--- AnyEvent-MP/MP.pm 2009/08/14 15:31:21 1.53 +++ AnyEvent-MP/MP.pm 2012/02/28 18:37:24 1.121 @@ -1,23 +1,20 @@ =head1 NAME -AnyEvent::MP - multi-processing/message-passing framework +AnyEvent::MP - erlang-style multi-processing/message-passing framework =head1 SYNOPSIS use AnyEvent::MP; - $NODE # contains this node's noderef - NODE # returns this node's noderef - NODE $port # returns the noderef of the port + $NODE # contains this node's node ID + NODE # returns this node's node ID $SELF # receiving/own port id in rcv callbacks # initialise the node so it can send/receive messages - initialise_node; # -OR- - initialise_node "localhost:4040"; # -OR- - initialise_node "slave/", "localhost:4040" + configure; - # ports are message endpoints + # ports are message destinations # sending messages snd $port, type => data...; @@ -25,43 +22,50 @@ snd @msg_with_first_element_being_a_port; # creating/using ports, the simple way - my $simple_port = port { my @msg = @_; 0 }; + my $simple_port = port { my @msg = @_ }; # creating/using ports, tagged message matching my $port = port; - rcv $port, ping => sub { snd $_[0], "pong"; 0 }; - rcv $port, pong => sub { warn "pong received\n"; 0 }; + rcv $port, ping => sub { snd $_[0], "pong" }; + rcv $port, pong => sub { warn "pong received\n" }; # create a port on another node my $port = spawn $node, $initfunc, @initdata; + # destroy a port again + kil $port; # "normal" kill + kil $port, my_error => "everything is broken"; # error kill + # monitoring - mon $port, $cb->(@msg) # callback is invoked on death - mon $port, $otherport # kill otherport on abnormal death - mon $port, $otherport, @msg # send message on death + mon $localport, $cb->(@msg) # callback is invoked on death + mon $localport, $otherport # kill otherport on abnormal death + mon $localport, $otherport, @msg # send message on death + + # temporarily execute code in port context + peval $port, sub { die "kill the port!" }; + + # execute callbacks in $SELF port context + my $timer = AE::timer 1, 0, psub { + die "kill the port, delayed"; + }; =head1 CURRENT STATUS - AnyEvent::MP - stable API, should work - AnyEvent::MP::Intro - outdated - AnyEvent::MP::Kernel - WIP - AnyEvent::MP::Transport - mostly stable - - stay tuned. + bin/aemp - stable. + AnyEvent::MP - stable API, should work. + AnyEvent::MP::Intro - explains most concepts. + AnyEvent::MP::Kernel - mostly stable API. + AnyEvent::MP::Global - stable API. =head1 DESCRIPTION This module (-family) implements a simple message passing framework. Despite its simplicity, you can securely message other processes running -on the same or other hosts. +on the same or other hosts, and you can supervise entities remotely. For an introduction to this module family, see the L -manual page. - -At the moment, this module family is severly broken and underdocumented, -so do not use. This was uploaded mainly to reserve the CPAN namespace - -stay tuned! +manual page and the examples under F. =head1 CONCEPTS @@ -69,41 +73,99 @@ =item port -A port is something you can send messages to (with the C function). +Not to be confused with a TCP port, a "port" is something you can send +messages to (with the C function). Ports allow you to register C handlers that can match all or just -some messages. Messages will not be queued. +some messages. Messages send to ports will not be queued, regardless of +anything was listening for them or not. + +Ports are represented by (printable) strings called "port IDs". -=item port id - C +=item port ID - C -A port ID is the concatenation of a noderef, a hash-mark (C<#>) as -separator, and a port name (a printable string of unspecified format). An -exception is the the node port, whose ID is identical to its node -reference. +A port ID is the concatenation of a node ID, a hash-mark (C<#>) as +separator, and a port name (a printable string of unspecified format). =item node A node is a single process containing at least one port - the node port, -which provides nodes to manage each other remotely, and to create new +which enables nodes to manage each other remotely, and to create new ports. -Nodes are either private (single-process only), slaves (connected to a -master node only) or public nodes (connectable from unrelated nodes). +Nodes are either public (have one or more listening ports) or private +(no listening ports). Private nodes cannot talk to other private nodes +currently, but all nodes can talk to public nodes. + +Nodes is represented by (printable) strings called "node IDs". + +=item node ID - C<[A-Za-z0-9_\-.:]*> + +A node ID is a string that