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

Comparing AnyEvent-Fork/Fork.pm (file contents):
Revision 1.44 by root, Thu Apr 18 10:49:59 2013 UTC vs.
Revision 1.61 by root, Wed Nov 20 15:24:28 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 can 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 $/; <DATA> })
		269	->run ("doit", sub { ... });
		270
		271	__DATA__
		272
		273	sub doit {
		274	... do something!
		275	}
		276
		277	=head2 For stingy standalone programs: do not rely on external files at
		278	all.
		279
		280	For single-file scripts it can be inconvenient to rely on external
		281	files - even when using a C<DATA> section, you still need to C<exec> an
		282	external perl interpreter, which might not be available when using
		283	L<App::Staticperl>, L<Urlader> or L<PAR::Packer> for example.
		284
		285	Two modules help here - L<AnyEvent::Fork::Early> forks a template process
		286	for all further calls to C<new_exec>, and L<AnyEvent::Fork::Template>
		287	forks the main program as a template process.
		288
		289	Here is how your main program should look like:
		290
		291	#! perl
		292
		293	# optional, as the very first thing.
		294	# in case modules want to create their own processes.
		295	use AnyEvent::Fork::Early;
		296
		297	# next, load all modules you need in your template process
		298	use Example::My::Module
		299	use Example::Whatever;
		300
		301	# next, put your run function definition and anything else you
		302	# need, but do not use code outside of BEGIN blocks.
		303	sub worker_run {
		304	my ($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.
		332
		333	All these processes are called "child processes" (whether they are direct
		334	children or not), while the process that manages them is called the
		335	"parent process".
259		336
260	Each such process comes with its own file handle that can be used to	337	Each such process comes with its own file handle that can be used to
261	communicate with it (it's actually a socket - one end in the new process,	338	communicate with it (it's actually a socket - one end in the new process,
262	one end in the main process), and among the things you can do in it are	339	one end in the main process), and among the things you can do in it are
263	load modules, fork new processes, send file handles to it, and execute	340	load modules, fork new processes, send file handles to it, and execute
…		…
373	use AnyEvent;	450	use AnyEvent;
374	use AnyEvent::Util ();	451	use AnyEvent::Util ();
375		452
376	use IO::FDPass;	453	use IO::FDPass;
377		454
378	our $VERSION = 0.6;	455	our $VERSION = 1.2;
379		456
380	# the early fork template process	457	# the early fork template process
381	our $EARLY;	458	our $EARLY;
382		459
383	# the empty template process	460	# the empty template process
…		…
431	# send string	508	# send string
432	my $len = syswrite $self->[FH], $self->[QUEUE][0];	509	my $len = syswrite $self->[FH], $self->[QUEUE][0];
433		510
434	unless ($len) {	511	unless ($len) {
435	return if $! == Errno::EAGAIN \|\| $! == Errno::EWOULDBLOCK;	512	return if $! == Errno::EAGAIN \|\| $! == Errno::EWOULDBLOCK;
436	undef $self->[3];	513	undef $self->[WW];
437	die "AnyEvent::Fork: command write failure: $!";	514	die "AnyEvent::Fork: command write failure: $!";
438	}	515	}
439		516
440	substr $self->[QUEUE][0], 0, $len, "";	517	substr $self->[QUEUE][0], 0, $len, "";
441	shift @{ $self->[QUEUE] } unless length $self->[QUEUE][0];	518	shift @{ $self->[QUEUE] } unless length $self->[QUEUE][0];
…		…
444		521
445	# everything written	522	# everything written
446	undef $self->[WW];	523	undef $self->[WW];
447		524
448	# invoke run callback, if any	525	# invoke run callback, if any
		526	if ($self->[CB]) {
449	$self->[CB]->($self->[FH]) if $self->[CB];	527	$self->[CB]->($self->[FH]);
		528	@$self = ();
		529	}
450	};	530	};
451		531
452	() # make sure we don't leak the watcher	532	() # make sure we don't leak the watcher
453	}	533	}
454		534
…		…
525		605
526	You should use C<new> whenever possible, except when having a template	606	You should use C<new> whenever possible, except when having a template
527	process around is unacceptable.	607	process around is unacceptable.
