1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | AnyEvent::MP - multi-processing/message-passing framework |
3 | AnyEvent::MP - erlang-style multi-processing/message-passing framework |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use AnyEvent::MP; |
7 | use AnyEvent::MP; |
8 | |
8 | |
9 | $NODE # contains this node's noderef |
9 | $NODE # contains this node's node ID |
10 | NODE # returns this node's noderef |
10 | NODE # returns this node's node ID |
11 | NODE $port # returns the noderef of the port |
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12 | |
11 | |
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12 | $SELF # receiving/own port id in rcv callbacks |
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13 | |
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14 | # initialise the node so it can send/receive messages |
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15 | configure; |
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16 | |
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17 | # ports are message destinations |
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18 | |
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19 | # sending messages |
13 | snd $port, type => data...; |
20 | snd $port, type => data...; |
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21 | snd $port, @msg; |
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22 | snd @msg_with_first_element_being_a_port; |
14 | |
23 | |
15 | $SELF # receiving/own port id in rcv callbacks |
24 | # creating/using ports, the simple way |
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25 | my $simple_port = port { my @msg = @_ }; |
16 | |
26 | |
17 | rcv $port, smartmatch => $cb->($port, @msg); |
27 | # creating/using ports, tagged message matching |
18 | |
28 | my $port = port; |
19 | # examples: |
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20 | rcv $port2, ping => sub { snd $_[0], "pong"; 0 }; |
29 | rcv $port, ping => sub { snd $_[0], "pong" }; |
21 | rcv $port1, pong => sub { warn "pong received\n" }; |
30 | rcv $port, pong => sub { warn "pong received\n" }; |
22 | snd $port2, ping => $port1; |
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23 | |
31 | |
24 | # more, smarter, matches (_any_ is exported by this module) |
32 | # create a port on another node |
25 | rcv $port, [child_died => $pid] => sub { ... |
33 | my $port = spawn $node, $initfunc, @initdata; |
26 | rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3 |
34 | |
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35 | # destroy a port again |
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36 | kil $port; # "normal" kill |
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37 | kil $port, my_error => "everything is broken"; # error kill |
27 | |
38 | |
28 | # monitoring |
39 | # monitoring |
29 | mon $port, $cb->(@msg) # callback is invoked on death |
40 | mon $localport, $cb->(@msg) # callback is invoked on death |
30 | mon $port, $otherport # kill otherport on abnormal death |
41 | mon $localport, $otherport # kill otherport on abnormal death |
31 | mon $port, $otherport, @msg # send message on death |
42 | mon $localport, $otherport, @msg # send message on death |
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43 | |
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44 | # temporarily execute code in port context |
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45 | peval $port, sub { die "kill the port!" }; |
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46 | |
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47 | # execute callbacks in $SELF port context |
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48 | my $timer = AE::timer 1, 0, psub { |
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49 | die "kill the port, delayed"; |
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50 | }; |
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51 | |
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52 | =head1 CURRENT STATUS |
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53 | |
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54 | bin/aemp - stable. |
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55 | AnyEvent::MP - stable API, should work. |
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56 | AnyEvent::MP::Intro - explains most concepts. |
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57 | AnyEvent::MP::Kernel - mostly stable API. |
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58 | AnyEvent::MP::Global - stable API. |
32 | |
59 | |
33 | =head1 DESCRIPTION |
60 | =head1 DESCRIPTION |
34 | |
61 | |
35 | This module (-family) implements a simple message passing framework. |
62 | This module (-family) implements a simple message passing framework. |
36 | |
63 | |
37 | Despite its simplicity, you can securely message other processes running |
64 | Despite its simplicity, you can securely message other processes running |
38 | on the same or other hosts. |
65 | on the same or other hosts, and you can supervise entities remotely. |
39 | |
66 | |
40 | For an introduction to this module family, see the L<AnyEvent::MP::Intro> |
67 | For an introduction to this module family, see the L<AnyEvent::MP::Intro> |
41 | manual page. |
68 | manual page and the examples under F<eg/>. |
42 | |
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43 | At the moment, this module family is severly broken and underdocumented, |
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44 | so do not use. This was uploaded mainly to reserve the CPAN namespace - |
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45 | stay tuned! The basic API should be finished, however. |
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46 | |
69 | |
47 | =head1 CONCEPTS |
70 | =head1 CONCEPTS |
48 | |
71 | |
49 | =over 4 |
72 | =over 4 |
50 | |
73 | |
51 | =item port |
74 | =item port |
52 | |
75 | |
53 | A port is something you can send messages to (with the C<snd> function). |
76 | Not to be confused with a TCP port, a "port" is something you can send |
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77 | messages to (with the C<snd> function). |
54 | |
78 | |
55 | Some ports allow you to register C<rcv> handlers that can match specific |
79 | Ports allow you to register C<rcv> handlers that can match all or just |
56 | messages. All C<rcv> handlers will receive messages they match, messages |
80 | some messages. Messages send to ports will not be queued, regardless of |
57 | will not be queued. |
81 | anything was listening for them or not. |
58 | |
82 | |
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83 | Ports are represented by (printable) strings called "port IDs". |
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84 | |
59 | =item port id - C<noderef#portname> |
85 | =item port ID - C<nodeid#portname> |
60 | |
86 | |
61 | A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as |
87 | A port ID is the concatenation of a node ID, a hash-mark (C<#>) |
62 | separator, and a port name (a printable string of unspecified format). An |
88 | as separator, and a port name (a printable string of unspecified |
63 | exception is the the node port, whose ID is identical to its node |
89 | format created by AnyEvent::MP). |
64 | reference. |
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65 | |
90 | |
66 | =item node |
91 | =item node |
67 | |
92 | |
68 | A node is a single process containing at least one port - the node |
93 | A node is a single process containing at least one port - the node port, |
69 | port. You can send messages to node ports to find existing ports or to |
94 | which enables nodes to manage each other remotely, and to create new |
70 | create new ports, among other things. |
95 | ports. |
71 | |
96 | |
72 | Nodes are either private (single-process only), slaves (connected to a |
97 | Nodes are either public (have one or more listening ports) or private |
73 | master node only) or public nodes (connectable from unrelated nodes). |
98 | (no listening ports). Private nodes cannot talk to other private nodes |
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99 | currently, but all nodes can talk to public nodes. |
74 | |
100 | |
75 | =item noderef - C<host:port,host:port...>, C<id@noderef>, C<id> |
101 | Nodes is represented by (printable) strings called "node IDs". |
76 | |
102 | |
77 | A node reference is a string that either simply identifies the node (for |
103 | =item node ID - C<[A-Za-z0-9_\-.:]*> |
78 | private and slave nodes), or contains a recipe on how to reach a given |
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79 | node (for public nodes). |
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80 | |
104 | |
81 | This recipe is simply a comma-separated list of C<address:port> pairs (for |
105 | A node ID is a string that uniquely identifies the node within a |
82 | TCP/IP, other protocols might look different). |
106 | network. Depending on the configuration used, node IDs can look like a |
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107 | hostname, a hostname and a port, or a random string. AnyEvent::MP itself |
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108 | doesn't interpret node IDs in any way except to uniquely identify a node. |
83 | |
109 | |
84 | Node references come in two flavours: resolved (containing only numerical |
110 | =item binds - C<ip:port> |
85 | addresses) or unresolved (where hostnames are used instead of addresses). |
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86 | |
111 | |
87 | Before using an unresolved node reference in a message you first have to |
112 | Nodes can only talk to each other by creating some kind of connection to |
88 | resolve it. |
113 | each other. To do this, nodes should listen on one or more local transport |
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114 | endpoints - binds. |
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115 | |
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116 | Currently, only standard C<ip:port> specifications can be used, which |
