… | |
… | |
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; # -OR- |
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17 | initialise_node "localhost:4040"; # -OR- |
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18 | initialise_node "slave/", "localhost:4040" |
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19 | |
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20 | # ports are message endpoints |
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21 | |
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22 | # sending messages |
12 | snd $port, type => data...; |
23 | snd $port, type => data...; |
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24 | snd $port, @msg; |
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25 | snd @msg_with_first_element_being_a_port; |
13 | |
26 | |
14 | rcv $port, smartmatch => $cb->($port, @msg); |
27 | # creating/using ports, the simple way |
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28 | my $simple_port = port { my @msg = @_; 0 }; |
15 | |
29 | |
16 | # examples: |
30 | # creating/using ports, tagged message matching |
|
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31 | my $port = port; |
17 | rcv $port2, ping => sub { snd $_[0], "pong"; 0 }; |
32 | rcv $port, ping => sub { snd $_[0], "pong"; 0 }; |
18 | rcv $port1, pong => sub { warn "pong received\n" }; |
33 | rcv $port, pong => sub { warn "pong received\n"; 0 }; |
19 | snd $port2, ping => $port1; |
|
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20 | |
34 | |
21 | # more, smarter, matches (_any_ is exported by this module) |
35 | # create a port on another node |
22 | rcv $port, [child_died => $pid] => sub { ... |
36 | my $port = spawn $node, $initfunc, @initdata; |
23 | rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3 |
37 | |
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38 | # monitoring |
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39 | mon $port, $cb->(@msg) # callback is invoked on death |
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40 | mon $port, $otherport # kill otherport on abnormal death |
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41 | mon $port, $otherport, @msg # send message on death |
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42 | |
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43 | =head1 CURRENT STATUS |
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44 | |
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45 | AnyEvent::MP - stable API, should work |
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46 | AnyEvent::MP::Intro - outdated |
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47 | AnyEvent::MP::Kernel - WIP |
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48 | AnyEvent::MP::Transport - mostly stable |
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49 | |
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50 | stay tuned. |
24 | |
51 | |
25 | =head1 DESCRIPTION |
52 | =head1 DESCRIPTION |
26 | |
53 | |
27 | This module (-family) implements a simple message passing framework. |
54 | This module (-family) implements a simple message passing framework. |
28 | |
55 | |
29 | Despite its simplicity, you can securely message other processes running |
56 | Despite its simplicity, you can securely message other processes running |
30 | on the same or other hosts. |
57 | on the same or other hosts. |
31 | |
58 | |
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59 | For an introduction to this module family, see the L<AnyEvent::MP::Intro> |
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60 | manual page. |
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61 | |
32 | At the moment, this module family is severly brokena nd underdocumented, |
62 | At the moment, this module family is severly broken and underdocumented, |
33 | so do not use. This was uploaded mainly to resreve the CPAN namespace - |
63 | so do not use. This was uploaded mainly to reserve the CPAN namespace - |
34 | stay tuned! |
64 | stay tuned! |
35 | |
65 | |
36 | =head1 CONCEPTS |
66 | =head1 CONCEPTS |
37 | |
67 | |
38 | =over 4 |
68 | =over 4 |
39 | |
69 | |
40 | =item port |
70 | =item port |
41 | |
71 | |
42 | A port is something you can send messages to with the C<snd> function, and |
72 | A port is something you can send messages to (with the C<snd> function). |
43 | you can register C<rcv> handlers with. All C<rcv> handlers will receive |
73 | |
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74 | Ports allow you to register C<rcv> handlers that can match all or just |
44 | messages they match, messages will not be queued. |
75 | some messages. Messages will not be queued. |
45 | |
76 | |
46 | =item port id - C<noderef#portname> |
77 | =item port id - C<noderef#portname> |
47 | |
78 | |
48 | A port id is always the noderef, a hash-mark (C<#>) as separator, followed |
79 | A port ID is the concatenation of a noderef, a hash-mark (C<#>) as |
49 | by a port name (a printable string of unspecified format). |
80 | separator, and a port name (a printable string of unspecified format). An |
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81 | exception is the the node port, whose ID is identical to its node |
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82 | reference. |
50 | |
83 | |
51 | =item node |
84 | =item node |
52 | |
85 | |
53 | A node is a single process containing at least one port - the node |
86 | 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, |
87 | which provides nodes to manage each other remotely, and to create new |
55 | among other things. |
88 | ports. |
56 | |
89 | |
57 | Initially, nodes are either private (single-process only) or hidden |
90 | Nodes are either private (single-process only), slaves (connected to a |
58 | (connected to a master node only). Only when they epxlicitly "become |
91 | master node only) or public nodes (connectable from unrelated nodes). |
59 | public" can you send them messages from unrelated other nodes. |
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60 | |
92 | |
61 | =item noderef - C<host:port,host:port...>, C<id@noderef>, C<id> |
93 | =item noderef - C<host:port,host:port...>, C<id@noderef>, C<id> |
62 | |
94 | |
63 | A noderef is a string that either uniquely identifies a given node (for |
95 | A node reference is a string that either simply identifies the node (for |
64 | private and hidden nodes), or contains a recipe on how to reach a given |
96 | private and slave nodes), or contains a recipe on how to reach a given |
65 | node (for public nodes). |
97 | node (for public nodes). |
66 | |
98 | |
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99 | This recipe is simply a comma-separated list of C<address:port> pairs (for |
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100 | TCP/IP, other protocols might look different). |
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101 | |
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102 | Node references come in two flavours: resolved (containing only numerical |
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103 | addresses) or unresolved (where hostnames are used instead of addresses). |
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104 | |
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105 | Before using an unresolved node reference in a message you first have to |
