AnyEvent-MP/MP/DataConn.pm

=head1 NAME

AnyEvent::MP::DataConn - create socket connections between nodes

=head1 SYNOPSIS

   use AnyEvent::MP::DataConn;

=head1 DESCRIPTION

This module can be used to create socket connections between the local and
a remote node in the aemp network. The socket can be used freely for any
purpose, and in most cases, this mechanism is a good way to transport big
chunks of binary data.

The connections created by this module use the same security mechanisms
as normal AEMP connections (secure authentication, optional use of TLS),
and in fact, use the same listening port as AEMP connections, so when two
nodes can reach each other, they can, with high probability, creare a data
connection between them.

The protocol is, however, not the AEMP transport protocol, so this will
only work between nodes implementing the "aemp-dataconn" protocol.

=head1 FUNCTIONS

=over 4

=cut

package AnyEvent::MP::DataConn;

use common::sense;
use Carp ();
use POSIX ();

use AnyEvent ();
use AnyEvent::Util ();

use AnyEvent::MP;
use AnyEvent::MP::Kernel ();
use AnyEvent::MP::Global ();

our $ID = "a";
our %STATE;

# another node tells us to await a connection
sub _expect {
   my ($id, $port, $timeout, $initspec) = @_;

   $STATE{$id} = {
      id   => $id,
      to   => (AE::timer $timeout, 0, sub {
         $STATE{$id}{done}(undef);
      }),
      done => sub {
         my ($hdl, $error) = @_;

         %{delete $STATE{$id}} = ();

         if (defined $hdl) {
            my ($func, @args) = @$initspec;
            (AnyEvent::MP::Kernel::load_func $func)->(@args, $hdl);
         } else {
            kil $port, AnyEvent::MP::DataConn:: => $error;
         }
      },
   };
}

# AEMP::Transport call for dataconn-connections
sub _inject {
   my ($conn, $error) = @_;

   my $hdl = defined $error ? undef : delete $conn->{hdl};
   my $id = $conn->{local_greeting}{dataconn_id} || $conn->{remote_greeting}{dataconn_id}
      or return;

   $conn->destroy;

   ($STATE{$id} or return)->{done}($hdl, $error);
}

# actively connect to some other node
sub _connect {
   my ($id, $node) = @_;

   my $state = $STATE{$id}
      or return;

   my $addr = $AnyEvent::MP::Global::addr{$node};

   @$addr
      or return $state->{done}(undef, "$node: no listeners found");

   # I love hardcoded constants  !
   $state->{next} = AE::timer 0, 2, sub {
      my $endpoint = shift @$addr
         or return delete $state->{next};

      my ($host, $port) = AnyEvent::Socket::parse_hostport $endpoint
         or return;

      my $transport; $transport = AnyEvent::MP::Transport::mp_connect
         $host, $port,
         protocol => "aemp-dataconn",
         local_greeting => { dataconn_id => $id },
         sub { $transport->destroy }, #TODO: destroys handshaked conenctions too early
      ;
   };
}

=item AnyEvent::MP::DataConn::connect_to $node, $timeout, [$initfunc, @initdata], $cb->($handle)

Creates a socket connection between the local node and the node C<$node>
(which can also be specified as a port). One of the nodes must have
listening ports ("binds").

When the connection could be successfully created, the C<$initfunc>
will be called with the given C<@initdata> on the remote node (similar
to C<snd_to_func> or C<spawn>), and the C<AnyEvent::Handle> object
representing the remote connection end as additional argument.

Also, the callback given as last argument will be called with the
AnyEvent::Handle object for the local side.

The AnyEvent::Handle objects will be in a "quiescent" state - you could rip
out the file handle and forget about it, but it is recommended to use it,
as the security settings might have called for a TLS connection. If you
opt to use it, you at least have to set an C<on_error> callback.

In case of any error (timeout etc.), nothing will be called on
the remote side, and the local port will be C<kil>'ed with an C<<
AnyEvent::MP::DataConn => "error message" >> kill reason.

The timeout should be large enough to cover at least four network
round-trips and one message round-trip.