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117 | specify TCP ports to listen on. So a bind is basically just a tcp socket |
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118 | in listening mode thta accepts conenctions form other nodes. |
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119 | |
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120 | =item seed nodes |
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121 | |
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122 | When a node starts, it knows nothing about the network it is in - it |
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123 | needs to connect to at least one other node that is already in the |
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124 | network. These other nodes are called "seed nodes". |
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125 | |
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126 | Seed nodes themselves are not special - they are seed nodes only because |
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127 | some other node I<uses> them as such, but any node can be used as seed |
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128 | node for other nodes, and eahc node cna use a different set of seed nodes. |
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129 | |
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130 | In addition to discovering the network, seed nodes are also used to |
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131 | maintain the network - all nodes using the same seed node form are part of |
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132 | the same network. If a network is split into multiple subnets because e.g. |
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133 | the network link between the parts goes down, then using the same seed |
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134 | nodes for all nodes ensures that eventually the subnets get merged again. |
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135 | |
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136 | Seed nodes are expected to be long-running, and at least one seed node |
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137 | should always be available. They should also be relatively responsive - a |
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138 | seed node that blocks for long periods will slow down everybody else. |
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139 | |
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140 | For small networks, it's best if every node uses the same set of seed |
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141 | nodes. For large networks, it can be useful to specify "regional" seed |
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142 | nodes for most nodes in an area, and use all seed nodes as seed nodes for |
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143 | each other. What's important is that all seed nodes connections form a |
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144 | complete graph, so that the network cannot split into separate subnets |
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145 | forever. |
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146 | |
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147 | Seed nodes are represented by seed IDs. |
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148 | |
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149 | =item seed IDs - C<host:port> |
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150 | |
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151 | Seed IDs are transport endpoint(s) (usually a hostname/IP address and a |
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152 | TCP port) of nodes that should be used as seed nodes. |
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153 | |
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154 | =item global nodes |
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155 | |
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156 | An AEMP network needs a discovery service - nodes need to know how to |
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157 | connect to other nodes they only know by name. In addition, AEMP offers a |
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158 | distributed "group database", which maps group names to a list of strings |
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159 | - for example, to register worker ports. |
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160 | |
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161 | A network needs at least one global node to work, and allows every node to |
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162 | be a global node. |
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163 | |
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164 | Any node that loads the L<AnyEvent::MP::Global> module becomes a global |
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165 | node and tries to keep connections to all other nodes. So while it can |
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166 | make sense to make every node "global" in small networks, it usually makes |
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167 | sense to only make seed nodes into global nodes in large networks (nodes |
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168 | keep connections to seed nodes and global nodes, so makign them the same |
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169 | reduces overhead). |
89 | |
170 | |
90 | =back |
171 | =back |
91 | |
172 | |
92 | =head1 VARIABLES/FUNCTIONS |
173 | =head1 VARIABLES/FUNCTIONS |
93 | |
174 | |
… | |
… | |
95 | |
176 | |
96 | =cut |
177 | =cut |
97 | |
178 | |
98 | package AnyEvent::MP; |
179 | package AnyEvent::MP; |
99 | |
180 | |
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181 | use AnyEvent::MP::Config (); |
100 | use AnyEvent::MP::Base; |
182 | use AnyEvent::MP::Kernel; |
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183 | use AnyEvent::MP::Kernel qw(%NODE %PORT %PORT_DATA $UNIQ $RUNIQ $ID); |
101 | |
184 | |
102 | use common::sense; |
185 | use common::sense; |
103 | |
186 | |
104 | use Carp (); |
187 | use Carp (); |
105 | |
188 | |
106 | use AE (); |
189 | use AE (); |
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190 | use Guard (); |
107 | |
191 | |
108 | use base "Exporter"; |
192 | use base "Exporter"; |
109 | |
193 | |
110 | our $VERSION = '0.1'; |
194 | our $VERSION = $AnyEvent::MP::Config::VERSION; |
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195 | |
111 | our @EXPORT = qw( |
196 | our @EXPORT = qw( |
112 | NODE $NODE *SELF node_of _any_ |
197 | NODE $NODE *SELF node_of after |
113 | resolve_node initialise_node |
198 | configure |
114 | snd rcv mon kil reg psub |
199 | snd rcv mon mon_guard kil psub peval spawn cal |
115 | port |
200 | port |
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201 | db_set db_del db_reg |
116 | ); |
202 | ); |
117 | |
203 | |
118 | our $SELF; |
204 | our $SELF; |
119 | |
205 | |
120 | sub _self_die() { |
206 | sub _self_die() { |
… | |
… | |
123 | kil $SELF, die => $msg; |
209 | kil $SELF, die => $msg; |
124 | } |
210 | } |
125 | |
211 | |
126 | =item $thisnode = NODE / $NODE |
212 | =item $thisnode = NODE / $NODE |
127 | |
213 | |
128 | The C<NODE> function returns, and the C<$NODE> variable contains |
214 | The C<NODE> function returns, and the C<$NODE> variable contains, the node |
129 | the noderef of the local node. The value is initialised by a call |
215 | ID of the node running in the current process. This value is initialised by |
130 | to C<become_public> or C<become_slave>, after which all local port |
216 | a call to C<configure>. |
131 | identifiers become invalid. |
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132 | |
217 | |
133 | =item $noderef = node_of $port |
218 | =item $nodeid = node_of $port |
134 | |
219 | |
135 | Extracts and returns the noderef from a portid or a noderef. |
220 | Extracts and returns the node ID from a port ID or a node ID. |
136 | |
221 | |
137 | =item initialise_node $noderef, $seednode, $seednode... |
222 | =item configure $profile, key => value... |
138 | |
223 | |
139 | =item initialise_node "slave/", $master, $master... |
224 | =item configure key => value... |
140 | |
225 | |
141 | Before a node can talk to other nodes on the network it has to initialise |
226 | Before a node can talk to other nodes on the network (i.e. enter |
142 | itself - the minimum a node needs to know is it's own name, and optionally |
227 | "distributed mode") it has to configure itself - the minimum a node needs |
143 | it should know the noderefs of some other nodes in the network. |
228 | to know is its own name, and optionally it should know the addresses of |
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229 | some other nodes in the network to discover other nodes. |
144 | |
230 | |
145 | This function initialises a node - it must be called exactly once (or |
231 | This function configures a node - it must be called exactly once (or |
146 | never) before calling other AnyEvent::MP functions. |
232 | never) before calling other AnyEvent::MP functions. |
147 | |
233 | |
148 | All arguments are noderefs, which can be either resolved or unresolved. |
234 | The key/value pairs are basically the same ones as documented for the |
149 | |
235 | F<aemp> command line utility (sans the set/del prefix), with two additions: |
150 | There are two types of networked nodes, public nodes and slave nodes: |
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151 | |
236 | |
152 | =over 4 |
237 | =over 4 |
153 | |
238 | |
154 | =item public nodes |
239 | =item norc => $boolean (default false) |
155 | |
240 | |
156 | For public nodes, C<$noderef> must either be a (possibly unresolved) |
241 | If true, then the rc file (e.g. F<~/.perl-anyevent-mp>) will I<not> |
157 | noderef, in which case it will be resolved, or C<undef> (or missing), in |
242 | be consulted - all configuraiton options must be specified in the |
158 | which case the noderef will be guessed. |