528		608
529	The path to the perl interpreter is divined using various methods - first	609	The path to the perl interpreter is divined using various methods - first
530	C<$^X> is investigated to see if the path ends with something that sounds	610	C<$^X> is investigated to see if the path ends with something that looks
531	as if it were the perl interpreter. Failing this, the module falls back to	611	as if it were the perl interpreter. Failing this, the module falls back to
532	using C<$Config::Config{perlpath}>.	612	using C<$Config::Config{perlpath}>.
533		613
		614	The path to perl can also be overriden by setting the global variable
		615	C<$AnyEvent::Fork::PERL> - it's value will be used for all subsequent
		616	invocations.
		617
534	=cut	618	=cut
		619
		620	our $PERL;
535		621
536	sub new_exec {	622	sub new_exec {
537	my ($self) = @_;	623	my ($self) = @_;
538		624
539	return $EARLY->fork	625	return $EARLY->fork
540	if $EARLY;	626	if $EARLY;
541		627
		628	unless (defined $PERL) {
542	# first find path of perl	629	# first find path of perl
543	my $perl = $;	630	my $perl = $;
544		631
545	# first we try $^X, but the path must be absolute (always on win32), and end in sth.	632	# first we try $^X, but the path must be absolute (always on win32), and end in sth.
546	# that looks like perl. this obviously only works for posix and win32	633	# that looks like perl. this obviously only works for posix and win32
547	unless (	634	unless (
548	($^O eq "MSWin32" \|\| $perl =~ m%^/%)	635	($^O eq "MSWin32" \|\| $perl =~ m%^/%)
549	&& $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i	636	&& $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i
550	) {	637	) {
551	# if it doesn't look perlish enough, try Config	638	# if it doesn't look perlish enough, try Config
552	require Config;	639	require Config;
553	$perl = $Config::Config{perlpath};	640	$perl = $Config::Config{perlpath};
554	$perl =~ s/(?:\Q$Config::Config{_exe}\E)?$/$Config::Config{_exe}/;	641	$perl =~ s/(?:\Q$Config::Config{_exe}\E)?$/$Config::Config{_exe}/;
		642	}
		643
		644	$PERL = $perl;
555	}	645	}
556		646
557	require Proc::FastSpawn;	647	require Proc::FastSpawn;
558		648
559	my ($fh, $slave) = AnyEvent::Util::portable_socketpair;	649	my ($fh, $slave) = AnyEvent::Util::portable_socketpair;
…		…
567	#local $ENV{PERL5LIB} = join ":", grep !ref, @INC;	657	#local $ENV{PERL5LIB} = join ":", grep !ref, @INC;
568	my %env = %ENV;	658	my %env = %ENV;
569	$env{PERL5LIB} = join +($^O eq "MSWin32" ? ";" : ":"), grep !ref, @INC;	659	$env{PERL5LIB} = join +($^O eq "MSWin32" ? ";" : ":"), grep !ref, @INC;
570		660
571	my $pid = Proc::FastSpawn::spawn (	661	my $pid = Proc::FastSpawn::spawn (
572	$perl,	662	$PERL,
573	["perl", "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$],	663	["perl", "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$],
574	[map "$_=$env{$_}", keys %env],	664	[map "$_=$env{$_}", keys %env],
575	) or die "unable to spawn AnyEvent::Fork server: $!";	665	) or die "unable to spawn AnyEvent::Fork server: $!";
576		666
577	$self->_new ($fh, $pid)	667	$self->_new ($fh, $pid)
578	}	668	}
579		669
580	=item $pid = $proc->pid	670	=item $pid = $proc->pid
581		671
582	Returns the process id of the process I<iff it is a direct child of the	672	Returns the process id of the process I<iff it is a direct child of the
583	process running AnyEvent::Fork>, and C<undef> otherwise.	673	process running AnyEvent::Fork>, and C<undef> otherwise. As a general
		674	rule (that you cannot rely upon), processes created via C<new_exec>,
		675	L<AnyEvent::Fork::Early> or L<AnyEvent::Fork::Template> are direct
		676	children, while all other processes are not.
584		677
585	Normally, only processes created via C<< AnyEvent::Fork->new_exec >> and	678	Or in other words, you do not normally have to take care of zombies for
586	L<AnyEvent::Fork::Template> are direct children, and you are responsible	679	processes created via C<new>, but when in doubt, or zombies are a problem,
587	to clean up their zombies when they die.	680	you need to check whether a process is a diretc child by calling this
588		681	method, and possibly creating a child watcher or reap it manually.
