… | |
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4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use AnyEvent::MP; |
7 | use AnyEvent::MP; |
8 | |
8 | |
9 | NODE # returns this node identifier |
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10 | $NODE # contains this node identifier |
9 | $NODE # contains this node's noderef |
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10 | NODE # returns this node's noderef |
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11 | NODE $port # returns the noderef of the port |
11 | |
12 | |
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13 | $SELF # receiving/own port id in rcv callbacks |
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14 | |
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15 | # initialise the node so it can send/receive messages |
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16 | initialise_node; |
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17 | |
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18 | # ports are message endpoints |
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19 | |
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20 | # sending messages |
12 | snd $port, type => data...; |
21 | snd $port, type => data...; |
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22 | snd $port, @msg; |
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23 | snd @msg_with_first_element_being_a_port; |
13 | |
24 | |
14 | rcv $port, smartmatch => $cb->($port, @msg); |
25 | # creating/using ports, the simple way |
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26 | my $simple_port = port { my @msg = @_; 0 }; |
15 | |
27 | |
16 | # examples: |
28 | # creating/using ports, tagged message matching |
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29 | my $port = port; |
17 | rcv $port2, ping => sub { snd $_[0], "pong"; 0 }; |
30 | rcv $port, ping => sub { snd $_[0], "pong"; 0 }; |
18 | rcv $port1, pong => sub { warn "pong received\n" }; |
31 | rcv $port, pong => sub { warn "pong received\n"; 0 }; |
19 | snd $port2, ping => $port1; |
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20 | |
32 | |
21 | # more, smarter, matches (_any_ is exported by this module) |
33 | # create a port on another node |
22 | rcv $port, [child_died => $pid] => sub { ... |
34 | my $port = spawn $node, $initfunc, @initdata; |
23 | rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3 |
35 | |
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36 | # monitoring |
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37 | mon $port, $cb->(@msg) # callback is invoked on death |
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38 | mon $port, $otherport # kill otherport on abnormal death |
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39 | mon $port, $otherport, @msg # send message on death |
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40 | |
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41 | =head1 CURRENT STATUS |
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42 | |
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43 | AnyEvent::MP - stable API, should work |
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44 | AnyEvent::MP::Intro - outdated |
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45 | AnyEvent::MP::Kernel - WIP |
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46 | AnyEvent::MP::Transport - mostly stable |
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47 | |
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48 | stay tuned. |
24 | |
49 | |
25 | =head1 DESCRIPTION |
50 | =head1 DESCRIPTION |
26 | |
51 | |
27 | This module (-family) implements a simple message passing framework. |
52 | This module (-family) implements a simple message passing framework. |
28 | |
53 | |
29 | Despite its simplicity, you can securely message other processes running |
54 | Despite its simplicity, you can securely message other processes running |
30 | on the same or other hosts. |
55 | on the same or other hosts. |
31 | |
56 | |
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57 | For an introduction to this module family, see the L<AnyEvent::MP::Intro> |
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58 | manual page. |
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59 | |
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60 | At the moment, this module family is severly broken and underdocumented, |
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61 | so do not use. This was uploaded mainly to reserve the CPAN namespace - |
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62 | stay tuned! |
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63 | |
32 | =head1 CONCEPTS |
64 | =head1 CONCEPTS |
33 | |
65 | |
34 | =over 4 |
66 | =over 4 |
35 | |
67 | |
36 | =item port |
68 | =item port |
37 | |
69 | |
38 | A port is something you can send messages to with the C<snd> function, and |
70 | A port is something you can send messages to (with the C<snd> function). |
39 | you can register C<rcv> handlers with. All C<rcv> handlers will receive |
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40 | messages they match, messages will not be queued. |
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41 | |
71 | |
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72 | Ports allow you to register C<rcv> handlers that can match all or just |
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73 | some messages. Messages send to ports will not be queued, regardless of |
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74 | anything was listening for them or not. |
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75 | |
42 | =item port id - C<pid@host#portname> |
76 | =item port ID - C<noderef#portname> |
43 | |
77 | |
44 | A port id is always the node id, a hash-mark (C<#>) as separator, followed |
78 | A port ID is the concatenation of a noderef, a hash-mark (C<#>) as |
45 | by a port name. |
79 | separator, and a port name (a printable string of unspecified format). An |
46 | |
80 | exception is the the node port, whose ID is identical to its node |
47 | A port name can be a well known port (basically an identifier/bareword), |
81 | reference. |
48 | or a generated name, consisting of node id, a dot (C<.>), and an |
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49 | identifier. |
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50 | |
82 | |
51 | =item node |
83 | =item node |
52 | |
84 | |
53 | A node is a single process containing at least one port - the node |
85 | A node is a single process containing at least one port - the node port, |
54 | port. You can send messages to node ports to let them create new ports, |
86 | which provides nodes to manage each other remotely, and to create new |
55 | among other things. |
87 | ports. |
56 | |
88 | |
57 | Initially, nodes are either private (single-process only) or hidden |
89 | Nodes are either private (single-process only), slaves (can only talk to |