Example: on node1, establish a connection to node2 and send a line of text,
one node2, provide a receiver function.

   # node1, code executes in some port context
   AnyEvent::MP::DataConn::connect_to "node2", 5, ["pkg::receiver", 1], sub {
      my ($hdl) = @_;
      warn "connection established, sending line.\n"
      $hdl->push_write ("blabla\n")
   };

   # node2
   sub pkg::receiver {
      my ($one, $hdl) = @_;
      warn "connection established, wait for a line...\n"

      $hdl->push_read (line => sub {
         warn "received a line: $_[1]\n";
         undef $hdl;
      });
   }

=cut

sub connect_to($$$;@) {
   my ($node, $timeout, $initspec, $cb) = @_;
   my $port = $SELF;
   $node = node_of $node;

   my $id = (++$ID) . "\@$NODE";

   # damn, why do my simple state hashes resemble objects so quickly
   my $state = $STATE{$id} = {
      id   => (++$ID) . "\@$NODE",
      to   => (AE::timer $timeout, 0, sub {
         $STATE{$id}{done}(undef, "$node: unable to establish connection within $timeout seconds");
      }),
      done => sub {
         my ($hdl, $error) = @_;

         delete $AnyEvent::MP::Global::ON_SETUP{$id};
         %{delete $STATE{$id}} = ();

         if (defined $hdl) {
            $cb->($hdl);
         } else {
            kil $port, AnyEvent::MP::DataConn:: => $error;
         }
      },
   };

   if (AnyEvent::MP::Kernel::port_is_local $node) {
      return kil $port, AnyEvent::MP::DataConn:: =>
         "connect_to does not yet support local/local connections, please bug me about it";

   } else {
      AnyEvent::MP::Kernel::snd_to_func $node, AnyEvent::MP::DataConn::_expect:: => $id, $port, $timeout, $initspec;

      $state->{wait} = sub {
         if (my $addr = $AnyEvent::MP::Global::addr{$node}) {
            delete $AnyEvent::MP::Global::ON_SETUP{$id};

            # continue connect
            if (@$addr) {
               # node has listeners, so connect
               _connect $id, $node;
            } else {
               # no listeners, ask it to connect to us
               AnyEvent::MP::Kernel::snd_to_func $node, AnyEvent::MP::DataConn::_connect:: => $id, $NODE;
            }
         } else {
            # wait for the next global setup handshake
            # due to the round-trip at the beginning, this should never be necessary
            $AnyEvent::MP::Global::ON_SETUP{$id} = $state->{wait};
         };
      };

      # we actually have to make sure that the connection arrives after the expect message, and
      # the easiest way to do this is to use an rpc call.
      AnyEvent::MP::Kernel::snd_on $node, port { $state->{wait}() };
   }
}

=back

=head1 SEE ALSO

L<AnyEvent::MP>.