uniquely identifies the node within a +network. Depending on the configuration used, node IDs can look like a +hostname, a hostname and a port, or a random string. AnyEvent::MP itself +doesn't interpret node IDs in any way except to uniquely identify a node. + +=item binds - C + +Nodes can only talk to each other by creating some kind of connection to +each other. To do this, nodes should listen on one or more local transport +endpoints - binds. + +Currently, only standard C specifications can be used, which +specify TCP ports to listen on. So a bind is basically just a tcp socket +in listening mode thta accepts conenctions form other nodes. + +=item seed nodes -=item noderef - C, C, C +When a node starts, it knows nothing about the network it is in - it +needs to connect to at least one other node that is already in the +network. These other nodes are called "seed nodes". -A node reference is a string that either simply identifies the node (for -private and slave nodes), or contains a recipe on how to reach a given -node (for public nodes). +Seed nodes themselves are not special - they are seed nodes only because +some other node I them as such, but any node can be used as seed +node for other nodes, and eahc node cna use a different set of seed nodes. -This recipe is simply a comma-separated list of C pairs (for -TCP/IP, other protocols might look different). +In addition to discovering the network, seed nodes are also used to +maintain the network - all nodes using the same seed node form are part of +the same network. If a network is split into multiple subnets because e.g. +the network link between the parts goes down, then using the same seed +nodes for all nodes ensures that eventually the subnets get merged again. -Node references come in two flavours: resolved (containing only numerical -addresses) or unresolved (where hostnames are used instead of addresses). +Seed nodes are expected to be long-running, and at least one seed node +should always be available. They should also be relatively responsive - a +seed node that blocks for long periods will slow down everybody else. -Before using an unresolved node reference in a message you first have to -resolve it. +For small networks, it's best if every node uses the same set of seed +nodes. For large networks, it can be useful to specify "regional" seed +nodes for most nodes in an area, and use all seed nodes as seed nodes for +each other. What's important is that all seed nodes connections form a +complete graph, so that the network cannot split into separate subnets +forever. + +Seed nodes are represented by seed IDs. + +=item seed IDs - C + +Seed IDs are transport endpoint(s) (usually a hostname/IP address and a +TCP port) of nodes that should be used as seed nodes. + +=item global nodes + +An AEMP network needs a discovery service - nodes need to know how to +connect to other nodes they only know by name. In addition, AEMP offers a +distributed "group database", which maps group names to a list of strings +- for example, to register worker ports. + +A network needs at least one global node to work, and allows every node to +be a global node. + +Any node that loads the L module becomes a global +node and tries to keep connections to all other nodes. So while it can +make sense to make every node "global" in small networks, it usually makes +sense to only make seed nodes into global nodes in large networks (nodes +keep connections to seed nodes and global nodes, so makign them the same +reduces overhead). =back @@ -115,7 +177,9 @@ package AnyEvent::MP; +use AnyEvent::MP::Config (); use AnyEvent::MP::Kernel; +use AnyEvent::MP::Kernel qw(%NODE %PORT %PORT_DATA $UNIQ $RUNIQ $ID); use common::sense; @@ -125,12 +189,12 @@ use base "Exporter"; -our $VERSION = $AnyEvent::MP::Kernel::VERSION; +our $VERSION = $AnyEvent::MP::Config::VERSION; our @EXPORT = qw( - NODE $NODE *SELF node_of _any_ - resolve_node initialise_node - snd rcv mon kil reg psub spawn + NODE $NODE *SELF node_of after + configure + snd rcv mon mon_guard kil psub peval spawn cal port ); @@ -144,156 +208,152 @@ =item $thisnode = NODE / $NODE -The C function returns, and the C<$NODE> variable contains the -noderef of the local node. The value is initialised by a call to -C. +The C function returns, and the C<$NODE> variable contains, the node +ID of the node running in the current process. This value is initialised by +a call to C. -=item $noderef = node_of $port +=item $nodeid = node_of $port -Extracts and returns the noderef from a port ID or a noderef. +Extracts and returns the node ID from a port