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 | |
13 | $SELF # receiving/own port id in rcv callbacks |
12 | $SELF # receiving/own port id in rcv callbacks |
14 | |
13 | |
15 | # initialise the node so it can send/receive messages |
14 | # initialise the node so it can send/receive messages |
16 | initialise_node; |
15 | configure; |
17 | |
16 | |
18 | # ports are message endpoints |
17 | # ports are message destinations |
19 | |
18 | |
20 | # sending messages |
19 | # sending messages |
21 | snd $port, type => data...; |
20 | snd $port, type => data...; |
22 | snd $port, @msg; |
21 | snd $port, @msg; |
23 | snd @msg_with_first_element_being_a_port; |
22 | snd @msg_with_first_element_being_a_port; |
24 | |
23 | |
25 | # creating/using ports, the simple way |
24 | # creating/using ports, the simple way |
26 | my $simple_port = port { my @msg = @_; 0 }; |
25 | my $simple_port = port { my @msg = @_ }; |
27 | |
26 | |
28 | # creating/using ports, tagged message matching |
27 | # creating/using ports, tagged message matching |
29 | my $port = port; |
28 | my $port = port; |
30 | rcv $port, ping => sub { snd $_[0], "pong"; 0 }; |
29 | rcv $port, ping => sub { snd $_[0], "pong" }; |
31 | rcv $port, pong => sub { warn "pong received\n"; 0 }; |
30 | rcv $port, pong => sub { warn "pong received\n" }; |
32 | |
31 | |
33 | # create a port on another node |
32 | # create a port on another node |
34 | my $port = spawn $node, $initfunc, @initdata; |
33 | my $port = spawn $node, $initfunc, @initdata; |
35 | |
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 |
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38 | |
36 | # monitoring |
39 | # monitoring |
37 | mon $port, $cb->(@msg) # callback is invoked on death |
40 | mon $port, $cb->(@msg) # callback is invoked on death |
38 | mon $port, $otherport # kill otherport on abnormal death |
41 | mon $port, $localport # kill localport on abnormal death |
39 | mon $port, $otherport, @msg # send message on death |
42 | mon $port, $localport, @msg # send message on death |
40 | |
43 | |
41 | =head1 CURRENT STATUS |
44 | # temporarily execute code in port context |
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45 | peval $port, sub { die "kill the port!" }; |
42 | |
46 | |
43 | AnyEvent::MP - stable API, should work |
47 | # execute callbacks in $SELF port context |
44 | AnyEvent::MP::Intro - outdated |
48 | my $timer = AE::timer 1, 0, psub { |
45 | AnyEvent::MP::Kernel - WIP |
49 | die "kill the port, delayed"; |
46 | AnyEvent::MP::Transport - mostly stable |
50 | }; |
47 | |
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48 | stay tuned. |
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49 | |
51 | |
50 | =head1 DESCRIPTION |
52 | =head1 DESCRIPTION |
51 | |
53 | |
52 | This module (-family) implements a simple message passing framework. |
54 | This module (-family) implements a simple message passing framework. |
53 | |
55 | |
54 | Despite its simplicity, you can securely message other processes running |
56 | Despite its simplicity, you can securely message other processes running |
55 | on the same or other hosts. |
57 | on the same or other hosts, and you can supervise entities remotely. |
56 | |
58 | |
57 | For an introduction to this module family, see the L<AnyEvent::MP::Intro> |
59 | For an introduction to this module family, see the L<AnyEvent::MP::Intro> |
58 | manual page. |
60 | manual page and the examples under F<eg/>. |
59 | |
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60 | At the moment, this module family is severly broken and underdocumented, |
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61 | so do not use. This was uploaded mainly to reserve the CPAN namespace - |
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62 | stay tuned! |
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63 | |
61 | |
64 | =head1 CONCEPTS |
62 | =head1 CONCEPTS |
65 | |
63 | |
66 | =over 4 |
64 | =over 4 |
67 | |
65 | |
68 | =item port |
66 | =item port |
69 | |
67 | |
70 | A port is something you can send messages to (with the C<snd> function). |
68 | Not to be confused with a TCP port, a "port" is something you can send |
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69 | messages to (with the C<snd> function). |
71 | |
70 | |
72 | Ports allow you to register C<rcv> handlers that can match all or just |
71 | Ports allow you to register C<rcv> handlers that can match all or just |
73 | some messages. Messages send to ports will not be queued, regardless of |
72 | some messages. Messages send to ports will not be queued, regardless of |
74 | anything was listening for them or not. |
73 | anything was listening for them or not. |
75 | |
74 | |
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75 | Ports are represented by (printable) strings called "port IDs". |
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76 | |
76 | =item port ID - C<noderef#portname> |
77 | =item port ID - C<nodeid#portname> |
77 | |
78 | |
78 | A port ID is the concatenation of a noderef, a hash-mark (C<#>) as |
79 | A port ID is the concatenation of a node ID, a hash-mark (C<#>) |
79 | separator, and a port name (a printable string of unspecified format). An |
80 | as separator, and a port name (a printable string of unspecified |
80 | exception is the the node port, whose ID is identical to its node |
81 | format created by AnyEvent::MP). |
81 | reference. |
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82 | |
82 | |
83 | =item node |
83 | =item node |
84 | |
84 | |
85 | A node is a single process containing at least one port - the node port, |
85 | A node is a single process containing at least one port - the node port, |
86 | which provides nodes to manage each other remotely, and to create new |
86 | which enables nodes to manage each other remotely, and to create new |
87 | ports. |
87 | ports. |
88 | |
88 | |
89 | Nodes are either private (single-process only), slaves (can only talk to |
89 | Nodes are either public (have one or more listening ports) or private |
90 | public nodes, but do not need an open port) or public nodes (connectable |
90 | (no listening ports). Private nodes cannot talk to other private nodes |
91 | from any other node). |
91 | currently, but all nodes can talk to public nodes. |
92 | |
92 | |
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93 | Nodes is represented by (printable) strings called "node IDs". |
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94 | |
93 | =item node ID - C<[a-za-Z0-9_\-.:]+> |
95 | =item node ID - C<[A-Za-z0-9_\-.:]*> |
94 | |
96 | |
95 | A node ID is a string that uniquely identifies the node within a |
97 | A node ID is a string that uniquely identifies the node within a |
96 | network. Depending on the configuration used, node IDs can look like a |
98 | network. Depending on the configuration used, node IDs can look like a |
97 | hostname, a hostname and a port, or a random string. AnyEvent::MP itself |
99 | hostname, a hostname and a port, or a random string. AnyEvent::MP itself |
98 | doesn't interpret node IDs in any way. |
100 | doesn't interpret node IDs in any way except to uniquely identify a node. |
99 | |
101 | |
100 | =item binds - C<ip:port> |
102 | =item binds - C<ip:port> |
101 | |
103 | |
102 | Nodes can only talk to each other by creating some kind of connection to |
104 | Nodes can only talk to each other by creating some kind of connection to |
103 | each other. To do this, nodes should listen on one or more local transport |
105 | each other. To do this, nodes should listen on one or more local transport |
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106 | endpoints - binds. |
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107 | |
104 | endpoints - binds. Currently, only standard C<ip:port> specifications can |
108 | Currently, only standard C<ip:port> specifications can be used, which |
105 | be used, which specify TCP ports to listen on. |
109 | specify TCP ports to listen on. So a bind is basically just a tcp socket |
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110 | in listening mode thta accepts conenctions form other nodes. |
106 | |
111 | |
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112 | =item seed nodes |
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113 | |
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114 | When a node starts, it knows nothing about the network it is in - it |
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115 | needs to connect to at least one other node that is already in the |
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116 | network. These other nodes are called "seed nodes". |
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117 | |
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118 | Seed nodes themselves are not special - they are seed nodes only because |
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119 | some other node I<uses> them as such, but any node can be used as seed |
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120 | node for other nodes, and eahc node cna use a different set of seed nodes. |
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121 | |
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122 | In addition to discovering the network, seed nodes are also used to |
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123 | maintain the network - all nodes using the same seed node form are part of |
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124 | the same network. If a network is split into multiple subnets because e.g. |
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125 | the network link between the parts goes down, then using the same seed |
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126 | nodes for all nodes ensures that eventually the subnets get merged again. |
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127 | |
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128 | Seed nodes are expected to be long-running, and at least one seed node |
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129 | should always be available. They should also be relatively responsive - a |
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130 | seed node that blocks for long periods will slow down everybody else. |
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131 | |
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132 | For small networks, it's best if every node uses the same set of seed |
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133 | nodes. For large networks, it can be useful to specify "regional" seed |