=head1 AUTHOR

 Marc Lehmann <schmorp@schmorp.de>
 http://home.schmorp.de/

=cut

1

Revision:	1.4
Committed:	Sun Nov 8 23:49:40 2009 UTC (14 years, 6 months ago) by root
Branch:	MAIN
Changes since 1.3:	+41 -13 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3			AnyEvent::MP::DataConn - create socket connections between nodes
4
5			=head1 SYNOPSIS
6
7			use AnyEvent::MP::DataConn;
8
9			=head1 DESCRIPTION
10
11			This module can be used to create socket connections between the local and
12			a remote node in the aemp network. The socket can be used freely for any
13			purpose, and in most cases, this mechanism is a good way to transport big
14			chunks of binary data.
15
16			The connections created by this module use the same security mechanisms
17			as normal AEMP connections (secure authentication, optional use of TLS),
18			and in fact, use the same listening port as AEMP connections, so when two
19			nodes can reach each other, they can, with high probability, creare a data
20			connection between them.
21
22			The protocol is, however, not the AEMP transport protocol, so this will
23			only work between nodes implementing the "aemp-dataconn" protocol.
24
25			=head1 FUNCTIONS
26
27			=over 4
28
29			=cut
30
31			package AnyEvent::MP::DataConn;
32
33			use common::sense;
34			use Carp ();
35			use POSIX ();
36
37			use AnyEvent ();
38			use AnyEvent::Util ();
39
40			use AnyEvent::MP;
41	root	1.2	use AnyEvent::MP::Kernel ();
42			use AnyEvent::MP::Global ();
43
44			our $ID = "a";
45			our %STATE;
46
47	root	1.3	# another node tells us to await a connection
48			sub _expect {
49	root	1.4	my ($id, $port, $timeout, $initspec) = @_;
50	root	1.2
51	root	1.3	$STATE{$id} = {
52			id => $id,
53			to => (AE::timer $timeout, 0, sub {
54	root	1.4	$STATE{$id}{done}(undef);
55	root	1.3	}),
56			done => sub {
57			my ($hdl, $error) = @_;
58
59			%{delete $STATE{$id}} = ();
60	root	1.2
61	root	1.3	if (defined $hdl) {
62			my ($func, @args) = @$initspec;
63			(AnyEvent::MP::Kernel::load_func $func)->(@args, $hdl);
64	root	1.4	} else {
65			kil $port, AnyEvent::MP::DataConn:: => $error;
66	root	1.3	}
67	root	1.2	},
68			};
69			}
70	root	1.1
71	root	1.3	# AEMP::Transport call for dataconn-connections
72	root	1.1	sub _inject {
73			my ($conn, $error) = @_;
74	root	1.2
75	root	1.3	my $hdl = defined $error ? undef : delete $conn->{hdl};
76			my $id = $conn->{local_greeting}{dataconn_id} \|\| $conn->{remote_greeting}{dataconn_id}
77			or return;
78
79			$conn->destroy;
80
81	root	1.4	($STATE{$id} or return)->{done}($hdl, $error);
82	root	1.1	}
83
84	root	1.3	# actively connect to some other node
85	root	1.2	sub _connect {
86	root	1.3	my ($id, $node) = @_;
87	root	1.2
88			my $state = $STATE{$id}
89			or return;
90
91	root	1.3	my $addr = $AnyEvent::MP::Global::addr{$node};
92	root	1.2
93			@$addr
94	root	1.4	or return $state->{done}(undef, "$node: no listeners found");
95	root	1.2
96	root	1.3	# I love hardcoded constants !
97	root	1.2	$state->{next} = AE::timer 0, 2, sub {
98			my $endpoint = shift @$addr
99			or return delete $state->{next};
100
101			my ($host, $port) = AnyEvent::Socket::parse_hostport $endpoint
102			or return;
103
104			my $transport; $transport = AnyEvent::MP::Transport::mp_connect
105			$host, $port,
106			protocol => "aemp-dataconn",
107	root	1.3	local_greeting => { dataconn_id => $id },
108			sub { $transport->destroy }, #TODO: destroys handshaked conenctions too early
109	root	1.2	;
110			};
111			}
112
113			=item AnyEvent::MP::DataConn::connect_to $node, $timeout, [$initfunc, @initdata], $cb->($handle)
114	root	1.1
115			Creates a socket connection between the local node and the node C<$node>
116	root	1.4	(which can also be specified as a port). One of the nodes must have
117			listening ports ("binds").
118	root	1.1
119			When the connection could be successfully created, the C<$initfunc>
120			will be called with the given C<@initdata> on the remote node (similar
121			to C<snd_to_func> or C<spawn>), and the C<AnyEvent::Handle> object