ID or a node ID. -=item initialise_node $noderef, $seednode, $seednode... +=item configure $profile, key => value... -=item initialise_node "slave/", $master, $master... +=item configure key => value... -Before a node can talk to other nodes on the network it has to initialise -itself - the minimum a node needs to know is it's own name, and optionally -it should know the noderefs of some other nodes in the network. +Before a node can talk to other nodes on the network (i.e. enter +"distributed mode") it has to configure itself - the minimum a node needs +to know is its own name, and optionally it should know the addresses of +some other nodes in the network to discover other nodes. -This function initialises a node - it must be called exactly once (or +This function configures a node - it must be called exactly once (or never) before calling other AnyEvent::MP functions. -All arguments (optionally except for the first) are noderefs, which can be -either resolved or unresolved. - -The first argument will be looked up in the configuration database first -(if it is C then the current nodename will be used instead) to find -the relevant configuration profile (see L). If none is found then -the default configuration is used. The configuration supplies additional -seed/master nodes and can override the actual noderef. - -There are two types of networked nodes, public nodes and slave nodes: +The key/value pairs are basically the same ones as documented for the +F command line utility (sans the set/del prefix), with two additions: =over 4 -=item public nodes +=item norc => $boolean (default false) -For public nodes, C<$noderef> (supplied either directly to -C or indirectly via a profile or the nodename) must be a -noderef (possibly unresolved, in which case it will be resolved). - -After resolving, the node will bind itself on all endpoints and try to -connect to all additional C<$seednodes> that are specified. Seednodes are -optional and can be used to quickly bootstrap the node into an existing -network. - -=item slave nodes - -When the C<$noderef> (either as given or overriden by the config file) -is the special string C, then the node will become a slave -node. Slave nodes cannot be contacted from outside and will route most of -their traffic to the master node that they attach to. - -At least one additional noderef is required (either by specifying it -directly or because it is part of the configuration profile): The node -will try to connect to all of them and will become a slave attached to the -first node it can successfully connect to. - -=back +If true, then the rc file (e.g. F<~/.perl-anyevent-mp>) will I +be consulted - all configuraiton options must be specified in the +C call. -This function will block until all nodes have been resolved and, for slave -nodes, until it has successfully established a connection to a master -server. +=item force => $boolean (default false) -Example: become a public node listening on the guessed noderef, or the one -specified via C for the current node. This should be the most common -form of invocation for "daemon"-type nodes. +IF true, then the values specified in the C will take +precedence over any values configured via the rc file. The default is for +the rc file to override any options specified in the program. - initialise_node; - -Example: become a slave node to any of the the seednodes specified via -C. This form is often used for commandline clients. - - initialise_node "slave/"; - -Example: become a slave node to any of the specified master servers. This -form is also often used for commandline clients. - - initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net"; - -Example: become a public node, and try to contact some well-known master -servers to become part of the network. - - initialise_node undef, "master1", "master2"; - -Example: become a public node listening on port C<4041>. - - initialise_node 4041; +=back -Example: become a public node, only visible on localhost port 4044. +=over 4 - initialise_node "localhost:4044"; +=item step 1, gathering configuration from profiles -=item $cv = resolve_node $noderef +The function first looks up a profile in the aemp configuration (see the +L commandline utility). The profile name can be specified via the +named C parameter or can simply be the first parameter). If it is +missing, then the nodename (F) will be used as profile name. + +The profile data is then gathered as follows: + +First, all remaining key => value pairs (all of which are conveniently +undocumented at the moment) will be interpreted as