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134 | nodes for most nodes in an area, and use all seed nodes as seed nodes for |
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135 | each other. What's important is that all seed nodes connections form a |
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136 | complete graph, so that the network cannot split into separate subnets |
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137 | forever. |
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138 | |
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139 | Seed nodes are represented by seed IDs. |
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140 | |
107 | =item seeds - C<host:port> |
141 | =item seed IDs - C<host:port> |
108 | |
142 | |
109 | When a node starts, it knows nothing about the network. To teach the node |
143 | Seed IDs are transport endpoint(s) (usually a hostname/IP address and a |
110 | about the network it first has to contact some other node within the |
144 | TCP port) of nodes that should be used as seed nodes. |
111 | network. This node is called a seed. |
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112 | |
145 | |
113 | Seeds are transport endpoint(s) of as many nodes as one wants. Those nodes |
146 | =item global nodes |
114 | are expected to be long-running, and at least one of those should always |
147 | |
115 | be available. When nodes run out of connections (e.g. due to a network |
148 | An AEMP network needs a discovery service - nodes need to know how to |
116 | error), they try to re-establish connections to some seednodes again to |
149 | connect to other nodes they only know by name. In addition, AEMP offers a |
117 | join the network. |
150 | distributed "group database", which maps group names to a list of strings |
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151 | - for example, to register worker ports. |
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152 | |
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153 | A network needs at least one global node to work, and allows every node to |
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154 | be a global node. |
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155 | |
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156 | Any node that loads the L<AnyEvent::MP::Global> module becomes a global |
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157 | node and tries to keep connections to all other nodes. So while it can |
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158 | make sense to make every node "global" in small networks, it usually makes |
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159 | sense to only make seed nodes into global nodes in large networks (nodes |
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160 | keep connections to seed nodes and global nodes, so makign them the same |
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161 | reduces overhead). |
118 | |
162 | |
119 | =back |
163 | =back |
120 | |
164 | |
121 | =head1 VARIABLES/FUNCTIONS |
165 | =head1 VARIABLES/FUNCTIONS |
122 | |
166 | |
… | |
… | |
124 | |
168 | |
125 | =cut |
169 | =cut |
126 | |
170 | |
127 | package AnyEvent::MP; |
171 | package AnyEvent::MP; |
128 | |
172 | |
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173 | use AnyEvent::MP::Config (); |
129 | use AnyEvent::MP::Kernel; |
174 | use AnyEvent::MP::Kernel; |
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175 | use AnyEvent::MP::Kernel qw(%NODE %PORT %PORT_DATA $UNIQ $RUNIQ $ID); |
130 | |
176 | |
131 | use common::sense; |
177 | use common::sense; |
132 | |
178 | |
133 | use Carp (); |
179 | use Carp (); |
134 | |
180 | |
135 | use AE (); |
181 | use AE (); |
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182 | use Guard (); |
136 | |
183 | |
137 | use base "Exporter"; |
184 | use base "Exporter"; |
138 | |
185 | |
139 | our $VERSION = $AnyEvent::MP::Kernel::VERSION; |
186 | our $VERSION = $AnyEvent::MP::Config::VERSION; |
140 | |
187 | |
141 | our @EXPORT = qw( |
188 | our @EXPORT = qw( |
142 | NODE $NODE *SELF node_of after |
189 | NODE $NODE *SELF node_of after |
143 | resolve_node initialise_node |
190 | configure |
144 | snd rcv mon mon_guard kil reg psub spawn |
191 | snd rcv mon mon_guard kil psub peval spawn cal |
145 | port |
192 | port |
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193 | db_set db_del db_reg |
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194 | db_mon db_family db_keys db_values |
146 | ); |
195 | ); |
147 | |
196 | |
148 | our $SELF; |
197 | our $SELF; |
149 | |
198 | |
150 | sub _self_die() { |
199 | sub _self_die() { |
… | |
… | |
153 | kil $SELF, die => $msg; |
202 | kil $SELF, die => $msg; |
154 | } |
203 | } |
155 | |
204 | |
156 | =item $thisnode = NODE / $NODE |
205 | =item $thisnode = NODE / $NODE |
157 | |
206 | |
158 | The C<NODE> function returns, and the C<$NODE> variable contains the node |
207 | The C<NODE> function returns, and the C<$NODE> variable contains, the node |
159 | ID of the node running in the current process. This value is initialised by |
208 | ID of the node running in the current process. This value is initialised by |
160 | a call to C<initialise_node>. |
209 | a call to C<configure>. |
161 | |
210 | |
162 | =item $nodeid = node_of $port |
211 | =item $nodeid = node_of $port |
163 | |
212 | |
164 | Extracts and returns the node ID part from a port ID or a node ID. |
213 | Extracts and returns the node ID from a port ID or a node ID. |
165 | |
214 | |
166 | =item initialise_node $profile_name |
215 | =item configure $profile, key => value... |
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216 | |
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217 | =item configure key => value... |
167 | |
218 | |
168 | Before a node can talk to other nodes on the network (i.e. enter |
219 | Before a node can talk to other nodes on the network (i.e. enter |
169 | "distributed mode") it has to initialise itself - the minimum a node needs |
220 | "distributed mode") it has to configure itself - the minimum a node needs |
170 | to know is its own name, and optionally it should know the addresses of |
221 | to know is its own name, and optionally it should know the addresses of |
171 | some other nodes in the network to discover other nodes. |
222 | some other nodes in the network to discover other nodes. |
172 | |
223 | |
173 | This function initialises a node - it must be called exactly once (or |
224 | This function configures a node - it must be called exactly once (or |
174 | never) before calling other AnyEvent::MP functions. |
225 | never) before calling other AnyEvent::MP functions. |
175 | |
226 | |
176 | The first argument is a profile name. If it is C<undef> or missing, then |
227 | The key/value pairs are basically the same ones as documented for the |
177 | the current nodename will be used instead (i.e. F<uname -n>). |
228 | F<aemp> command line utility (sans the set/del prefix), with these additions: |
178 | |
229 | |
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230 | =over 4 |
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231 | |
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232 | =item norc => $boolean (default false) |
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233 | |
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234 | If true, then the rc file (e.g. F<~/.perl-anyevent-mp>) will I<not> |
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235 | be consulted - all configuraiton options must be specified in the |
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236 | C<configure> call. |
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237 | |
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238 | =item force => $boolean (default false) |
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239 | |
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240 | IF true, then the values specified in the C<configure> will take |
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241 | precedence over any values configured via the rc file. The default is for |
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242 | the rc file to override any options specified in the program. |
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243 | |
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244 | =item secure => $pass->(@msg) |
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245 | |
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246 | In addition to specifying a boolean, you can specify a code reference that |
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247 | is called for every code execution attempt - the execution request is |
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248 | granted iff the callback returns a true value. |
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249 | |
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250 | Most of the time the callback should look only at |
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251 | C<$AnyEvent::MP::Kernel::SRCNODE> to make a decision, and not at the |
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252 | actual message (which can be about anything, and is mostly provided for |
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253 | diagnostic purposes). |
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254 | |
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255 | See F<semp setsecure> for more info. |
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256 | |
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257 | =back |
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258 | |
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259 | =over 4 |
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260 | |
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261 | =item step 1, gathering configuration from profiles |
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262 | |
179 | The function then looks up the profile in the aemp configuration (see the |
263 | The function first looks up a profile in the aemp configuration (see the |
180 | L<aemp> commandline utility). |
264 | L<aemp> commandline utility). The profile name can be specified via the |
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265 | named C<profile> parameter or can simply be the first parameter). If it is |
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266 | missing, then the nodename (F<uname -n>) will be used as profile name. |
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267 | |