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106 | resolve it. |
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107 | |
67 | =back |
108 | =back |
68 | |
109 | |
69 | =head1 VARIABLES/FUNCTIONS |
110 | =head1 VARIABLES/FUNCTIONS |
70 | |
111 | |
71 | =over 4 |
112 | =over 4 |
72 | |
113 | |
73 | =cut |
114 | =cut |
74 | |
115 | |
75 | package AnyEvent::MP; |
116 | package AnyEvent::MP; |
76 | |
117 | |
77 | use AnyEvent::MP::Base; |
118 | use AnyEvent::MP::Kernel; |
78 | |
119 | |
79 | use common::sense; |
120 | use common::sense; |
80 | |
121 | |
81 | use Carp (); |
122 | use Carp (); |
82 | |
123 | |
83 | use AE (); |
124 | use AE (); |
84 | |
125 | |
85 | use base "Exporter"; |
126 | use base "Exporter"; |
86 | |
127 | |
87 | our $VERSION = '0.02'; |
128 | our $VERSION = $AnyEvent::MP::Kernel::VERSION; |
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129 | |
88 | our @EXPORT = qw( |
130 | our @EXPORT = qw( |
89 | NODE $NODE $PORT snd rcv mon del _any_ |
131 | NODE $NODE *SELF node_of after |
90 | create_port create_port_on |
132 | resolve_node initialise_node |
91 | create_miniport |
133 | snd rcv mon mob_guard kil reg psub spawn |
92 | become_slave become_public |
134 | port |
93 | ); |
135 | ); |
94 | |
136 | |
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137 | our $SELF; |
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138 | |
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139 | sub _self_die() { |
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140 | my $msg = $@; |
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141 | $msg =~ s/\n+$// unless ref $msg; |
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142 | kil $SELF, die => $msg; |
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143 | } |
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144 | |
95 | =item NODE / $NODE |
145 | =item $thisnode = NODE / $NODE |
96 | |
146 | |
97 | The C<NODE ()> function and the C<$NODE> variable contain the noderef of |
147 | The C<NODE> function returns, and the C<$NODE> variable contains the |
98 | the local node. The value is initialised by a call to C<become_public> or |
148 | noderef of the local node. The value is initialised by a call to |
99 | C<become_slave>, after which all local port identifiers become invalid. |
149 | C<initialise_node>. |
100 | |
150 | |
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151 | =item $noderef = node_of $port |
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152 | |
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153 | Extracts and returns the noderef from a port ID or a noderef. |
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154 | |
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155 | =item initialise_node $noderef, $seednode, $seednode... |
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156 | |
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157 | =item initialise_node "slave/", $master, $master... |
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158 | |
|
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159 | Before a node can talk to other nodes on the network it has to initialise |
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160 | itself - the minimum a node needs to know is it's own name, and optionally |
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161 | it should know the noderefs of some other nodes in the network. |
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162 | |
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163 | This function initialises a node - it must be called exactly once (or |
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164 | never) before calling other AnyEvent::MP functions. |
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165 | |
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166 | All arguments (optionally except for the first) are noderefs, which can be |
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167 | either resolved or unresolved. |
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168 | |
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169 | The first argument will be looked up in the configuration database first |
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170 | (if it is C<undef> then the current nodename will be used instead) to find |
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171 | the relevant configuration profile (see L<aemp>). If none is found then |
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172 | the default configuration is used. The configuration supplies additional |
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173 | seed/master nodes and can override the actual noderef. |
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174 | |
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175 | There are two types of networked nodes, public nodes and slave nodes: |
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176 | |
|
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177 | =over 4 |
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178 | |
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179 | =item public nodes |
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180 | |
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181 | For public nodes, C<$noderef> (supplied either directly to |
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182 | C<initialise_node> or indirectly via a profile or the nodename) must be a |
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183 | noderef (possibly unresolved, in which case it will be resolved). |
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184 | |
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185 | After resolving, the node will bind itself on all endpoints and try to |
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186 | connect to all additional C<$seednodes> that are specified. Seednodes are |
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187 | optional and can be used to quickly bootstrap the node into an existing |
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188 | network. |
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189 | |
|
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190 | =item slave nodes |
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191 | |
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192 | When the C<$noderef> (either as given or overriden by the config file) |
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193 | is the special string C<slave/>, then the node will become a slave |
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194 | node. Slave nodes cannot be contacted from outside and will route most of |
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195 | their traffic to the master node that they attach to. |
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196 | |
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197 | At least one additional noderef is required (either by specifying it |
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198 | directly or because it is part of the configuration profile): The node |
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199 | will try to connect to all of them and will become a slave attached to the |
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200 | first node it can successfully connect to. |