58 | (connected to a father node only). Only when they epxlicitly "go public" |
90 | public nodes, but do not need an open port) or public nodes (connectable |
59 | can you send them messages form unrelated other nodes. |
91 | from any other node). |
60 | |
92 | |
61 | Public nodes automatically connect to all other public nodes in a network |
93 | =item node ID - C<[a-za-Z0-9_\-.:]+> |
62 | when they connect, creating a full mesh. |
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63 | |
94 | |
64 | =item node id - C<host:port>, C<id@host>, C<id> |
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65 | |
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66 | A node ID is a string that either uniquely identifies a given node (For |
95 | A node ID is a string that uniquely identifies the node within a |
67 | private and hidden nodes), or contains a recipe on how to reach a given |
96 | network. Depending on the configuration used, node IDs can look like a |
68 | node (for public nodes). |
97 | hostname, a hostname and a port, or a random string. AnyEvent::MP itself |
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98 | doesn't interpret node IDs in any way. |
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99 | |
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100 | =item binds - C<ip:port> |
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101 | |
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102 | Nodes can only talk to each other by creating some kind of connection to |
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103 | each other. To do this, nodes should listen on one or more local transport |
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104 | endpoints - binds. Currently, only standard C<ip:port> specifications can |
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105 | be used, which specify TCP ports to listen on. |
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106 | |
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107 | =item seeds - C<host:port> |
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108 | |
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109 | When a node starts, it knows nothing about the network. To teach the node |
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110 | about the network it first has to contact some other node within the |
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111 | network. This node is called a seed. |
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112 | |
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113 | Seeds are transport endpoint(s) of as many nodes as one wants. Those nodes |
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114 | are expected to be long-running, and at least one of those should always |
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115 | be available. When nodes run out of connections (e.g. due to a network |
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116 | error), they try to re-establish connections to some seednodes again to |
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117 | join the network. |
69 | |
118 | |
70 | =back |
119 | =back |
71 | |
120 | |
72 | =head1 FUNCTIONS |
121 | =head1 VARIABLES/FUNCTIONS |
73 | |
122 | |
74 | =over 4 |
123 | =over 4 |
75 | |
124 | |
76 | =cut |
125 | =cut |
77 | |
126 | |
78 | package AnyEvent::MP; |
127 | package AnyEvent::MP; |
79 | |
128 | |
80 | use AnyEvent::MP::Util (); |
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81 | use AnyEvent::MP::Node; |
129 | use AnyEvent::MP::Kernel; |
82 | use AnyEvent::MP::Transport; |
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83 | |
130 | |
84 | use utf8; |
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85 | use common::sense; |
131 | use common::sense; |
86 | |
132 | |
87 | use Carp (); |
133 | use Carp (); |
88 | |
134 | |
89 | use AE (); |
135 | use AE (); |
90 | |
136 | |
91 | use base "Exporter"; |
137 | use base "Exporter"; |
92 | |
138 | |
93 | our $VERSION = '0.0'; |
139 | our $VERSION = $AnyEvent::MP::Kernel::VERSION; |
94 | our @EXPORT = qw(NODE $NODE $PORT snd rcv _any_); |
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95 | |
140 | |
96 | our $DEFAULT_SECRET; |
141 | our @EXPORT = qw( |
97 | our $DEFAULT_PORT = "4040"; |
142 | NODE $NODE *SELF node_of after |
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143 | resolve_node initialise_node |
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144 | snd rcv mon mon_guard kil reg psub spawn |
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145 | port |
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146 | ); |
98 | |
147 | |
99 | our $CONNECT_INTERVAL = 5; # new connect every 5s, at least |
148 | our $SELF; |
100 | our $CONNECT_TIMEOUT = 30; # includes handshake |
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101 | |
149 | |
102 | sub default_secret { |
150 | sub _self_die() { |
103 | unless (defined $DEFAULT_SECRET) { |
151 | my $msg = $@; |
104 | if (open my $fh, "<$ENV{HOME}/.aemp-secret") { |
152 | $msg =~ s/\n+$// unless ref $msg; |
105 | sysread $fh, $DEFAULT_SECRET, -s $fh; |
153 | kil $SELF, die => $msg; |
106 | } else { |
154 | } |
107 | $DEFAULT_SECRET = AnyEvent::MP::Util::nonce 32; |
155 | |
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156 | =item $thisnode = NODE / $NODE |
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157 | |
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158 | The C<NODE> function returns, and the C<$NODE> variable contains the node |
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159 | ID of the node running in the current process. This value is initialised by |
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160 | a call to C<initialise_node>. |
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161 | |
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162 | =item $nodeid = node_of $port |
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163 | |
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164 | Extracts and returns the node ID part from a port ID or a node ID. |
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165 | |
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166 | =item initialise_node $profile_name |
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167 | |
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168 | Before a node can talk to other nodes on the network (i.e. enter |
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169 | "distributed mode") it has to initialise itself - the minimum a node needs |
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170 | to know is its own name, and optionally it should know the addresses of |
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171 | some other nodes in the network to discover other nodes. |
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172 | |
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173 | This function initialises a node - it must be called exactly once (or |