122	root	1.2	representing the remote connection end as additional argument.
123	root	1.1
124	root	1.2	Also, the callback given as last argument will be called with the
125			AnyEvent::Handle object for the local side.
126	root	1.1
127	root	1.2	The AnyEvent::Handle objects will be in a "quiescent" state - you could rip
128	root	1.1	out the file handle and forget about it, but it is recommended to use it,
129	root	1.2	as the security settings might have called for a TLS connection. If you
130	root	1.1	opt to use it, you at least have to set an C<on_error> callback.
131
132	root	1.2	In case of any error (timeout etc.), nothing will be called on
133			the remote side, and the local port will be C<kil>'ed with an C<<
134	root	1.1	AnyEvent::MP::DataConn => "error message" >> kill reason.
135
136	root	1.4	The timeout should be large enough to cover at least four network
137			round-trips and one message round-trip.
138
139			Example: on node1, establish a connection to node2 and send a line of text,
140			one node2, provide a receiver function.
141
142			# node1, code executes in some port context
143			AnyEvent::MP::DataConn::connect_to "node2", 5, ["pkg::receiver", 1], sub {
144			my ($hdl) = @_;
145			warn "connection established, sending line.\n"
146			$hdl->push_write ("blabla\n")
147			};
148
149			# node2
150			sub pkg::receiver {
151			my ($one, $hdl) = @_;
152			warn "connection established, wait for a line...\n"
153
154			$hdl->push_read (line => sub {
155			warn "received a line: $_[1]\n";
156			undef $hdl;
157			});
158			}
159
160	root	1.1	=cut
161
162			sub connect_to($$$;@) {
163	root	1.4	my ($node, $timeout, $initspec, $cb) = @_;
164	root	1.1	my $port = $SELF;
165			$node = node_of $node;
166
167	root	1.2	my $id = (++$ID) . "\@$NODE";
168	root	1.1
169	root	1.2	# damn, why do my simple state hashes resemble objects so quickly
170			my $state = $STATE{$id} = {
171	root	1.3	id => (++$ID) . "\@$NODE",
172			to => (AE::timer $timeout, 0, sub {
173	root	1.4	$STATE{$id}{done}(undef, "$node: unable to establish connection within $timeout seconds");
174	root	1.2	}),
175	root	1.3	done => sub {
176			my ($hdl, $error) = @_;
177
178			delete $AnyEvent::MP::Global::ON_SETUP{$id};
179			%{delete $STATE{$id}} = ();
180
181			if (defined $hdl) {
182	root	1.4	$cb->($hdl);
183	root	1.3	} else {
184			kil $port, AnyEvent::MP::DataConn:: => $error;
185			}
186	root	1.2	},
187	root	1.1	};
188
189	root	1.2	if (AnyEvent::MP::Kernel::port_is_local $node) {
190	root	1.1	return kil $port, AnyEvent::MP::DataConn:: =>
191			"connect_to does not yet support local/local connections, please bug me about it";
192	root	1.2
193	root	1.1	} else {
194	root	1.4	AnyEvent::MP::Kernel::snd_to_func $node, AnyEvent::MP::DataConn::_expect:: => $id, $port, $timeout, $initspec;
195	root	1.2
196			$state->{wait} = sub {
197			if (my $addr = $AnyEvent::MP::Global::addr{$node}) {
198			delete $AnyEvent::MP::Global::ON_SETUP{$id};
199
200			# continue connect
201			if (@$addr) {
202			# node has listeners, so connect
203	root	1.3	_connect $id, $node;
204	root	1.2	} else {
205			# no listeners, ask it to connect to us
206	root	1.4	AnyEvent::MP::Kernel::snd_to_func $node, AnyEvent::MP::DataConn::_connect:: => $id, $NODE;
207	root	1.2	}
208			} else {
209			# wait for the next global setup handshake
210	root	1.4	# due to the round-trip at the beginning, this should never be necessary
211	root	1.2	$AnyEvent::MP::Global::ON_SETUP{$id} = $state->{wait};
212			};
213	root	1.1	};
214	root	1.2
215	root	1.4	# we actually have to make sure that the connection arrives after the expect message, and
216			# the easiest way to do this is to use an rpc call.
217			AnyEvent::MP::Kernel::snd_on $node, port { $state->{wait}() };
218	root	1.1	}
219			}
220
221			=back
222
223			=head1 SEE ALSO
224
225			L<AnyEvent::MP>.
226
227			=head1 AUTHOR
228
229			Marc Lehmann <schmorp@schmorp.de>
230			http://home.schmorp.de/
231
232			=cut
233
234			1
235