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201 | |
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202 | Note that slave nodes cannot change their name, and consequently, their |
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203 | master, so if the master goes down, the slave node will not function well |
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204 | anymore until it can re-establish conenciton to its master. This makes |
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205 | slave nodes unsuitable for long-term nodes or fault-tolerant networks. |
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206 | |
|
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207 | =back |
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208 | |
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209 | This function will block until all nodes have been resolved and, for slave |
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210 | nodes, until it has successfully established a connection to a master |
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211 | server. |
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212 | |
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213 | All the seednodes will also be specially marked to automatically retry |
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214 | connecting to them infinitely. |
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215 | |
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216 | Example: become a public node listening on the guessed noderef, or the one |
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217 | specified via C<aemp> for the current node. This should be the most common |
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218 | form of invocation for "daemon"-type nodes. |
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219 | |
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220 | initialise_node; |
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221 | |
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222 | Example: become a slave node to any of the the seednodes specified via |
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223 | C<aemp>. This form is often used for commandline clients. |
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224 | |
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225 | initialise_node "slave/"; |
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226 | |
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227 | Example: become a slave node to any of the specified master servers. This |
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228 | form is also often used for commandline clients. |
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229 | |
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230 | initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net"; |
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231 | |
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232 | Example: become a public node, and try to contact some well-known master |
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233 | servers to become part of the network. |
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234 | |
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235 | initialise_node undef, "master1", "master2"; |
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236 | |
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237 | Example: become a public node listening on port C<4041>. |
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238 | |
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239 | initialise_node 4041; |
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240 | |
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241 | Example: become a public node, only visible on localhost port 4044. |
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242 | |
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243 | initialise_node "localhost:4044"; |
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244 | |
|
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245 | =item $cv = resolve_node $noderef |
|
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246 | |
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247 | Takes an unresolved node reference that may contain hostnames and |
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248 | abbreviated IDs, resolves all of them and returns a resolved node |
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249 | reference. |
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250 | |
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251 | In addition to C<address:port> pairs allowed in resolved noderefs, the |
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252 | following forms are supported: |
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253 | |
|
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254 | =over 4 |
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255 | |
|
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256 | =item the empty string |
|
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257 | |
|
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258 | An empty-string component gets resolved as if the default port (4040) was |
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259 | specified. |
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260 | |
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261 | =item naked port numbers (e.g. C<1234>) |
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262 | |
|
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263 | These are resolved by prepending the local nodename and a colon, to be |
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264 | further resolved. |
|
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265 | |
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266 | =item hostnames (e.g. C<localhost:1234>, C<localhost>) |
|
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267 | |
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268 | These are resolved by using AnyEvent::DNS to resolve them, optionally |
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269 | looking up SRV records for the C<aemp=4040> port, if no port was |
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270 | specified. |
|
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271 | |
|
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272 | =back |
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273 | |
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274 | =item $SELF |
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275 | |
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276 | Contains the current port id while executing C<rcv> callbacks or C<psub> |
|
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277 | blocks. |
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278 | |
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279 | =item SELF, %SELF, @SELF... |
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280 | |
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281 | Due to some quirks in how perl exports variables, it is impossible to |