243 | C<configure> call. |
159 | |
244 | |
160 | Afterwards, the node will bind itself on all endpoints and try to connect |
245 | =item force => $boolean (default false) |
161 | to all additional C<$seednodes> that are specified. Seednodes are optional |
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162 | and can be used to quickly bootstrap the node into an existing network. |
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163 | |
246 | |
164 | =item slave nodes |
247 | IF true, then the values specified in the C<configure> will take |
165 | |
248 | precedence over any values configured via the rc file. The default is for |
166 | When the C<$noderef> is the special string C<slave/>, then the node will |
249 | the rc file to override any options specified in the program. |
167 | become a slave node. Slave nodes cannot be contacted from outside and will |
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168 | route most of their traffic to the master node that they attach to. |
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169 | |
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170 | At least one additional noderef is required: The node will try to connect |
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171 | to all of them and will become a slave attached to the first node it can |
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172 | successfully connect to. |
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173 | |
250 | |
174 | =back |
251 | =back |
175 | |
252 | |
176 | This function will block until all nodes have been resolved and, for slave |
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177 | nodes, until it has successfully established a connection to a master |
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178 | server. |
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179 | |
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180 | Example: become a public node listening on the default node. |
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181 | |
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182 | initialise_node; |
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183 | |
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184 | Example: become a public node, and try to contact some well-known master |
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185 | servers to become part of the network. |
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186 | |
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187 | initialise_node undef, "master1", "master2"; |
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188 | |
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189 | Example: become a public node listening on port C<4041>. |
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190 | |
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191 | initialise_node 4041; |
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192 | |
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193 | Example: become a public node, only visible on localhost port 4044. |
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194 | |
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195 | initialise_node "locahost:4044"; |
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196 | |
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197 | Example: become a slave node to any of the specified master servers. |
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198 | |
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199 | initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net"; |
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200 | |
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201 | =item $cv = resolve_node $noderef |
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202 | |
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203 | Takes an unresolved node reference that may contain hostnames and |
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204 | abbreviated IDs, resolves all of them and returns a resolved node |
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205 | reference. |
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206 | |
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207 | In addition to C<address:port> pairs allowed in resolved noderefs, the |
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208 | following forms are supported: |
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209 | |
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210 | =over 4 |
253 | =over 4 |
211 | |
254 | |
212 | =item the empty string |
255 | =item step 1, gathering configuration from profiles |
213 | |
256 | |
214 | An empty-string component gets resolved as if the default port (4040) was |
257 | The function first looks up a profile in the aemp configuration (see the |
215 | specified. |
258 | L<aemp> commandline utility). The profile name can be specified via the |
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259 | named C<profile> parameter or can simply be the first parameter). If it is |
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260 | missing, then the nodename (F<uname -n>) will be used as profile name. |
216 | |
261 | |
217 | =item naked port numbers (e.g. C<1234>) |
262 | The profile data is then gathered as follows: |
218 | |
263 | |
219 | These are resolved by prepending the local nodename and a colon, to be |
264 | First, all remaining key => value pairs (all of which are conveniently |
220 | further resolved. |
265 | undocumented at the moment) will be interpreted as configuration |
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266 | data. Then they will be overwritten by any values specified in the global |
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267 | default configuration (see the F<aemp> utility), then the chain of |
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268 | profiles chosen by the profile name (and any C<parent> attributes). |
221 | |
269 | |
222 | =item hostnames (e.g. C<localhost:1234>, C<localhost>) |
270 | That means that the values specified in the profile have highest priority |
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271 | and the values specified directly via C<configure> have lowest priority, |
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272 | and can only be used to specify defaults. |
223 | |
273 | |
224 | These are resolved by using AnyEvent::DNS to resolve them, optionally |
274 | If the profile specifies a node ID, then this will become the node ID of |
225 | looking up SRV records for the C<aemp=4040> port, if no port was |
275 | this process. If not, then the profile name will be used as node ID, with |
226 | specified. |
276 | a unique randoms tring (C</%u>) appended. |
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277 | |
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278 | The node ID can contain some C<%> sequences that are expanded: C<%n> |
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279 | is expanded to the local nodename, C<%u> is replaced by a random |
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280 | strign to make the node unique. For example, the F<aemp> commandline |
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281 | utility uses C<aemp/%n/%u> as nodename, which might expand to |
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282 | C<aemp/cerebro/ZQDGSIkRhEZQDGSIkRhE>. |
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283 | |
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284 | =item step 2, bind listener sockets |
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285 | |
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286 | The next step is to look up the binds in the profile, followed by binding |
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287 | aemp protocol listeners on all binds specified (it is possible and valid |
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288 | to have no binds, meaning that the node cannot be contacted form the |
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289 | outside. This means the node cannot talk to other nodes that also have no |
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290 | binds, but it can still talk to all "normal" nodes). |
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291 | |
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292 | If the profile does not specify a binds list, then a default of C<*> is |
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293 | used, meaning the node will bind on a dynamically-assigned port on every |
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294 | local IP address it finds. |
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295 | |
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296 | =item step 3, connect to seed nodes |
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297 | |
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298 | As the last step, the seed ID list from the profile is passed to the |
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299 | L<AnyEvent::MP::Global> module, which will then use it to keep |
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300 | connectivity with at least one node at any point in time. |
227 | |
301 | |
228 | =back |
302 | =back |
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303 | |
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304 | Example: become a distributed node using the local node name as profile. |
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305 | This should be the most common form of invocation for "daemon"-type nodes. |
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306 | |
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307 | configure |
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308 | |
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309 | Example: become a semi-anonymous node. This form is often used for |
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310 | commandline clients. |
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311 | |