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174 | never) before calling other AnyEvent::MP functions. |
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175 | |
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176 | The first argument is a profile name. If it is C<undef> or missing, then |
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177 | the current nodename will be used instead (i.e. F<uname -n>). |
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178 | |
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179 | The function then looks up the profile in the aemp configuration (see the |
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180 | L<aemp> commandline utility). |
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181 | |
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182 | If the profile specifies a node ID, then this will become the node ID of |
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183 | this process. If not, then the profile name will be used as node ID. The |
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184 | special node ID of C<anon/> will be replaced by a random node ID. |
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185 | |
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186 | The next step is to look up the binds in the profile, followed by binding |
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187 | aemp protocol listeners on all binds specified (it is possible and valid |
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188 | to have no binds, meaning that the node cannot be contacted form the |
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189 | outside. This means the node cannot talk to other nodes that also have no |
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190 | binds, but it can still talk to all "normal" nodes). |
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191 | |
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192 | If the profile does not specify a binds list, then the node ID will be |
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193 | treated as if it were of the form C<host:port>, which will be resolved and |
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194 | used as binds list. |
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195 | |
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196 | Lastly, the seeds list from the profile is passed to the |
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197 | L<AnyEvent::MP::Global> module, which will then use it to keep |
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198 | connectivity with at least on of those seed nodes at any point in time. |
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199 | |
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200 | Example: become a distributed node listening on the guessed noderef, or |
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201 | the one specified via C<aemp> for the current node. This should be the |
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202 | most common form of invocation for "daemon"-type nodes. |
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203 | |
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204 | initialise_node; |
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205 | |
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206 | Example: become an anonymous node. This form is often used for commandline |
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207 | clients. |
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208 | |
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209 | initialise_node "anon/"; |
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210 | |
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211 | Example: become a distributed node. If there is no profile of the given |
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212 | name, or no binds list was specified, resolve C<localhost:4044> and bind |
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213 | on the resulting addresses. |
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214 | |
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215 | initialise_node "localhost:4044"; |
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216 | |
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217 | =item $SELF |
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218 | |
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219 | Contains the current port id while executing C<rcv> callbacks or C<psub> |
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220 | blocks. |
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221 | |
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222 | =item SELF, %SELF, @SELF... |
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223 | |
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224 | Due to some quirks in how perl exports variables, it is impossible to |
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225 | just export C<$SELF>, all the symbols called C<SELF> are exported by this |
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226 | module, but only C<$SELF> is currently used. |
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227 | |
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228 | =item snd $port, type => @data |
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229 | |
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230 | =item snd $port, @msg |
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231 | |
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232 | Send the given message to the given port ID, which can identify either |
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233 | a local or a remote port, and must be a port ID. |
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234 | |
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235 | While the message can be about anything, it is highly recommended to use a |
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236 | string as first element (a port ID, or some word that indicates a request |
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237 | type etc.). |
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238 | |
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239 | The message data effectively becomes read-only after a call to this |
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240 | function: modifying any argument is not allowed and can cause many |
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241 | problems. |
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242 | |
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243 | The type of data you can transfer depends on the transport protocol: when |
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244 | JSON is used, then only strings, numbers and arrays and hashes consisting |