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282 | just export C<$SELF>, all the symbols called C<SELF> are exported by this |
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283 | module, but only C<$SELF> is currently used. |
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284 | |
101 | =item snd $portid, type => @data |
285 | =item snd $port, type => @data |
102 | |
286 | |
103 | =item snd $portid, @msg |
287 | =item snd $port, @msg |
104 | |
288 | |
105 | Send the given message to the given port ID, which can identify either |
289 | Send the given message to the given port ID, which can identify either |
106 | a local or a remote port, and can be either a string or soemthignt hat |
290 | a local or a remote port, and must be a port ID. |
107 | stringifies a sa port ID (such as a port object :). |
|
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108 | |
291 | |
109 | While the message can be about anything, it is highly recommended to use a |
292 | While the message can be about anything, it is highly recommended to use a |
110 | string as first element (a portid, or some word that indicates a request |
293 | string as first element (a port ID, or some word that indicates a request |
111 | type etc.). |
294 | type etc.). |
112 | |
295 | |
113 | The message data effectively becomes read-only after a call to this |
296 | The message data effectively becomes read-only after a call to this |
114 | function: modifying any argument is not allowed and can cause many |
297 | function: modifying any argument is not allowed and can cause many |
115 | problems. |
298 | problems. |
… | |
… | |
118 | JSON is used, then only strings, numbers and arrays and hashes consisting |
301 | JSON is used, then only strings, numbers and arrays and hashes consisting |
119 | of those are allowed (no objects). When Storable is used, then anything |
302 | of those are allowed (no objects). When Storable is used, then anything |
120 | that Storable can serialise and deserialise is allowed, and for the local |
303 | that Storable can serialise and deserialise is allowed, and for the local |
121 | node, anything can be passed. |
304 | node, anything can be passed. |
122 | |
305 | |
|
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306 | =item $local_port = port |
|
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307 | |
|
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308 | Create a new local port object and returns its port ID. Initially it has |
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309 | no callbacks set and will throw an error when it receives messages. |
|
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310 | |
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311 | =item $local_port = port { my @msg = @_ } |
|
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312 | |
|
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313 | Creates a new local port, and returns its ID. Semantically the same as |
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314 | creating a port and calling C<rcv $port, $callback> on it. |
|
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315 | |
|
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316 | The block will be called for every message received on the port, with the |
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317 | global variable C<$SELF> set to the port ID. Runtime errors will cause the |
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318 | port to be C<kil>ed. The message will be passed as-is, no extra argument |
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319 | (i.e. no port ID) will be passed to the callback. |
|
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320 | |
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321 | If you want to stop/destroy the port, simply C<kil> it: |
|
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322 | |
|
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323 | my $port = port { |
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324 | my @msg = @_; |
|
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325 | ... |
|
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326 | kil $SELF; |
|
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327 | }; |
|
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328 | |
|
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329 | =cut |
|
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330 | |
|
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331 | sub rcv($@); |
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332 | |
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333 | sub _kilme { |
|
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334 | die "received message on port without callback"; |
|
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335 | } |
|
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336 | |
|
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337 | sub port(;&) { |
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338 | my $id = "$UNIQ." . $ID++; |
|
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339 | my $port = "$NODE#$id"; |
|
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340 | |
|
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341 | rcv $port, shift || \&_kilme; |
|
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342 | |
|
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343 | $port |
|
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344 | } |
|
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345 | |
|
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346 | =item rcv $local_port, $callback->(@msg) |
|
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347 | |
|
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348 | Replaces the default callback on the specified port. There is no way to |
|
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349 | remove the default callback: use C<sub { }> to disable it, or better |
|
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350 | C<kil> the port when it is no longer needed. |
|
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351 | |
|
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352 | The global C<$SELF> (exported by this module) contains C<$port> while |
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353 | executing the callback. Runtime errors during callback execution will |
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354 | result in the port being C<kil>ed. |
|
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355 | |
|
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356 | The default callback received all messages not matched by a more specific |
|
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357 | C<tag> match. |
|
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358 | |
|
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359 | =item rcv $local_port, tag => $callback->(@msg_without_tag), ... |
|
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360 | |
|
|
361 | Register (or replace) callbacks to be called on messages starting with the |
|
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362 | given tag on the given port (and return the port), or unregister it (when |
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363 | C<$callback> is C<$undef> or missing). There can only be one callback |
|
