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

Comparing AnyEvent-Fork/Fork.pm (file contents):
Revision 1.47 by root, Thu Apr 18 20:17:34 2013 UTC vs.
Revision 1.58 by root, Sun Aug 25 21:10:10 2013 UTC

…		…
38		38
39	If you need some form of RPC, you could use the L<AnyEvent::Fork::RPC>	39	If you need some form of RPC, you could use the L<AnyEvent::Fork::RPC>
40	companion module, which adds simple RPC/job queueing to a process created	40	companion module, which adds simple RPC/job queueing to a process created
41	by this module.	41	by this module.
42		42
		43	And if you need some automatic process pool management on top of
		44	L<AnyEvent::Fork::RPC>, you can look at the L<AnyEvent::Fork::Pool>
		45	companion module.
		46
43	Or you can implement it yourself in whatever way you like, use some	47	Or you can implement it yourself in whatever way you like: use some
44	message-passing module such as L<AnyEvent::MP>, some pipe such as	48	message-passing module such as L<AnyEvent::MP>, some pipe such as
45	L<AnyEvent::ZeroMQ>, use L<AnyEvent::Handle> on both sides to send	49	L<AnyEvent::ZeroMQ>, use L<AnyEvent::Handle> on both sides to send
46	e.g. JSON or Storable messages, and so on.	50	e.g. JSON or Storable messages, and so on.
47		51
48	=head2 COMPARISON TO OTHER MODULES	52	=head2 COMPARISON TO OTHER MODULES
…		…
250	->send_arg ("/bin/echo", "hi")	254	->send_arg ("/bin/echo", "hi")
251	->run ("run", my $cv = AE::cv);	255	->run ("run", my $cv = AE::cv);
252		256
253	my $stderr = $cv->recv;	257	my $stderr = $cv->recv;
254		258
		259	=head2 For stingy users: put the worker code into a C<DATA> section.
		260
		261	When you want to be stingy with files, you cna put your code into the
		262	C<DATA> section of your module (or program):
		263
		264	use AnyEvent::Fork;
		265
		266	AnyEvent::Fork
		267	->new
		268	->eval (do { local $/; <DATA> })
		269	->run ("doit", sub { ... });
		270
		271	__DATA__
		272
		273	sub doit {
		274	... do something!
		275	}
		276
		277	=head2 For stingy standalone programs: do not rely on external files at
		278	all.
		279
		280	For single-file scripts it can be inconvenient to rely on external
		281	files - even when using < C<DATA> section, you still need to C<exec>
		282	an external perl interpreter, which might not be available when using
		283	L<App::Staticperl>, L<Urlader> or L<PAR::Packer> for example.
		284
		285	Two modules help here - L<AnyEvent::Fork::Early> forks a template process
		286	for all further calls to C<new_exec>, and L<AnyEvent::Fork::Template>
		287	forks the main program as a template process.
		288
		289	Here is how your main program should look like:
		290
		291	#! perl
		292
		293	# optional, as the very first thing.
		294	# in case modules want to create their own processes.
		295	use AnyEvent::Fork::Early;
		296
		297	# next, load all modules you need in your template process
		298	use Example::My::Module
		299	use Example::Whatever;
		300
		301	# next, put your run function definition and anything else you
		302	# need, but do not use code outside of BEGIN blocks.
		303	sub worker_run {
		304	my ($fh, @args) = @_;
		305	...
		306	}
		307
		308	# now preserve everything so far as AnyEvent::Fork object
		309	# in §TEMPLATE.
		310	use AnyEvent::Fork::Template;
		311
		312	# do not put code outside of BEGIN blocks until here
		313
		314	# now use the $TEMPLATE process in any way you like
		315
		316	# for example: create 10 worker processes
		317	my @worker;
		318	my $cv = AE::cv;
		319	for (1..10) {
		320	$cv->begin;
		321	$TEMPLATE->fork->send_arg ($_)->run ("worker_run", sub {
		322	push @worker, shift;
		323	$cv->end;
		324	});
		325	}
		326	$cv->recv;
		327
255	=head1 CONCEPTS	328	=head1 CONCEPTS
256		329
257	This module can create new processes either by executing a new perl	330	This module can create new processes either by executing a new perl
258	process, or by forking from an existing "template" process.	331	process, or by forking from an existing "template" process.