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312 | configure nodeid => "myscript/%n/%u"; |
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313 | |
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314 | Example: configure a node using a profile called seed, which is suitable |
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315 | for a seed node as it binds on all local addresses on a fixed port (4040, |
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316 | customary for aemp). |
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317 | |
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318 | # use the aemp commandline utility |
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319 | # aemp profile seed binds '*:4040' |
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320 | |
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321 | # then use it |
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322 | configure profile => "seed"; |
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323 | |
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324 | # or simply use aemp from the shell again: |
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325 | # aemp run profile seed |
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326 | |
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327 | # or provide a nicer-to-remember nodeid |
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|
328 | # aemp run profile seed nodeid "$(hostname)" |
229 | |
329 | |
230 | =item $SELF |
330 | =item $SELF |
231 | |
331 | |
232 | Contains the current port id while executing C<rcv> callbacks or C<psub> |
332 | Contains the current port id while executing C<rcv> callbacks or C<psub> |
233 | blocks. |
333 | blocks. |
234 | |
334 | |
235 | =item SELF, %SELF, @SELF... |
335 | =item *SELF, SELF, %SELF, @SELF... |
236 | |
336 | |
237 | Due to some quirks in how perl exports variables, it is impossible to |
337 | Due to some quirks in how perl exports variables, it is impossible to |
238 | just export C<$SELF>, all the symbols called C<SELF> are exported by this |
338 | just export C<$SELF>, all the symbols named C<SELF> are exported by this |
239 | module, but only C<$SELF> is currently used. |
339 | module, but only C<$SELF> is currently used. |
240 | |
340 | |
241 | =item snd $port, type => @data |
341 | =item snd $port, type => @data |
242 | |
342 | |
243 | =item snd $port, @msg |
343 | =item snd $port, @msg |
244 | |
344 | |
245 | Send the given message to the given port ID, which can identify either |
345 | Send the given message to the given port, which can identify either a |
246 | a local or a remote port, and can be either a string or soemthignt hat |
346 | local or a remote port, and must be a port ID. |
247 | stringifies a sa port ID (such as a port object :). |
|
|
248 | |
347 | |
249 | While the message can be about anything, it is highly recommended to use a |
348 | While the message can be almost anything, it is highly recommended to |
250 | string as first element (a portid, or some word that indicates a request |
349 | use a string as first element (a port ID, or some word that indicates a |
251 | type etc.). |
350 | request type etc.) and to consist if only simple perl values (scalars, |
|
|
351 | arrays, hashes) - if you think you need to pass an object, think again. |
252 | |
352 | |
253 | The message data effectively becomes read-only after a call to this |
353 | The message data logically becomes read-only after a call to this |
254 | function: modifying any argument is not allowed and can cause many |
354 | function: modifying any argument (or values referenced by them) is |
255 | problems. |
355 | forbidden, as there can be considerable time between the call to C<snd> |
|
|
356 | and the time the message is actually being serialised - in fact, it might |
|
|
357 | never be copied as within the same process it is simply handed to the |
|
|
358 | receiving port. |
256 | |
359 | |
257 | The type of data you can transfer depends on the transport protocol: when |
360 | The type of data you can transfer depends on the transport protocol: when |
258 | JSON is used, then only strings, numbers and arrays and hashes consisting |
361 | JSON is used, then only strings, numbers and arrays and hashes consisting |
259 | of those are allowed (no objects). When Storable is used, then anything |
362 | of those are allowed (no objects). When Storable is used, then anything |
260 | that Storable can serialise and deserialise is allowed, and for the local |
363 | that Storable can serialise and deserialise is allowed, and for the local |
261 | node, anything can be passed. |
364 | node, anything can be passed. Best rely only on the common denominator of |
|
|
365 | these. |
262 | |
366 | |
263 | =item $local_port = port |
367 | =item $local_port = port |
264 | |
368 | |
265 | Create a new local port object that can be used either as a pattern |
369 | Create a new local port object and returns its port ID. Initially it has |
266 | matching port ("full port") or a single-callback port ("miniport"), |
370 | no callbacks set and will throw an error when it receives messages. |
267 | depending on how C<rcv> callbacks are bound to the object. |
|
|
268 | |
371 | |
269 | =item $port = port { my @msg = @_; $finished } |
372 | =item $local_port = port { my @msg = @_ } |
270 | |
373 | |
271 | Creates a "miniport", that is, a very lightweight port without any pattern |
374 | Creates a new local port, and returns its ID. Semantically the same as |
272 | matching behind it, and returns its ID. Semantically the same as creating |
|
|
273 | a port and calling C<rcv $port, $callback> on it. |
375 | creating a port and calling C<rcv $port, $callback> on it. |
274 | |
376 | |
275 | The block will be called for every message received on the port. When the |
377 | The block will be called for every message received on the port, with the |
276 | callback returns a true value its job is considered "done" and the port |
378 | global variable C<$SELF> set to the port ID. Runtime errors will cause the |
277 | will be destroyed. Otherwise it will stay alive. |
379 | port to be C<kil>ed. The message will be passed as-is, no extra argument |
|
|
380 | (i.e. no port ID) will be passed to the callback. |
278 | |
381 | |
279 | The message will be passed as-is, no extra argument (i.e. no port id) will |
382 | If you want to stop/destroy the port, simply C<kil> it: |
280 | be passed to the callback. |
|
|
281 | |
383 | |
282 | If you need the local port id in the callback, this works nicely: |
384 | my $port = port { |
283 | |
385 | my @msg = @_; |
284 | my $port; $port = port { |
386 | ... |
285 | snd $otherport, reply => $port; |
387 | kil $SELF; |
286 | }; |
388 | }; |
287 | |
389 | |
288 | =cut |
390 | =cut |
289 | |
391 | |
290 | sub rcv($@); |
392 | sub rcv($@); |
291 | |
393 | |
|
|
394 | sub _kilme { |
|
|
395 | die "received message on port without callback"; |
|
|
396 | } |
|
|
397 | |
292 | sub port(;&) { |
398 | sub port(;&) { |
293 | my $id = "$UNIQ." . $ID++; |
399 | my $id = $UNIQ . ++$ID; |
294 | my $port = "$NODE#$id"; |
400 | my $port = "$NODE#$id"; |
295 | |
401 | |
296 | if (@_) { |
402 | rcv $port, shift || \&_kilme; |
297 | rcv $port, shift; |
|
|
298 | } else { |
|
|
299 | $PORT{$id} = sub { }; # nop |
|
|
300 | } |
|
|
301 | |
403 | |
302 | $port |
404 | $port |
303 | } |
405 | } |
304 | |
406 | |
305 | =item reg $port, $name |
|
|
306 | |
|
|
307 | =item reg $name |
|
|
308 | |
|
|
309 | Registers the given port (or C<$SELF><<< if missing) under the name |
|
|
310 | C<$name>. If the name already exists it is replaced. |
|
|
311 | |
|
|
312 | A port can only be registered under one well known name. |
|
|
313 | |
|
|
314 | A port automatically becomes unregistered when it is killed. |
|
|
315 | |
|
|
316 | =cut |
|
|
317 | |
|
|
318 | sub reg(@) { |
|
|
319 | my $port = @_ > 1 ? shift : $SELF || Carp::croak 'reg: called with one argument only, but $SELF not set,'; |
|
|
320 | |
|
|
321 | $REG{$_[0]} = $port; |
|
|
322 | } |
|
|
323 | |
|
|
324 | =item rcv $port, $callback->(@msg) |
407 | =item rcv $local_port, $callback->(@msg) |
325 | |
408 | |
326 | Replaces the callback on the specified miniport (after converting it to |
409 | Replaces the default callback on the specified port. There is no way to |
327 | one if required). |
410 | remove the default callback: use C<sub { }> to disable it, or better |
328 | |
411 | C<kil> the port when it is no longer needed. |
329 | =item rcv $port, tagstring => $callback->(@msg), ... |
|
|
330 | |
|
|
331 | =item rcv $port, $smartmatch => $callback->(@msg), ... |
|
|
332 | |
|
|
333 | =item rcv $port, [$smartmatch...] => $callback->(@msg), ... |
|
|
334 | |
|
|
335 | Register callbacks to be called on matching messages on the given full |
|
|
336 | port (after converting it to one if required) and return the port. |
|
|
337 | |
|
|
338 | The callback has to return a true value when its work is done, after |
|
|
339 | which is will be removed, or a false value in which case it will stay |
|
|
340 | registered. |
|
|
341 | |
412 | |
342 | The global C<$SELF> (exported by this module) contains C<$port> while |
413 | The global C<$SELF> (exported by this module) contains C<$port> while |
343 | executing the callback. |
414 | executing the callback. Runtime errors during callback execution will |
|
|
415 | result in the port being C<kil>ed. |
344 | |
416 | |
345 | Runtime errors wdurign callback execution will result in the port being |
417 | The default callback received all messages not matched by a more specific |
346 | C<kil>ed. |
418 | C<tag> match. |
347 | |
419 | |
348 | If the match is an array reference, then it will be matched against the |
420 | =item rcv $local_port, tag => $callback->(@msg_without_tag), ... |
349 | first elements of the message, otherwise only the first element is being |
|
|
350 | matched. |
|
|
351 | |
421 | |
352 | Any element in the match that is specified as C<_any_> (a function |
422 | Register (or replace) callbacks to be called on messages starting with the |
353 | exported by this module) matches any single element of the message. |