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268 | The profile data is then gathered as follows: |
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269 | |
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270 | First, all remaining key => value pairs (all of which are conveniently |
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271 | undocumented at the moment) will be interpreted as configuration |
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272 | data. Then they will be overwritten by any values specified in the global |
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273 | default configuration (see the F<aemp> utility), then the chain of |
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274 | profiles chosen by the profile name (and any C<parent> attributes). |
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275 | |
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276 | That means that the values specified in the profile have highest priority |
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277 | and the values specified directly via C<configure> have lowest priority, |
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278 | and can only be used to specify defaults. |
181 | |
279 | |
182 | If the profile specifies a node ID, then this will become the node ID of |
280 | If the profile specifies a node ID, then this will become the node ID of |
183 | this process. If not, then the profile name will be used as node ID. The |
281 | this process. If not, then the profile name will be used as node ID, with |
184 | special node ID of C<anon/> will be replaced by a random node ID. |
282 | a unique randoms tring (C</%u>) appended. |
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283 | |
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284 | The node ID can contain some C<%> sequences that are expanded: C<%n> |
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285 | is expanded to the local nodename, C<%u> is replaced by a random |
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286 | strign to make the node unique. For example, the F<aemp> commandline |
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287 | utility uses C<aemp/%n/%u> as nodename, which might expand to |
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288 | C<aemp/cerebro/ZQDGSIkRhEZQDGSIkRhE>. |
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289 | |
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290 | =item step 2, bind listener sockets |
185 | |
291 | |
186 | The next step is to look up the binds in the profile, followed by binding |
292 | The next step is to look up the binds in the profile, followed by binding |
187 | aemp protocol listeners on all binds specified (it is possible and valid |
293 | aemp protocol listeners on all binds specified (it is possible and valid |
188 | to have no binds, meaning that the node cannot be contacted form the |
294 | to have no binds, meaning that the node cannot be contacted form the |
189 | outside. This means the node cannot talk to other nodes that also have no |
295 | outside. This means the node cannot talk to other nodes that also have no |
190 | binds, but it can still talk to all "normal" nodes). |
296 | binds, but it can still talk to all "normal" nodes). |
191 | |
297 | |
192 | If the profile does not specify a binds list, then the node ID will be |
298 | If the profile does not specify a binds list, then a default of C<*> is |
193 | treated as if it were of the form C<host:port>, which will be resolved and |
299 | used, meaning the node will bind on a dynamically-assigned port on every |
194 | used as binds list. |
300 | local IP address it finds. |
195 | |
301 | |
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302 | =item step 3, connect to seed nodes |
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303 | |
196 | Lastly, the seeds list from the profile is passed to the |
304 | As the last step, the seed ID list from the profile is passed to the |
197 | L<AnyEvent::MP::Global> module, which will then use it to keep |
305 | L<AnyEvent::MP::Global> module, which will then use it to keep |
198 | connectivity with at least on of those seed nodes at any point in time. |
306 | connectivity with at least one node at any point in time. |
199 | |
307 | |
200 | Example: become a distributed node listening on the guessed noderef, or |
308 | =back |
201 | the one specified via C<aemp> for the current node. This should be the |
309 | |
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310 | Example: become a distributed node using the local node name as profile. |
202 | most common form of invocation for "daemon"-type nodes. |
311 | This should be the most common form of invocation for "daemon"-type nodes. |
203 | |
312 | |
204 | initialise_node; |
313 | configure |
205 | |
314 | |
206 | Example: become an anonymous node. This form is often used for commandline |
315 | Example: become a semi-anonymous node. This form is often used for |
207 | clients. |
316 | commandline clients. |
208 | |
317 | |
209 | initialise_node "anon/"; |
318 | configure nodeid => "myscript/%n/%u"; |
210 | |
319 | |
211 | Example: become a distributed node. If there is no profile of the given |
320 | Example: configure a node using a profile called seed, which is suitable |
212 | name, or no binds list was specified, resolve C<localhost:4044> and bind |
321 | for a seed node as it binds on all local addresses on a fixed port (4040, |
213 | on the resulting addresses. |
322 | customary for aemp). |
214 | |
323 | |
215 | initialise_node "localhost:4044"; |
324 | # use the aemp commandline utility |
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325 | # aemp profile seed binds '*:4040' |
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326 | |
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327 | # then use it |
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328 | configure profile => "seed"; |
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329 | |
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330 | # or simply use aemp from the shell again: |
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331 | # aemp run profile seed |
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332 | |
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333 | # or provide a nicer-to-remember nodeid |
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334 | # aemp run profile seed nodeid "$(hostname)" |
216 | |
335 | |
217 | =item $SELF |
336 | =item $SELF |
218 | |
337 | |
219 | Contains the current port id while executing C<rcv> callbacks or C<psub> |
338 | Contains the current port id while executing C<rcv> callbacks or C<psub> |
220 | blocks. |
339 | blocks. |
221 | |
340 | |
222 | =item SELF, %SELF, @SELF... |
341 | =item *SELF, SELF, %SELF, @SELF... |
223 | |
342 | |
224 | Due to some quirks in how perl exports variables, it is impossible to |
343 | Due to some quirks in how perl exports variables, it is impossible to |
225 | just export C<$SELF>, all the symbols called C<SELF> are exported by this |
344 | just export C<$SELF>, all the symbols named C<SELF> are exported by this |
226 | module, but only C<$SELF> is currently used. |
345 | module, but only C<$SELF> is currently used. |
227 | |
346 | |
228 | =item snd $port, type => @data |
347 | =item snd $port, type => @data |
229 | |
348 | |
230 | =item snd $port, @msg |
349 | =item snd $port, @msg |
231 | |
350 | |
232 | Send the given message to the given port ID, which can identify either |
351 | Send the given message to the given port, which can identify either a |
233 | a local or a remote port, and must be a port ID. |
352 | local or a remote port, and must be a port ID. |
234 | |
353 | |
235 | While the message can be about anything, it is highly recommended to use a |
354 | While the message can be almost anything, it is highly recommended to |
236 | string as first element (a port ID, or some word that indicates a request |
355 | use a string as first element (a port ID, or some word that indicates a |
237 | type etc.). |
356 | request type etc.) and to consist if only simple perl values (scalars, |
|
|
357 | arrays, hashes) - if you think you need to pass an object, think again. |
238 | |
358 | |
239 | The message data effectively becomes read-only after a call to this |
359 | The message data logically becomes read-only after a call to this |
240 | function: modifying any argument is not allowed and can cause many |
360 | function: modifying any argument (or values referenced by them) is |
241 | problems. |
361 | forbidden, as there can be considerable time between the call to C<snd> |
|
|
362 | and the time the message is actually being serialised - in fact, it might |
|
|
363 | never be copied as within the same process it is simply handed to the |
|
|
364 | receiving port. |
242 | |
365 | |
243 | The type of data you can transfer depends on the transport protocol: when |
366 | The type of data you can transfer depends on the transport protocol: when |
244 | JSON is used, then only strings, numbers and arrays and hashes consisting |
367 | JSON is used, then only strings, numbers and arrays and hashes consisting |
245 | of those are allowed (no objects). When Storable is used, then anything |
368 | of those are allowed (no objects). When Storable is used, then anything |
246 | that Storable can serialise and deserialise is allowed, and for the local |
369 | that Storable can serialise and deserialise is allowed, and for the local |
247 | node, anything can be passed. |
370 | node, anything can be passed. Best rely only on the common denominator of |
|
|
371 | these. |
248 | |
372 | |
249 | =item $local_port = port |
373 | =item $local_port = port |
250 | |
374 | |
251 | Create a new local port object and returns its port ID. Initially it has |
375 | Create a new local port object and returns its port ID. Initially it has |
252 | no callbacks set and will throw an error when it receives messages. |
376 | no callbacks set and will throw an error when it receives messages. |
… | |
… | |
271 | |
395 | |
272 | =cut |
396 | =cut |
273 | |
397 | |
274 | sub rcv($@); |
398 | sub rcv($@); |
275 | |
399 | |
276 | sub _kilme { |
400 | my $KILME = sub { |
277 | die "received message on port without callback"; |
401 | (my $tag = substr $_[0], 0, 30) =~ s/([\x20-\x7e])/./g; |
278 | } |
402 | kil $SELF, unhandled_message => "no callback found for message '$tag'"; |
|
|
403 | }; |
279 | |
404 | |
280 | sub port(;&) { |
405 | sub port(;&) { |
281 | my $id = "$UNIQ." . $ID++; |
406 | my $id = $UNIQ . ++$ID; |
282 | my $port = "$NODE#$id"; |
407 | my $port = "$NODE#$id"; |
283 | |
408 | |