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364 | registered for each tag. |
|
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365 | |
|
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366 | The original message will be passed to the callback, after the first |
|
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367 | element (the tag) has been removed. The callback will use the same |
|
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368 | environment as the default callback (see above). |
|
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369 | |
|
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370 | Example: create a port and bind receivers on it in one go. |
|
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371 | |
|
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372 | my $port = rcv port, |
|
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373 | msg1 => sub { ... }, |
|
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374 | msg2 => sub { ... }, |
|
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375 | ; |
|
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376 | |
|
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377 | Example: create a port, bind receivers and send it in a message elsewhere |
|
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378 | in one go: |
|
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379 | |
|
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380 | snd $otherport, reply => |
|
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381 | rcv port, |
|
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382 | msg1 => sub { ... }, |
|
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383 | ... |
|
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384 | ; |
|
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385 | |
|
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386 | Example: temporarily register a rcv callback for a tag matching some port |
|
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387 | (e.g. for a rpc reply) and unregister it after a message was received. |
|
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388 | |
|
|
389 | rcv $port, $otherport => sub { |
|
|
390 | my @reply = @_; |
|
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391 | |
|
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392 | rcv $SELF, $otherport; |
|
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393 | }; |
|
|
394 | |
|
|
395 | =cut |
|
|
396 | |
|
|
397 | sub rcv($@) { |
|
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398 | my $port = shift; |
|
|
399 | my ($noderef, $portid) = split /#/, $port, 2; |
|
|
400 | |
|
|
401 | $NODE{$noderef} == $NODE{""} |
|
|
402 | or Carp::croak "$port: rcv can only be called on local ports, caught"; |
|
|
403 | |
|
|
404 | while (@_) { |
|
|
405 | if (ref $_[0]) { |
|
|
406 | if (my $self = $PORT_DATA{$portid}) { |
|
|
407 | "AnyEvent::MP::Port" eq ref $self |
|
|
408 | or Carp::croak "$port: rcv can only be called on message matching ports, caught"; |
|
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409 | |
|
|
410 | $self->[2] = shift; |
|
|
411 | } else { |
|
|
412 | my $cb = shift; |
|
|
413 | $PORT{$portid} = sub { |
|
|
414 | local $SELF = $port; |
|
|
415 | eval { &$cb }; _self_die if $@; |
|
|
416 | }; |
|
|
417 | } |
|
|
418 | } elsif (defined $_[0]) { |
|
|
419 | my $self = $PORT_DATA{$portid} ||= do { |
|
|
420 | my $self = bless [$PORT{$port} || sub { }, { }, $port], "AnyEvent::MP::Port"; |
|
|
421 | |
|
|
422 | $PORT{$portid} = sub { |
|
|
423 | local $SELF = $port; |
|
|
424 | |
|
|
425 | if (my $cb = $self->[1]{$_[0]}) { |
|
|
426 | shift; |
|
|
427 | eval { &$cb }; _self_die if $@; |
|
|
428 | } else { |
|
|
429 | &{ $self->[0] }; |
|
|
430 | } |
|
|
431 | }; |
|
|
432 | |
|
|
433 | $self |
|
|
434 | }; |
|
|
435 | |
|
|
436 | "AnyEvent::MP::Port" eq ref $self |
|
|
437 | or Carp::croak "$port: rcv can only be called on message matching ports, caught"; |
|
|
438 | |
|
|
439 | my ($tag, $cb) = splice @_, 0, 2; |
|
|
440 | |
|
|
441 | if (defined $cb) { |
|
|
442 | $self->[1]{$tag} = $cb; |
|
|
443 | } else { |
|
|
444 | delete $self->[1]{$tag}; |
|
|
445 | } |
|
|
446 | } |
|
|
447 | } |
|
|
448 | |
|
|
449 | $port |
|
|
450 | } |
|
|
451 | |
|
|
452 | =item $closure = psub { BLOCK } |
|
|
453 | |
|
|
454 | Remembers C<$SELF> and creates a closure out of the BLOCK. When the |
|
|
455 | closure is executed, sets up the environment in the same way as in C<rcv> |
|
|
456 | callbacks, i.e. runtime errors will cause the port to get C<kil>ed. |
|
|
457 | |
|
|
458 | This is useful when you register callbacks from C<rcv> callbacks: |
|
|
459 | |
|
|
460 | rcv delayed_reply => sub { |
|
|
461 | my ($delay, @reply) = @_; |
|
|
462 | my $timer = AE::timer $delay, 0, psub { |
|
|
463 | snd @reply, $SELF; |
|
|
464 | }; |
|
|
465 | }; |
|
|
466 | |
|
|
467 | =cut |
|
|
468 | |
|
|
469 | sub psub(&) { |
|
|
470 | my $cb = shift; |
|
|
471 | |
|
|
472 | my $port = $SELF |
|
|
473 | or Carp::croak "psub can only be called from within rcv or psub callbacks, not"; |
|
|
474 | |
|
|
475 | sub { |
|
|
476 | local $SELF = $port; |
|
|
477 | |
|
|
478 | if (wantarray) { |
|
|
479 | my @res = eval { &$cb }; |
|
|
480 | _self_die if $@; |
|
|
481 | @res |
|
|
482 | } else { |
|
|
483 | my $res = eval { &$cb }; |
|
|
484 | _self_die if $@; |
|
|
485 | $res |
|
|
486 | } |
|
|
487 | } |
|
|
488 | } |
|
|
489 | |
123 | =item $guard = mon $portid, $cb->() |
490 | =item $guard = mon $port, $cb->(@reason) |
124 | |
491 | |
125 | Monitor the given port and call the given callback when the port is |
492 | =item $guard = mon $port, $rcvport |
126 | destroyed or connection to it's node is lost. |
|
|
127 | |
493 | |
128 | #TODO |
494 | =item $guard = mon $port |
|
|
495 | |
|
|
496 | =item $guard = mon $port, $rcvport, @msg |
|
|
497 | |
|
|
498 | Monitor the given port and do something when the port is killed or |
|
|
499 | messages to it were lost, and optionally return a guard that can be used |
|
|
500 | to stop monitoring again. |
|
|
501 | |
|
|
502 | C<mon> effectively guarantees that, in the absence of hardware failures, |
|
|
503 | that after starting the monitor, either all messages sent to the port |
|
|
504 | will arrive, or the monitoring action will be invoked after possible |
|
|
505 | message loss has been detected. No messages will be lost "in between" |
|
|
506 | (after the first lost message no further messages will be received by the |
|
|
507 | port). After the monitoring action was invoked, further messages might get |
|
|
508 | delivered again. |
|
|
509 | |
|
|
510 | Note that monitoring-actions are one-shot: once released, they are removed |
|
|
511 | and will not trigger again. |
|
|
512 | |
|
|
513 | In the first form (callback), the callback is simply called with any |
|
|
514 | number of C<@reason> elements (no @reason means that the port was deleted |
|
|
515 | "normally"). Note also that I<< the callback B<must> never die >>, so use |
|
|
516 | C<eval> if unsure. |
|
|
517 | |
|
|
518 | In the second form (another port given), the other port (C<$rcvport>) |
|
|
519 | will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on |
|
|
520 | "normal" kils nothing happens, while under all other conditions, the other |
|
|
521 | port is killed with the same reason. |
|
|
522 | |
|
|