423 | given tag on the given port (and return the port), or unregister it (when |
|
|
424 | C<$callback> is C<$undef> or missing). There can only be one callback |
|
|
425 | registered for each tag. |
354 | |
426 | |
355 | While not required, it is highly recommended that the first matching |
427 | The original message will be passed to the callback, after the first |
356 | element is a string identifying the message. The one-string-only match is |
428 | element (the tag) has been removed. The callback will use the same |
357 | also the most efficient match (by far). |
429 | environment as the default callback (see above). |
358 | |
430 | |
359 | Example: create a port and bind receivers on it in one go. |
431 | Example: create a port and bind receivers on it in one go. |
360 | |
432 | |
361 | my $port = rcv port, |
433 | my $port = rcv port, |
362 | msg1 => sub { ...; 0 }, |
434 | msg1 => sub { ... }, |
363 | msg2 => sub { ...; 0 }, |
435 | msg2 => sub { ... }, |
364 | ; |
436 | ; |
365 | |
437 | |
366 | Example: create a port, bind receivers and send it in a message elsewhere |
438 | Example: create a port, bind receivers and send it in a message elsewhere |
367 | in one go: |
439 | in one go: |
368 | |
440 | |
369 | snd $otherport, reply => |
441 | snd $otherport, reply => |
370 | rcv port, |
442 | rcv port, |
371 | msg1 => sub { ...; 0 }, |
443 | msg1 => sub { ... }, |
372 | ... |
444 | ... |
373 | ; |
445 | ; |
374 | |
446 | |
|
|
447 | Example: temporarily register a rcv callback for a tag matching some port |
|
|
448 | (e.g. for an rpc reply) and unregister it after a message was received. |
|
|
449 | |
|
|
450 | rcv $port, $otherport => sub { |
|
|
451 | my @reply = @_; |
|
|
452 | |
|
|
453 | rcv $SELF, $otherport; |
|
|
454 | }; |
|
|
455 | |
375 | =cut |
456 | =cut |
376 | |
457 | |
377 | sub rcv($@) { |
458 | sub rcv($@) { |
378 | my $port = shift; |
459 | my $port = shift; |
379 | my ($noderef, $portid) = split /#/, $port, 2; |
460 | my ($nodeid, $portid) = split /#/, $port, 2; |
380 | |
461 | |
381 | ($NODE{$noderef} || add_node $noderef) == $NODE{""} |
462 | $NODE{$nodeid} == $NODE{""} |
382 | or Carp::croak "$port: rcv can only be called on local ports, caught"; |
463 | or Carp::croak "$port: rcv can only be called on local ports, caught"; |
383 | |
464 | |
384 | if (@_ == 1) { |
465 | while (@_) { |
|
|
466 | if (ref $_[0]) { |
|
|
467 | if (my $self = $PORT_DATA{$portid}) { |
|
|
468 | "AnyEvent::MP::Port" eq ref $self |
|
|
469 | or Carp::croak "$port: rcv can only be called on message matching ports, caught"; |
|
|
470 | |
|
|
471 | $self->[0] = shift; |
|
|
472 | } else { |
385 | my $cb = shift; |
473 | my $cb = shift; |
386 | delete $PORT_DATA{$portid}; |
|
|
387 | $PORT{$portid} = sub { |
474 | $PORT{$portid} = sub { |
388 | local $SELF = $port; |
475 | local $SELF = $port; |
389 | eval { |
476 | eval { &$cb }; _self_die if $@; |
390 | &$cb |
477 | }; |
391 | and kil $port; |
|
|
392 | }; |
478 | } |
393 | _self_die if $@; |
479 | } elsif (defined $_[0]) { |
394 | }; |
|
|
395 | } else { |
|
|
396 | my $self = $PORT_DATA{$portid} ||= do { |
480 | my $self = $PORT_DATA{$portid} ||= do { |
397 | my $self = bless { |
481 | my $self = bless [$PORT{$portid} || sub { }, { }, $port], "AnyEvent::MP::Port"; |
398 | id => $port, |
|
|
399 | }, "AnyEvent::MP::Port"; |
|
|
400 | |
482 | |
401 | $PORT{$portid} = sub { |
483 | $PORT{$portid} = sub { |
402 | local $SELF = $port; |
484 | local $SELF = $port; |
403 | |
485 | |
404 | eval { |
|
|
405 | for (@{ $self->{rc0}{$_[0]} }) { |
486 | if (my $cb = $self->[1]{$_[0]}) { |
406 | $_ && &{$_->[0]} |
487 | shift; |
407 | && undef $_; |
488 | eval { &$cb }; _self_die if $@; |
408 | } |
489 | } else { |
409 | |
|
|
410 | for (@{ $self->{rcv}{$_[0]} }) { |
|
|
411 | $_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1] |
|
|
412 | && &{$_->[0]} |
490 | &{ $self->[0] }; |
413 | && undef $_; |
|
|
414 | } |
|
|
415 | |
|
|
416 | for (@{ $self->{any} }) { |
|
|
417 | $_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1] |
|
|
418 | && &{$_->[0]} |
|
|
419 | && undef $_; |
|
|
420 | } |
491 | } |
421 | }; |
492 | }; |
422 | _self_die if $@; |
493 | |
|
|
494 | $self |
423 | }; |
495 | }; |
424 | |
496 | |
425 | $self |
|
|
426 | }; |
|
|
427 | |
|
|
428 | "AnyEvent::MP::Port" eq ref $self |
497 | "AnyEvent::MP::Port" eq ref $self |
429 | or Carp::croak "$port: rcv can only be called on message matching ports, caught"; |
498 | or Carp::croak "$port: rcv can only be called on message matching ports, caught"; |
430 | |
499 | |
431 | while (@_) { |
|
|
432 | my ($match, $cb) = splice @_, 0, 2; |
500 | my ($tag, $cb) = splice @_, 0, 2; |
433 | |
501 | |
434 | if (!ref $match) { |
502 | if (defined $cb) { |
435 | push @{ $self->{rc0}{$match} }, [$cb]; |
503 | $self->[1]{$tag} = $cb; |
436 | } elsif (("ARRAY" eq ref $match && !ref $match->[0])) { |
|
|
437 | my ($type, @match) = @$match; |
|
|
438 | @match |
|
|
439 | ? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match] |
|
|
440 | : push @{ $self->{rc0}{$match->[0]} }, [$cb]; |
|
|
441 | } else { |
504 | } else { |
442 | push @{ $self->{any} }, [$cb, $match]; |
505 | delete $self->[1]{$tag}; |
443 | } |
506 | } |
444 | } |
507 | } |
445 | } |
508 | } |
446 | |
509 | |
447 | $port |
510 | $port |
448 | } |
511 | } |
449 | |
512 | |
|
|
513 | =item peval $port, $coderef[, @args] |
|
|
514 | |
|
|
515 | Evaluates the given C<$codref> within the contetx of C<$port>, that is, |
|
|
516 | when the code throews an exception the C<$port> will be killed. |
|
|
517 | |
|
|
518 | Any remaining args will be passed to the callback. Any return values will |
|
|
519 | be returned to the caller. |
|
|
520 | |
|
|
521 | This is useful when you temporarily want to execute code in the context of |
|
|
522 | a port. |
|
|
523 | |
|
|
524 | Example: create a port and run some initialisation code in it's context. |
|
|
525 | |
|
|
526 | my $port = port { ... }; |
|
|
527 | |
|
|
528 | peval $port, sub { |
|
|
529 | init |
|
|
530 | or die "unable to init"; |
|
|
531 | }; |
|
|
532 | |
|
|
533 | =cut |
|
|
534 | |
|
|
535 | sub peval($$) { |
|
|
536 | local $SELF = shift; |
|
|
537 | my $cb = shift; |
|
|
538 | |
|
|
539 | if (wantarray) { |
|
|
540 | my @res = eval { &$cb }; |
|
|
541 | _self_die if $@; |
|
|
542 | @res |
|
|
543 | } else { |
|
|
544 | my $res = eval { &$cb }; |
|
|
545 | _self_die if $@; |
|
|
546 | $res |
|
|
547 | } |
|
|
548 | } |
|
|
549 | |
450 | =item $closure = psub { BLOCK } |
550 | =item $closure = psub { BLOCK } |
451 | |
551 | |
452 | Remembers C<$SELF> and creates a closure out of the BLOCK. When the |
552 | Remembers C<$SELF> and creates a closure out of the BLOCK. When the |
453 | closure is executed, sets up the environment in the same way as in C<rcv> |
553 | closure is executed, sets up the environment in the same way as in C<rcv> |
454 | callbacks, i.e. runtime errors will cause the port to get C<kil>ed. |
554 | callbacks, i.e. runtime errors will cause the port to get C<kil>ed. |
|
|
555 | |
|
|
556 | The effect is basically as if it returned C<< sub { peval $SELF, sub { |
|
|
557 | BLOCK }, @_ } >>. |
455 | |
558 | |
456 | This is useful when you register callbacks from C<rcv> callbacks: |
559 | This is useful when you register callbacks from C<rcv> callbacks: |
457 | |
560 | |
458 | rcv delayed_reply => sub { |
561 | rcv delayed_reply => sub { |
459 | my ($delay, @reply) = @_; |
562 | my ($delay, @reply) = @_; |
… | |
… | |
483 | $res |
586 | $res |
484 | } |
587 | } |
485 | } |
588 | } |
486 | } |
589 | } |
487 | |
590 | |
488 | =item $guard = mon $port, $cb->(@reason) |
591 | =item $guard = mon $port, $cb->(@reason) # call $cb when $port dies |
489 | |
592 | |
490 | =item $guard = mon $port, $rcvport |
593 | =item $guard = mon $port, $rcvport # kill $rcvport when $port dies |
491 | |
594 | |
492 | =item $guard = mon $port |
595 | =item $guard = mon $port # kill $SELF when $port dies |
493 | |
596 | |
494 | =item $guard = mon $port, $rcvport, @msg |
597 | =item $guard = mon $port, $rcvport, @msg # send a message when $port dies |
495 | |
598 | |
496 | Monitor the given port and do something when the port is killed, and |
599 | Monitor the given port and do something when the port is killed or |
497 | optionally return a guard that can be used to stop monitoring again. |
600 | messages to it were lost, and optionally return a guard that can be used |
|
|
601 | to stop monitoring again. |
498 | |
602 | |
499 | In the first form (callback), the callback is simply called with any |
603 | In the first form (callback), the callback is simply called with any |
500 | number of C<@reason> elements (no @reason means that the port was deleted |
604 | number of C<@reason> elements (no @reason means that the port was deleted |
501 | "normally"). Note also that I<< the callback B<must> never die >>, so use |
605 | "normally"). Note also that I<< the callback B<must> never die >>, so use |
502 | C<eval> if unsure. |
606 | C<eval> if unsure. |
503 | |
607 | |
504 | In the second form (another port given), the other port (C<$rcvport) |
608 | In the second form (another port given), the other port (C<$rcvport>) |
505 | will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on |
609 | will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on |
506 | "normal" kils nothing happens, while under all other conditions, the other |
610 | "normal" kils nothing happens, while under all other conditions, the other |
507 | port is killed with the same reason. |
611 | port is killed with the same reason. |
508 | |
612 | |
509 | The third form (kill self) is the same as the second form, except that |
613 | The third form (kill self) is the same as the second form, except that |
510 | C<$rvport> defaults to C<$SELF>. |
614 | C<$rvport> defaults to C<$SELF>. |
511 | |
615 | |
512 | In the last form (message), a message of the form C<@msg, @reason> will be |
616 | In the last form (message), a message of the form C<@msg, @reason> will be |
513 | C<snd>. |
617 | C<snd>. |
|
|
618 | |
|
|
619 | Monitoring-actions are one-shot: once messages are lost (and a monitoring |
|
|
620 | alert was raised), they are removed and will not trigger again. |