284 | rcv $port, shift || \&_kilme; |
409 | rcv $port, shift || $KILME; |
285 | |
410 | |
286 | $port |
411 | $port |
287 | } |
412 | } |
288 | |
413 | |
289 | =item rcv $local_port, $callback->(@msg) |
414 | =item rcv $local_port, $callback->(@msg) |
… | |
… | |
294 | |
419 | |
295 | The global C<$SELF> (exported by this module) contains C<$port> while |
420 | The global C<$SELF> (exported by this module) contains C<$port> while |
296 | executing the callback. Runtime errors during callback execution will |
421 | executing the callback. Runtime errors during callback execution will |
297 | result in the port being C<kil>ed. |
422 | result in the port being C<kil>ed. |
298 | |
423 | |
299 | The default callback received all messages not matched by a more specific |
424 | The default callback receives all messages not matched by a more specific |
300 | C<tag> match. |
425 | C<tag> match. |
301 | |
426 | |
302 | =item rcv $local_port, tag => $callback->(@msg_without_tag), ... |
427 | =item rcv $local_port, tag => $callback->(@msg_without_tag), ... |
303 | |
428 | |
304 | Register (or replace) callbacks to be called on messages starting with the |
429 | Register (or replace) callbacks to be called on messages starting with the |
… | |
… | |
325 | msg1 => sub { ... }, |
450 | msg1 => sub { ... }, |
326 | ... |
451 | ... |
327 | ; |
452 | ; |
328 | |
453 | |
329 | Example: temporarily register a rcv callback for a tag matching some port |
454 | Example: temporarily register a rcv callback for a tag matching some port |
330 | (e.g. for a rpc reply) and unregister it after a message was received. |
455 | (e.g. for an rpc reply) and unregister it after a message was received. |
331 | |
456 | |
332 | rcv $port, $otherport => sub { |
457 | rcv $port, $otherport => sub { |
333 | my @reply = @_; |
458 | my @reply = @_; |
334 | |
459 | |
335 | rcv $SELF, $otherport; |
460 | rcv $SELF, $otherport; |
… | |
… | |
337 | |
462 | |
338 | =cut |
463 | =cut |
339 | |
464 | |
340 | sub rcv($@) { |
465 | sub rcv($@) { |
341 | my $port = shift; |
466 | my $port = shift; |
342 | my ($noderef, $portid) = split /#/, $port, 2; |
467 | my ($nodeid, $portid) = split /#/, $port, 2; |
343 | |
468 | |
344 | $NODE{$noderef} == $NODE{""} |
469 | $NODE{$nodeid} == $NODE{""} |
345 | or Carp::croak "$port: rcv can only be called on local ports, caught"; |
470 | or Carp::croak "$port: rcv can only be called on local ports, caught"; |
346 | |
471 | |
347 | while (@_) { |
472 | while (@_) { |
348 | if (ref $_[0]) { |
473 | if (ref $_[0]) { |
349 | if (my $self = $PORT_DATA{$portid}) { |
474 | if (my $self = $PORT_DATA{$portid}) { |
350 | "AnyEvent::MP::Port" eq ref $self |
475 | "AnyEvent::MP::Port" eq ref $self |
351 | or Carp::croak "$port: rcv can only be called on message matching ports, caught"; |
476 | or Carp::croak "$port: rcv can only be called on message matching ports, caught"; |
352 | |
477 | |
353 | $self->[2] = shift; |
478 | $self->[0] = shift; |
354 | } else { |
479 | } else { |
355 | my $cb = shift; |
480 | my $cb = shift; |
356 | $PORT{$portid} = sub { |
481 | $PORT{$portid} = sub { |
357 | local $SELF = $port; |
482 | local $SELF = $port; |
358 | eval { &$cb }; _self_die if $@; |
483 | eval { &$cb }; _self_die if $@; |
359 | }; |
484 | }; |
360 | } |
485 | } |
361 | } elsif (defined $_[0]) { |
486 | } elsif (defined $_[0]) { |
362 | my $self = $PORT_DATA{$portid} ||= do { |
487 | my $self = $PORT_DATA{$portid} ||= do { |
363 | my $self = bless [$PORT{$port} || sub { }, { }, $port], "AnyEvent::MP::Port"; |
488 | my $self = bless [$PORT{$portid} || sub { }, { }, $port], "AnyEvent::MP::Port"; |
364 | |
489 | |
365 | $PORT{$portid} = sub { |
490 | $PORT{$portid} = sub { |
366 | local $SELF = $port; |
491 | local $SELF = $port; |
367 | |
492 | |
368 | if (my $cb = $self->[1]{$_[0]}) { |
493 | if (my $cb = $self->[1]{$_[0]}) { |
… | |
… | |
390 | } |
515 | } |
391 | |
516 | |
392 | $port |
517 | $port |
393 | } |
518 | } |
394 | |
519 | |
|
|
520 | =item peval $port, $coderef[, @args] |
|
|
521 | |
|
|
522 | Evaluates the given C<$codref> within the contetx of C<$port>, that is, |
|
|
523 | when the code throews an exception the C<$port> will be killed. |
|
|
524 | |
|
|
525 | Any remaining args will be passed to the callback. Any return values will |
|
|
526 | be returned to the caller. |
|
|
527 | |
|
|
528 | This is useful when you temporarily want to execute code in the context of |
|
|
529 | a port. |
|
|
530 | |
|
|
531 | Example: create a port and run some initialisation code in it's context. |
|
|
532 | |
|
|
533 | my $port = port { ... }; |
|
|
534 | |
|
|
535 | peval $port, sub { |
|
|
536 | init |
|
|
537 | or die "unable to init"; |
|
|
538 | }; |
|
|
539 | |
|
|
540 | =cut |
|
|
541 | |
|
|
542 | sub peval($$) { |
|
|
543 | local $SELF = shift; |
|
|
544 | my $cb = shift; |
|
|
545 | |
|
|
546 | if (wantarray) { |
|
|
547 | my @res = eval { &$cb }; |
|
|
548 | _self_die if $@; |
|
|
549 | @res |
|
|
550 | } else { |
|
|
551 | my $res = eval { &$cb }; |
|
|
552 | _self_die if $@; |
|
|
553 | $res |
|
|
554 | } |
|
|
555 | } |
|
|
556 | |
395 | =item $closure = psub { BLOCK } |
557 | =item $closure = psub { BLOCK } |
396 | |
558 | |
397 | Remembers C<$SELF> and creates a closure out of the BLOCK. When the |
559 | Remembers C<$SELF> and creates a closure out of the BLOCK. When the |
398 | closure is executed, sets up the environment in the same way as in C<rcv> |
560 | closure is executed, sets up the environment in the same way as in C<rcv> |
399 | callbacks, i.e. runtime errors will cause the port to get C<kil>ed. |
561 | callbacks, i.e. runtime errors will cause the port to get C<kil>ed. |
|
|
562 | |
|
|
563 | The effect is basically as if it returned C<< sub { peval $SELF, sub { |
|
|
564 | BLOCK }, @_ } >>. |
400 | |
565 | |
401 | This is useful when you register callbacks from C<rcv> callbacks: |
566 | This is useful when you register callbacks from C<rcv> callbacks: |
402 | |
567 | |
403 | rcv delayed_reply => sub { |
568 | rcv delayed_reply => sub { |
404 | my ($delay, @reply) = @_; |
569 | my ($delay, @reply) = @_; |
… | |
… | |
428 | $res |
593 | $res |
429 | } |
594 | } |
430 | } |
595 | } |
431 | } |
596 | } |
432 | |
597 | |
433 | =item $guard = mon $port, $cb->(@reason) |
598 | =item $guard = mon $port, $rcvport # kill $rcvport when $port dies |
434 | |
599 | |
435 | =item $guard = mon $port, $rcvport |
600 | =item $guard = mon $port # kill $SELF when $port dies |
436 | |
601 | |
437 | =item $guard = mon $port |
602 | =item $guard = mon $port, $cb->(@reason) # call $cb when $port dies |
438 | |
603 | |
439 | =item $guard = mon $port, $rcvport, @msg |
604 | =item $guard = mon $port, $rcvport, @msg # send a message when $port dies |
440 | |
605 | |
441 | Monitor the given port and do something when the port is killed or |
606 | Monitor the given port and do something when the port is killed or |
442 | messages to it were lost, and optionally return a guard that can be used |
607 | messages to it were lost, and optionally return a guard that can be used |
443 | to stop monitoring again. |
608 | to stop monitoring again. |
444 | |
609 | |
|
|
610 | The first two forms distinguish between "normal" and "abnormal" kil's: |
|
|
611 | |
|
|
612 | In the first form (another port given), if the C<$port> is C<kil>'ed with |
|
|
613 | a non-empty reason, the other port (C<$rcvport>) will be kil'ed with the |
|
|
614 | same reason. That is, on "normal" kil's nothing happens, while under all |
|
|
615 | other conditions, the other port is killed with the same reason. |
|
|
616 | |
|
|
617 | The second form (kill self) is the same as the first form, except that |
|
|
618 | C<$rvport> defaults to C<$SELF>. |
|
|
619 | |
|
|
620 | The remaining forms don't distinguish between "normal" and "abnormal" kil's |
|
|
621 | - it's up to the callback or receiver to check whether the C<@reason> is |
|
|
622 | empty and act accordingly. |
|
|
623 | |
|
|
624 | In the third form (callback), the callback is simply called with any |
|
|
625 | number of C<@reason> elements (empty @reason means that the port was deleted |
|
|
626 | "normally"). Note also that I<< the callback B<must> never die >>, so use |
|
|
627 | C<eval> if unsure. |
|
|
628 | |
|
|
629 | In the last form (message), a message of the form C<$rcvport, @msg, |
|
|
630 | @reason> will be C<snd>. |
|
|
631 | |
|
|
632 | Monitoring-actions are one-shot: once messages are lost (and a monitoring |
|
|
633 | alert was raised), they are removed and will not trigger again, even if it |
|
|
634 | turns out that the port is still alive. |
|
|
635 | |
|
|
636 | As a rule of thumb, monitoring requests should always monitor a remote |
|
|
637 | port locally (using a local C<$rcvport> or a callback). The reason is that |
|
|
638 | kill messages might get lost, just like any other message. Another less |
|
|
639 | obvious reason is that even monitoring requests can get lost (for example, |
|
|
640 | when the connection to the other node goes down permanently). When |
|
|
641 | monitoring a port locally these problems do not exist. |
|
|
642 | |
445 | C<mon> effectively guarantees that, in the absence of hardware failures, |
643 | C<mon> effectively guarantees that, in the absence of hardware failures, |
446 | that after starting the monitor, either all messages sent to the port |
644 | after starting the monitor, either all messages sent to the port will |
447 | will arrive, or the monitoring action will be invoked after possible |
645 | arrive, or the monitoring action will be invoked after possible message |
448 | message loss has been detected. No messages will be lost "in between" |
646 | loss has been detected. No messages will be lost "in between" (after |
449 | (after the first lost message no further messages will be received by the |
647 | the first lost message no further messages will be received by the |
450 | port). After the monitoring action was invoked, further messages might get |
648 | port). After the monitoring action was invoked, further messages might get |
451 | delivered again. |
649 | delivered again. |
452 | |
650 | |
453 | Note that monitoring-actions are one-shot: once released, they are removed |
651 | Inter-host-connection timeouts and monitoring depend on the transport |
454 | and will not trigger again. |
652 | used. The only transport currently implemented is TCP, and AnyEvent::MP |
|
|
653 | relies on TCP to detect node-downs (this can take 10-15 minutes on a |
|
|
654 | non-idle connection, and usually around two hours for idle connections). |
455 | |
655 | |
456 | In the first form (callback), the callback is simply called with any |