523 | The third form (kill self) is the same as the second form, except that |
|
|
524 | C<$rvport> defaults to C<$SELF>. |
|
|
525 | |
|
|
526 | In the last form (message), a message of the form C<@msg, @reason> will be |
|
|
527 | C<snd>. |
|
|
528 | |
|
|
529 | As a rule of thumb, monitoring requests should always monitor a port from |
|
|
530 | a local port (or callback). The reason is that kill messages might get |
|
|
531 | lost, just like any other message. Another less obvious reason is that |
|
|
532 | even monitoring requests can get lost (for exmaple, when the connection |
|
|
533 | to the other node goes down permanently). When monitoring a port locally |
|
|
534 | these problems do not exist. |
|
|
535 | |
|
|
536 | Example: call a given callback when C<$port> is killed. |
|
|
537 | |
|
|
538 | mon $port, sub { warn "port died because of <@_>\n" }; |
|
|
539 | |
|
|
540 | Example: kill ourselves when C<$port> is killed abnormally. |
|
|
541 | |
|
|
542 | mon $port; |
|
|
543 | |
|
|
544 | Example: send us a restart message when another C<$port> is killed. |
|
|
545 | |
|
|
546 | mon $port, $self => "restart"; |
129 | |
547 | |
130 | =cut |
548 | =cut |
131 | |
549 | |
132 | sub mon { |
550 | sub mon { |
133 | my ($noderef, $port) = split /#/, shift, 2; |
551 | my ($noderef, $port) = split /#/, shift, 2; |
134 | |
552 | |
135 | my $node = AnyEvent::MP::Base::add_node $noderef; |
553 | my $node = $NODE{$noderef} || add_node $noderef; |
136 | |
554 | |
137 | my $cb = shift; |
555 | my $cb = @_ ? shift : $SELF || Carp::croak 'mon: called with one argument only, but $SELF not set,'; |
|
|
556 | |
|
|
557 | unless (ref $cb) { |
|
|
558 | if (@_) { |
|
|
559 | # send a kill info message |
|
|
560 | my (@msg) = ($cb, @_); |
|
|
561 | $cb = sub { snd @msg, @_ }; |
|
|
562 | } else { |
|
|
563 | # simply kill other port |
|
|
564 | my $port = $cb; |
|
|
565 | $cb = sub { kil $port, @_ if @_ }; |
|
|
566 | } |
|
|
567 | } |
138 | |
568 | |
139 | $node->monitor ($port, $cb); |
569 | $node->monitor ($port, $cb); |
140 | |
570 | |
141 | defined wantarray |
571 | defined wantarray |
142 | and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) } |
572 | and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) } |
143 | } |
573 | } |
144 | |
574 | |
145 | =item $local_port = create_port |
575 | =item $guard = mon_guard $port, $ref, $ref... |
146 | |
576 | |
147 | Create a new local port object. See the next section for allowed methods. |
577 | Monitors the given C<$port> and keeps the passed references. When the port |
|
|
578 | is killed, the references will be freed. |
148 | |
579 | |
149 | =cut |
580 | Optionally returns a guard that will stop the monitoring. |
150 | |
581 | |
151 | sub create_port { |
582 | This function is useful when you create e.g. timers or other watchers and |
152 | my $id = "$AnyEvent::MP::Base::UNIQ." . $AnyEvent::MP::Base::ID++; |
583 | want to free them when the port gets killed: |
153 | |
584 | |
154 | my $self = bless { |
585 | $port->rcv (start => sub { |
155 | id => "$NODE#$id", |
586 | my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub { |
156 | names => [$id], |
587 | undef $timer if 0.9 < rand; |
157 | }, "AnyEvent::MP::Port"; |
588 | }); |
|
|
589 | }); |
158 | |
590 | |
159 | $AnyEvent::MP::Base::PORT{$id} = sub { |
591 | =cut |
160 | unshift @_, $self; |
|
|
161 | |
592 | |
162 | for (@{ $self->{rc0}{$_[1]} }) { |
593 | sub mon_guard { |
163 | $_ && &{$_->[0]} |
594 | my ($port, @refs) = @_; |
164 | && undef $_; |
595 | |
|
|
596 | #TODO: mon-less form? |
|
|
597 | |
|
|
598 | mon $port, sub { 0 && @refs } |
|
|
599 | } |
|
|
600 | |
|
|
601 | =item kil $port[, @reason] |
|
|
602 | |
|
|
603 | Kill the specified port with the given C<@reason>. |
|
|
604 | |
|
|
605 | If no C<@reason> is specified, then the port is killed "normally" (linked |
|
|
606 | ports will not be kileld, or even notified). |
|
|
607 | |
|
|
608 | Otherwise, linked ports get killed with the same reason (second form of |
|
|
609 | C<mon>, see below). |
|
|
610 | |
|
|
611 | Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks |
|
|
612 | will be reported as reason C<< die => $@ >>. |
|
|
613 | |
|
|
614 | Transport/communication errors are reported as C<< transport_error => |
|
|
615 | $message >>. |
|
|
616 | |
|
|
617 | =cut |
|
|
618 | |
|
|
619 | =item $port = spawn $node, $initfunc[, @initdata] |
|
|
620 | |
|
|
621 | Creates a port on the node C<$node> (which can also be a port ID, in which |
|
|
622 | case it's the node where that port resides). |
|
|
623 | |
|
|
624 | The port ID of the newly created port is return immediately, and it is |
|
|
625 | permissible to immediately start sending messages or monitor the port. |
|
|
626 | |
|
|
627 | After the port has been created, the init function is |
|
|
628 | called. This function must be a fully-qualified function name |
|
|
629 | (e.g. C<MyApp::Chat::Server::init>). To specify a function in the main |
|
|
630 | program, use C<::name>. |
|
|
631 | |
|
|
632 | If the function doesn't exist, then the node tries to C<require> |
|
|
633 | the package, then the package above the package and so on (e.g. |
|
|
634 | C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function |
|
|
635 | exists or it runs out of package names. |
|
|
636 | |
|
|
637 | The init function is then called with the newly-created port as context |
|
|
638 | object (C<$SELF>) and the C<@initdata> values as arguments. |
|
|
639 | |
|
|
640 | A common idiom is to pass your own port, monitor the spawned port, and |
|
|
641 | in the init function, monitor the original port. This two-way monitoring |
|
|
642 | ensures that both ports get cleaned up when there is a problem. |
|
|
643 | |
|
|
644 | Example: spawn a chat server port on C<$othernode>. |
|
|
645 | |
|
|
646 | # this node, executed from within a port context: |
|
|
647 | my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF; |
|
|
648 | mon $server; |
|
|
649 | |
|
|
650 | # init function on C<$othernode> |
|
|
651 | sub connect { |
|
|
652 | my ($srcport) = @_; |
|
|
653 | |
|
|
654 | mon $srcport; |
|
|
655 | |
|
|
656 | rcv $SELF, sub { |
|
|
657 | ... |
165 | } |
658 | }; |
|
|
659 | } |
166 | |
660 | |
167 | for (@{ $self->{rcv}{$_[1]} }) { |
661 | =cut |
168 | $_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1] |
|
|
169 | && &{$_->[0]} |
|
|
170 | && undef $_; |
|
|
171 | } |
|
|
172 | |
662 | |
173 | for (@{ $self->{any} }) { |
663 | sub _spawn { |
174 | $_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1] |
664 | my $port = shift; |
175 | && &{$_->[0]} |
665 | my $init = shift; |
176 | && undef $_; |
666 | |
177 | } |
667 | local $SELF = "$NODE#$port"; |
|
|
668 | eval { |
|
|
669 | &{ load_func $init } |
178 | }; |
670 | }; |
179 | |
671 | _self_die if $@; |
180 | $self |
|
|
181 | } |
672 | } |
182 | |
673 | |
183 | =item $portid = miniport { my @msg = @_; $finished } |
674 | sub spawn(@) { |
|
|
675 | my ($noderef, undef) = split /#/, shift, 2; |
184 | |
676 | |
185 | Creates a "mini port", that is, a very lightweight port without any |
677 | my $id = "$RUNIQ." . $ID++; |
186 | pattern matching behind it, and returns its ID. |
|
|
187 | |
678 | |
188 | The block will be called for every message received on the port. When the |
679 | $_[0] =~ /::/ |
189 | callback returns a true value its job is considered "done" and the port |
680 | or Carp::croak "spawn init function must be a fully-qualified name, caught"; |