configuration +data. Then they will be overwritten by any values specified in the global +default configuration (see the F utility), then the chain of +profiles chosen by the profile name (and any C attributes). + +That means that the values specified in the profile have highest priority +and the values specified directly via C have lowest priority, +and can only be used to specify defaults. + +If the profile specifies a node ID, then this will become the node ID of +this process. If not, then the profile name will be used as node ID. The +special node ID of C will be replaced by a random node ID. + +=item step 2, bind listener sockets + +The next step is to look up the binds in the profile, followed by binding +aemp protocol listeners on all binds specified (it is possible and valid +to have no binds, meaning that the node cannot be contacted form the +outside. This means the node cannot talk to other nodes that also have no +binds, but it can still talk to all "normal" nodes). + +If the profile does not specify a binds list, then a default of C<*> is +used, meaning the node will bind on a dynamically-assigned port on every +local IP address it finds. + +=item step 3, connect to seed nodes + +As the last step, the seed ID list from the profile is passed to the +L module, which will then use it to keep +connectivity with at least one node at any point in time. -Takes an unresolved node reference that may contain hostnames and -abbreviated IDs, resolves all of them and returns a resolved node -reference. +=back -In addition to C pairs allowed in resolved noderefs, the -following forms are supported: +Example: become a distributed node using the local node name as profile. +This should be the most common form of invocation for "daemon"-type nodes. -=over 4 + configure -=item the empty string +Example: become an anonymous node. This form is often used for commandline +clients. -An empty-string component gets resolved as if the default port (4040) was -specified. + configure nodeid => "anon/"; -=item naked port numbers (e.g. C<1234>) +Example: configure a node using a profile called seed, which is suitable +for a seed node as it binds on all local addresses on a fixed port (4040, +customary for aemp). -These are resolved by prepending the local nodename and a colon, to be -further resolved. + # use the aemp commandline utility + # aemp profile seed nodeid anon/ binds '*:4040' -=item hostnames (e.g. C, C) + # then use it + configure profile => "seed"; -These are resolved by using AnyEvent::DNS to resolve them, optionally -looking up SRV records for the C port, if no port was -specified. + # or simply use aemp from the shell again: + # aemp run profile seed -=back + # or provide a nicer-to-remember nodeid + # aemp run profile seed nodeid "$(hostname)" =item $SELF Contains the current port id while executing C callbacks or C blocks. -=item SELF, %SELF, @SELF... +=item *SELF, SELF, %SELF, @SELF... Due to some quirks in how perl exports variables, it is impossible to -just export C<$SELF>, all the symbols called C are exported by this +just export C<$SELF>, all the symbols named C are exported by this module, but only C<$SELF> is currently used. =item snd $port, type => @data =item snd $port, @msg -Send the given message to the given port ID, which can identify either -a local or a remote port, and must be a port ID. +Send the given message to the given port, which can identify either a +local or a remote port, and must be a port ID. -While the message can be about anything, it is highly recommended to use a -string as first element (a port ID, or some word that indicates a request -type etc.). - -The message data effectively becomes read-only after a call to this -function: modifying any argument is not allowed and can cause many -problems. +While the message can be almost anything, it is highly recommended to +use a string as first element (a port ID, or some word that indicates a +request type etc.) and to consist if only simple perl values (scalars, +arrays, hashes) - if you think you need to pass an object, think again. + +The message data logically becomes read-only after a call to this +function: modifying any argument (or values referenced by them) is +forbidden, as there can be considerable time between the call to C +and the time the message is actually being serialised - in fact, it might +never be copied as within the same process it is simply handed to the +receiving port. The type of data you can transfer depends on the transport protocol: when JSON is used, then only strings, numbers and arrays and hashes