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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.122 by root, Wed Feb 29 18:44:59 2012 UTC vs.
Revision 1.127 by root, Sat Mar 3 20:35:10 2012 UTC

 Ports are represented by (printable) strings called "port IDs".
 =item port ID - C<nodeid#portname>
-A port ID is the concatenation of a node ID, a hash-mark (C<#>) as
+A port ID is the concatenation of a node ID, a hash-mark (C<#>)
-separator, and a port name (a printable string of unspecified format).
+as separator, and a port name (a printable string of unspecified
+format created by AnyEvent::MP).
 =item node
 A node is a single process containing at least one port - the node port,
 which enables nodes to manage each other remotely, and to create new
 use common::sense;
 use Carp ();
 use AE ();
+use Guard ();
 use base "Exporter";
 our $VERSION = $AnyEvent::MP::Config::VERSION;
 our @EXPORT = qw(
    NODE $NODE *SELF node_of after
    configure
    snd rcv mon mon_guard kil psub peval spawn cal
    port
+   db_set db_del db_reg
 );
 our $SELF;
 sub _self_die() {
 This function configures a node - it must be called exactly once (or
 never) before calling other AnyEvent::MP functions.
 The key/value pairs are basically the same ones as documented for the
-F<aemp> command line utility (sans the set/del prefix), with two additions:
+F<aemp> command line utility (sans the set/del prefix), with these additions:
 =over 4
 =item norc => $boolean (default false)
 =item force => $boolean (default false)
 IF true, then the values specified in the C<configure> 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.
+=item secure => $pass->($nodeid)
+In addition to specifying a boolean, you can specify a code reference that
+is called for every remote execution attempt - the execution request is
+granted iff the callback returns a true value.
+See F<semp setsecure> for more info.
 =back
 =over 4
 and the values specified directly via C<configure> 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, with
-a slash (C</>) attached.
+a unique randoms tring (C</%u>) appended.
-If the node ID (or profile name) ends with a slash (C</>), then a random
+The node ID can contain some C<%> sequences that are expanded: C<%n>
-string is appended to make it unique.
+is expanded to the local nodename, C<%u> is replaced by a random
+strign to make the node unique. For example, the F<aemp> commandline
+utility uses C<aemp/%n/%u> as nodename, which might expand to
+C<aemp/cerebro/ZQDGSIkRhEZQDGSIkRhE>.
 =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
 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.
    configure
-Example: become an anonymous node. This form is often used for commandline
+Example: become a semi-anonymous node. This form is often used for
-clients.
+commandline clients.
-   configure nodeid => "anon/";
+   configure nodeid => "myscript/%n/%u";
 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).
 sub _kilme {
    die "received message on port without callback";
 }
 sub port(;&) {
-   my $id = "$UNIQ." . ++$ID;
+   my $id = $UNIQ . ++$ID;
    my $port = "$NODE#$id";
    rcv $port, shift || \&_kilme;
    $port
    }
    $node->monitor ($port, $cb);
    defined wantarray
-      and ($cb += 0, AnyEvent::Util::guard { $node->unmonitor ($port, $cb) })
+      and ($cb += 0, Guard::guard { $node->unmonitor ($port, $cb) })
 }
 =item $guard = mon_guard $port, $ref, $ref...
 Monitors the given C<$port> and keeps the passed references. When the port
 }
 sub spawn(@) {
    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";
    snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
    $port
 }
 =back
+=head1 DISTRIBUTED DATABASE
+AnyEvent::MP comes with a simple distributed database. The database will
+be mirrored asynchronously at all global nodes. Other nodes bind to one of
+the global nodes for their needs.
+The database consists of a two-level hash - a hash contains a hash which
+contains values.
+The top level hash key is called "family", and the second-level hash key
+is called "subkey" or simply "key".
+The family must be alphanumeric, i.e. start with a letter and consist
+of letters, digits, underscores and colons (C<[A-Za-z][A-Za-z0-9_:]*>,
+pretty much like Perl module names.
+As the family namespace is global, it is recommended to prefix family names
+with the name of the application or module using it.
+The subkeys must be non-empty strings, with no further restrictions.
+The values should preferably be strings, but other perl scalars should
+work as well (such as undef, arrays and hashes).
+Every database entry is owned by one node - adding the same family/subkey
+combination on multiple nodes will not cause discomfort for AnyEvent::MP,
+but the result might be nondeterministic, i.e. the key might have
+different values on different nodes.
+Different subkeys in the same family can be owned by different nodes
+without problems, and in fact, this is the common method to create worker
+pools. For example, a worker port for image scaling might do this:
+   db_set my_image_scalers => $port;
+And clients looking for an image scaler will want to get the
+C<my_image_scalers> keys:
+   db_keys "my_image_scalers" => 60 => sub {
+   #d##TODO#
+=over
+=item db_set $family => $subkey [=> $value]
+Sets (or replaces) a key to the database - if C<$value> is omitted,
+C<undef> is used instead.
+=item db_del $family => $subkey
+Deletes a key from the database.
+=item $guard = db_reg $family => $subkey [=> $value]
+Sets the key on the database and returns a guard. When the guard is
+destroyed, the key is deleted from the database. If C<$value> is missing,
+then C<undef> is used.
+=cut
+=back
 =head1 AnyEvent::MP vs. Distributed Erlang
 AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
 == aemp node, Erlang process == aemp port), so many of the documents and
 programming techniques employed by Erlang apply to AnyEvent::MP. Here is a

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.122 by root, Wed Feb 29 18:44:59 2012 UTC vs. Revision 1.127 by root, Sat Mar 3 20:35:10 2012 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.122 by root, Wed Feb 29 18:44:59 2012 UTC vs.
Revision 1.127 by root, Sat Mar 3 20:35:10 2012 UTC