190 | will be destroyed. Otherwise it will stay alive. |
|
|
191 | |
681 | |
192 | The message will be passed as-is, no extra argument (i.e. no port id) will |
682 | snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_; |
193 | be passed to the callback. |
|
|
194 | |
683 | |
195 | If you need the local port id in the callback, this works nicely: |
684 | "$noderef#$id" |
|
|
685 | } |
196 | |
686 | |
197 | my $port; $port = miniport { |
687 | =item after $timeout, @msg |
198 | snd $otherport, reply => $port; |
688 | |
|
|
689 | =item after $timeout, $callback |
|
|
690 | |
|
|
691 | Either sends the given message, or call the given callback, after the |
|
|
692 | specified number of seconds. |
|
|
693 | |
|
|
694 | This is simply a utility function that come sin handy at times. |
|
|
695 | |
|
|
696 | =cut |
|
|
697 | |
|
|
698 | sub after($@) { |
|
|
699 | my ($timeout, @action) = @_; |
|
|
700 | |
|
|
701 | my $t; $t = AE::timer $timeout, 0, sub { |
|
|
702 | undef $t; |
|
|
703 | ref $action[0] |
|
|
704 | ? $action[0]() |
|
|
705 | : snd @action; |
199 | }; |
706 | }; |
200 | |
|
|
201 | =cut |
|
|
202 | |
|
|
203 | sub miniport(&) { |
|
|
204 | my $cb = shift; |
|
|
205 | my $id = "$AnyEvent::MP::Base::UNIQ." . $AnyEvent::MP::Base::ID++; |
|
|
206 | |
|
|
207 | $AnyEvent::MP::Base::PORT{$id} = sub { |
|
|
208 | &$cb |
|
|
209 | and del $id; |
|
|
210 | }; |
|
|
211 | |
|
|
212 | "$NODE#$id" |
|
|
213 | } |
707 | } |
214 | |
|
|
215 | package AnyEvent::MP::Port; |
|
|
216 | |
708 | |
217 | =back |
709 | =back |
218 | |
710 | |
219 | =head1 METHODS FOR PORT OBJECTS |
711 | =head1 AnyEvent::MP vs. Distributed Erlang |
|
|
712 | |
|
|
713 | AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node |
|
|
714 | == aemp node, Erlang process == aemp port), so many of the documents and |
|
|
715 | programming techniques employed by Erlang apply to AnyEvent::MP. Here is a |
|
|
716 | sample: |
|
|
717 | |
|
|
718 | http://www.Erlang.se/doc/programming_rules.shtml |
|
|
719 | http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4 |
|
|
720 | http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6 |
|
|
721 | http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5 |
|
|
722 | |
|
|
723 | Despite the similarities, there are also some important differences: |
220 | |
724 | |
221 | =over 4 |
725 | =over 4 |
222 | |
726 | |
223 | =item "$port" |
727 | =item * Node references contain the recipe on how to contact them. |
224 | |
728 | |
225 | A port object stringifies to its port ID, so can be used directly for |
729 | Erlang relies on special naming and DNS to work everywhere in the |
226 | C<snd> operations. |
730 | same way. AEMP relies on each node knowing it's own address(es), with |
|
|
731 | convenience functionality. |
227 | |
732 | |
228 | =cut |
733 | This means that AEMP requires a less tightly controlled environment at the |
|
|
734 | cost of longer node references and a slightly higher management overhead. |
229 | |
735 | |
230 | use overload |
736 | =item * Erlang has a "remote ports are like local ports" philosophy, AEMP |
231 | '""' => sub { $_[0]{id} }, |
737 | uses "local ports are like remote ports". |
232 | fallback => 1; |
|
|
233 | |
738 | |
234 | sub TO_JSON { $_[0]{id} } |
739 | The failure modes for local ports are quite different (runtime errors |
|
|
740 | only) then for remote ports - when a local port dies, you I<know> it dies, |
|
|
741 | when a connection to another node dies, you know nothing about the other |
|
|
742 | port. |
235 | |
743 | |
236 | =item $port->rcv (type => $callback->($port, @msg)) |
744 | Erlang pretends remote ports are as reliable as local ports, even when |
|
|
745 | they are not. |
237 | |
746 | |
238 | =item $port->rcv ($smartmatch => $callback->($port, @msg)) |
747 | AEMP encourages a "treat remote ports differently" philosophy, with local |
|
|
748 | ports being the special case/exception, where transport errors cannot |
|
|
749 | occur. |
239 | |
750 | |
240 | =item $port->rcv ([$smartmatch...] => $callback->($port, @msg)) |
751 | =item * Erlang uses processes and a mailbox, AEMP does not queue. |
241 | |
752 | |
242 | Register a callback on the given port. |
753 | Erlang uses processes that selectively receive messages, and therefore |
|
|
754 | needs a queue. AEMP is event based, queuing messages would serve no |
|
|
755 | useful purpose. For the same reason the pattern-matching abilities of |
|
|
756 | AnyEvent::MP are more limited, as there is little need to be able to |
|
|
757 | filter messages without dequeing them. |
243 | |
758 | |
244 | The callback has to return a true value when its work is done, after |
759 | (But see L<Coro::MP> for a more Erlang-like process model on top of AEMP). |
245 | which is will be removed, or a false value in which case it will stay |
|
|
246 | registered. |
|
|
247 | |
760 | |
248 | If the match is an array reference, then it will be matched against the |
761 | =item * Erlang sends are synchronous, AEMP sends are asynchronous. |
249 | first elements of the message, otherwise only the first element is being |
|
|
250 | matched. |
|
|
251 | |
762 | |
252 | Any element in the match that is specified as C<_any_> (a function |
763 | Sending messages in Erlang is synchronous and blocks the process (and |
253 | exported by this module) matches any single element of the message. |
764 | so does not need a queue that can overflow). AEMP sends are immediate, |
|
|
765 | connection establishment is handled in the background. |
254 | |
766 | |
255 | While not required, it is highly recommended that the first matching |
767 | =item * Erlang suffers from silent message loss, AEMP does not. |
256 | element is a string identifying the message. The one-string-only match is |
|
|
257 | also the most efficient match (by far). |
|
|
258 | |
768 | |
259 | =cut |
769 | Erlang makes few guarantees on messages delivery - messages can get lost |
|
|
770 | without any of the processes realising it (i.e. you send messages a, b, |
|
|
771 | and c, and the other side only receives messages a and c). |
260 | |
772 | |
261 | sub rcv($@) { |
773 | AEMP guarantees correct ordering, and the guarantee that there are no |
262 | my ($self, $match, $cb) = @_; |
774 | holes in the message sequence. |
263 | |
775 | |
264 | if (!ref $match) { |
776 | =item * In Erlang, processes can be declared dead and later be found to be |
265 | push @{ $self->{rc0}{$match} }, [$cb]; |
777 | alive. |
266 | } elsif (("ARRAY" eq ref $match && !ref $match->[0])) { |
|
|
267 | my ($type, @match) = @$match; |
|
|
268 | @match |
|
|
269 | ? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match] |
|
|
270 | : push @{ $self->{rc0}{$match->[0]} }, [$cb]; |
|
|
271 | } else { |
|
|
272 | push @{ $self->{any} }, [$cb, $match]; |
|
|
273 | } |
|
|
274 | } |
|
|
275 | |
778 | |
276 | =item $port->register ($name) |
779 | In Erlang it can happen that a monitored process is declared dead and |
|
|
780 | linked processes get killed, but later it turns out that the process is |
|
|
781 | still alive - and can receive messages. |
277 | |
782 | |
278 | Registers the given port under the well known name C<$name>. If the name |
783 | In AEMP, when port monitoring detects a port as dead, then that port will |
279 | already exists it is replaced. |
784 | eventually be killed - it cannot happen that a node detects a port as dead |
|
|