consisting of those are allowed (no objects). When Storable is used, then anything that Storable can serialise and deserialise is allowed, and for the local -node, anything can be passed. +node, anything can be passed. Best rely only on the common denominator of +these. =item $local_port = port @@ -327,7 +387,7 @@ } sub port(;&) { - my $id = "$UNIQ." . $ID++; + my $id = "$UNIQ." . ++$ID; my $port = "$NODE#$id"; rcv $port, shift || \&_kilme; @@ -350,9 +410,10 @@ =item rcv $local_port, tag => $callback->(@msg_without_tag), ... -Register callbacks to be called on messages starting with the given tag on -the given port (and return the port), or unregister it (when C<$callback> -is C<$undef>). +Register (or replace) callbacks to be called on messages starting with the +given tag on the given port (and return the port), or unregister it (when +C<$callback> is C<$undef> or missing). There can only be one callback +registered for each tag. The original message will be passed to the callback, after the first element (the tag) has been removed. The callback will use the same @@ -374,13 +435,22 @@ ... ; +Example: temporarily register a rcv callback for a tag matching some port +(e.g. for an rpc reply) and unregister it after a message was received. + + rcv $port, $otherport => sub { + my @reply = @_; + + rcv $SELF, $otherport; + }; + =cut sub rcv($@) { my $port = shift; - my ($noderef, $portid) = split /#/, $port, 2; + my ($nodeid, $portid) = split /#/, $port, 2; - ($NODE{$noderef} || add_node $noderef) == $NODE{""} + $NODE{$nodeid} == $NODE{""} or Carp::croak "$port: rcv can only be called on local ports, caught"; while (@_) { @@ -389,7 +459,7 @@ "AnyEvent::MP::Port" eq ref $self or Carp::croak "$port: rcv can only be called on message matching ports, caught"; - $self->[2] = shift; + $self->[0] = shift; } else { my $cb = shift; $PORT{$portid} = sub { @@ -399,7 +469,7 @@ } } elsif (defined $_[0]) { my $self = $PORT_DATA{$portid} ||= do { - my $self = bless [$PORT{$port} || sub { }, { }, $port], "AnyEvent::MP::Port"; + my $self = bless [$PORT{$portid} || sub { }, { }, $port], "AnyEvent::MP::Port"; $PORT{$portid} = sub { local $SELF = $port; @@ -431,12 +501,52 @@ $port } +=item peval $port, $coderef[, @args] + +Evaluates the given C<$codref> within the contetx of C<$port>, that is, +when the code throews an exception the C<$port> will be killed. + +Any remaining args will be passed to the callback. Any return values will +be returned to the caller. + +This is useful when you temporarily want to execute code in the context of +a port. + +Example: create a port and run some initialisation code in it's context. + + my $port = port { ... }; + + peval $port, sub { + init + or die "unable to init"; + }; + +=cut + +sub peval($$) { + local $SELF = shift; + my $cb = shift; + + if (wantarray) { + my @res = eval { &$cb }; + _self_die if $@; + @res + } else { + my $res = eval { &$cb }; + _self_die if $@; + $res + } +} + =item $closure = psub { BLOCK } Remembers C<$SELF> and creates a closure out of the BLOCK. When the closure is executed, sets up the environment in the same way as in C callbacks, i.e. runtime errors will cause the port to get Ced. +The effect is basically as if it returned C<< sub { peval $SELF, sub { +BLOCK }, @_ } >>. + This is useful when you register callbacks from C callbacks: rcv delayed_reply => sub { @@ -469,33 +579,25 @@ } } -=item $guard = mon $port, $cb->(@reason) +=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies -=item $guard = mon $port, $rcvport +=item $guard = mon $port, $rcvport # kill $rcvport when $port dies -=item $guard = mon $port +=item $guard = mon $port # kill $SELF when $port dies -=item $guard = mon $port, $rcvport, @msg +=item $guard = mon $port, $rcvport, @msg # send a message when $port dies Monitor the given port and do something when the port is killed or messages to it were lost, and optionally return a guard that can be used to stop monitoring again. -C effectively guarantees that, in the absence of hardware failures, -that after starting the monitor, either all messages sent to the port -will arrive, or the monitoring action will be invoked after possible -message loss has been detected. No messages will be lost "in between" -(after the first lost message no further messages will be received by the -port). After the monitoring action was invoked, further messages might get -delivered again. - In the first form (callback), the callback is simply called with any number of C<@reason> elements (no @reason means that the port was deleted "normally"). Note also that I<< the callback