514 | |
621 | |
515 | As a rule of thumb, monitoring requests should always monitor a port from |
622 | As a rule of thumb, monitoring requests should always monitor a port from |
516 | a local port (or callback). The reason is that kill messages might get |
623 | a local port (or callback). The reason is that kill messages might get |
517 | lost, just like any other message. Another less obvious reason is that |
624 | lost, just like any other message. Another less obvious reason is that |
518 | even monitoring requests can get lost (for exmaple, when the connection |
625 | even monitoring requests can get lost (for example, when the connection |
519 | to the other node goes down permanently). When monitoring a port locally |
626 | to the other node goes down permanently). When monitoring a port locally |
520 | these problems do not exist. |
627 | these problems do not exist. |
521 | |
628 | |
|
|
629 | C<mon> effectively guarantees that, in the absence of hardware failures, |
|
|
630 | after starting the monitor, either all messages sent to the port will |
|
|
631 | arrive, or the monitoring action will be invoked after possible message |
|
|
632 | loss has been detected. No messages will be lost "in between" (after |
|
|
633 | the first lost message no further messages will be received by the |
|
|
634 | port). After the monitoring action was invoked, further messages might get |
|
|
635 | delivered again. |
|
|
636 | |
|
|
637 | Inter-host-connection timeouts and monitoring depend on the transport |
|
|
638 | used. The only transport currently implemented is TCP, and AnyEvent::MP |
|
|
639 | relies on TCP to detect node-downs (this can take 10-15 minutes on a |
|
|
640 | non-idle connection, and usually around two hours for idle connections). |
|
|
641 | |
|
|
642 | This means that monitoring is good for program errors and cleaning up |
|
|
643 | stuff eventually, but they are no replacement for a timeout when you need |
|
|
644 | to ensure some maximum latency. |
|
|
645 | |
522 | Example: call a given callback when C<$port> is killed. |
646 | Example: call a given callback when C<$port> is killed. |
523 | |
647 | |
524 | mon $port, sub { warn "port died because of <@_>\n" }; |
648 | mon $port, sub { warn "port died because of <@_>\n" }; |
525 | |
649 | |
526 | Example: kill ourselves when C<$port> is killed abnormally. |
650 | Example: kill ourselves when C<$port> is killed abnormally. |
… | |
… | |
532 | mon $port, $self => "restart"; |
656 | mon $port, $self => "restart"; |
533 | |
657 | |
534 | =cut |
658 | =cut |
535 | |
659 | |
536 | sub mon { |
660 | sub mon { |
537 | my ($noderef, $port) = split /#/, shift, 2; |
661 | my ($nodeid, $port) = split /#/, shift, 2; |
538 | |
662 | |
539 | my $node = $NODE{$noderef} || add_node $noderef; |
663 | my $node = $NODE{$nodeid} || add_node $nodeid; |
540 | |
664 | |
541 | my $cb = @_ ? $_[0] : $SELF || Carp::croak 'mon: called with one argument only, but $SELF not set,'; |
665 | my $cb = @_ ? shift : $SELF || Carp::croak 'mon: called with one argument only, but $SELF not set,'; |
542 | |
666 | |
543 | unless (ref $cb) { |
667 | unless (ref $cb) { |
544 | if (@_) { |
668 | if (@_) { |
545 | # send a kill info message |
669 | # send a kill info message |
546 | my (@msg) = @_; |
670 | my (@msg) = ($cb, @_); |
547 | $cb = sub { snd @msg, @_ }; |
671 | $cb = sub { snd @msg, @_ }; |
548 | } else { |
672 | } else { |
549 | # simply kill other port |
673 | # simply kill other port |
550 | my $port = $cb; |
674 | my $port = $cb; |
551 | $cb = sub { kil $port, @_ if @_ }; |
675 | $cb = sub { kil $port, @_ if @_ }; |
… | |
… | |
553 | } |
677 | } |
554 | |
678 | |
555 | $node->monitor ($port, $cb); |
679 | $node->monitor ($port, $cb); |
556 | |
680 | |
557 | defined wantarray |
681 | defined wantarray |
558 | and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) } |
682 | and ($cb += 0, Guard::guard { $node->unmonitor ($port, $cb) }) |
559 | } |
683 | } |
560 | |
684 | |
561 | =item $guard = mon_guard $port, $ref, $ref... |
685 | =item $guard = mon_guard $port, $ref, $ref... |
562 | |
686 | |
563 | Monitors the given C<$port> and keeps the passed references. When the port |
687 | Monitors the given C<$port> and keeps the passed references. When the port |
564 | is killed, the references will be freed. |
688 | is killed, the references will be freed. |
565 | |
689 | |
566 | Optionally returns a guard that will stop the monitoring. |
690 | Optionally returns a guard that will stop the monitoring. |
567 | |
691 | |
568 | This function is useful when you create e.g. timers or other watchers and |
692 | This function is useful when you create e.g. timers or other watchers and |
569 | want to free them when the port gets killed: |
693 | want to free them when the port gets killed (note the use of C<psub>): |
570 | |
694 | |
571 | $port->rcv (start => sub { |
695 | $port->rcv (start => sub { |
572 | my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub { |
696 | my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub { |
573 | undef $timer if 0.9 < rand; |
697 | undef $timer if 0.9 < rand; |
574 | }); |
698 | }); |
575 | }); |
699 | }); |
576 | |
700 | |
577 | =cut |
701 | =cut |
… | |
… | |
586 | |
710 | |
587 | =item kil $port[, @reason] |
711 | =item kil $port[, @reason] |
588 | |
712 | |
589 | Kill the specified port with the given C<@reason>. |
713 | Kill the specified port with the given C<@reason>. |
590 | |
714 | |
591 | If no C<@reason> is specified, then the port is killed "normally" (linked |
715 | If no C<@reason> is specified, then the port is killed "normally" - |
592 | ports will not be kileld, or even notified). |
716 | monitor callback will be invoked, but the kil will not cause linked ports |
|
|
717 | (C<mon $mport, $lport> form) to get killed. |
593 | |
718 | |
594 | Otherwise, linked ports get killed with the same reason (second form of |
719 | If a C<@reason> is specified, then linked ports (C<mon $mport, $lport> |
595 | C<mon>, see below). |
720 | form) get killed with the same reason. |
596 | |
721 | |
597 | Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks |
722 | Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks |
598 | will be reported as reason C<< die => $@ >>. |
723 | will be reported as reason C<< die => $@ >>. |
599 | |
724 | |
600 | Transport/communication errors are reported as C<< transport_error => |
725 | Transport/communication errors are reported as C<< transport_error => |
601 | $message >>. |
726 | $message >>. |
602 | |
727 | |
|
|
728 | =cut |
|
|
729 | |
|
|
730 | =item $port = spawn $node, $initfunc[, @initdata] |
|
|
731 | |
|
|
732 | Creates a port on the node C<$node> (which can also be a port ID, in which |
|
|
733 | case it's the node where that port resides). |
|
|
734 | |
|
|
735 | The port ID of the newly created port is returned immediately, and it is |
|
|
736 | possible to immediately start sending messages or to monitor the port. |
|
|
737 | |
|
|
738 | After the port has been created, the init function is called on the remote |
|
|
739 | node, in the same context as a C<rcv> callback. This function must be a |
|
|
740 | fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To |
|
|
741 | specify a function in the main program, use C<::name>. |
|
|
742 | |
|
|
743 | If the function doesn't exist, then the node tries to C<require> |
|
|
744 | the package, then the package above the package and so on (e.g. |
|
|
745 | C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function |
|
|
746 | exists or it runs out of package names. |
|
|
747 | |
|
|
748 | The init function is then called with the newly-created port as context |
|
|
749 | object (C<$SELF>) and the C<@initdata> values as arguments. It I<must> |
|
|
750 | call one of the C<rcv> functions to set callbacks on C<$SELF>, otherwise |
|
|
751 | the port might not get created. |
|
|
752 | |
|
|
753 | A common idiom is to pass a local port, immediately monitor the spawned |
|
|
754 | port, and in the remote init function, immediately monitor the passed |
|
|
755 | local port. This two-way monitoring ensures that both ports get cleaned up |
|
|
756 | when there is a problem. |
|
|
757 | |
|
|
758 | C<spawn> guarantees that the C<$initfunc> has no visible effects on the |
|
|
759 | caller before C<spawn> returns (by delaying invocation when spawn is |
|
|
760 | called for the local node). |
|
|
761 | |
|
|
762 | Example: spawn a chat server port on C<$othernode>. |
|
|
763 | |
|
|
764 | # this node, executed from within a port context: |
|
|
765 | my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF; |
|
|
766 | mon $server; |
|
|
767 | |
|
|
768 | # init function on C<$othernode> |
|
|
769 | sub connect { |
|
|
770 | my ($srcport) = @_; |
|
|
771 | |
|
|
772 | mon $srcport; |
|
|
773 | |
|
|
774 | rcv $SELF, sub { |
|
|
775 | ... |
|
|
776 | }; |
|
|
777 | } |
|
|
778 | |
|
|
779 | =cut |
|
|
780 | |
|
|
781 | sub _spawn { |
|
|
782 | my $port = shift; |
|
|
783 | my $init = shift; |
|
|
784 | |
|
|
785 | # rcv will create the actual port |
|
|
786 | local $SELF = "$NODE#$port"; |
|
|
787 | eval { |
|
|
788 | &{ load_func $init } |
|
|
789 | }; |
|
|
790 | _self_die if $@; |
|
|
791 | } |
|
|
792 | |
|
|
793 | sub spawn(@) { |
|
|
794 | my ($nodeid, undef) = split /#/, shift, 2; |
|
|
795 | |
|
|
796 | my $id = $RUNIQ . ++$ID; |
|
|
797 | |
|
|
798 | $_[0] =~ /::/ |
|
|
799 | or Carp::croak "spawn init function must be a fully-qualified name, caught"; |
|
|
800 | |
|
|
801 | snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_; |
|
|
802 | |
|
|
803 | "$nodeid#$id" |
|
|
804 | } |
|
|
805 | |
|
|
806 | |
|
|
807 | =item after $timeout, @msg |
|
|
808 | |
|
|
809 | =item after $timeout, $callback |
|
|
810 | |
|
|
811 | Either sends the given message, or call the given callback, after the |
|
|
812 | specified number of seconds. |
|
|
813 | |
|
|
814 | This is simply a utility function that comes in handy at times - the |
|
|
815 | AnyEvent::MP author is not convinced of the wisdom of having it, though, |
|
|
816 | so it may go away in the future. |
|
|
817 | |
|
|
818 | =cut |
|
|
819 | |
|
|
820 | sub after($@) { |
|
|
821 | my ($timeout, @action) = @_; |
|