259		332
…		…
377	use AnyEvent;	450	use AnyEvent;
378	use AnyEvent::Util ();	451	use AnyEvent::Util ();
379		452
380	use IO::FDPass;	453	use IO::FDPass;
381		454
382	our $VERSION = 0.7;	455	our $VERSION = 1.1;
383		456
384	# the early fork template process	457	# the early fork template process
385	our $EARLY;	458	our $EARLY;
386		459
387	# the empty template process	460	# the empty template process
…		…
435	# send string	508	# send string
436	my $len = syswrite $self->[FH], $self->[QUEUE][0];	509	my $len = syswrite $self->[FH], $self->[QUEUE][0];
437		510
438	unless ($len) {	511	unless ($len) {
439	return if $! == Errno::EAGAIN \|\| $! == Errno::EWOULDBLOCK;	512	return if $! == Errno::EAGAIN \|\| $! == Errno::EWOULDBLOCK;
440	undef $self->[3];	513	undef $self->[WW];
441	die "AnyEvent::Fork: command write failure: $!";	514	die "AnyEvent::Fork: command write failure: $!";
442	}	515	}
443		516
444	substr $self->[QUEUE][0], 0, $len, "";	517	substr $self->[QUEUE][0], 0, $len, "";
445	shift @{ $self->[QUEUE] } unless length $self->[QUEUE][0];	518	shift @{ $self->[QUEUE] } unless length $self->[QUEUE][0];
…		…
448		521
449	# everything written	522	# everything written
450	undef $self->[WW];	523	undef $self->[WW];
451		524
452	# invoke run callback, if any	525	# invoke run callback, if any
		526	if ($self->[CB]) {
453	$self->[CB]->($self->[FH]) if $self->[CB];	527	$self->[CB]->($self->[FH]);
		528	@$self = ();
		529	}
454	};	530	};
455		531
456	() # make sure we don't leak the watcher	532	() # make sure we don't leak the watcher
457	}	533	}
458		534
…		…
529		605
530	You should use C<new> whenever possible, except when having a template	606	You should use C<new> whenever possible, except when having a template
531	process around is unacceptable.	607	process around is unacceptable.
532		608
533	The path to the perl interpreter is divined using various methods - first	609	The path to the perl interpreter is divined using various methods - first
534	C<$^X> is investigated to see if the path ends with something that sounds	610	C<$^X> is investigated to see if the path ends with something that looks
535	as if it were the perl interpreter. Failing this, the module falls back to	611	as if it were the perl interpreter. Failing this, the module falls back to
536	using C<$Config::Config{perlpath}>.	612	using C<$Config::Config{perlpath}>.
537		613
		614	The path to perl can also be overriden by setting the global variable
		615	C<$AnyEvent::Fork::PERL> - it's value will be used for all subsequent
		616	invocations.
		617
538	=cut	618	=cut
		619
		620	our $PERL;
539		621
540	sub new_exec {	622	sub new_exec {
541	my ($self) = @_;	623	my ($self) = @_;
542		624
543	return $EARLY->fork	625	return $EARLY->fork
544	if $EARLY;	626	if $EARLY;
545		627
		628	unless (defined $PERL) {
546	# first find path of perl	629	# first find path of perl
547	my $perl = $;	630	my $perl = $;
548		631
549	# first we try $^X, but the path must be absolute (always on win32), and end in sth.	632	# first we try $^X, but the path must be absolute (always on win32), and end in sth.
550	# that looks like perl. this obviously only works for posix and win32	633	# that looks like perl. this obviously only works for posix and win32
551	unless (	634	unless (
552	($^O eq "MSWin32" \|\| $perl =~ m%^/%)	635	($^O eq "MSWin32" \|\| $perl =~ m%^/%)
553	&& $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i	636	&& $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i
554	) {	637	) {
555	# if it doesn't look perlish enough, try Config	638	# if it doesn't look perlish enough, try Config
556	require Config;	639	require Config;
557	$perl = $Config::Config{perlpath};	640	$perl = $Config::Config{perlpath};
558	$perl =~ s/(?:\Q$Config::Config{_exe}\E)?$/$Config::Config{_exe}/;	641	$perl =~ s/(?:\Q$Config::Config{_exe}\E)?$/$Config::Config{_exe}/;
		642	}
		643
		644	$PERL = $perl;
559	}	645	}
560		646
561	require Proc::FastSpawn;	647	require Proc::FastSpawn;
562		648
563	my ($fh, $slave) = AnyEvent::Util::portable_socketpair;	649	my ($fh, $slave) = AnyEvent::Util::portable_socketpair;
…		…
571	#local $ENV{PERL5LIB} = join ":", grep !ref, @INC;	657	#local $ENV{PERL5LIB} = join ":", grep !ref, @INC;
572	my %env = %ENV;	658	my %env = %ENV;
573	$env{PERL5LIB} = join +($^O eq "MSWin32" ? ";" : ":"), grep !ref, @INC;	659	$env{PERL5LIB} = join +($^O eq "MSWin32" ? ";" : ":"), grep !ref, @INC;
574		660
575	my $pid = Proc::FastSpawn::spawn (	661	my $pid = Proc::FastSpawn::spawn (
576	$perl,	662	$PERL,
577	["perl", "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$],	663	["perl", "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$],
578	[map "$_=$env{$_}", keys %env],	664	[map "$_=$env{$_}", keys %env],
579	) or die "unable to spawn AnyEvent::Fork server: $!";	665	) or die "unable to spawn AnyEvent::Fork server: $!";
580		666
581	$self->_new ($fh, $pid)	667	$self->_new ($fh, $pid)
…		…
730		816
731	Even if not used otherwise, the socket can be a good indicator for the	817	Even if not used otherwise, the socket can be a good indicator for the
732	existence of the process - if the other process exits, you get a readable	818	existence of the process - if the other process exits, you get a readable
733	event on it, because exiting the process closes the socket (if it didn't	819	event on it, because exiting the process closes the socket (if it didn't
734	create any children using fork).	820	create any children using fork).