B never die >>, so use C if unsure. In the second form (another port given), the other port (C<$rcvport>) -will be C'ed with C<@reason>, iff a @reason was specified, i.e. on +will be C'ed with C<@reason>, if a @reason was specified, i.e. on "normal" kils nothing happens, while under all other conditions, the other port is killed with the same reason. @@ -505,13 +607,33 @@ In the last form (message), a message of the form C<@msg, @reason> will be C. +Monitoring-actions are one-shot: once messages are lost (and a monitoring +alert was raised), they are removed and will not trigger again. + As a rule of thumb, monitoring requests should always monitor a port from a local port (or callback). The reason is that kill messages might get lost, just like any other message. Another less obvious reason is that -even monitoring requests can get lost (for exmaple, when the connection +even monitoring requests can get lost (for example, when the connection to the other node goes down permanently). When monitoring a port locally these problems do not exist. +C effectively guarantees that, in the absence of hardware failures, +after starting the monitor, either all messages sent to the port will +arrive, or the monitoring action will be invoked after possible message +loss has been detected. No messages will be lost "in between" (after +the first lost message no further messages will be received by the +port). After the monitoring action was invoked, further messages might get +delivered again. + +Inter-host-connection timeouts and monitoring depend on the transport +used. The only transport currently implemented is TCP, and AnyEvent::MP +relies on TCP to detect node-downs (this can take 10-15 minutes on a +non-idle connection, and usually around two hours for idle connections). + +This means that monitoring is good for program errors and cleaning up +stuff eventually, but they are no replacement for a timeout when you need +to ensure some maximum latency. + Example: call a given callback when C<$port> is killed. mon $port, sub { warn "port died because of <@_>\n" }; @@ -527,9 +649,9 @@ =cut sub mon { - my ($noderef, $port) = split /#/, shift, 2; + my ($nodeid, $port) = split /#/, shift, 2; - my $node = $NODE{$noderef} || add_node $noderef; + my $node = $NODE{$nodeid} || add_node $nodeid; my $cb = @_ ? shift : $SELF || Carp::croak 'mon: called with one argument only, but $SELF not set,'; @@ -548,7 +670,7 @@ $node->monitor ($port, $cb); defined wantarray - and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) } + and ($cb += 0, AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }) } =item $guard = mon_guard $port, $ref, $ref... @@ -559,10 +681,10 @@ Optionally returns a guard that will stop the monitoring. This function is useful when you create e.g. timers or other watchers and -want to free them when the port gets killed: +want to free them when the port gets killed (note the use of C): $port->rcv (start => sub { - my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub { + my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub { undef $timer if 0.9 < rand; }); }); @@ -581,11 +703,12 @@ Kill the specified port with the given C<@reason>. -If no C<@reason> is specified, then the port is killed "normally" (linked -ports will not be kileld, or even notified). +If no C<@reason> is specified, then the port is killed "normally" - +monitor callback will be invoked, but the kil will not cause linked ports +(C form) to get killed. -Otherwise, linked ports get killed with the same reason (second form of -C, see below). +If a C<@reason> is specified, then linked ports (C +form) get killed with the same reason. Runtime errors while evaluating C callbacks or inside C blocks will be reported as reason C<< die => $@ >>. @@ -600,13 +723,13 @@ Creates a port on the node C<$node> (which can also be a port ID, in which case it's the node where that port resides). -The port ID of the newly created port is return immediately, and it is -permissible to immediately start sending messages or monitor the port. +The port ID of the newly created port is returned immediately, and it is +possible to immediately start sending messages or to monitor the port. -After the port has been created, the init function is -called. This function must be a fully-qualified function name -(e.g. C). To specify a function in the main -program, use C<::name>. +After the port has been created, the init function is called on the remote +node, in the same context as a C callback. This function must be a +fully-qualified function name (e.g. C). To +specify a function