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245 | of those are allowed (no objects). When Storable is used, then anything |
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246 | that Storable can serialise and deserialise is allowed, and for the local |
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247 | node, anything can be passed. |
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248 | |
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249 | =item $local_port = port |
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250 | |
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251 | Create a new local port object and returns its port ID. Initially it has |
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252 | no callbacks set and will throw an error when it receives messages. |
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253 | |
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254 | =item $local_port = port { my @msg = @_ } |
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255 | |
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256 | Creates a new local port, and returns its ID. Semantically the same as |
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257 | creating a port and calling C<rcv $port, $callback> on it. |
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258 | |
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259 | The block will be called for every message received on the port, with the |
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260 | global variable C<$SELF> set to the port ID. Runtime errors will cause the |
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261 | port to be C<kil>ed. The message will be passed as-is, no extra argument |
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262 | (i.e. no port ID) will be passed to the callback. |
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263 | |
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264 | If you want to stop/destroy the port, simply C<kil> it: |
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265 | |
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266 | my $port = port { |
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267 | my @msg = @_; |
108 | } |
268 | ... |
109 | } |
269 | kil $SELF; |
110 | |
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111 | $DEFAULT_SECRET |
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112 | } |
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113 | |
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114 | our $UNIQ = sprintf "%x.%x", $$, time; # per-process/node unique cookie |
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115 | our $PUBLIC = 0; |
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116 | our $NODE; |
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117 | our $PORT; |
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118 | |
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119 | our %NODE; # node id to transport mapping, or "undef", for local node |
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120 | our %PORT; # local ports |
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121 | our %LISTENER; # local transports |
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122 | |
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123 | sub NODE() { $NODE } |
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124 | |
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125 | { |
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126 | use POSIX (); |
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127 | my $nodename = (POSIX::uname)[1]; |
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128 | $NODE = "$$\@$nodename"; |
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129 | } |
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130 | |
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131 | sub _ANY_() { 1 } |
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132 | sub _any_() { \&_ANY_ } |
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133 | |
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134 | sub add_node { |
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135 | my ($noderef) = @_; |
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136 | |
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137 | return $NODE{$noderef} |
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138 | if exists $NODE{$noderef}; |
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139 | |
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140 | for (split /,/, $noderef) { |
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141 | return $NODE{$noderef} = $NODE{$_} |
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142 | if exists $NODE{$_}; |
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143 | } |
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144 | |
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145 | # for indirect sends, use a different class |
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146 | my $node = new AnyEvent::MP::Node::Direct $noderef; |
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147 | |
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148 | $NODE{$_} = $node |
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149 | for $noderef, split /,/, $noderef; |
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150 | |
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151 | $node |
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152 | } |
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153 | |
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154 | sub snd($@) { |
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155 | my ($noderef, $port) = split /#/, shift, 2; |
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156 | |
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157 | add_node $noderef |
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158 | unless exists $NODE{$noderef}; |
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159 | |
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160 | $NODE{$noderef}->send ([$port, [@_]]); |
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161 | } |
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162 | |
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163 | sub _inject { |
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164 | my ($port, $msg) = @{+shift}; |
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165 | |
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166 | $port = $PORT{$port} |
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167 | or return; |
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168 | |
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169 | use Data::Dumper; |
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170 | warn Dumper $msg; |