656 | This means that monitoring is good for program errors and cleaning up |
457 | number of C<@reason> elements (no @reason means that the port was deleted |
657 | stuff eventually, but they are no replacement for a timeout when you need |
458 | "normally"). Note also that I<< the callback B<must> never die >>, so use |
658 | to ensure some maximum latency. |
459 | C<eval> if unsure. |
|
|
460 | |
|
|
461 | In the second form (another port given), the other port (C<$rcvport>) |
|
|
462 | will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on |
|
|
463 | "normal" kils nothing happens, while under all other conditions, the other |
|
|
464 | port is killed with the same reason. |
|
|
465 | |
|
|
466 | The third form (kill self) is the same as the second form, except that |
|
|
467 | C<$rvport> defaults to C<$SELF>. |
|
|
468 | |
|
|
469 | In the last form (message), a message of the form C<@msg, @reason> will be |
|
|
470 | C<snd>. |
|
|
471 | |
|
|
472 | As a rule of thumb, monitoring requests should always monitor a port from |
|
|
473 | a local port (or callback). The reason is that kill messages might get |
|
|
474 | lost, just like any other message. Another less obvious reason is that |
|
|
475 | even monitoring requests can get lost (for exmaple, when the connection |
|
|
476 | to the other node goes down permanently). When monitoring a port locally |
|
|
477 | these problems do not exist. |
|
|
478 | |
659 | |
479 | Example: call a given callback when C<$port> is killed. |
660 | Example: call a given callback when C<$port> is killed. |
480 | |
661 | |
481 | mon $port, sub { warn "port died because of <@_>\n" }; |
662 | mon $port, sub { warn "port died because of <@_>\n" }; |
482 | |
663 | |
… | |
… | |
489 | mon $port, $self => "restart"; |
670 | mon $port, $self => "restart"; |
490 | |
671 | |
491 | =cut |
672 | =cut |
492 | |
673 | |
493 | sub mon { |
674 | sub mon { |
494 | my ($noderef, $port) = split /#/, shift, 2; |
675 | my ($nodeid, $port) = split /#/, shift, 2; |
495 | |
676 | |
496 | my $node = $NODE{$noderef} || add_node $noderef; |
677 | my $node = $NODE{$nodeid} || add_node $nodeid; |
497 | |
678 | |
498 | my $cb = @_ ? shift : $SELF || Carp::croak 'mon: called with one argument only, but $SELF not set,'; |
679 | my $cb = @_ ? shift : $SELF || Carp::croak 'mon: called with one argument only, but $SELF not set,'; |
499 | |
680 | |
500 | unless (ref $cb) { |
681 | unless (ref $cb) { |
501 | if (@_) { |
682 | if (@_) { |
… | |
… | |
510 | } |
691 | } |
511 | |
692 | |
512 | $node->monitor ($port, $cb); |
693 | $node->monitor ($port, $cb); |
513 | |
694 | |
514 | defined wantarray |
695 | defined wantarray |
515 | and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) } |
696 | and ($cb += 0, Guard::guard { $node->unmonitor ($port, $cb) }) |
516 | } |
697 | } |
517 | |
698 | |
518 | =item $guard = mon_guard $port, $ref, $ref... |
699 | =item $guard = mon_guard $port, $ref, $ref... |
519 | |
700 | |
520 | Monitors the given C<$port> and keeps the passed references. When the port |
701 | Monitors the given C<$port> and keeps the passed references. When the port |
521 | is killed, the references will be freed. |
702 | is killed, the references will be freed. |
522 | |
703 | |
523 | Optionally returns a guard that will stop the monitoring. |
704 | Optionally returns a guard that will stop the monitoring. |
524 | |
705 | |
525 | This function is useful when you create e.g. timers or other watchers and |
706 | This function is useful when you create e.g. timers or other watchers and |
526 | want to free them when the port gets killed: |
707 | want to free them when the port gets killed (note the use of C<psub>): |
527 | |
708 | |
528 | $port->rcv (start => sub { |
709 | $port->rcv (start => sub { |
529 | my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub { |
710 | my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub { |
530 | undef $timer if 0.9 < rand; |
711 | undef $timer if 0.9 < rand; |
531 | }); |
712 | }); |
532 | }); |
713 | }); |
533 | |
714 | |
534 | =cut |
715 | =cut |
… | |
… | |
543 | |
724 | |
544 | =item kil $port[, @reason] |
725 | =item kil $port[, @reason] |
545 | |
726 | |
546 | Kill the specified port with the given C<@reason>. |
727 | Kill the specified port with the given C<@reason>. |
547 | |
728 | |
548 | If no C<@reason> is specified, then the port is killed "normally" (linked |
729 | If no C<@reason> is specified, then the port is killed "normally" - |
549 | ports will not be kileld, or even notified). |
730 | monitor callback will be invoked, but the kil will not cause linked ports |
|
|
731 | (C<mon $mport, $lport> form) to get killed. |
550 | |
732 | |
551 | Otherwise, linked ports get killed with the same reason (second form of |
733 | If a C<@reason> is specified, then linked ports (C<mon $mport, $lport> |
552 | C<mon>, see below). |
734 | form) get killed with the same reason. |
553 | |
735 | |
554 | Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks |
736 | Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks |
555 | will be reported as reason C<< die => $@ >>. |
737 | will be reported as reason C<< die => $@ >>. |
556 | |
738 | |
557 | Transport/communication errors are reported as C<< transport_error => |
739 | Transport/communication errors are reported as C<< transport_error => |
558 | $message >>. |
740 | $message >>. |
559 | |
741 | |
560 | =cut |
742 | Common idioms: |
|
|
743 | |
|
|
744 | # silently remove yourself, do not kill linked ports |
|
|
745 | kil $SELF; |
|
|
746 | |
|
|
747 | # report a failure in some detail |
|
|
748 | kil $SELF, failure_mode_1 => "it failed with too high temperature"; |
|
|
749 | |
|
|
750 | # do not waste much time with killing, just die when something goes wrong |
|
|
751 | open my $fh, "<file" |
|
|
752 | or die "file: $!"; |
561 | |
753 | |
562 | =item $port = spawn $node, $initfunc[, @initdata] |
754 | =item $port = spawn $node, $initfunc[, @initdata] |
563 | |
755 | |
564 | Creates a port on the node C<$node> (which can also be a port ID, in which |
756 | Creates a port on the node C<$node> (which can also be a port ID, in which |
565 | case it's the node where that port resides). |
757 | case it's the node where that port resides). |
566 | |
758 | |
567 | The port ID of the newly created port is return immediately, and it is |
759 | The port ID of the newly created port is returned immediately, and it is |
568 | permissible to immediately start sending messages or monitor the port. |
760 | possible to immediately start sending messages or to monitor the port. |
569 | |
761 | |
570 | After the port has been created, the init function is |
762 | After the port has been created, the init function is called on the remote |
571 | called. This function must be a fully-qualified function name |
763 | node, in the same context as a C<rcv> callback. This function must be a |
572 | (e.g. C<MyApp::Chat::Server::init>). To specify a function in the main |
764 | fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To |
573 | program, use C<::name>. |
765 | specify a function in the main program, use C<::name>. |
574 | |
766 | |
575 | If the function doesn't exist, then the node tries to C<require> |
767 | If the function doesn't exist, then the node tries to C<require> |
576 | the package, then the package above the package and so on (e.g. |
768 | the package, then the package above the package and so on (e.g. |
577 | C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function |
769 | C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function |
578 | exists or it runs out of package names. |
770 | exists or it runs out of package names. |
579 | |
771 | |
580 | The init function is then called with the newly-created port as context |
772 | The init function is then called with the newly-created port as context |
581 | object (C<$SELF>) and the C<@initdata> values as arguments. |
773 | object (C<$SELF>) and the C<@initdata> values as arguments. It I<must> |
|
|
774 | call one of the C<rcv> functions to set callbacks on C<$SELF>, otherwise |
|
|
775 | the port might not get created. |
582 | |
776 | |
583 | A common idiom is to pass your own port, monitor the spawned port, and |
777 | A common idiom is to pass a local port, immediately monitor the spawned |
584 | in the init function, monitor the original port. This two-way monitoring |
778 | port, and in the remote init function, immediately monitor the passed |
585 | ensures that both ports get cleaned up when there is a problem. |
779 | local port. This two-way monitoring ensures that both ports get cleaned up |
|
|
780 | when there is a problem. |
|
|
781 | |
|
|
782 | C<spawn> guarantees that the C<$initfunc> has no visible effects on the |
|
|
783 | caller before C<spawn> returns (by delaying invocation when spawn is |
|
|
784 | called for the local node). |
586 | |
785 | |
587 | Example: spawn a chat server port on C<$othernode>. |
786 | Example: spawn a chat server port on C<$othernode>. |
588 | |
787 | |
589 | # this node, executed from within a port context: |
788 | # this node, executed from within a port context: |
590 | my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF; |
789 | my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF; |
… | |
… | |
605 | |
804 | |
606 | sub _spawn { |
805 | sub _spawn { |
607 | my $port = shift; |
806 | my $port = shift; |
608 | my $init = shift; |
807 | my $init = shift; |
609 | |
808 | |
|
|
809 | # rcv will create the actual port |
610 | local $SELF = "$NODE#$port"; |
810 | local $SELF = "$NODE#$port"; |
611 | eval { |
811 | eval { |
612 | &{ load_func $init } |
812 | &{ load_func $init } |
613 | }; |
813 | }; |
614 | _self_die if $@; |
814 | _self_die if $@; |
615 | } |
815 | } |
616 | |
816 | |
617 | sub spawn(@) { |
817 | sub spawn(@) { |
618 | my ($noderef, undef) = split /#/, shift, 2; |
818 | my ($nodeid, undef) = split /#/, shift, 2; |
619 | |
819 | |
620 | my $id = "$RUNIQ." . $ID++; |
820 | my $id = $RUNIQ . ++$ID; |
621 | |
821 | |
622 | $_[0] =~ /::/ |
822 | $_[0] =~ /::/ |
623 | or Carp::croak "spawn init function must be a fully-qualified name, caught"; |
823 | or Carp::croak "spawn init function must be a fully-qualified name, caught"; |
624 | |
824 | |
625 | snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_; |
825 | snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_; |
626 | |
826 | |
627 | "$noderef#$id" |
827 | "$nodeid#$id" |
628 | } |
828 | } |
|
|
829 | |
629 | |
830 | |
630 | =item after $timeout, @msg |
831 | =item after $timeout, @msg |
631 | |
832 | |
632 | =item after $timeout, $callback |
833 | =item after $timeout, $callback |
633 | |
834 | |
