[ViewVC] Diff of: cvs/AnyEvent-MP/MP.pm

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.62 by root, Thu Aug 27 07:12:48 2009 UTC vs.
Revision 1.65 by root, Fri Aug 28 01:00:34 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
72	A port is something you can send messages to (with the C<snd> function).	70	A port is something you can send messages to (with the C<snd> function).
73		71
74	Ports allow you to register C<rcv> handlers that can match all or just	72	Ports allow you to register C<rcv> handlers that can match all or just
75	some messages. Messages will not be queued.	73	some messages. Messages send to ports will not be queued, regardless of
		74	anything was listening for them or not.
76		75
77	=item port id - C<noderef#portname>	76	=item port ID - C<noderef#portname>
78		77
79	A port ID is the concatenation of a noderef, a hash-mark (C<#>) as	78	A port ID is the concatenation of a noderef, a hash-mark (C<#>) as
80	separator, and a port name (a printable string of unspecified format). An	79	separator, and a port name (a printable string of unspecified format). An
81	exception is the the node port, whose ID is identical to its node	80	exception is the the node port, whose ID is identical to its node
82	reference.	81	reference.
…		…
89		88
90	Nodes are either private (single-process only), slaves (can only talk to	89	Nodes are either private (single-process only), slaves (can only talk to
91	public nodes, but do not need an open port) or public nodes (connectable	90	public nodes, but do not need an open port) or public nodes (connectable
92	from any other node).	91	from any other node).
93		92
94	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	93	=item node ID - C<[a-za-Z0-9_\-.:]+>
95		94
96	A node reference is a string that either simply identifies the node (for	95	A node ID is a string that uniquely identifies the node within a
97	private and slave nodes), or contains a recipe on how to reach a given	96	network. Depending on the configuration used, node IDs can look like a
98	node (for public nodes).	97	hostname, a hostname and a port, or a random string. AnyEvent::MP itself
		98	doesn't interpret node IDs in any way.
99		99
100	This recipe is simply a comma-separated list of C<address:port> pairs (for	100	=item binds - C<ip:port>
101	TCP/IP, other protocols might look different).
102		101
103	Node references come in two flavours: resolved (containing only numerical	102	Nodes can only talk to each other by creating some kind of connection to
104	addresses) or unresolved (where hostnames are used instead of addresses).	103	each other. To do this, nodes should listen on one or more local transport
		104	endpoints - binds. Currently, only standard C<ip:port> specifications can
		105	be used, which specify TCP ports to listen on.
105		106
106	Before using an unresolved node reference in a message you first have to	107	=item seeds - C<host:port>
107	resolve it.	108
		109	When a node starts, it knows nothing about the network. To teach the node
		110	about the network it first has to contact some other node within the
		111	network. This node is called a seed.
		112
		113	Seeds are transport endpoint(s) of as many nodes as one wants. Those nodes
		114	are expected to be long-running, and at least one of those should always
		115	be available. When nodes run out of connections (e.g. due to a network
		116	error), they try to re-establish connections to some seednodes again to
		117	join the network.
108		118
109	=back	119	=back
110		120
111	=head1 VARIABLES/FUNCTIONS	121	=head1 VARIABLES/FUNCTIONS
112		122
…		…
143	kil $SELF, die => $msg;	153	kil $SELF, die => $msg;
144	}	154	}
145		155
146	=item $thisnode = NODE / $NODE	156	=item $thisnode = NODE / $NODE
147		157
148	The C<NODE> function returns, and the C<$NODE> variable contains the	158	The C<NODE> function returns, and the C<$NODE> variable contains the node
149	noderef of the local node. The value is initialised by a call to	159	ID of the node running in the current process. This value is initialised by
150	C<initialise_node>.	160	a call to C<initialise_node>.
151		161
152	=item $noderef = node_of $port	162	=item $nodeid = node_of $port
153		163
154	Extracts and returns the noderef from a port ID or a noderef.	164	Extracts and returns the node ID part from a port ID or a node ID.
155		165
156	=item initialise_node $noderef, $seednode, $seednode...	166	=item initialise_node $profile_name
157		167
158	=item initialise_node "slave/", $master, $master...
159
160	Before a node can talk to other nodes on the network it has to initialise	168	Before a node can talk to other nodes on the network (i.e. enter
161	itself - 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
162	it should know the noderefs of some other nodes in the network.	170	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.
163		172
164	This function initialises a node - it must be called exactly once (or	173	This function initialises a node - it must be called exactly once (or
165	never) before calling other AnyEvent::MP functions.	174	never) before calling other AnyEvent::MP functions.
166		175
167	All arguments (optionally except for the first) are noderefs, which can be	176	The first argument is a profile name. If it is C<undef> or missing, then
168	either resolved or unresolved.	177	the current nodename will be used instead (i.e. F<uname -n>).
169		178
170	The first argument will be looked up in the configuration database first	179	The function then looks up the profile in the aemp configuration (see the
171	(if it is C<undef> then the current nodename will be used instead) to find	180	L<aemp> commandline utility).
172	the relevant configuration profile (see L<aemp>). If none is found then
173	the default configuration is used. The configuration supplies additional
174	seed/master nodes and can override the actual noderef.