		821
		822	=over 4
		823
		824	=item Compatibility to L<AnyEvent::Fork::Remote>
		825
		826	If you want to write code that works with both this module and
		827	L<AnyEvent::Fork::Remote>, you need to write your code so that it assumes
		828	there are two file handles for communications, which might not be unix
		829	domain sockets. The C<run> function should start like this:
		830
		831	sub run {
		832	my ($rfh, @args) = @_; # @args is your normal arguments
		833	my $wfh = fileno $rfh ? $rfh : *STDOUT;
		834
		835	# now use $rfh for reading and $wfh for writing
		836	}
		837
		838	This checks whether the passed file handle is, in fact, the process
		839	C<STDIN> handle. If it is, then the function was invoked visa
		840	L<AnyEvent::Fork::Remote>, so STDIN should be used for reading and
		841	C<STDOUT> should be used for writing.
		842
		843	In all other cases, the function was called via this module, and there is
		844	only one file handle that should be sued for reading and writing.
		845
		846	=back
735		847
736	Example: create a template for a process pool, pass a few strings, some	848	Example: create a template for a process pool, pass a few strings, some
737	file handles, then fork, pass one more string, and run some code.	849	file handles, then fork, pass one more string, and run some code.
738		850
739	my $pool = AnyEvent::Fork	851	my $pool = AnyEvent::Fork
…		…
773	$self->_cmd (r => $func);	885	$self->_cmd (r => $func);
774	}	886	}
775		887
776	=back	888	=back
777		889
		890	=head2 EXPERIMENTAL METHODS
		891
		892	These methods might go away completely or change behaviour, at any time.
		893
		894	=over 4
		895
		896	=item $proc->to_fh ($cb->($fh)) # EXPERIMENTAL, MIGHT BE REMOVED
		897
		898	Flushes all commands out to the process and then calls the callback with
		899	the communications socket.
		900
		901	The process object becomes unusable on return from this function - any
		902	further method calls result in undefined behaviour.
		903
		904	The point of this method is to give you a file handle that you can pass
		905	to another process. In that other process, you can call C<new_from_fh
		906	AnyEvent::Fork $fh> to create a new C<AnyEvent::Fork> object from it,
		907	thereby effectively passing a fork object to another process.
		908
		909	=cut
		910
		911	sub to_fh {
		912	my ($self, $cb) = @_;
		913
		914	$self->[CB] = $cb;
		915
		916	unless ($self->[WW]) {
		917	$self->[CB]->($self->[FH]);
		918	@$self = ();