634 | Either sends the given message, or call the given callback, after the |
835 | Either sends the given message, or call the given callback, after the |
635 | specified number of seconds. |
836 | specified number of seconds. |
636 | |
837 | |
637 | This is simply a utility function that come sin handy at times. |
838 | This is simply a utility function that comes in handy at times - the |
|
|
839 | AnyEvent::MP author is not convinced of the wisdom of having it, though, |
|
|
840 | so it may go away in the future. |
638 | |
841 | |
639 | =cut |
842 | =cut |
640 | |
843 | |
641 | sub after($@) { |
844 | sub after($@) { |
642 | my ($timeout, @action) = @_; |
845 | my ($timeout, @action) = @_; |
… | |
… | |
647 | ? $action[0]() |
850 | ? $action[0]() |
648 | : snd @action; |
851 | : snd @action; |
649 | }; |
852 | }; |
650 | } |
853 | } |
651 | |
854 | |
|
|
855 | #=item $cb2 = timeout $seconds, $cb[, @args] |
|
|
856 | |
|
|
857 | =item cal $port, @msg, $callback[, $timeout] |
|
|
858 | |
|
|
859 | A simple form of RPC - sends a message to the given C<$port> with the |
|
|
860 | given contents (C<@msg>), but adds a reply port to the message. |
|
|
861 | |
|
|
862 | The reply port is created temporarily just for the purpose of receiving |
|
|
863 | the reply, and will be C<kil>ed when no longer needed. |
|
|
864 | |
|
|
865 | A reply message sent to the port is passed to the C<$callback> as-is. |
|
|
866 | |
|
|
867 | If an optional time-out (in seconds) is given and it is not C<undef>, |
|
|
868 | then the callback will be called without any arguments after the time-out |
|
|
869 | elapsed and the port is C<kil>ed. |
|
|
870 | |
|
|
871 | If no time-out is given (or it is C<undef>), then the local port will |
|
|
872 | monitor the remote port instead, so it eventually gets cleaned-up. |
|
|
873 | |
|
|
874 | Currently this function returns the temporary port, but this "feature" |
|
|
875 | might go in future versions unless you can make a convincing case that |
|
|
876 | this is indeed useful for something. |
|
|
877 | |
|
|
878 | =cut |
|
|
879 | |
|
|
880 | sub cal(@) { |
|
|
881 | my $timeout = ref $_[-1] ? undef : pop; |
|
|
882 | my $cb = pop; |
|
|
883 | |
|
|
884 | my $port = port { |
|
|
885 | undef $timeout; |
|
|
886 | kil $SELF; |
|
|
887 | &$cb; |
|
|
888 | }; |
|
|
889 | |
|
|
890 | if (defined $timeout) { |
|
|
891 | $timeout = AE::timer $timeout, 0, sub { |
|
|
892 | undef $timeout; |
|
|
893 | kil $port; |
|
|
894 | $cb->(); |
|
|
895 | }; |
|
|
896 | } else { |
|
|
897 | mon $_[0], sub { |
|
|
898 | kil $port; |
|
|
899 | $cb->(); |
|
|
900 | }; |
|
|
901 | } |
|
|
902 | |
|
|
903 | push @_, $port; |
|
|
904 | &snd; |
|
|
905 | |
|
|
906 | $port |
|
|
907 | } |
|
|
908 | |
|
|
909 | =back |
|
|
910 | |
|
|
911 | =head1 DISTRIBUTED DATABASE |
|
|
912 | |
|
|
913 | AnyEvent::MP comes with a simple distributed database. The database will |
|
|
914 | be mirrored asynchronously on all global nodes. Other nodes bind to one |
|
|
915 | of the global nodes for their needs. Every node has a "local database" |
|
|
916 | which contains all the values that are set locally. All local databases |
|
|
917 | are merged together to form the global database, which can be queried. |
|
|
918 | |
|
|
919 | The database structure is that of a two-level hash - the database hash |
|
|
920 | contains hashes which contain values, similarly to a perl hash of hashes, |
|
|
921 | i.e.: |
|
|
922 | |
|
|
923 | $DATABASE{$family}{$subkey} = $value |
|
|
924 | |
|
|
925 | The top level hash key is called "family", and the second-level hash key |
|
|
926 | is called "subkey" or simply "key". |
|
|
927 | |
|
|
928 | The family must be alphanumeric, i.e. start with a letter and consist |
|
|
929 | of letters, digits, underscores and colons (C<[A-Za-z][A-Za-z0-9_:]*>, |
|
|
930 | pretty much like Perl module names. |
|
|
931 | |
|
|
932 | As the family namespace is global, it is recommended to prefix family names |
|
|
933 | with the name of the application or module using it. |
|
|
934 | |
|
|
935 | The subkeys must be non-empty strings, with no further restrictions. |
|
|
936 | |
|
|
937 | The values should preferably be strings, but other perl scalars should |
|
|
938 | work as well (such as C<undef>, arrays and hashes). |
|
|
939 | |
|
|
940 | Every database entry is owned by one node - adding the same family/subkey |
|
|
941 | combination on multiple nodes will not cause discomfort for AnyEvent::MP, |
|
|
942 | but the result might be nondeterministic, i.e. the key might have |
|
|
943 | different values on different nodes. |
|
|
944 | |
|
|
945 | Different subkeys in the same family can be owned by different nodes |
|
|
946 | without problems, and in fact, this is the common method to create worker |
|
|
947 | pools. For example, a worker port for image scaling might do this: |
|
|
948 | |
|
|
949 | db_set my_image_scalers => $port; |
|
|
950 | |
|
|
951 | And clients looking for an image scaler will want to get the |
|
|
952 | C<my_image_scalers> keys from time to time: |
|
|
953 | |
|
|
954 | db_keys my_image_scalers => sub { |
|
|
955 | @ports = @{ $_[0] }; |
|
|
956 | }; |
|
|
957 | |
|
|
958 | Or better yet, they want to monitor the database family, so they always |
|
|
959 | have a reasonable up-to-date copy: |
|
|
960 | |
|
|
961 | db_mon my_image_scalers => sub { |
|
|
962 | @ports = keys %{ $_[0] }; |
|
|
963 | }; |
|
|
964 | |
|
|
965 | In general, you can set or delete single subkeys, but query and monitor |
|
|
966 | whole families only. |
|
|
967 | |
|
|
968 | If you feel the need to monitor or query a single subkey, try giving it |
|
|
969 | it's own family. |
|
|
970 | |
|
|
971 | =over |
|
|
972 | |
|
|
973 | =item $guard = db_set $family => $subkey [=> $value] |
|
|
974 | |
|
|
975 | Sets (or replaces) a key to the database - if C<$value> is omitted, |
|
|
976 | C<undef> is used instead. |
|
|
977 | |
|
|
978 | When called in non-void context, C<db_set> returns a guard that |
|
|
979 | automatically calls C<db_del> when it is destroyed. |
|
|
980 | |
|
|
981 | =item db_del $family => $subkey... |
|
|
982 | |
|
|
983 | Deletes one or more subkeys from the database family. |
|
|
984 | |
|
|
985 | =item $guard = db_reg $family => $port => $value |
|
|
986 | |
|
|
987 | =item $guard = db_reg $family => $port |
|
|
988 | |
|
|
989 | =item $guard = db_reg $family |
|
|
990 | |
|
|
991 | Registers a port in the given family and optionally returns a guard to |
|
|
992 | remove it. |
|
|
993 | |
|
|
994 | This function basically does the same as: |
|
|
995 | |
|
|
996 | db_set $family => $port => $value |
|
|
997 | |
|
|
998 | Except that the port is monitored and automatically removed from the |
|
|
999 | database family when it is kil'ed. |
|
|
1000 | |
|
|
1001 | If C<$value> is missing, C<undef> is used. If C<$port> is missing, then |
|
|
1002 | C<$SELF> is used. |
|
|
1003 | |
|
|
1004 | This function is most useful to register a port in some port group (which |
|
|
1005 | is just another name for a database family), and have it removed when the |
|
|
1006 | port is gone. This works best when the port is a local port. |
|
|
1007 | |
|
|
1008 | =cut |
|
|
1009 | |
|
|
1010 | sub db_reg($$;$) { |
|
|
1011 | my $family = shift; |
|
|
1012 | my $port = @_ ? shift : $SELF; |
|
|
1013 | |
|
|
1014 | my $clr = sub { db_del $family => $port }; |
|
|
1015 | mon $port, $clr; |
|
|
1016 | |
|
|
1017 | db_set $family => $port => $_[0]; |
|
|
1018 | |
|
|
1019 | defined wantarray |
|
|
1020 | and &Guard::guard ($clr) |
|
|
1021 | } |
|
|
1022 | |
|
|
1023 | =item db_family $family => $cb->(\%familyhash) |
|
|
1024 | |
|
|
1025 | Queries the named database C<$family> and call the callback with the |
|
|
1026 | family represented as a hash. You can keep and freely modify the hash. |
|
|
1027 | |
|
|
1028 | =item db_keys $family => $cb->(\@keys) |
|
|
1029 | |
|
|
1030 | Same as C<db_family>, except it only queries the family I<subkeys> and passes |
|
|
1031 | them as array reference to the callback. |
|
|
1032 | |
|
|
1033 | =item db_values $family => $cb->(\@values) |
|
|
1034 | |
|
|
1035 | Same as C<db_family>, except it only queries the family I<values> and passes them |
|
|
1036 | as array reference to the callback. |
|
|
1037 | |
|
|
1038 | =item $guard = db_mon $family => $cb->($familyhash, \@added, \@changed, \@deleted) |
|
|
1039 | |
|
|
1040 | Creates a monitor on the given database family. Each time a key is set |
|
|
1041 | or or is deleted the callback is called with a hash containing the |
|
|
1042 | database family and three lists of added, changed and deleted subkeys, |
|
|
1043 | respectively. If no keys have changed then the array reference might be |
|
|
1044 | C<undef> or even missing. |
|
|
1045 | |
|
|
1046 | If not called in void context, a guard object is returned that, when |
|
|
1047 | destroyed, stops the monitor. |
|
|
1048 | |
|
|
1049 | The family hash reference and the key arrays belong to AnyEvent::MP and |
|
|
1050 | B<must not be modified or stored> by the callback. When in doubt, make a |
|
|
1051 | copy. |
|
|
1052 | |
|
|
1053 | As soon as possible after the monitoring starts, the callback will be |
|
|
1054 | called with the intiial contents of the family, even if it is empty, |
|
|
1055 | i.e. there will always be a timely call to the callback with the current |
|
|
1056 | contents. |
|
|
1057 | |
|
|
1058 | It is possible that the callback is called with a change event even though |
|
|
1059 | the subkey is already present and the value has not changed. |
|
|
1060 | |
|
|
1061 | The monitoring stops when the guard object is destroyed. |
|
|
1062 | |
|
|
1063 | Example: on every change to the family "mygroup", print out all keys. |
|
|
1064 | |
|
|
1065 | my $guard = db_mon mygroup => sub { |
|
|
1066 | my ($family, $a, $c, $d) = @_; |
|
|
1067 | print "mygroup members: ", (join " ", keys %$family), "\n"; |
|
|
1068 | }; |
|
|
1069 | |
|
|
1070 | Exmaple: wait until the family "My::Module::workers" is non-empty. |
|
|
1071 | |
|
|
1072 | my $guard; $guard = db_mon My::Module::workers => sub { |
|
|
1073 | my ($family, $a, $c, $d) = @_; |
|
|
1074 | return unless %$family; |
|
|
1075 | undef $guard; |
|
|
1076 | print "My::Module::workers now nonempty\n"; |
|
|
1077 | }; |
|
|
1078 | |
|
|
1079 | Example: print all changes to the family "AnyRvent::Fantasy::Module". |
|
|
1080 | |
|
|
1081 | my $guard = db_mon AnyRvent::Fantasy::Module => sub { |
|
|
1082 | my ($family, $a, $c, $d) = @_; |
|
|
1083 | |
|
|
1084 | print "+$_=$family->{$_}\n" for @$a; |
|
|
1085 | print "*$_=$family->{$_}\n" for @$c; |
|
|
1086 | print "-$_=$family->{$_}\n" for @$d; |
|
|
1087 | }; |
|
|
1088 | |
|
|
1089 | =cut |
