class DRb::DRbServer
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
.
Constants
- INSECURE_METHOD
List of insecure methods.
These methods are not callable via dRuby.
Attributes
The configuration of this DRbServer
The front object of the DRbServer.
This object receives remote method calls made on the server's URI
alone, with an object id.
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.
The URI
of this DRbServer.
Public Class Methods
Set
the default value for the :argc_limit option.
See new(). The initial default value is 256.
# File lib/drb/drb.rb, line 1360 def self.default_argc_limit(argc) @@argc_limit = argc end
Set
the default value for the :load_limit option.
See new(). The initial default value is 25 MB.
# File lib/drb/drb.rb, line 1367 def self.default_load_limit(sz) @@load_limit = sz 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.
# File lib/drb/drb.rb, line 1454 def initialize(uri=nil, front=nil, config_or_acl=nil) if Hash === config_or_acl config = config_or_acl.dup else acl = config_or_acl || @@acl config = { :tcp_acl => acl } end @config = self.class.make_config(config) @protocol = DRbProtocol.open_server(uri, @config) @uri = @protocol.uri @exported_uri = [@uri] @front = front @idconv = @config[:idconv] @grp = ThreadGroup.new @thread = run DRb.regist_server(self) end
Get the default value of the :verbose option.
# File lib/drb/drb.rb, line 1397 def self.verbose @@verbose end
Set
the default value of the :verbose option.
See new(). The initial default value is false.
# File lib/drb/drb.rb, line 1392 def self.verbose=(on) @@verbose = on end
Public Instance Methods
Is this server alive?
# File lib/drb/drb.rb, line 1514 def alive? @thread.alive? 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.
# File lib/drb/drb.rb, line 1602 def check_insecure_method(obj, msg_id) return true if Proc === obj && msg_id == :__drb_yield raise(ArgumentError, "#{any_to_s(msg_id)} is not a symbol") unless Symbol == msg_id.class raise(SecurityError, "insecure method `#{msg_id}'") if insecure_method?(msg_id) case obj when Object if obj.private_methods.include?(msg_id) desc = any_to_s(obj) raise NoMethodError, "private method `#{msg_id}' called for #{desc}" elsif obj.protected_methods.include?(msg_id) desc = any_to_s(obj) raise NoMethodError, "protected method `#{msg_id}' called for #{desc}" else true end else if Kernel.instance_method(:private_methods).bind(obj).call.include?(msg_id) desc = any_to_s(obj) raise NoMethodError, "private method `#{msg_id}' called for #{desc}" elsif Kernel.instance_method(:protected_methods).bind(obj).call.include?(msg_id) desc = any_to_s(obj) raise NoMethodError, "protected method `#{msg_id}' called for #{desc}" else true end end end
Is uri
the URI
for this server?
# File lib/drb/drb.rb, line 1519 def here?(uri) @exported_uri.include?(uri) end
Stop this server.
# File lib/drb/drb.rb, line 1524 def stop_service DRb.remove_server(self) if Thread.current['DRb'] && Thread.current['DRb']['server'] == self Thread.current['DRb']['stop_service'] = true else shutdown end end
Convert a local object to a dRuby reference.
# File lib/drb/drb.rb, line 1541 def to_id(obj) return nil if obj.__id__ == front.__id__ @idconv.to_id(obj) end
Convert a dRuby reference to the local object it refers to.
# File lib/drb/drb.rb, line 1534 def to_obj(ref) return front if ref.nil? return front[ref.to_s] if DRbURIOption === ref @idconv.to_obj(ref) end
Get whether the server is in verbose mode.
In verbose mode, failed calls are logged to stdout.
# File lib/drb/drb.rb, line 1511 def verbose; @config[:verbose]; end
Set
whether to operate in verbose mode.
In verbose mode, failed calls are logged to stdout.
# File lib/drb/drb.rb, line 1506 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.
# File lib/drb/drb.rb, line 1588 def any_to_s(obj) "#{obj}:#{obj.class}" rescue Kernel.instance_method(:to_s).bind_call(obj) end
# File lib/drb/drb.rb, line 1701 def error_print(exception) exception.backtrace.inject(true) do |first, x| if first $stderr.puts "#{x}: #{exception} (#{exception.class})" else $stderr.puts "\tfrom #{x}" end false end end
Has a method been included in the list of insecure methods?
# File lib/drb/drb.rb, line 1582 def insecure_method?(msg_id) INSECURE_METHOD.include?(msg_id) 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.
# File lib/drb/drb.rb, line 1719 def main_loop client0 = @protocol.accept return nil if !client0 Thread.start(client0) do |client| @grp.add Thread.current Thread.current['DRb'] = { 'client' => client , 'server' => self } DRb.mutex.synchronize do client_uri = client.uri @exported_uri << client_uri unless @exported_uri.include?(client_uri) end loop do begin succ = false invoke_method = InvokeMethod.new(self, client) succ, result = invoke_method.perform error_print(result) if !succ && verbose unless DRbConnError === result && result.message == 'connection closed' client.send_reply(succ, result) end rescue Exception => e error_print(e) if verbose ensure client.close unless succ if Thread.current['DRb']['stop_service'] shutdown break end break unless succ end end end end
Starts the DRb
main loop in a new thread.
# File lib/drb/drb.rb, line 1563 def run Thread.start do begin while main_loop end ensure @protocol.close if @protocol end end end
# File lib/drb/drb.rb, line 1548 def shutdown current = Thread.current if @protocol.respond_to? :shutdown @protocol.shutdown else [@thread, *@grp.list].each { |thread| thread.kill unless thread == current # xxx: Thread#kill } end @thread.join unless @thread == current end