175		181
176	There are two types of networked nodes, public nodes and slave nodes:	182	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
		184	special node ID of C<anon/> will be replaced by a random node ID.
177		185
178	=over 4	186	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
		188	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
		190	binds, but it can still talk to all "normal" nodes).
179		191
180	=item public nodes	192	If the profile does not specify a binds list, then the node ID will be
		193	treated as if it were of the form C<host:port>, which will be resolved and
		194	used as binds list.
181		195
182	For public nodes, C<$noderef> (supplied either directly to	196	Lastly, the seeds list from the profile is passed to the
183	C<initialise_node> or indirectly via a profile or the nodename) must be a	197	L<AnyEvent::MP::Global> module, which will then use it to keep
184	noderef (possibly unresolved, in which case it will be resolved).	198	connectivity with at least on of those seed nodes at any point in time.
185		199
186	After resolving, the node will bind itself on all endpoints.
187
188	=item slave nodes
189
190	When the C<$noderef> (either as given or overriden by the config file)
191	is the special string C<slave/>, then the node will become a slave
192	node. Slave nodes cannot be contacted from outside, and cannot talk to
193	each other (at least in this version of AnyEvent::MP).
194
195	Slave nodes work by creating connections to all public nodes, using the
196	L<AnyEvent::MP::Global> service.
197
198	=back
199
200	After initialising itself, the node will connect to all additional
201	C<$seednodes> that are specified diretcly or via a profile. Seednodes are
202	optional and can be used to quickly bootstrap the node into an existing
203	network.
204
205	All the seednodes will also be specially marked to automatically retry
206	connecting to them indefinitely, so make sure that seednodes are really
207	reliable and up (this might also change in the future).
208
209	Example: become a public node listening on the guessed noderef, or the one	200	Example: become a distributed node listening on the guessed noderef, or
210	specified via C<aemp> for the current node. This should be the most common	201	the one specified via C<aemp> for the current node. This should be the
211	form of invocation for "daemon"-type nodes.	202	most common form of invocation for "daemon"-type nodes.
212		203
213	initialise_node;	204	initialise_node;
214		205
215	Example: become a slave node to any of the the seednodes specified via	206	Example: become an anonymous node. This form is often used for commandline
216	C<aemp>. This form is often used for commandline clients.	207	clients.
217		208
218	initialise_node "slave/";	209	initialise_node "anon/";
219		210
220	Example: become a public node, and try to contact some well-known master	211	Example: become a distributed node. If there is no profile of the given
221	servers to become part of the network.	212	name, or no binds list was specified, resolve C<localhost:4044> and bind
222		213	on the resulting addresses.
223	initialise_node undef, "master1", "master2";
224
225	Example: become a public node listening on port C<4041>.
226
227	initialise_node 4041;
228
229	Example: become a public node, only visible on localhost port 4044.
230		214
231	initialise_node "localhost:4044";	215	initialise_node "localhost:4044";
232
233	=item $cv = resolve_node $noderef
234
235	Takes an unresolved node reference that may contain hostnames and
236	abbreviated IDs, resolves all of them and returns a resolved node
237	reference.
238
239	In addition to C<address:port> pairs allowed in resolved noderefs, the
240	following forms are supported:
241
242	=over 4
243
244	=item the empty string
245
246	An empty-string component gets resolved as if the default port (4040) was
247	specified.
248
249	=item naked port numbers (e.g. C<1234>)
250
251	These are resolved by prepending the local nodename and a colon, to be
252	further resolved.
253
254	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
255
256	These are resolved by using AnyEvent::DNS to resolve them, optionally
257	looking up SRV records for the C<aemp=4040> port, if no port was
258	specified.
259
260	=back
261		216
262	=item $SELF	217	=item $SELF
263		218
264	Contains the current port id while executing C<rcv> callbacks or C<psub>	219	Contains the current port id while executing C<rcv> callbacks or C<psub>
265	blocks.	220	blocks.
…		…
710		665
711	Despite the similarities, there are also some important differences:	666	Despite the similarities, there are also some important differences:
712		667
713	=over 4	668	=over 4
714		669
715	=item * Node references contain the recipe on how to contact them.	670	=item * Node IDs are arbitrary strings in AEMP.
716		671
717	Erlang relies on special naming and DNS to work everywhere in the	672	Erlang relies on special naming and DNS to work everywhere in the same
718	same way. AEMP relies on each node knowing it's own address(es), with	673	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
719	convenience functionality.	674	configuraiton or DNS), but will otherwise discover other odes itself.
720
721	This means that AEMP requires a less tightly controlled environment at the
722	cost of longer node references and a slightly higher management overhead.
723		675
724	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP	676	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
725	uses "local ports are like remote ports".	677	uses "local ports are like remote ports".
726		678
727	The failure modes for local ports are quite different (runtime errors	679	The failure modes for local ports are quite different (runtime errors

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.62 by root, Thu Aug 27 07:12:48 2009 UTC vs. Revision 1.65 by root, Fri Aug 28 01:00:34 2009 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.62 by root, Thu Aug 27 07:12:48 2009 UTC vs.
Revision 1.65 by root, Fri Aug 28 01:00:34 2009 UTC