|
822 | |
|
|
823 | my $t; $t = AE::timer $timeout, 0, sub { |
|
|
824 | undef $t; |
|
|
825 | ref $action[0] |
|
|
826 | ? $action[0]() |
|
|
827 | : snd @action; |
|
|
828 | }; |
|
|
829 | } |
|
|
830 | |
|
|
831 | =item cal $port, @msg, $callback[, $timeout] |
|
|
832 | |
|
|
833 | A simple form of RPC - sends a message to the given C<$port> with the |
|
|
834 | given contents (C<@msg>), but adds a reply port to the message. |
|
|
835 | |
|
|
836 | The reply port is created temporarily just for the purpose of receiving |
|
|
837 | the reply, and will be C<kil>ed when no longer needed. |
|
|
838 | |
|
|
839 | A reply message sent to the port is passed to the C<$callback> as-is. |
|
|
840 | |
|
|
841 | If an optional time-out (in seconds) is given and it is not C<undef>, |
|
|
842 | then the callback will be called without any arguments after the time-out |
|
|
843 | elapsed and the port is C<kil>ed. |
|
|
844 | |
|
|
845 | If no time-out is given (or it is C<undef>), then the local port will |
|
|
846 | monitor the remote port instead, so it eventually gets cleaned-up. |
|
|
847 | |
|
|
848 | Currently this function returns the temporary port, but this "feature" |
|
|
849 | might go in future versions unless you can make a convincing case that |
|
|
850 | this is indeed useful for something. |
|
|
851 | |
|
|
852 | =cut |
|
|
853 | |
|
|
854 | sub cal(@) { |
|
|
855 | my $timeout = ref $_[-1] ? undef : pop; |
|
|
856 | my $cb = pop; |
|
|
857 | |
|
|
858 | my $port = port { |
|
|
859 | undef $timeout; |
|
|
860 | kil $SELF; |
|
|
861 | &$cb; |
|
|
862 | }; |
|
|
863 | |
|
|
864 | if (defined $timeout) { |
|
|
865 | $timeout = AE::timer $timeout, 0, sub { |
|
|
866 | undef $timeout; |
|
|
867 | kil $port; |
|
|
868 | $cb->(); |
|
|
869 | }; |
|
|
870 | } else { |
|
|
871 | mon $_[0], sub { |
|
|
872 | kil $port; |
|
|
873 | $cb->(); |
|
|
874 | }; |
|
|
875 | } |
|
|
876 | |
|
|
877 | push @_, $port; |
|
|
878 | &snd; |
|
|
879 | |
|
|
880 | $port |
|
|
881 | } |
|
|
882 | |
603 | =back |
883 | =back |
604 | |
884 | |
605 | =head1 NODE MESSAGES |
885 | =head1 DISTRIBUTED DATABASE |
606 | |
886 | |
607 | Nodes understand the following messages sent to them. Many of them take |
887 | AnyEvent::MP comes with a simple distributed database. The database will |
608 | arguments called C<@reply>, which will simply be used to compose a reply |
888 | be mirrored asynchronously at all global nodes. Other nodes bind to one of |
609 | message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and |
889 | the global nodes for their needs. |
610 | the remaining arguments are simply the message data. |
|
|
611 | |
890 | |
612 | While other messages exist, they are not public and subject to change. |
891 | The database consists of a two-level hash - a hash contains a hash which |
|
|
892 | contains values. |
613 | |
893 | |
|
|
894 | The top level hash key is called "family", and the second-level hash key |
|
|
895 | is called "subkey" or simply "key". |
|
|
896 | |
|
|
897 | The family must be alphanumeric, i.e. start with a letter and consist |
|
|
898 | of letters, digits, underscores and colons (C<[A-Za-z][A-Za-z0-9_:]*>, |
|
|
899 | pretty much like Perl module names. |
|
|
900 | |
|
|
901 | As the family namespace is global, it is recommended to prefix family names |
|
|
902 | with the name of the application or module using it. |
|
|
903 | |
|
|
904 | The subkeys must be non-empty strings, with no further restrictions. |
|
|
905 | |
|
|
906 | The values should preferably be strings, but other perl scalars should |
|
|
907 | work as well (such as undef, arrays and hashes). |
|
|
908 | |
|
|
909 | Every database entry is owned by one node - adding the same family/subkey |
|
|
910 | combination on multiple nodes will not cause discomfort for AnyEvent::MP, |
|
|
911 | but the result might be nondeterministic, i.e. the key might have |
|
|
912 | different values on different nodes. |
|
|
913 | |
|
|
914 | Different subkeys in the same family can be owned by different nodes |
|
|
915 | without problems, and in fact, this is the common method to create worker |
|
|
916 | pools. For example, a worker port for image scaling might do this: |
|
|
917 | |
|
|
918 | db_set my_image_scalers => $port; |
|
|
919 | |
|
|
920 | And clients looking for an image scaler will want to get the |
|
|
921 | C<my_image_scalers> keys: |
|
|
922 | |
|
|
923 | db_keys "my_image_scalers" => 60 => sub { |
|
|
924 | #d##TODO# |
|
|
925 | |
614 | =over 4 |
926 | =over |
615 | |
927 | |
616 | =cut |
928 | =item db_set $family => $subkey [=> $value] |
617 | |
929 | |
618 | =item lookup => $name, @reply |
930 | Sets (or replaces) a key to the database - if C<$value> is omitted, |
|
|
931 | C<undef> is used instead. |
619 | |
932 | |
620 | Replies with the port ID of the specified well-known port, or C<undef>. |
933 | =item db_del $family => $subkey |
621 | |
934 | |
622 | =item devnull => ... |
935 | Deletes a key from the database. |
623 | |
936 | |
624 | Generic data sink/CPU heat conversion. |
937 | =item $guard = db_reg $family => $subkey [=> $value] |
625 | |
938 | |
626 | =item relay => $port, @msg |
939 | Sets the key on the database and returns a guard. When the guard is |
|
|
940 | destroyed, the key is deleted from the database. If C<$value> is missing, |
|
|
941 | then C<undef> is used. |
627 | |
942 | |
628 | Simply forwards the message to the given port. |
943 | =cut |
629 | |
|
|
630 | =item eval => $string[ @reply] |
|
|
631 | |
|
|
632 | Evaluates the given string. If C<@reply> is given, then a message of the |
|
|
633 | form C<@reply, $@, @evalres> is sent. |
|
|
634 | |
|
|
635 | Example: crash another node. |
|
|
636 | |
|
|
637 | snd $othernode, eval => "exit"; |
|
|
638 | |
|
|
639 | =item time => @reply |
|
|
640 | |
|
|
641 | Replies the the current node time to C<@reply>. |
|
|
642 | |
|
|
643 | Example: tell the current node to send the current time to C<$myport> in a |
|
|
644 | C<timereply> message. |
|
|
645 | |
|
|
646 | snd $NODE, time => $myport, timereply => 1, 2; |
|
|
647 | # => snd $myport, timereply => 1, 2, <time> |
|
|
648 | |
944 | |
649 | =back |
945 | =back |
650 | |
946 | |
651 | =head1 AnyEvent::MP vs. Distributed Erlang |
947 | =head1 AnyEvent::MP vs. Distributed Erlang |
652 | |
948 | |
653 | AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node |
949 | AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node |
654 | == aemp node, Erlang process == aemp port), so many of the documents and |
950 | == aemp node, Erlang process == aemp port), so many of the documents and |
655 | programming techniques employed by Erlang apply to AnyEvent::MP. Here is a |
951 | programming techniques employed by Erlang apply to AnyEvent::MP. Here is a |
656 | sample: |
952 | sample: |
657 | |
953 | |
658 | http://www.Erlang.se/doc/programming_rules.shtml |
954 | http://www.erlang.se/doc/programming_rules.shtml |
659 | http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4 |
955 | http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4 |
660 | http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6 |
956 | http://erlang.org/download/erlang-book-part1.pdf # chapters 5 and 6 |
661 | http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5 |
957 | http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5 |
662 | |
958 | |
663 | Despite the similarities, there are also some important differences: |
959 | Despite the similarities, there are also some important differences: |
664 | |
960 | |
665 | =over 4 |
961 | =over 4 |
666 | |
962 | |
667 | =item * Node references contain the recipe on how to contact them. |
963 | =item * Node IDs are arbitrary strings in AEMP. |
668 | |
964 | |
669 | Erlang relies on special naming and DNS to work everywhere in the |
965 | Erlang relies on special naming and DNS to work everywhere in the same |
670 | same way. AEMP relies on each node knowing it's own address(es), with |
966 | way. AEMP relies on each node somehow knowing its own address(es) (e.g. by |
671 | convenience functionality. |
967 | configuration or DNS), and possibly the addresses of some seed nodes, but |
|
|
968 | will otherwise discover other nodes (and their IDs) itself. |
672 | |
969 | |
673 | This means that AEMP requires a less tightly controlled environment at the |
970 | =item * Erlang has a "remote ports are like local ports" philosophy, AEMP |
674 | cost of longer node references and a slightly higher management overhead. |
971 | uses "local ports are like remote ports". |
|
|
972 | |
|
|
973 | The failure modes for local ports are quite different (runtime errors |
|
|
974 | only) then for remote ports - when a local port dies, you I<know> it dies, |
|
|
975 | when a connection to another node dies, you know nothing about the other |
|
|
976 | port. |
|
|
977 | |
|
|
978 | Erlang pretends remote ports are as reliable as local ports, even when |
|
|
979 | they are not. |
|
|
980 | |
|
|
981 | AEMP encourages a "treat remote ports differently" philosophy, with local |
|
|
982 | ports being the special case/exception, where transport errors cannot |
|
|
983 | occur. |
675 | |
984 | |
676 | =item * Erlang uses processes and a mailbox, AEMP does not queue. |
985 | =item * Erlang uses processes and a mailbox, AEMP does not queue. |
677 | |
986 | |
678 | Erlang uses processes that selctively receive messages, and therefore |
987 | Erlang uses processes that selectively receive messages out of order, and |
679 | needs a queue. AEMP is event based, queuing messages would serve no useful |
988 | therefore needs a queue. AEMP is event based, queuing messages would serve |
680 | purpose. |
989 | no useful purpose. For the same reason the pattern-matching abilities |
|
|
990 | of AnyEvent::MP are more limited, as there is little need to be able to |
|
|
991 | filter messages without dequeuing them. |
681 | |
992 | |
682 | (But see L<Coro::MP> for a more Erlang-like process model on top of AEMP). |
993 | This is not a philosophical difference, but simply stems from AnyEvent::MP |
|
|
994 | being event-based, while Erlang is process-based. |
|
|
995 | |
|
|
996 | You cna have a look at L<Coro::MP> for a more Erlang-like process model on |
|
|
