       end
1609:     end

[Source]

      # File lib/drb/drb.rb, line 1429
1429:     def run
1430:       Thread.start do
1431:         begin
1432:           while true
1433:             main_loop
1434:           end
1435:         ensure
1436:           @protocol.close if @protocol
1437:           kill_sub_thread
1438:         end
1439:       end
1440:     end

[Validate]