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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.59 by root, Mon Aug 17 03:56:34 2009 UTC vs.
Revision 1.64 by root, Fri Aug 28 00:58:44 2009 UTC

11 NODE $port # returns the noderef of the port 11 NODE $port # returns the noderef of the port
12 12
13 $SELF # receiving/own port id in rcv callbacks 13 $SELF # receiving/own port id in rcv callbacks
14 14
15 # initialise the node so it can send/receive messages 15 # initialise the node so it can send/receive messages
16 initialise_node; # -OR- 16 initialise_node;
17 initialise_node "localhost:4040"; # -OR-
18 initialise_node "slave/", "localhost:4040"
19 17
20 # ports are message endpoints 18 # ports are message endpoints
21 19
22 # sending messages 20 # sending messages
23 snd $port, type => data...; 21 snd $port, type => data...;
70=item port 68=item port
71 69
72A port is something you can send messages to (with the C<snd> function). 70A port is something you can send messages to (with the C<snd> function).
73 71
74Ports allow you to register C<rcv> handlers that can match all or just 72Ports allow you to register C<rcv> handlers that can match all or just
75some messages. Messages will not be queued. 73some messages. Messages send to ports will not be queued, regardless of
74anything was listening for them or not.
76 75
77=item port id - C<noderef#portname> 76=item port ID - C<noderef#portname>
78 77
79A port ID is the concatenation of a noderef, a hash-mark (C<#>) as 78A port ID is the concatenation of a noderef, a hash-mark (C<#>) as
80separator, and a port name (a printable string of unspecified format). An 79separator, and a port name (a printable string of unspecified format). An
81exception is the the node port, whose ID is identical to its node 80exception is the the node port, whose ID is identical to its node
82reference. 81reference.
85 84
86A node is a single process containing at least one port - the node port, 85A node is a single process containing at least one port - the node port,
87which provides nodes to manage each other remotely, and to create new 86which provides nodes to manage each other remotely, and to create new
88ports. 87ports.
89 88
90Nodes are either private (single-process only), slaves (connected to a 89Nodes are either private (single-process only), slaves (can only talk to
91master node only) or public nodes (connectable from unrelated nodes). 90public nodes, but do not need an open port) or public nodes (connectable
91from any other node).
92 92
93=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id> 93=item node ID - C<[a-za-Z0-9_\-.:]+>
94 94
95A node reference is a string that either simply identifies the node (for 95A node ID is a string that uniquely identifies the node within a
96private and slave nodes), or contains a recipe on how to reach a given 96network. Depending on the configuration used, node IDs can look like a
97node (for public nodes). 97hostname, a hostname and a port, or a random string. AnyEvent::MP itself
98doesn't interpret node IDs in any way.
98 99
99This recipe is simply a comma-separated list of C<address:port> pairs (for 100=item binds - C<ip:port>
100TCP/IP, other protocols might look different).
101 101
102Node references come in two flavours: resolved (containing only numerical 102Nodes can only talk to each other by creating some kind of connection to
103addresses) or unresolved (where hostnames are used instead of addresses). 103each other. To do this, nodes should listen on one or more local transport
104endpoints - binds. Currently, only standard C<ip:port> specifications can
105be used, which specify TCP ports to listen on.
104 106
105Before using an unresolved node reference in a message you first have to 107=item seeds - C<host:port>
106resolve it. 108
109When a node starts, it knows nothing about the network. To teach the node
110about the network it first has to contact some other node within the
111network. This node is called a seed.
112
113Seeds are transport endpoint(s) of as many nodes as one wants. Those nodes
114are expected to be long-running, and at least one of those should always
115be available. When nodes run out of connections (e.g. due to a network
116error), they try to re-establish connections to some seednodes again to
117join the network.
107 118
108=back 119=back
109 120
110=head1 VARIABLES/FUNCTIONS 121=head1 VARIABLES/FUNCTIONS
111 122
128our $VERSION = $AnyEvent::MP::Kernel::VERSION; 139our $VERSION = $AnyEvent::MP::Kernel::VERSION;
129 140
130our @EXPORT = qw( 141our @EXPORT = qw(
131 NODE $NODE *SELF node_of after 142 NODE $NODE *SELF node_of after
132 resolve_node initialise_node 143 resolve_node initialise_node
133 snd rcv mon kil reg psub spawn 144 snd rcv mon mon_guard kil reg psub spawn
134 port 145 port
135); 146);
136 147
137our $SELF; 148our $SELF;
138 149
142 kil $SELF, die => $msg; 153 kil $SELF, die => $msg;
143} 154}
144 155
145=item $thisnode = NODE / $NODE 156=item $thisnode = NODE / $NODE
146 157
147The C<NODE> function returns, and the C<$NODE> variable contains the 158The C<NODE> function returns, and the C<$NODE> variable contains the node
148noderef of the local node. The value is initialised by a call to 159ID of the node running in the current process. This value is initialised by
149C<initialise_node>. 160a call to C<initialise_node>.
150 161
151=item $noderef = node_of $port 162=item $nodeid = node_of $port
152 163
153Extracts and returns the noderef from a port ID or a noderef. 164Extracts and returns the node ID part from a port ID or a node ID.
154 165
155=item initialise_node $noderef, $seednode, $seednode... 166=item initialise_node $profile_name
156 167
157=item initialise_node "slave/", $master, $master...