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171 | } |
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172 | |
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173 | sub normalise_noderef($) { |
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174 | my ($noderef) = @_; |
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175 | |
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176 | my $cv = AE::cv; |
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177 | my @res; |
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178 | |
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179 | $cv->begin (sub { |
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180 | my %seen; |
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181 | my @refs; |
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182 | for (sort { $a->[0] <=> $b->[0] } @res) { |
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183 | push @refs, $_->[1] unless $seen{$_->[1]}++ |
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184 | } |
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185 | shift->send (join ",", @refs); |
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186 | }); |
270 | }; |
187 | |
271 | |
188 | $noderef = $DEFAULT_PORT unless length $noderef; |
272 | =cut |
189 | |
273 | |
190 | my $idx; |
274 | sub rcv($@); |
191 | for my $t (split /,/, $noderef) { |
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192 | my $pri = ++$idx; |
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193 | |
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194 | #TODO: this should be outside normalise_noderef and in become_public |
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195 | if ($t =~ /^\d*$/) { |
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196 | my $nodename = (POSIX::uname)[1]; |
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197 | |
275 | |
198 | $cv->begin; |
276 | sub _kilme { |
199 | AnyEvent::Socket::resolve_sockaddr $nodename, $t || "aemp=$DEFAULT_PORT", "tcp", 0, undef, sub { |
277 | die "received message on port without callback"; |
200 | for (@_) { |
278 | } |
201 | my ($service, $host) = AnyEvent::Socket::unpack_sockaddr $_->[3]; |
279 | |
202 | push @res, [ |
280 | sub port(;&) { |
203 | $pri += 1e-5, |
281 | my $id = "$UNIQ." . $ID++; |
204 | AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $host, $service |
282 | my $port = "$NODE#$id"; |
205 | ]; |
283 | |
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284 | rcv $port, shift || \&_kilme; |
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285 | |
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286 | $port |
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287 | } |
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288 | |
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289 | =item rcv $local_port, $callback->(@msg) |
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290 | |
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291 | Replaces the default callback on the specified port. There is no way to |
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292 | remove the default callback: use C<sub { }> to disable it, or better |
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293 | C<kil> the port when it is no longer needed. |
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294 | |
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295 | The global C<$SELF> (exported by this module) contains C<$port> while |
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296 | executing the callback. Runtime errors during callback execution will |
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297 | result in the port being C<kil>ed. |
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298 | |
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299 | The default callback received all messages not matched by a more specific |
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300 | C<tag> match. |
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301 | |
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302 | =item rcv $local_port, tag => $callback->(@msg_without_tag), ... |
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303 | |
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304 | Register (or replace) callbacks to be called on messages starting with the |
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305 | given tag on the given port (and return the port), or unregister it (when |
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306 | C<$callback> is C<$undef> or missing). There can only be one callback |
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307 | registered for each tag. |
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308 | |
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309 | The original message will be passed to the callback, after the first |
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310 | element (the tag) has been removed. The callback will use the same |
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311 | environment as the default callback (see above). |
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312 | |
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313 | Example: create a port and bind receivers on it in one go. |
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314 | |
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315 | my $port = rcv port, |
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316 | msg1 => sub { ... }, |
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317 | msg2 => sub { ... }, |
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318 | ; |
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319 | |
|
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320 | Example: create a port, bind receivers and send it in a message elsewhere |
|
|
321 | in one go: |
|
|
322 | |
|
|
323 | snd $otherport, reply => |
|
|
324 | rcv port, |
|
|
325 | msg1 => sub { ... }, |
|
|
326 | ... |
|
|
327 | ; |
|
|
328 | |
|
|
329 | Example: temporarily register a rcv callback for a tag matching some port |
|
|
330 | (e.g. for a rpc reply) and unregister it after a message was received. |
|
|
331 | |
|
|
332 | rcv $port, $otherport => sub { |
|
|
333 | my @reply = @_; |
|
|
334 | |
|
|
335 | rcv $SELF, $otherport; |
|
|
336 | }; |
|
|
337 | |
|
|
338 | =cut |
|
|
339 | |
|
|
340 | sub rcv($@) { |
|
|
341 | my $port = shift; |
|
|
342 | my ($noderef, $portid) = split /#/, $port, 2; |
|
|
343 | |
|
|
344 | $NODE{$noderef} == $NODE{""} |
|
|
345 | or Carp::croak "$port: rcv can only be called on local ports, caught"; |
|
|
346 | |
|
|
347 | while (@_) { |
|
|
348 | if (ref $_[0]) { |
|
|
349 | if (my $self = $PORT_DATA{$portid}) { |
|
|
350 | "AnyEvent::MP::Port" eq ref $self |
|
|
351 | or Carp::croak "$port: rcv can only be called on message matching ports, caught"; |
|
|
352 | |
|
|
353 | $self->[2] = shift; |
|
|
354 | } else { |
|
|
355 | my $cb = shift; |