785 | and then later sends messages to it, finding it is still alive. |
280 | |
786 | |
281 | A port can only be registered under one well known name. |
787 | =item * Erlang can send messages to the wrong port, AEMP does not. |
282 | |
788 | |
283 | =cut |
789 | In Erlang it is quite likely that a node that restarts reuses a process ID |
|
|
790 | known to other nodes for a completely different process, causing messages |
|
|
791 | destined for that process to end up in an unrelated process. |
284 | |
792 | |
285 | sub register { |
793 | AEMP never reuses port IDs, so old messages or old port IDs floating |
286 | my ($self, $name) = @_; |
794 | around in the network will not be sent to an unrelated port. |
287 | |
795 | |
288 | $self->{wkname} = $name; |
796 | =item * Erlang uses unprotected connections, AEMP uses secure |
289 | $AnyEvent::MP::Base::WKP{$name} = "$self"; |
797 | authentication and can use TLS. |
290 | } |
|
|
291 | |
798 | |
292 | =item $port->destroy |
799 | AEMP can use a proven protocol - SSL/TLS - to protect connections and |
|
|
800 | securely authenticate nodes. |
293 | |
801 | |
294 | Explicitly destroy/remove/nuke/vaporise the port. |
802 | =item * The AEMP protocol is optimised for both text-based and binary |
|
|
803 | communications. |
295 | |
804 | |
296 | Ports are normally kept alive by there mere existance alone, and need to |
805 | The AEMP protocol, unlike the Erlang protocol, supports both |
297 | be destroyed explicitly. |
806 | language-independent text-only protocols (good for debugging) and binary, |
|
|
807 | language-specific serialisers (e.g. Storable). |
298 | |
808 | |
299 | =cut |
809 | It has also been carefully designed to be implementable in other languages |
|
|
810 | with a minimum of work while gracefully degrading fucntionality to make the |
|
|
811 | protocol simple. |
300 | |
812 | |
301 | sub destroy { |
813 | =item * AEMP has more flexible monitoring options than Erlang. |
302 | my ($self) = @_; |
|
|
303 | |
814 | |
304 | AnyEvent::MP::Base::del $self->{id}; |
815 | In Erlang, you can chose to receive I<all> exit signals as messages |
|
|
816 | or I<none>, there is no in-between, so monitoring single processes is |
|
|
817 | difficult to implement. Monitoring in AEMP is more flexible than in |
|
|
818 | Erlang, as one can choose between automatic kill, exit message or callback |
|
|
819 | on a per-process basis. |
305 | |
820 | |
306 | delete $AnyEvent::MP::Base::WKP{ $self->{wkname} }; |
821 | =item * Erlang tries to hide remote/local connections, AEMP does not. |
307 | |
822 | |
308 | delete $AnyEvent::MP::Base::PORT{$_} |
823 | Monitoring in Erlang is not an indicator of process death/crashes, |
309 | for @{ $self->{names} }; |
824 | as linking is (except linking is unreliable in Erlang). |
310 | } |
825 | |
|
|
826 | In AEMP, you don't "look up" registered port names or send to named ports |
|
|
827 | that might or might not be persistent. Instead, you normally spawn a port |
|
|
828 | on the remote node. The init function monitors the you, and you monitor |
|
|
829 | the remote port. Since both monitors are local to the node, they are much |
|
|
830 | more reliable. |
|
|
831 | |
|
|
832 | This also saves round-trips and avoids sending messages to the wrong port |
|
|
833 | (hard to do in Erlang). |
311 | |
834 | |
312 | =back |
835 | =back |
313 | |
836 | |
314 | =head1 FUNCTIONS FOR NODES |
837 | =head1 RATIONALE |
315 | |
838 | |
316 | =over 4 |
839 | =over 4 |
317 | |
840 | |
318 | =item mon $noderef, $callback->($noderef, $status, $) |
841 | =item Why strings for ports and noderefs, why not objects? |
319 | |
842 | |
320 | Monitors the given noderef. |
843 | We considered "objects", but found that the actual number of methods |
|
|
844 | thatc an be called are very low. Since port IDs and noderefs travel over |
|
|
845 | the network frequently, the serialising/deserialising would add lots of |
|
|
846 | overhead, as well as having to keep a proxy object. |
321 | |
847 | |
322 | =item become_public endpoint... |
848 | Strings can easily be printed, easily serialised etc. and need no special |
|
|
849 | procedures to be "valid". |
323 | |
850 | |
324 | Tells the node to become a public node, i.e. reachable from other nodes. |
851 | And a a miniport consists of a single closure stored in a global hash - it |
|
|
852 | can't become much cheaper. |
325 | |
853 | |
326 | If no arguments are given, or the first argument is C<undef>, then |
854 | =item Why favour JSON, why not real serialising format such as Storable? |
327 | AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the |
|
|
328 | local nodename resolves to. |
|
|
329 | |
855 | |
330 | Otherwise the first argument must be an array-reference with transport |
856 | In fact, any AnyEvent::MP node will happily accept Storable as framing |
331 | endpoints ("ip:port", "hostname:port") or port numbers (in which case the |
857 | format, but currently there is no way to make a node use Storable by |
332 | local nodename is used as hostname). The endpoints are all resolved and |
858 | default. |
333 | will become the node reference. |
|
|
334 | |
859 | |
335 | =cut |
860 | The default framing protocol is JSON because a) JSON::XS is many times |
|
|
861 | faster for small messages and b) most importantly, after years of |
|
|
862 | experience we found that object serialisation is causing more problems |
|
|
863 | than it gains: Just like function calls, objects simply do not travel |
|
|
864 | easily over the network, mostly because they will always be a copy, so you |
|
|
865 | always have to re-think your design. |
336 | |
866 | |
337 | =back |
867 | Keeping your messages simple, concentrating on data structures rather than |
338 | |
868 | objects, will keep your messages clean, tidy and efficient. |
339 | =head1 NODE MESSAGES |
|
|
340 | |
|
|
341 | Nodes understand the following messages sent to them. Many of them take |
|
|
342 | arguments called C<@reply>, which will simply be used to compose a reply |
|
|
343 | message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and |
|
|
344 | the remaining arguments are simply the message data. |
|
|
345 | |
|
|
346 | =over 4 |
|
|
347 | |
|
|
348 | =cut |
|
|
349 | |
|
|
350 | =item wkp => $name, @reply |
|
|
351 | |
|
|
352 | Replies with the port ID of the specified well-known port, or C<undef>. |
|
|
353 | |
|
|
354 | =item devnull => ... |
|
|
355 | |
|
|
356 | Generic data sink/CPU heat conversion. |
|
|
357 | |
|
|
358 | =item relay => $port, @msg |
|
|
359 | |
|
|
360 | Simply forwards the message to the given port. |
|
|
361 | |
|
|
362 | =item eval => $string[ @reply] |
|
|
363 | |
|
|
364 | Evaluates the given string. If C<@reply> is given, then a message of the |
|
|
365 | form C<@reply, $@, @evalres> is sent. |
|
|
366 | |
|
|
367 | Example: crash another node. |
|
|
368 | |
|
|
369 | snd $othernode, eval => "exit"; |
|
|
370 | |
|
|
371 | =item time => @reply |
|
|
372 | |
|
|
373 | Replies the the current node time to C<@reply>. |
|
|
374 | |
|
|
375 | Example: tell the current node to send the current time to C<$myport> in a |
|
|
376 | C<timereply> message. |
|
|
377 | |
|
|
378 | snd $NODE, time => $myport, timereply => 1, 2; |
|
|
379 | # => snd $myport, timereply => 1, 2, <time> |
|
|
380 | |
869 | |
381 | =back |
870 | =back |
382 | |
871 | |
383 | =head1 SEE ALSO |
872 | =head1 SEE ALSO |
384 | |
873 | |