|
|
1090 | |
652 | =back |
1091 | =back |
653 | |
1092 | |
654 | =head1 AnyEvent::MP vs. Distributed Erlang |
1093 | =head1 AnyEvent::MP vs. Distributed Erlang |
655 | |
1094 | |
656 | AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node |
1095 | AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node |
657 | == aemp node, Erlang process == aemp port), so many of the documents and |
1096 | == aemp node, Erlang process == aemp port), so many of the documents and |
658 | programming techniques employed by Erlang apply to AnyEvent::MP. Here is a |
1097 | programming techniques employed by Erlang apply to AnyEvent::MP. Here is a |
659 | sample: |
1098 | sample: |
660 | |
1099 | |
661 | http://www.Erlang.se/doc/programming_rules.shtml |
1100 | http://www.erlang.se/doc/programming_rules.shtml |
662 | http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4 |
1101 | http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4 |
663 | http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6 |
1102 | http://erlang.org/download/erlang-book-part1.pdf # chapters 5 and 6 |
664 | http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5 |
1103 | http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5 |
665 | |
1104 | |
666 | Despite the similarities, there are also some important differences: |
1105 | Despite the similarities, there are also some important differences: |
667 | |
1106 | |
668 | =over 4 |
1107 | =over 4 |
669 | |
1108 | |
670 | =item * Node references contain the recipe on how to contact them. |
1109 | =item * Node IDs are arbitrary strings in AEMP. |
671 | |
1110 | |
672 | Erlang relies on special naming and DNS to work everywhere in the |
1111 | Erlang relies on special naming and DNS to work everywhere in the same |
673 | same way. AEMP relies on each node knowing it's own address(es), with |
1112 | way. AEMP relies on each node somehow knowing its own address(es) (e.g. by |
674 | convenience functionality. |
1113 | configuration or DNS), and possibly the addresses of some seed nodes, but |
675 | |
1114 | will otherwise discover other nodes (and their IDs) itself. |
676 | This means that AEMP requires a less tightly controlled environment at the |
|
|
677 | cost of longer node references and a slightly higher management overhead. |
|
|
678 | |
1115 | |
679 | =item * Erlang has a "remote ports are like local ports" philosophy, AEMP |
1116 | =item * Erlang has a "remote ports are like local ports" philosophy, AEMP |
680 | uses "local ports are like remote ports". |
1117 | uses "local ports are like remote ports". |
681 | |
1118 | |
682 | The failure modes for local ports are quite different (runtime errors |
1119 | The failure modes for local ports are quite different (runtime errors |
… | |
… | |
691 | ports being the special case/exception, where transport errors cannot |
1128 | ports being the special case/exception, where transport errors cannot |
692 | occur. |
1129 | occur. |
693 | |
1130 | |
694 | =item * Erlang uses processes and a mailbox, AEMP does not queue. |
1131 | =item * Erlang uses processes and a mailbox, AEMP does not queue. |
695 | |
1132 | |
696 | Erlang uses processes that selectively receive messages, and therefore |
1133 | Erlang uses processes that selectively receive messages out of order, and |
697 | needs a queue. AEMP is event based, queuing messages would serve no |
1134 | therefore needs a queue. AEMP is event based, queuing messages would serve |
698 | useful purpose. For the same reason the pattern-matching abilities of |
1135 | no useful purpose. For the same reason the pattern-matching abilities |
699 | AnyEvent::MP are more limited, as there is little need to be able to |
1136 | of AnyEvent::MP are more limited, as there is little need to be able to |
700 | filter messages without dequeing them. |
1137 | filter messages without dequeuing them. |
701 | |
1138 | |
702 | (But see L<Coro::MP> for a more Erlang-like process model on top of AEMP). |
1139 | This is not a philosophical difference, but simply stems from AnyEvent::MP |
|
|
1140 | being event-based, while Erlang is process-based. |
|
|
1141 | |
|
|
1142 | You cna have a look at L<Coro::MP> for a more Erlang-like process model on |
|
|
1143 | top of AEMP and Coro threads. |
703 | |
1144 | |
704 | =item * Erlang sends are synchronous, AEMP sends are asynchronous. |
1145 | =item * Erlang sends are synchronous, AEMP sends are asynchronous. |
705 | |
1146 | |
706 | Sending messages in Erlang is synchronous and blocks the process (and |
1147 | Sending messages in Erlang is synchronous and blocks the process until |
|
|
1148 | a conenction has been established and the message sent (and so does not |
707 | so does not need a queue that can overflow). AEMP sends are immediate, |
1149 | need a queue that can overflow). AEMP sends return immediately, connection |
708 | connection establishment is handled in the background. |
1150 | establishment is handled in the background. |
709 | |
1151 | |
710 | =item * Erlang suffers from silent message loss, AEMP does not. |
1152 | =item * Erlang suffers from silent message loss, AEMP does not. |
711 | |
1153 | |
712 | Erlang makes few guarantees on messages delivery - messages can get lost |
1154 | Erlang implements few guarantees on messages delivery - messages can get |
713 | without any of the processes realising it (i.e. you send messages a, b, |
1155 | lost without any of the processes realising it (i.e. you send messages a, |
714 | and c, and the other side only receives messages a and c). |
1156 | b, and c, and the other side only receives messages a and c). |
715 | |
1157 | |
716 | AEMP guarantees correct ordering, and the guarantee that there are no |
1158 | AEMP guarantees (modulo hardware errors) correct ordering, and the |
|
|
1159 | guarantee that after one message is lost, all following ones sent to the |
|
|
1160 | same port are lost as well, until monitoring raises an error, so there are |
717 | holes in the message sequence. |
1161 | no silent "holes" in the message sequence. |
718 | |
1162 | |
719 | =item * In Erlang, processes can be declared dead and later be found to be |
1163 | If you want your software to be very reliable, you have to cope with |
720 | alive. |
1164 | corrupted and even out-of-order messages in both Erlang and AEMP. AEMP |
721 | |
1165 | simply tries to work better in common error cases, such as when a network |
722 | In Erlang it can happen that a monitored process is declared dead and |
1166 | link goes down. |
723 | linked processes get killed, but later it turns out that the process is |
|
|
724 | still alive - and can receive messages. |
|
|
725 | |
|
|
726 | In AEMP, when port monitoring detects a port as dead, then that port will |
|
|
727 | eventually be killed - it cannot happen that a node detects a port as dead |
|
|
728 | and then later sends messages to it, finding it is still alive. |
|
|
729 | |
1167 | |
730 | =item * Erlang can send messages to the wrong port, AEMP does not. |
1168 | =item * Erlang can send messages to the wrong port, AEMP does not. |
731 | |
1169 | |
732 | In Erlang it is quite likely that a node that restarts reuses a process ID |
1170 | In Erlang it is quite likely that a node that restarts reuses an Erlang |
733 | known to other nodes for a completely different process, causing messages |
1171 | process ID known to other nodes for a completely different process, |
734 | destined for that process to end up in an unrelated process. |
1172 | causing messages destined for that process to end up in an unrelated |
|
|
1173 | process. |
735 | |
1174 | |
736 | AEMP never reuses port IDs, so old messages or old port IDs floating |
1175 | AEMP does not reuse port IDs, so old messages or old port IDs floating |
737 | around in the network will not be sent to an unrelated port. |
1176 | around in the network will not be sent to an unrelated port. |
738 | |
1177 | |
739 | =item * Erlang uses unprotected connections, AEMP uses secure |
1178 | =item * Erlang uses unprotected connections, AEMP uses secure |
740 | authentication and can use TLS. |
1179 | authentication and can use TLS. |
741 | |
1180 | |
742 | AEMP can use a proven protocol - SSL/TLS - to protect connections and |
1181 | AEMP can use a proven protocol - TLS - to protect connections and |
743 | securely authenticate nodes. |
1182 | securely authenticate nodes. |
744 | |
1183 | |
745 | =item * The AEMP protocol is optimised for both text-based and binary |
1184 | =item * The AEMP protocol is optimised for both text-based and binary |
746 | communications. |
1185 | communications. |
747 | |
1186 | |
748 | The AEMP protocol, unlike the Erlang protocol, supports both |
1187 | The AEMP protocol, unlike the Erlang protocol, supports both programming |
749 | language-independent text-only protocols (good for debugging) and binary, |
1188 | language independent text-only protocols (good for debugging), and binary, |
750 | language-specific serialisers (e.g. Storable). |
1189 | language-specific serialisers (e.g. Storable). By default, unless TLS is |
|
|
1190 | used, the protocol is actually completely text-based. |
751 | |
1191 | |
752 | It has also been carefully designed to be implementable in other languages |
1192 | It has also been carefully designed to be implementable in other languages |
753 | with a minimum of work while gracefully degrading fucntionality to make the |
1193 | with a minimum of work while gracefully degrading functionality to make the |
754 | protocol simple. |
1194 | protocol simple. |
755 | |
1195 | |
756 | =item * AEMP has more flexible monitoring options than Erlang. |
1196 | =item * AEMP has more flexible monitoring options than Erlang. |
757 | |
1197 | |
758 | In Erlang, you can chose to receive I<all> exit signals as messages |
1198 | In Erlang, you can chose to receive I<all> exit signals as messages or |
759 | or I<none>, there is no in-between, so monitoring single processes is |
1199 | I<none>, there is no in-between, so monitoring single Erlang processes is |
760 | difficult to implement. Monitoring in AEMP is more flexible than in |
1200 | difficult to implement. |
761 | Erlang, as one can choose between automatic kill, exit message or callback |
1201 | |
762 | on a per-process basis. |
1202 | Monitoring in AEMP is more flexible than in Erlang, as one can choose |
|
|
1203 | between automatic kill, exit message or callback on a per-port basis. |
763 | |
1204 | |
764 | =item * Erlang tries to hide remote/local connections, AEMP does not. |
1205 | =item * Erlang tries to hide remote/local connections, AEMP does not. |
765 | |
1206 | |
766 | Monitoring in Erlang is not an indicator of process death/crashes, |