|
|
356 | $PORT{$portid} = sub { |
|
|
357 | local $SELF = $port; |
|
|
358 | eval { &$cb }; _self_die if $@; |
206 | } |
359 | }; |
207 | $cv->end; |
360 | } |
|
|
361 | } elsif (defined $_[0]) { |
|
|
362 | my $self = $PORT_DATA{$portid} ||= do { |
|
|
363 | my $self = bless [$PORT{$port} || sub { }, { }, $port], "AnyEvent::MP::Port"; |
|
|
364 | |
|
|
365 | $PORT{$portid} = sub { |
|
|
366 | local $SELF = $port; |
|
|
367 | |
|
|
368 | if (my $cb = $self->[1]{$_[0]}) { |
|
|
369 | shift; |
|
|
370 | eval { &$cb }; _self_die if $@; |
|
|
371 | } else { |
|
|
372 | &{ $self->[0] }; |
|
|
373 | } |
|
|
374 | }; |
|
|
375 | |
|
|
376 | $self |
208 | }; |
377 | }; |
209 | |
378 | |
210 | # my (undef, undef, undef, undef, @ipv4) = gethostbyname $nodename; |
379 | "AnyEvent::MP::Port" eq ref $self |
211 | # |
380 | or Carp::croak "$port: rcv can only be called on message matching ports, caught"; |
212 | # for (@ipv4) { |
381 | |
213 | # push @res, [ |
382 | my ($tag, $cb) = splice @_, 0, 2; |
214 | # $pri, |
383 | |
215 | # AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $_, $t || $DEFAULT_PORT, |
384 | if (defined $cb) { |
216 | # ]; |
385 | $self->[1]{$tag} = $cb; |
217 | # } |
|
|
218 | } else { |
386 | } else { |
219 | my ($host, $port) = AnyEvent::Socket::parse_hostport $t, "aemp=$DEFAULT_PORT" |
387 | delete $self->[1]{$tag}; |
220 | or Carp::croak "$t: unparsable transport descriptor"; |
|
|
221 | |
|
|
222 | $cv->begin; |
|
|
223 | AnyEvent::Socket::resolve_sockaddr $host, $port, "tcp", 0, undef, sub { |
|
|
224 | for (@_) { |
|
|
225 | my ($service, $host) = AnyEvent::Socket::unpack_sockaddr $_->[3]; |
|
|
226 | push @res, [ |
|
|
227 | $pri += 1e-5, |
|
|
228 | AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $host, $service |
|
|
229 | ]; |
|
|
230 | } |
|
|
231 | $cv->end; |
|
|
232 | } |
388 | } |
233 | } |
389 | } |
234 | } |
390 | } |
235 | |
391 | |
236 | $cv->end; |
392 | $port |
237 | |
|
|
238 | $cv |
|
|
239 | } |
393 | } |
240 | |
394 | |
241 | sub become_public { |
395 | =item $closure = psub { BLOCK } |
242 | return if $PUBLIC; |
|
|
243 | |
396 | |
244 | my $noderef = join ",", ref $_[0] ? @{+shift} : shift; |
397 | Remembers C<$SELF> and creates a closure out of the BLOCK. When the |
245 | my @args = @_; |
398 | closure is executed, sets up the environment in the same way as in C<rcv> |
|
|
399 | callbacks, i.e. runtime errors will cause the port to get C<kil>ed. |
246 | |
400 | |
247 | $NODE = (normalise_noderef $noderef)->recv; |
401 | This is useful when you register callbacks from C<rcv> callbacks: |
248 | |
402 | |
249 | my $self = new AnyEvent::MP::Node::Self noderef => $NODE; |
403 | rcv delayed_reply => sub { |
250 | |
404 | my ($delay, @reply) = @_; |
251 | $NODE{""} = $self; # empty string == local node |
405 | my $timer = AE::timer $delay, 0, psub { |
252 | |
406 | snd @reply, $SELF; |
253 | for my $t (split /,/, $NODE) { |
|
|
254 | $NODE{$t} = $self; |
|
|
255 | |
|
|
256 | my ($host, $port) = AnyEvent::Socket::parse_hostport $t; |
|
|
257 | |
|
|
258 | $LISTENER{$t} = AnyEvent::MP::Transport::mp_server $host, $port, |
|
|
259 | @args, |
|
|
260 | on_error => sub { |
|
|
261 | die "on_error<@_>\n";#d# |
|
|
262 | }, |
|
|
263 | on_connect => sub { |
|
|
264 | my ($tp) = @_; |
|
|
265 | |
|
|
266 | $NODE{$tp->{remote_id}} = $_[0]; |
|
|
267 | }, |
|
|
268 | sub { |
|
|
269 | my ($tp) = @_; |
|
|
270 | |
|
|
271 | $NODE{"$tp->{peerhost}:$tp->{peerport}"} = $tp; |
|
|
272 | }, |
|
|
273 | ; |
407 | }; |
|
|
408 | }; |
|
|
409 | |
|
|
410 | =cut |
|
|
411 | |
|
|
412 | sub psub(&) { |
|
|
413 | my $cb = shift; |
|
|
414 | |
|
|
415 | my $port = $SELF |
|
|
416 | or Carp::croak "psub can only be called from within rcv or psub callbacks, not"; |
|
|
417 | |
|
|
418 | sub { |
|
|
419 | local $SELF = $port; |
|
|
420 | |
|
|
421 | if (wantarray) { |
|
|
422 | my @res = eval { &$cb }; |
|
|
423 | _self_die if $@; |
|
|
424 | @res |
|
|
425 | } else { |
|
|
426 | my $res = eval { &$cb }; |
|
|
427 | _self_die if $@; |
|
|
428 | $res |
|
|
429 | } |
274 | } |
430 | } |
275 | |
|
|
276 | $PUBLIC = 1; |
|
|
277 | } |
431 | } |
|
|
432 | |
|
|
433 | =item $guard = mon $port, $cb->(@reason) |
|
|
434 | |
|
|
435 | =item $guard = mon $port, $rcvport |
|
|
436 | |
|
|
437 | =item $guard = mon $port |
|
|
438 | |
|
|
439 | =item $guard = mon $port, $rcvport, @msg |
|
|
440 | |
|
|
441 | Monitor the given port and do something when the port is killed or |
|
|
442 | messages to it were lost, and optionally return a guard that can be used |
|
|
443 | to stop monitoring again. |
|
|
444 | |
|
|
445 | C<mon> effectively guarantees that, in the absence of hardware failures, |
|
|
446 | that after starting the monitor, either all messages sent to the port |
|
|
447 | will arrive, or the monitoring action will be invoked after possible |
|
|
448 | message loss has been detected. No messages will be lost "in between" |
|
|
449 | (after the first lost message no further messages will be received by the |
|
|
450 | port). After the monitoring action was invoked, further messages might get |
|
|
451 | delivered again. |
|
|
452 | |
|
|
453 | Note that monitoring-actions are one-shot: once released, they are removed |
|
|
454 | and will not trigger again. |
|
|
455 | |
|
|
456 | In the first form (callback), the callback is simply called with any |
|
|
457 | number of C<@reason> elements (no @reason means that the port was deleted |
|
|
458 | "normally"). Note also that I<< the callback B<must> never die >>, so use |
|
|
459 | C<eval> if unsure. |
|
|
460 | |
|
|
461 | In the second form (another port given), the other port (C<$rcvport>) |
|
|
462 | will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on |
|
|
463 | "normal" kils nothing happens, while under all other conditions, the other |
|
|
464 | port is killed with the same reason. |
|
|
465 | |
|
|
466 | The third form (kill self) is the same as the second form, except that |
|
|
467 | C<$rvport> defaults to C<$SELF>. |
|
|
468 | |
|
|
469 | In the last form (message), a message of the form C<@msg, @reason> will be |
|
|
470 | C<snd>. |
|
|
471 | |
|
|
472 | As a rule of thumb, monitoring requests should always monitor a port from |
|
|
473 | a local port (or callback). The reason is that kill messages might get |
|
|
474 | lost, just like any other message. Another less obvious reason is that |
|
|
475 | even monitoring requests can get lost (for exmaple, when the connection |
|
|
476 | to the other node goes down permanently). When monitoring a port locally |
|
|
477 | these problems do not exist. |
|
|
478 | |
|
|
479 | Example: call a given callback when C<$port> is killed. |
|
|
480 | |
|
|
481 | mon $port, sub { warn "port died because of <@_>\n" }; |
|
|
482 | |
|
|
483 | Example: kill ourselves when C<$port> is killed abnormally. |
|
|
484 | |
|
|
485 | mon $port; |
|
|
486 | |
|
|
487 | Example: send us a restart message when another C<$port> is killed. |
|
|
488 | |
|
|
489 | mon $port, $self => "restart"; |