997 | top of AEMP and Coro threads. |
683 | |
998 | |
684 | =item * Erlang sends are synchronous, AEMP sends are asynchronous. |
999 | =item * Erlang sends are synchronous, AEMP sends are asynchronous. |
685 | |
1000 | |
686 | Sending messages in Erlang is synchronous and blocks the process. AEMP |
1001 | Sending messages in Erlang is synchronous and blocks the process until |
687 | sends are immediate, connection establishment is handled in the |
1002 | a conenction has been established and the message sent (and so does not |
688 | background. |
1003 | need a queue that can overflow). AEMP sends return immediately, connection |
|
|
1004 | establishment is handled in the background. |
689 | |
1005 | |
690 | =item * Erlang can silently lose messages, AEMP cannot. |
1006 | =item * Erlang suffers from silent message loss, AEMP does not. |
691 | |
1007 | |
692 | Erlang makes few guarantees on messages delivery - messages can get lost |
1008 | Erlang implements few guarantees on messages delivery - messages can get |
693 | without any of the processes realising it (i.e. you send messages a, b, |
1009 | lost without any of the processes realising it (i.e. you send messages a, |
694 | and c, and the other side only receives messages a and c). |
1010 | b, and c, and the other side only receives messages a and c). |
695 | |
1011 | |
696 | AEMP guarantees correct ordering, and the guarantee that there are no |
1012 | AEMP guarantees (modulo hardware errors) correct ordering, and the |
|
|
1013 | guarantee that after one message is lost, all following ones sent to the |
|
|
1014 | same port are lost as well, until monitoring raises an error, so there are |
697 | holes in the message sequence. |
1015 | no silent "holes" in the message sequence. |
698 | |
1016 | |
699 | =item * In Erlang, processes can be declared dead and later be found to be |
1017 | If you want your software to be very reliable, you have to cope with |
700 | alive. |
1018 | corrupted and even out-of-order messages in both Erlang and AEMP. AEMP |
701 | |
1019 | simply tries to work better in common error cases, such as when a network |
702 | In Erlang it can happen that a monitored process is declared dead and |
1020 | link goes down. |
703 | linked processes get killed, but later it turns out that the process is |
|
|
704 | still alive - and can receive messages. |
|
|
705 | |
|
|
706 | In AEMP, when port monitoring detects a port as dead, then that port will |
|
|
707 | eventually be killed - it cannot happen that a node detects a port as dead |
|
|
708 | and then later sends messages to it, finding it is still alive. |
|
|
709 | |
1021 | |
710 | =item * Erlang can send messages to the wrong port, AEMP does not. |
1022 | =item * Erlang can send messages to the wrong port, AEMP does not. |
711 | |
1023 | |
712 | In Erlang it is quite possible that a node that restarts reuses a process |
1024 | In Erlang it is quite likely that a node that restarts reuses an Erlang |
713 | ID known to other nodes for a completely different process, causing |
1025 | process ID known to other nodes for a completely different process, |
714 | messages destined for that process to end up in an unrelated process. |
1026 | causing messages destined for that process to end up in an unrelated |
|
|
1027 | process. |
715 | |
1028 | |
716 | AEMP never reuses port IDs, so old messages or old port IDs floating |
1029 | AEMP does not reuse port IDs, so old messages or old port IDs floating |
717 | around in the network will not be sent to an unrelated port. |
1030 | around in the network will not be sent to an unrelated port. |
718 | |
1031 | |
719 | =item * Erlang uses unprotected connections, AEMP uses secure |
1032 | =item * Erlang uses unprotected connections, AEMP uses secure |
720 | authentication and can use TLS. |
1033 | authentication and can use TLS. |
721 | |
1034 | |
722 | AEMP can use a proven protocol - SSL/TLS - to protect connections and |
1035 | AEMP can use a proven protocol - TLS - to protect connections and |
723 | securely authenticate nodes. |
1036 | securely authenticate nodes. |
724 | |
1037 | |
725 | =item * The AEMP protocol is optimised for both text-based and binary |
1038 | =item * The AEMP protocol is optimised for both text-based and binary |
726 | communications. |
1039 | communications. |
727 | |
1040 | |
728 | The AEMP protocol, unlike the Erlang protocol, supports both |
1041 | The AEMP protocol, unlike the Erlang protocol, supports both programming |
729 | language-independent text-only protocols (good for debugging) and binary, |
1042 | language independent text-only protocols (good for debugging), and binary, |
730 | language-specific serialisers (e.g. Storable). |
1043 | language-specific serialisers (e.g. Storable). By default, unless TLS is |
|
|
1044 | used, the protocol is actually completely text-based. |
731 | |
1045 | |
732 | It has also been carefully designed to be implementable in other languages |
1046 | It has also been carefully designed to be implementable in other languages |
733 | with a minimum of work while gracefully degrading fucntionality to make the |
1047 | with a minimum of work while gracefully degrading functionality to make the |
734 | protocol simple. |
1048 | protocol simple. |
735 | |
1049 | |
736 | =item * AEMP has more flexible monitoring options than Erlang. |
1050 | =item * AEMP has more flexible monitoring options than Erlang. |
737 | |
1051 | |
738 | In Erlang, you can chose to receive I<all> exit signals as messages |
1052 | In Erlang, you can chose to receive I<all> exit signals as messages or |
739 | or I<none>, there is no in-between, so monitoring single processes is |
1053 | I<none>, there is no in-between, so monitoring single Erlang processes is |
740 | difficult to implement. Monitoring in AEMP is more flexible than in |
1054 | difficult to implement. |
741 | Erlang, as one can choose between automatic kill, exit message or callback |
1055 | |
742 | on a per-process basis. |
1056 | Monitoring in AEMP is more flexible than in Erlang, as one can choose |
|
|
1057 | between automatic kill, exit message or callback on a per-port basis. |
743 | |
1058 | |
744 | =item * Erlang tries to hide remote/local connections, AEMP does not. |
1059 | =item * Erlang tries to hide remote/local connections, AEMP does not. |
745 | |
1060 | |
746 | Monitoring in Erlang is not an indicator of process death/crashes, |
1061 | Monitoring in Erlang is not an indicator of process death/crashes, in the |
747 | as linking is (except linking is unreliable in Erlang). |
1062 | same way as linking is (except linking is unreliable in Erlang). |
748 | |
1063 | |
749 | In AEMP, you don't "look up" registered port names or send to named ports |
1064 | In AEMP, you don't "look up" registered port names or send to named ports |
750 | that might or might not be persistent. Instead, you normally spawn a port |
1065 | that might or might not be persistent. Instead, you normally spawn a port |
751 | on the remote node. The init function monitors the you, and you monitor |
1066 | on the remote node. The init function monitors you, and you monitor the |
752 | the remote port. Since both monitors are local to the node, they are much |
1067 | remote port. Since both monitors are local to the node, they are much more |
753 | more reliable. |
1068 | reliable (no need for C<spawn_link>). |
754 | |
1069 | |
755 | This also saves round-trips and avoids sending messages to the wrong port |
1070 | This also saves round-trips and avoids sending messages to the wrong port |
756 | (hard to do in Erlang). |
1071 | (hard to do in Erlang). |
757 | |
1072 | |
758 | =back |
1073 | =back |
759 | |
1074 | |
|
|
1075 | =head1 RATIONALE |
|
|
1076 | |
|
|
1077 | =over 4 |
|
|
1078 | |
|
|
1079 | =item Why strings for port and node IDs, why not objects? |
|
|
1080 | |
|
|
1081 | We considered "objects", but found that the actual number of methods |
|
|
1082 | that can be called are quite low. Since port and node IDs travel over |
|
|
1083 | the network frequently, the serialising/deserialising would add lots of |
|
|
1084 | overhead, as well as having to keep a proxy object everywhere. |
|
|
1085 | |
|
|
1086 | Strings can easily be printed, easily serialised etc. and need no special |
|
|
1087 | procedures to be "valid". |
|
|
1088 | |
|
|
1089 | And as a result, a port with just a default receiver consists of a single |
|
|
1090 | code reference stored in a global hash - it can't become much cheaper. |
|
|
1091 | |
|
|
1092 | =item Why favour JSON, why not a real serialising format such as Storable? |
|
|
1093 | |
|
|
1094 | In fact, any AnyEvent::MP node will happily accept Storable as framing |
|
|
1095 | format, but currently there is no way to make a node use Storable by |
|
|
1096 | default (although all nodes will accept it). |
|
|
1097 | |
|
|
1098 | The default framing protocol is JSON because a) JSON::XS is many times |
|
|
1099 | faster for small messages and b) most importantly, after years of |
|
|
1100 | experience we found that object serialisation is causing more problems |
|
|
1101 | than it solves: Just like function calls, objects simply do not travel |
|
|
1102 | easily over the network, mostly because they will always be a copy, so you |
|
|
1103 | always have to re-think your design. |
|
|
1104 | |
|
|
1105 | Keeping your messages simple, concentrating on data structures rather than |
|
|
1106 | objects, will keep your messages clean, tidy and efficient. |
|
|
1107 | |
|
|
1108 | =back |
|
|
1109 | |
760 | =head1 SEE ALSO |
1110 | =head1 SEE ALSO |
|
|
1111 | |
|
|
1112 | L<AnyEvent::MP::Intro> - a gentle introduction. |
|
|
1113 | |
|
|
1114 | L<AnyEvent::MP::Kernel> - more, lower-level, stuff. |
|
|
1115 | |
|
|
1116 | L<AnyEvent::MP::Global> - network maintenance and port groups, to find |
|
|
1117 | your applications. |
|
|
1118 | |
|
|
1119 | L<AnyEvent::MP::DataConn> - establish data connections between nodes. |
|
|
1120 | |
|
|
1121 | L<AnyEvent::MP::LogCatcher> - simple service to display log messages from |
|
|
1122 | all nodes. |
761 | |
1123 | |
762 | L<AnyEvent>. |
1124 | L<AnyEvent>. |
763 | |
1125 | |
764 | =head1 AUTHOR |
1126 | =head1 AUTHOR |
765 | |
1127 | |