		919	}
		920	}
		921
		922	=item new_from_fh AnyEvent::Fork $fh # EXPERIMENTAL, MIGHT BE REMOVED
		923
		924	Takes a file handle originally rceeived by the C<to_fh> method and creates
		925	a new C<AnyEvent:Fork> object. The child process itself will not change in
		926	any way, i.e. it will keep all the modifications done to it before calling
		927	C<to_fh>.
		928
		929	The new object is very much like the original object, except that the
		930	C<pid> method will return C<undef> even if the process is a direct child.
		931
		932	=cut
		933
		934	sub new_from_fh {
		935	my ($class, $fh) = @_;
		936
		937	$class->_new ($fh)
		938	}
		939
		940	=back
		941
778	=head1 PERFORMANCE	942	=head1 PERFORMANCE
779		943
780	Now for some unscientific benchmark numbers (all done on an amd64	944	Now for some unscientific benchmark numbers (all done on an amd64
781	GNU/Linux box). These are intended to give you an idea of the relative	945	GNU/Linux box). These are intended to give you an idea of the relative
782	performance you can expect, they are not meant to be absolute performance	946	performance you can expect, they are not meant to be absolute performance
…		…
788		952
789	2079 new processes per second, using manual socketpair + fork	953	2079 new processes per second, using manual socketpair + fork
790		954
791	Then I did the same thing, but instead of calling fork, I called	955	Then I did the same thing, but instead of calling fork, I called
792	AnyEvent::Fork->new->run ("CORE::exit") and then again waited for the	956	AnyEvent::Fork->new->run ("CORE::exit") and then again waited for the
793	socket form the child to close on exit. This does the same thing as manual	957	socket from the child to close on exit. This does the same thing as manual
794	socket pair + fork, except that what is forked is the template process	958	socket pair + fork, except that what is forked is the template process
795	(2440kB), and the socket needs to be passed to the server at the other end	959	(2440kB), and the socket needs to be passed to the server at the other end
796	of the socket first.	960	of the socket first.
797		961
798	2307 new processes per second, using AnyEvent::Fork->new	962	2307 new processes per second, using AnyEvent::Fork->new
…		…
905	to make it so, mostly due to the bloody broken perl that nobody seems to	1069	to make it so, mostly due to the bloody broken perl that nobody seems to
906	care about. The fork emulation is a bad joke - I have yet to see something	1070	care about. The fork emulation is a bad joke - I have yet to see something
907	useful that you can do with it without running into memory corruption	1071	useful that you can do with it without running into memory corruption
908	issues or other braindamage. Hrrrr.	1072	issues or other braindamage. Hrrrr.
909		1073
		1074	Since fork is endlessly broken on win32 perls (it doesn't even remotely
		1075	work within it's documented limits) and quite obviously it's not getting
		1076	improved any time soon, the best way to proceed on windows would be to
		1077	always use C<new_exec> and thus never rely on perl's fork "emulation".
		1078
910	Cygwin perl is not supported at the moment due to some hilarious	1079	Cygwin perl is not supported at the moment due to some hilarious
911	shortcomings of its API - see L<IO::FDPoll> for more details.	1080	shortcomings of its API - see L<IO::FDPoll> for more details. If you never
		1081	use C<send_fh> and always use C<new_exec> to create processes, it should
		1082	work though.
912		1083
913	=head1 SEE ALSO	1084	=head1 SEE ALSO
914		1085
915	L<AnyEvent::Fork::Early>, to avoid executing a perl interpreter at all	1086	L<AnyEvent::Fork::Early>, to avoid executing a perl interpreter at all
916	(part of this distribution).	1087	(part of this distribution).
917		1088
918	L<AnyEvent::Fork::Template>, to create a process by forking the main	1089	L<AnyEvent::Fork::Template>, to create a process by forking the main
919	program at a convenient time (part of this distribution).	1090	program at a convenient time (part of this distribution).
920		1091
		1092	L<AnyEvent::Fork::Remote>, for another way to create processes that is
		1093	mostly compatible to this module and modules building on top of it, but
		1094	works better with remote processes.
		1095
921	L<AnyEvent::Fork::RPC>, for simple RPC to child processes (on CPAN).	1096	L<AnyEvent::Fork::RPC>, for simple RPC to child processes (on CPAN).
		1097
		1098	L<AnyEvent::Fork::Pool>, for simple worker process pool (on CPAN).
922		1099
923	=head1 AUTHOR AND CONTACT INFORMATION	1100	=head1 AUTHOR AND CONTACT INFORMATION
924		1101
925	Marc Lehmann <schmorp@schmorp.de>	1102	Marc Lehmann <schmorp@schmorp.de>
926	http://software.schmorp.de/pkg/AnyEvent-Fork	1103	http://software.schmorp.de/pkg/AnyEvent-Fork

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Comparing AnyEvent-Fork/Fork.pm (file contents): Revision 1.47 by root, Thu Apr 18 20:17:34 2013 UTC vs. Revision 1.58 by root, Sun Aug 25 21:10:10 2013 UTC

Diff Legend

Comparing AnyEvent-Fork/Fork.pm (file contents):
Revision 1.47 by root, Thu Apr 18 20:17:34 2013 UTC vs.
Revision 1.58 by root, Sun Aug 25 21:10:10 2013 UTC