|
|
490 | |
|
|
491 | =cut |
|
|
492 | |
|
|
493 | sub mon { |
|
|
494 | my ($noderef, $port) = split /#/, shift, 2; |
|
|
495 | |
|
|
496 | my $node = $NODE{$noderef} || add_node $noderef; |
|
|
497 | |
|
|
498 | my $cb = @_ ? shift : $SELF || Carp::croak 'mon: called with one argument only, but $SELF not set,'; |
|
|
499 | |
|
|
500 | unless (ref $cb) { |
|
|
501 | if (@_) { |
|
|
502 | # send a kill info message |
|
|
503 | my (@msg) = ($cb, @_); |
|
|
504 | $cb = sub { snd @msg, @_ }; |
|
|
505 | } else { |
|
|
506 | # simply kill other port |
|
|
507 | my $port = $cb; |
|
|
508 | $cb = sub { kil $port, @_ if @_ }; |
|
|
509 | } |
|
|
510 | } |
|
|
511 | |
|
|
512 | $node->monitor ($port, $cb); |
|
|
513 | |
|
|
514 | defined wantarray |
|
|
515 | and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) } |
|
|
516 | } |
|
|
517 | |
|
|
518 | =item $guard = mon_guard $port, $ref, $ref... |
|
|
519 | |
|
|
520 | Monitors the given C<$port> and keeps the passed references. When the port |
|
|
521 | is killed, the references will be freed. |
|
|
522 | |
|
|
523 | Optionally returns a guard that will stop the monitoring. |
|
|
524 | |
|
|
525 | This function is useful when you create e.g. timers or other watchers and |
|
|
526 | want to free them when the port gets killed: |
|
|
527 | |
|
|
528 | $port->rcv (start => sub { |
|
|
529 | my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub { |
|
|
530 | undef $timer if 0.9 < rand; |
|
|
531 | }); |
|
|
532 | }); |
|
|
533 | |
|
|
534 | =cut |
|
|
535 | |
|
|
536 | sub mon_guard { |
|
|
537 | my ($port, @refs) = @_; |
|
|
538 | |
|
|
539 | #TODO: mon-less form? |
|
|
540 | |
|
|
541 | mon $port, sub { 0 && @refs } |
|
|
542 | } |
|
|
543 | |
|
|
544 | =item kil $port[, @reason] |
|
|
545 | |
|
|
546 | Kill the specified port with the given C<@reason>. |
|
|
547 | |
|
|
548 | If no C<@reason> is specified, then the port is killed "normally" (linked |
|
|
549 | ports will not be kileld, or even notified). |
|
|
550 | |
|
|
551 | Otherwise, linked ports get killed with the same reason (second form of |
|
|
552 | C<mon>, see below). |
|
|
553 | |
|
|
554 | Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks |
|
|
555 | will be reported as reason C<< die => $@ >>. |
|
|
556 | |
|
|
557 | Transport/communication errors are reported as C<< transport_error => |
|
|
558 | $message >>. |
|
|
559 | |
|
|
560 | =cut |
|
|
561 | |
|
|
562 | =item $port = spawn $node, $initfunc[, @initdata] |
|
|
563 | |
|
|
564 | Creates a port on the node C<$node> (which can also be a port ID, in which |
|
|
565 | case it's the node where that port resides). |
|
|
566 | |
|
|
567 | The port ID of the newly created port is return immediately, and it is |
|
|
568 | permissible to immediately start sending messages or monitor the port. |
|
|
569 | |
|
|
570 | After the port has been created, the init function is |
|
|
571 | called. This function must be a fully-qualified function name |
|
|
572 | (e.g. C<MyApp::Chat::Server::init>). To specify a function in the main |
|
|
573 | program, use C<::name>. |
|
|
574 | |
|
|
575 | If the function doesn't exist, then the node tries to C<require> |
|
|
576 | the package, then the package above the package and so on (e.g. |
|
|
577 | C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function |
|
|
578 | exists or it runs out of package names. |
|
|
579 | |
|
|
580 | The init function is then called with the newly-created port as context |
|
|
581 | object (C<$SELF>) and the C<@initdata> values as arguments. |
|
|
582 | |
|
|
583 | A common idiom is to pass your own port, monitor the spawned port, and |
|
|
584 | in the init function, monitor the original port. This two-way monitoring |
|
|
585 | ensures that both ports get cleaned up when there is a problem. |
|
|
586 | |
|
|
587 | Example: spawn a chat server port on C<$othernode>. |
|
|
588 | |
|
|
589 | # this node, executed from within a port context: |
|
|
590 | my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF; |
|
|
591 | mon $server; |
|
|
592 | |
|
|
593 | # init function on C<$othernode> |
|
|
594 | sub connect { |
|
|
595 | my ($srcport) = @_; |
|
|
596 | |
|
|
597 | mon $srcport; |
|
|
598 | |
|
|
599 | rcv $SELF, sub { |
|
|
600 | ... |
|
|
601 | }; |
|
|
602 | } |
|
|
603 | |
|
|
604 | =cut |
|
|
605 | |
|
|
606 | sub _spawn { |
|
|
607 | my $port = shift; |
|
|
608 | my $init = shift; |
|
|
609 | |
|
|
610 | local $SELF = "$NODE#$port"; |
|
|
611 | eval { |
|
|
612 | &{ load_func $init } |
|
|
613 | }; |
|
|
614 | _self_die if $@; |
|
|
615 | } |
|
|
616 | |
|
|
617 | sub spawn(@) { |
|
|
618 | my ($noderef, undef) = split /#/, shift, 2; |
|
|
619 | |
|
|
620 | my $id = "$RUNIQ." . $ID++; |
|
|
621 | |
|
|
622 | $_[0] =~ /::/ |
|
|
623 | or Carp::croak "spawn init function must be a fully-qualified name, caught"; |
|
|
624 | |
|
|
625 | snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_; |
|
|
626 | |
|
|
627 | "$noderef#$id" |
|
|
628 | } |
|
|
629 | |
|
|
630 | =item after $timeout, @msg |
|
|
631 | |
|
|
632 | =item after $timeout, $callback |
|
|
633 | |
|
|
634 | Either sends the given message, or call the given callback, after the |
|
|
635 | specified number of seconds. |
|
|
636 | |
|
|
637 | This is simply a utility function that come sin handy at times. |
|
|
638 | |
|
|
639 | =cut |
|
|
640 | |
|
|
641 | sub after($@) { |
|
|
642 | my ($timeout, @action) = @_; |
|
|
643 | |
|
|
644 | my $t; $t = AE::timer $timeout, 0, sub { |
|
|
645 | undef $t; |
|
|
646 | ref $action[0] |
|
|
647 | ? $action[0]() |
|
|
648 | : snd @action; |
|
|
649 | }; |
|
|
650 | } |
|
|
651 | |
|
|
652 | =back |
|
|
653 | |
|
|
654 | =head1 AnyEvent::MP vs. Distributed Erlang |
|
|
655 | |
|
|
656 | AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node |
|
|
657 | == aemp node, Erlang process == aemp port), so many of the documents and |
|
|
658 | programming techniques employed by Erlang apply to AnyEvent::MP. Here is a |
|
|
659 | sample: |
|
|
660 | |
|
|
661 | http://www.Erlang.se/doc/programming_rules.shtml |
|
|
662 | http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4 |
|
|
663 | http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6 |
|
|
664 | http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5 |
|
|
665 | |
|
|
666 | Despite the similarities, there are also some important differences: |
|
|
667 | |
|
|
668 | =over 4 |
|
|
669 | |
|
|
670 | =item * Node references contain the recipe on how to contact them. |
|
|
671 | |
|
|
672 | Erlang relies on special naming and DNS to work everywhere in the |
|
|
673 | same way. AEMP relies on each node knowing it's own address(es), with |
|
|
674 | convenience functionality. |
|
|
675 | |
|
|
676 | This means that AEMP requires a less tightly controlled environment at the |
|
|
677 | cost of longer node references and a slightly higher management overhead. |
|
|
678 | |
|
|
679 | =item * Erlang has a "remote ports are like local ports" philosophy, AEMP |
|
|
680 | uses "local ports are like remote ports". |
