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lib/POE/Devel/ProcAlike.pm  view on Meta::CPAN

This module uses a static alias: "poe-devel-procalike" so you can always interact with it anytime it is loaded.

=head3 shutdown

Tells this module to shut down the underlying FUSE session and terminate itself.

	$_[KERNEL]->post( 'poe-devel-procalike', 'shutdown' );

=head3 register

( ONLY for PoCo module authors! )

Registers your L<Filesys::Virtual::Async> subclass with ProcAlike so you can expose your data in the filesystem.

Note: You MUST call() this event so ProcAlike will get the proper caller() info to determine mountpath. Furthermore,
ProcAlike only allows one registration per module!

	$_[KERNEL]->call( 'poe-devel-procalike', 'register', $myfsv );

=head3 unregister

( ONLY for PoCo module authors! )

Removes your registered object from the filesystem.

Note: You MUST call() this event so ProcAlike will get the proper caller() info to determine mountpath.

	$_[KERNEL]->call( 'poe-devel-procalike', 'unregister' );

=head2 Notes for PoCo module authors

You can expose your own data in any format you want! The way to do this is to create your own L<Filesys::Virtual::Async>
object and give it to ProcAlike. Here's how I would do the logic:

	my $ses = $_[KERNEL]->alias_resolve( 'poe-devel-procalike' );
	if ( $ses ) {
		require My::FsV; # a subclass of Filesys::Virtual::Async
		my $fsv = My::FsV->new( ... );
		if ( ! $_[KERNEL]->call( $ses, 'register', $fsv ) ) {
			warn "unable to register!";
		}
	}

Keep in mind that the alias is static, and you should be executing this code in the "preferred" package. What I mean
by this is that ProcAlike will take the info from caller() and determine the mountpoint from it. Here's an example:

	POE::Component::SimpleHTTP does a register, it will be mounted in:
	/modules/poe-component-simplehttp

	My::Module::SubClass does a register, it will be mounted in:
	/modules/my-module-subclass

Furthermore, ProcAlike only allows each package to register once, so you have to figure out how to create a singleton
and use that if your PoCo has been spawned N times. The reasoning behind this is to have a "uniform" filesystem
that would be valid across multiple invocations. If we allowed module authors to register any name, then we would
end up with possible collisions and wacky schemes like "$pkg$ses->ID" as the name...

Also, here's a tip: you don't have to implement the entire L<Filesys::Virtual::Async> API because FUSE doesn't use
them all! The ones you would have to do is: rmtree, scandir, move, copy, load, readdir, rmdir, mkdir, rename, mknod,
unlink, chmod, truncate, chown, utime, stat, write, open. To save even more time, you can subclass the
L<Filesys::Virtual::Async::inMemory> module and set readonly to true. Then you would have to subclass only those
methods: readdir, stat, open.

=head2 TODO

=over 4

=item * tunable parameters

Various people in #poe@magnet suggested having a system where we could do "sysctl-like" stuff with this filesystem.
I'm not entirely sure what we can "tune" in regards to POE but if you have any ideas please feel free to drop them
my way and we'll see what we can do :)

=item * pipe support

Again, people suggested the idea of "telnetting" into the filesystem via a pipe. The interface could be something
like PoCo-DebugShell, and we could expand it to accept zany commands :)

=item * module memory usage

I talked with some people, and this problem is much more complex than you would think it is. If somebody could
let me know of a snippet that measures this, I would love to include it in the perl output!

=item * POE::API::Peek crashes

There are some functions that causes segfaults for me! They are: session_memory_size, signals_watched_by_session, and
kernel_memory_size. If the situation improves, I would love to reinstate them in ProcAlike and expose the data, so
please let me know if it does.

=item * more stats

More stats are always welcome! If you have any ideas, please drop me a line.

=back

=head1 EXPORT

None.

=head1 SEE ALSO

L<POE>

L<Fuse>

L<Filesys::Virtual::Async>

=head1 SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc POE::Devel::ProcAlike

=head2 Websites

=over 4

=item * AnnoCPAN: Annotated CPAN documentation

L<http://annocpan.org/dist/POE-Devel-ProcAlike>