158
159Before a node can talk to other nodes on the network it has to initialise 168Before a node can talk to other nodes on the network (i.e. enter
160itself - the minimum a node needs to know is it's own name, and optionally 169"distributed mode") it has to initialise itself - the minimum a node needs
161it should know the noderefs of some other nodes in the network. 170to know is its own name, and optionally it should know the addresses of
171some other nodes in the network to discover other nodes.
162 172
163This function initialises a node - it must be called exactly once (or 173This function initialises a node - it must be called exactly once (or
164never) before calling other AnyEvent::MP functions. 174never) before calling other AnyEvent::MP functions.
165 175
166All arguments (optionally except for the first) are noderefs, which can be 176The first argument is a profile name. If it is C<undef> or missing, then
167either resolved or unresolved. 177the current nodename will be used instead (i.e. F<uname -n>).
168 178
169The first argument will be looked up in the configuration database first 179The function then looks up the profile in the aemp configuration (see the
170(if it is C<undef> then the current nodename will be used instead) to find 180L<aemp> commandline utility).
171the relevant configuration profile (see L<aemp>). If none is found then
172the default configuration is used. The configuration supplies additional
173seed/master nodes and can override the actual noderef.
174 181
175There are two types of networked nodes, public nodes and slave nodes: 182If the profile specifies a node ID, then this will become the node ID of
183this process. If not, then the profile name will be used as node ID. The
184special node ID of C<anon/> will be replaced by a random node ID.
176 185
177=over 4 186The next step is to look up the binds in the profile, followed by binding
187aemp protocol listeners on all binds specified (it is possible and valid
188to have no binds, meaning that the node cannot be contacted form the
189outside. This means the node cannot talk to other nodes that also have no
190binds, but it can still talk to all "normal" nodes).
178 191
179=item public nodes 192If the profile does not specify a binds list, then the node ID will be
193treated as if it were of the form C<host:port>, which will be resolved and
194used as binds list.
180 195
181For public nodes, C<$noderef> (supplied either directly to 196Lastly, the seeds list from the profile is passed to the
182C<initialise_node> or indirectly via a profile or the nodename) must be a 197L<AnyEvent::MP::Global> module, which will then use it to keep
183noderef (possibly unresolved, in which case it will be resolved). 198connectivity with at least on of those seed nodes at any point in time.
184 199
185After resolving, the node will bind itself on all endpoints and try to
186connect to all additional C<$seednodes> that are specified. Seednodes are
187optional and can be used to quickly bootstrap the node into an existing
188network.
189
190=item slave nodes
191
192When the C<$noderef> (either as given or overriden by the config file)
193is the special string C<slave/>, then the node will become a slave
194node. Slave nodes cannot be contacted from outside and will route most of
195their traffic to the master node that they attach to.
196
197At least one additional noderef is required (either by specifying it
198directly or because it is part of the configuration profile): The node
199will try to connect to all of them and will become a slave attached to the
200first node it can successfully connect to.
201
202Note that slave nodes cannot change their name, and consequently, their
203master, so if the master goes down, the slave node will not function well
204anymore until it can re-establish conenciton to its master. This makes
205slave nodes unsuitable for long-term nodes or fault-tolerant networks.
206
207=back
208
209This function will block until all nodes have been resolved and, for slave
210nodes, until it has successfully established a connection to a master
211server.
212
213All the seednodes will also be specially marked to automatically retry
214connecting to them infinitely.
215
216Example: become a public node listening on the guessed noderef, or the one 200Example: become a distributed node listening on the guessed noderef, or
217specified via C<aemp> for the current node. This should be the most common 201the one specified via C<aemp> for the current node. This should be the
218form of invocation for "daemon"-type nodes. 202most common form of invocation for "daemon"-type nodes.
219 203
220 initialise_node; 204 initialise_node;
221 205
222Example: become a slave node to any of the the seednodes specified via 206Example: become an anonymous node. This form is often used for commandline
223C<aemp>. This form is often used for commandline clients. 207clients.
224 208
225 initialise_node "slave/"; 209 initialise_node "anon/";
226 210
227Example: become a slave node to any of the specified master servers. This 211Example: become a distributed node. If there is no profile of the given
228form is also often used for commandline clients. 212name, or no binds list was specified, resolve C<localhost:4044> and bind
229 213on the resulting addresses.
230 initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
231
232Example: become a public node, and try to contact some well-known master
233servers to become part of the network.
234
235 initialise_node undef, "master1", "master2";
236
237Example: become a public node listening on port C<4041>.
238
239 initialise_node 4041;
240
241Example: become a public node, only visible on localhost port 4044.
242 214
243 initialise_node "localhost:4044"; 215 initialise_node "localhost:4044";
244
245=item $cv = resolve_node $noderef
246
247Takes an unresolved node reference that may contain hostnames and
248abbreviated IDs, resolves all of them and returns a resolved node
249reference.
250
251In addition to C<address:port> pairs allowed in resolved noderefs, the
252following forms are supported:
253
254=over 4
255
256=item the empty string
257
258An empty-string component gets resolved as if the default port (4040) was
259specified.
260
261=item naked port numbers (e.g. C<1234>)
262
263These are resolved by prepending the local nodename and a colon, to be
264further resolved.
265
266=item hostnames (e.g. C<localhost:1234>, C<localhost>)
267
268These are resolved by using AnyEvent::DNS to resolve them, optionally
269looking up SRV records for the C<aemp=4040> port, if no port was
270specified.
271
272=back
273 216
274=item $SELF 217=item $SELF
275 218
276Contains the current port id while executing C<rcv> callbacks or C<psub> 219Contains the current port id while executing C<rcv> callbacks or C<psub>
277blocks. 220blocks.

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