|
|
681 | |
|
|
682 | The failure modes for local ports are quite different (runtime errors |
|
|
683 | only) then for remote ports - when a local port dies, you I<know> it dies, |
|
|
684 | when a connection to another node dies, you know nothing about the other |
|
|
685 | port. |
|
|
686 | |
|
|
687 | Erlang pretends remote ports are as reliable as local ports, even when |
|
|
688 | they are not. |
|
|
689 | |
|
|
690 | AEMP encourages a "treat remote ports differently" philosophy, with local |
|
|
691 | ports being the special case/exception, where transport errors cannot |
|
|
692 | occur. |
|
|
693 | |
|
|
694 | =item * Erlang uses processes and a mailbox, AEMP does not queue. |
|
|
695 | |
|
|
696 | Erlang uses processes that selectively receive messages, and therefore |
|
|
697 | needs a queue. AEMP is event based, queuing messages would serve no |
|
|
698 | useful purpose. For the same reason the pattern-matching abilities of |
|
|
699 | AnyEvent::MP are more limited, as there is little need to be able to |
|
|
700 | filter messages without dequeing them. |
|
|
701 | |
|
|
702 | (But see L<Coro::MP> for a more Erlang-like process model on top of AEMP). |
|
|
703 | |
|
|
704 | =item * Erlang sends are synchronous, AEMP sends are asynchronous. |
|
|
705 | |
|
|
706 | Sending messages in Erlang is synchronous and blocks the process (and |
|
|
707 | so does not need a queue that can overflow). AEMP sends are immediate, |
|
|
708 | connection establishment is handled in the background. |
|
|
709 | |
|
|
710 | =item * Erlang suffers from silent message loss, AEMP does not. |
|
|
711 | |
|
|
712 | Erlang makes few guarantees on messages delivery - messages can get lost |
|
|
713 | without any of the processes realising it (i.e. you send messages a, b, |
|
|
714 | and c, and the other side only receives messages a and c). |
|
|
715 | |
|
|
716 | AEMP guarantees correct ordering, and the guarantee that there are no |
|
|
717 | holes in the message sequence. |
|
|
718 | |
|
|
719 | =item * In Erlang, processes can be declared dead and later be found to be |
|
|
720 | alive. |
|
|
721 | |
|
|
722 | In Erlang it can happen that a monitored process is declared dead and |
|
|
723 | linked processes get killed, but later it turns out that the process is |
|
|
724 | still alive - and can receive messages. |
|
|
725 | |
|
|
726 | In AEMP, when port monitoring detects a port as dead, then that port will |
|
|
727 | eventually be killed - it cannot happen that a node detects a port as dead |
|
|
728 | and then later sends messages to it, finding it is still alive. |
|
|
729 | |
|
|
730 | =item * Erlang can send messages to the wrong port, AEMP does not. |
|
|
731 | |
|
|
732 | In Erlang it is quite likely that a node that restarts reuses a process ID |
|
|
733 | known to other nodes for a completely different process, causing messages |
|
|
734 | destined for that process to end up in an unrelated process. |
|
|
735 | |
|
|
736 | AEMP never reuses port IDs, so old messages or old port IDs floating |
|
|
737 | around in the network will not be sent to an unrelated port. |
|
|
738 | |
|
|
739 | =item * Erlang uses unprotected connections, AEMP uses secure |
|
|
740 | authentication and can use TLS. |
|
|
741 | |
|
|
742 | AEMP can use a proven protocol - SSL/TLS - to protect connections and |
|
|
743 | securely authenticate nodes. |
|
|
744 | |
|
|
745 | =item * The AEMP protocol is optimised for both text-based and binary |
|
|
746 | communications. |
|
|
747 | |
|
|
748 | The AEMP protocol, unlike the Erlang protocol, supports both |
|
|
749 | language-independent text-only protocols (good for debugging) and binary, |
|
|
750 | language-specific serialisers (e.g. Storable). |
|
|
751 | |
|
|
752 | It has also been carefully designed to be implementable in other languages |
|
|
753 | with a minimum of work while gracefully degrading fucntionality to make the |
|
|
754 | protocol simple. |
|
|
755 | |
|
|
756 | =item * AEMP has more flexible monitoring options than Erlang. |
|
|
757 | |
|
|
758 | In Erlang, you can chose to receive I<all> exit signals as messages |
|
|
759 | or I<none>, there is no in-between, so monitoring single processes is |
|
|
760 | difficult to implement. Monitoring in AEMP is more flexible than in |
|
|
761 | Erlang, as one can choose between automatic kill, exit message or callback |
|
|
762 | on a per-process basis. |
|
|
763 | |
|
|
764 | =item * Erlang tries to hide remote/local connections, AEMP does not. |
|
|
765 | |
|
|
766 | Monitoring in Erlang is not an indicator of process death/crashes, |
|
|
767 | as linking is (except linking is unreliable in Erlang). |
|
|
768 | |
|
|
769 | In AEMP, you don't "look up" registered port names or send to named ports |
|
|
770 | that might or might not be persistent. Instead, you normally spawn a port |
|
|
771 | on the remote node. The init function monitors the you, and you monitor |
|
|
772 | the remote port. Since both monitors are local to the node, they are much |
|
|
773 | more reliable. |
|
|
774 | |
|
|
775 | This also saves round-trips and avoids sending messages to the wrong port |
|
|
776 | (hard to do in Erlang). |
|
|
777 | |
|
|
778 | =back |
|
|
779 | |
|
|
780 | =head1 RATIONALE |
|
|
781 | |
|
|
782 | =over 4 |
|
|
783 | |
|
|
784 | =item Why strings for ports and noderefs, why not objects? |
|
|
785 | |
|
|
786 | We considered "objects", but found that the actual number of methods |
|
|
787 | thatc an be called are very low. Since port IDs and noderefs travel over |
|
|
788 | the network frequently, the serialising/deserialising would add lots of |
|
|
789 | overhead, as well as having to keep a proxy object. |
|
|
790 | |
|
|
791 | Strings can easily be printed, easily serialised etc. and need no special |
|
|
792 | procedures to be "valid". |
|
|
793 | |
|
|
794 | And a a miniport consists of a single closure stored in a global hash - it |
|
|
795 | can't become much cheaper. |
|
|
796 | |
|
|
797 | =item Why favour JSON, why not real serialising format such as Storable? |
|
|
798 | |
|
|
799 | In fact, any AnyEvent::MP node will happily accept Storable as framing |
|
|
800 | format, but currently there is no way to make a node use Storable by |
|
|
801 | default. |
|
|
802 | |
|
|
803 | The default framing protocol is JSON because a) JSON::XS is many times |
|
|
804 | faster for small messages and b) most importantly, after years of |
|
|
805 | experience we found that object serialisation is causing more problems |
|
|
806 | than it gains: Just like function calls, objects simply do not travel |
|
|
807 | easily over the network, mostly because they will always be a copy, so you |
|
|
808 | always have to re-think your design. |
|
|
809 | |
|
|
810 | Keeping your messages simple, concentrating on data structures rather than |
|
|
811 | objects, will keep your messages clean, tidy and efficient. |
278 | |
812 | |
279 | =back |
813 | =back |
280 | |
814 | |
281 | =head1 SEE ALSO |
815 | =head1 SEE ALSO |
282 | |
816 | |