1207 | Monitoring in Erlang is not an indicator of process death/crashes, in the |
767 | as linking is (except linking is unreliable in Erlang). |
1208 | same way as linking is (except linking is unreliable in Erlang). |
768 | |
1209 | |
769 | In AEMP, you don't "look up" registered port names or send to named ports |
1210 | In AEMP, you don't "look up" registered port names or send to named ports |
770 | that might or might not be persistent. Instead, you normally spawn a port |
1211 | that might or might not be persistent. Instead, you normally spawn a port |
771 | on the remote node. The init function monitors the you, and you monitor |
1212 | on the remote node. The init function monitors you, and you monitor the |
772 | the remote port. Since both monitors are local to the node, they are much |
1213 | remote port. Since both monitors are local to the node, they are much more |
773 | more reliable. |
1214 | reliable (no need for C<spawn_link>). |
774 | |
1215 | |
775 | This also saves round-trips and avoids sending messages to the wrong port |
1216 | This also saves round-trips and avoids sending messages to the wrong port |
776 | (hard to do in Erlang). |
1217 | (hard to do in Erlang). |
777 | |
1218 | |
778 | =back |
1219 | =back |
779 | |
1220 | |
780 | =head1 RATIONALE |
1221 | =head1 RATIONALE |
781 | |
1222 | |
782 | =over 4 |
1223 | =over 4 |
783 | |
1224 | |
784 | =item Why strings for ports and noderefs, why not objects? |
1225 | =item Why strings for port and node IDs, why not objects? |
785 | |
1226 | |
786 | We considered "objects", but found that the actual number of methods |
1227 | We considered "objects", but found that the actual number of methods |
787 | thatc an be called are very low. Since port IDs and noderefs travel over |
1228 | that can be called are quite low. Since port and node IDs travel over |
788 | the network frequently, the serialising/deserialising would add lots of |
1229 | the network frequently, the serialising/deserialising would add lots of |
789 | overhead, as well as having to keep a proxy object. |
1230 | overhead, as well as having to keep a proxy object everywhere. |
790 | |
1231 | |
791 | Strings can easily be printed, easily serialised etc. and need no special |
1232 | Strings can easily be printed, easily serialised etc. and need no special |
792 | procedures to be "valid". |
1233 | procedures to be "valid". |
793 | |
1234 | |
794 | And a a miniport consists of a single closure stored in a global hash - it |
1235 | And as a result, a port with just a default receiver consists of a single |
795 | can't become much cheaper. |
1236 | code reference stored in a global hash - it can't become much cheaper. |
796 | |
1237 | |
797 | =item Why favour JSON, why not real serialising format such as Storable? |
1238 | =item Why favour JSON, why not a real serialising format such as Storable? |
798 | |
1239 | |
799 | In fact, any AnyEvent::MP node will happily accept Storable as framing |
1240 | In fact, any AnyEvent::MP node will happily accept Storable as framing |
800 | format, but currently there is no way to make a node use Storable by |
1241 | format, but currently there is no way to make a node use Storable by |
801 | default. |
1242 | default (although all nodes will accept it). |
802 | |
1243 | |
803 | The default framing protocol is JSON because a) JSON::XS is many times |
1244 | The default framing protocol is JSON because a) JSON::XS is many times |
804 | faster for small messages and b) most importantly, after years of |
1245 | faster for small messages and b) most importantly, after years of |
805 | experience we found that object serialisation is causing more problems |
1246 | experience we found that object serialisation is causing more problems |
806 | than it gains: Just like function calls, objects simply do not travel |
1247 | than it solves: Just like function calls, objects simply do not travel |
807 | easily over the network, mostly because they will always be a copy, so you |
1248 | easily over the network, mostly because they will always be a copy, so you |
808 | always have to re-think your design. |
1249 | always have to re-think your design. |
809 | |
1250 | |
810 | Keeping your messages simple, concentrating on data structures rather than |
1251 | Keeping your messages simple, concentrating on data structures rather than |
811 | objects, will keep your messages clean, tidy and efficient. |
1252 | objects, will keep your messages clean, tidy and efficient. |
812 | |
1253 | |
813 | =back |
1254 | =back |
814 | |
1255 | |
|
|
1256 | =head1 PORTING FROM AnyEvent::MP VERSION 1.X |
|
|
1257 | |
|
|
1258 | AEMP version 2 has a few major incompatible changes compared to version 1: |
|
|
1259 | |
|
|
1260 | =over 4 |
|
|
1261 | |
|
|
1262 | =item AnyEvent::MP::Global no longer has group management functions. |
|
|
1263 | |
|
|
1264 | At least not officially - the grp_* functions are still exported and might |
|
|
1265 | work, but they will be removed in some later release. |
|
|
1266 | |
|
|
1267 | AnyEvent::MP now comes with a distributed database that is more |
|
|
1268 | powerful. Its database families map closely to port groups, but the API |
|
|
1269 | has changed (the functions are also now exported by AnyEvent::MP). Here is |
|
|
1270 | a rough porting guide: |
|
|
1271 | |
|
|
1272 | grp_reg $group, $port # old |
|
|
1273 | db_reg $group, $port # new |
|
|
1274 | |
|
|
1275 | $list = grp_get $group # old |
|
|
1276 | db_keys $group, sub { my $list = shift } # new |
|
|
1277 | |
|
|
1278 | grp_mon $group, $cb->(\@ports, $add, $del) # old |
|
|
1279 | db_mon $group, $cb->(\%ports, $add, $change, $del) # new |
|
|
1280 | |
|
|
1281 | C<grp_reg> is a no-brainer (just replace by C<db_reg>), but C<grp_get> is |
|
|
1282 | no longer instant, because the local node might not have a copy of the |
|
|
1283 | group. You can either modify your code to allow for a callback, or use |
|
|
1284 | C<db_mon> to keep an updated copy of the group: |
|
|
1285 | |
|
|
1286 | my $local_group_copy; |
|
|
1287 | db_mon $group => sub { $local_group_copy = $_[0] }; |
|
|
1288 | |
|
|
1289 | # now "keys %$local_group_copy" always returns the most up-to-date |
|
|
1290 | # list of ports in the group. |
|
|
1291 | |
|
|
1292 | C<grp_mon> can be replaced by C<db_mon> with minor changes - C<db_mon> |
|
|
1293 | passes a hash as first argument, and an extra C<$chg> argument that can be |
|
|
1294 | ignored: |
|
|
1295 | |
|
|
1296 | db_mon $group => sub { |
|
|
1297 | my ($ports, $add, $chg, $lde) = @_; |
|
|
1298 | $ports = [keys %$ports]; |
|
|
1299 | |
|
|
1300 | # now $ports, $add and $del are the same as |
|
|
1301 | # were originally passed by grp_mon. |
|
|
1302 | ... |
|
|
1303 | }; |
|
|
1304 | |
|
|
1305 | =item Nodes not longer connect to all other nodes. |
|
|
1306 | |
|
|
1307 | In AEMP 1.x, every node automatically loads the L<AnyEvent::MP::Global> |
|
|
1308 | module, which in turn would create connections to all other nodes in the |
|
|
1309 | network (helped by the seed nodes). |
|
|
1310 | |
|
|
1311 | In version 2.x, global nodes still connect to all other global nodes, but |
|
|
1312 | other nodes don't - now every node either is a global node itself, or |
|
|
1313 | attaches itself to another global node. |
|
|
1314 | |
|
|
1315 | If a node isn't a global node itself, then it attaches itself to one |
|
|
1316 | of its seed nodes. If that seed node isn't a global node yet, it will |
|
|
1317 | automatically be upgraded to a global node. |
|
|
1318 | |
|
|
1319 | So in many cases, nothing needs to be changed - one just has to make sure |
|
|
1320 | that all seed nodes are meshed together with the other seed nodes (as with |
|
|
1321 | AEMP 1.x), and other nodes specify them as seed nodes. This is most easily |
|
|
1322 | achieved by specifying the same set of seed nodes for all nodes in the |
|
|
1323 | network. |
|
|
1324 | |
|
|
1325 | Not opening a connection to every other node is usually an advantage, |
|
|
1326 | except when you need the lower latency of an already established |
|
|
1327 | connection. To ensure a node establishes a connection to another node, |
|
|
1328 | you can monitor the node port (C<mon $node, ...>), which will attempt to |
|
|
1329 | create the connection (and notify you when the connection fails). |
|
|
1330 | |
|
|
1331 | =item Listener-less nodes (nodes without binds) are gone. |
|
|
1332 | |
|
|
1333 | And are not coming back, at least not in their old form. If no C<binds> |
|
|
1334 | are specified for a node, AnyEvent::MP assumes a default of C<*:*>. |
|
|
1335 | |
|
|
1336 | There are vague plans to implement some form of routing domains, which |
|
|
1337 | might or might not bring back listener-less nodes, but don't count on it. |
|
|
1338 | |
|
|
1339 | The fact that most connections are now optional somewhat mitigates this, |
|
|
1340 | as a node can be effectively unreachable from the outside without any |
|
|
1341 | problems, as long as it isn't a global node and only reaches out to other |
|
|
1342 | nodes (as opposed to being contacted from other nodes). |
|
|
1343 | |
|
|
1344 | =item $AnyEvent::MP::Kernel::WARN has gone. |
|
|
1345 | |
|
|
1346 | AnyEvent has acquired a logging framework (L<AnyEvent::Log>), and AEMP now |
|
|
1347 | uses this, and so should your programs. |
|
|
1348 | |
|
|
1349 | Every module now documents what kinds of messages it generates, with |
|
|
1350 | AnyEvent::MP acting as a catch all. |
|
|
1351 | |
|
|
1352 | On the positive side, this means that instead of setting |
|
|
1353 | C<PERL_ANYEVENT_MP_WARNLEVEL>, you can get away by setting C<AE_VERBOSE> - |
|
|
1354 | much less to type. |
|
|
1355 | |
|
|
1356 | =back |
|
|
1357 | |
|
|
1358 | =head1 LOGGING |
|
|
1359 | |
|
|
1360 | AnyEvent::MP does not normally log anything by itself, but sinc eit is the |
|
|
1361 | root of the contetx hierarchy for AnyEvent::MP modules, it will receive |
|
|
1362 | all log messages by submodules. |
|
|
1363 | |
815 | =head1 SEE ALSO |
1364 | =head1 SEE ALSO |
|
|
1365 | |
|
|
1366 | L<AnyEvent::MP::Intro> - a gentle introduction. |
|
|
1367 | |
|
|
1368 | L<AnyEvent::MP::Kernel> - more, lower-level, stuff. |
|
|
1369 | |
|
|
1370 | L<AnyEvent::MP::Global> - network maintenance and port groups, to find |
|
|
1371 | your applications. |
|
|
1372 | |
|
|
1373 | L<AnyEvent::MP::DataConn> - establish data connections between nodes. |
|
|
1374 | |
|
|
1375 | L<AnyEvent::MP::LogCatcher> - simple service to display log messages from |
|
|
1376 | all nodes. |
816 | |
1377 | |
817 | L<AnyEvent>. |
1378 | L<AnyEvent>. |
818 | |
1379 | |
819 | =head1 AUTHOR |
1380 | =head1 AUTHOR |
820 | |
1381 | |