in the main program, use C<::name>. If the function doesn't exist, then the node tries to C the package, then the package above the package and so on (e.g. @@ -614,11 +737,18 @@ exists or it runs out of package names. The init function is then called with the newly-created port as context -object (C<$SELF>) and the C<@initdata> values as arguments. - -A common idiom is to pass your own port, monitor the spawned port, and -in the init function, monitor the original port. This two-way monitoring -ensures that both ports get cleaned up when there is a problem. +object (C<$SELF>) and the C<@initdata> values as arguments. It I +call one of the C functions to set callbacks on C<$SELF>, otherwise +the port might not get created. + +A common idiom is to pass a local port, immediately monitor the spawned +port, and in the remote init function, immediately monitor the passed +local port. This two-way monitoring ensures that both ports get cleaned up +when there is a problem. + +C guarantees that the C<$initfunc> has no visible effects on the +caller before C returns (by delaying invocation when spawn is +called for the local node). Example: spawn a chat server port on C<$othernode>. @@ -643,6 +773,7 @@ my $port = shift; my $init = shift; + # rcv will create the actual port local $SELF = "$NODE#$port"; eval { &{ load_func $init } @@ -651,64 +782,94 @@ } sub spawn(@) { - my ($noderef, undef) = split /#/, shift, 2; + my ($nodeid, undef) = split /#/, shift, 2; - my $id = "$RUNIQ." . $ID++; + my $id = "$RUNIQ." . ++$ID; $_[0] =~ /::/ or Carp::croak "spawn init function must be a fully-qualified name, caught"; - ($NODE{$noderef} || add_node $noderef) - ->send (["", "AnyEvent::MP::_spawn" => $id, @_]); + snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_; - "$noderef#$id" + "$nodeid#$id" } -=back -=head1 NODE MESSAGES +=item after $timeout, @msg -Nodes understand the following messages sent to them. Many of them take -arguments called C<@reply>, which will simply be used to compose a reply -message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and -the remaining arguments are simply the message data. +=item after $timeout, $callback -While other messages exist, they are not public and subject to change. +Either sends the given message, or call the given callback, after the +specified number of seconds. -=over 4 +This is simply a utility function that comes in handy at times - the +AnyEvent::MP author is not convinced of the wisdom of having it, though, +so it may go away in the future. =cut -=item lookup => $name, @reply +sub after($@) { + my ($timeout, @action) = @_; -Replies with the port ID of the specified well-known port, or C. + my $t; $t = AE::timer $timeout, 0, sub { + undef $t; + ref $action[0] + ? $action[0]() + : snd @action; + }; +} -=item devnull => ... +=item cal $port, @msg, $callback[, $timeout] -Generic data sink/CPU heat conversion. +A simple form of RPC - sends a message to the given C<$port> with the +given contents (C<@msg>), but adds a reply port to the message. -=item relay => $port, @msg +The reply port is created temporarily just for the purpose of receiving +the reply, and will be Ced when no longer needed. -Simply forwards the message to the given port. +A reply message sent to the port is passed to the C<$callback> as-is. -=item eval => $string[ @reply] +If an optional time-out (in seconds) is given and it is not C, +then the callback will be called without any arguments after the time-out +elapsed and the port is Ced. -Evaluates the given string. If C<@reply> is given, then a message of the -form C<@reply, $@, @evalres> is sent. +If no time-out is given (or it is C), then the local port will +monitor the remote port instead, so it eventually gets cleaned-up. -Example: crash another node. +Currently this function returns the temporary port, but this "feature" +might go in future versions unless you can make a convincing case that +this is indeed useful for something. - snd $othernode, eval => "exit"; +=cut -=item time => @reply +sub cal(@) { + my $timeout = ref $_[-1] ? undef : pop; + my $cb = pop; -Replies the the current node time to C<@reply>. + my $port = port { + undef $timeout; + kil $SELF; + &$cb; + }; + + if (defined $timeout) { + $timeout = AE::timer $timeout, 0, sub { + undef $timeout; + kil $port; + $cb->(); + }; + } else { + mon $_[0], sub { + kil $port; + $cb->(); + }; + } -Example: tell the current node to send the current time to C<$myport> in a -C message. + push @_, $port; + &snd; - snd $NODE, time => $myport, timereply => 1, 2; - # => snd $myport, timereply => 1, 2,