589	All other processes are not direct children, and will be cleaned up by
590	AnyEvent::Fork itself.
591		682
592	=cut	683	=cut
593		684
594	sub pid {	685	sub pid {
595	$_[0][PID]	686	$_[0][PID]
…		…
726		817
727	Even if not used otherwise, the socket can be a good indicator for the	818	Even if not used otherwise, the socket can be a good indicator for the
728	existence of the process - if the other process exits, you get a readable	819	existence of the process - if the other process exits, you get a readable
729	event on it, because exiting the process closes the socket (if it didn't	820	event on it, because exiting the process closes the socket (if it didn't
730	create any children using fork).	821	create any children using fork).
		822
		823	=over 4
		824
		825	=item Compatibility to L<AnyEvent::Fork::Remote>
		826
		827	If you want to write code that works with both this module and
		828	L<AnyEvent::Fork::Remote>, you need to write your code so that it assumes
		829	there are two file handles for communications, which might not be unix
		830	domain sockets. The C<run> function should start like this:
		831
		832	sub run {
		833	my ($rfh, @args) = @_; # @args is your normal arguments
		834	my $wfh = fileno $rfh ? $rfh : *STDOUT;
		835
		836	# now use $rfh for reading and $wfh for writing
		837	}
		838
		839	This checks whether the passed file handle is, in fact, the process
		840	C<STDIN> handle. If it is, then the function was invoked visa
		841	L<AnyEvent::Fork::Remote>, so STDIN should be used for reading and
		842	C<STDOUT> should be used for writing.
		843
		844	In all other cases, the function was called via this module, and there is
		845	only one file handle that should be sued for reading and writing.
		846
		847	=back
731		848
732	Example: create a template for a process pool, pass a few strings, some	849	Example: create a template for a process pool, pass a few strings, some
733	file handles, then fork, pass one more string, and run some code.	850	file handles, then fork, pass one more string, and run some code.
734		851
735	my $pool = AnyEvent::Fork	852	my $pool = AnyEvent::Fork
…		…
769	$self->_cmd (r => $func);	886	$self->_cmd (r => $func);
770	}	887	}
771		888
772	=back	889	=back
773		890
		891	=head2 EXPERIMENTAL METHODS
		892
		893	These methods might go away completely or change behaviour, at any time.
		894
		895	=over 4
		896
		897	=item $proc->to_fh ($cb->($fh)) # EXPERIMENTAL, MIGHT BE REMOVED
		898
		899	Flushes all commands out to the process and then calls the callback with
		900	the communications socket.
		901
		902	The process object becomes unusable on return from this function - any
		903	further method calls result in undefined behaviour.
		904
		905	The point of this method is to give you a file handle that you can pass
		906	to another process. In that other process, you can call C<new_from_fh
		907	AnyEvent::Fork $fh> to create a new C<AnyEvent::Fork> object from it,
		908	thereby effectively passing a fork object to another process.
		909
		910	=cut
		911
		912	sub to_fh {
		913	my ($self, $cb) = @_;
		914
		915	$self->[CB] = $cb;
		916
		917	unless ($self->[WW]) {
		918	$self->[CB]->($self->[FH]);
		919	@$self = ();
		920	}
		921	}
		922
		923	=item new_from_fh AnyEvent::Fork $fh # EXPERIMENTAL, MIGHT BE REMOVED
		924
		925	Takes a file handle originally rceeived by the C<to_fh> method and creates
		926	a new C<AnyEvent:Fork> object. The child process itself will not change in
		927	any way, i.e. it will keep all the modifications done to it before calling
		928	C<to_fh>.
		929
		930	The new object is very much like the original object, except that the
		931	C<pid> method will return C<undef> even if the process is a direct child.
		932
		933	=cut
		934
		935	sub new_from_fh {
		936	my ($class, $fh) = @_;
		937
		938	$class->_new ($fh)
		939	}
		940
		941	=back
		942
774	=head1 PERFORMANCE	943	=head1 PERFORMANCE
775		944
776	Now for some unscientific benchmark numbers (all done on an amd64	945	Now for some unscientific benchmark numbers (all done on an amd64
777	GNU/Linux box). These are intended to give you an idea of the relative	946	GNU/Linux box). These are intended to give you an idea of the relative
778	performance you can expect, they are not meant to be absolute performance	947	performance you can expect, they are not meant to be absolute performance
…		…
784		953
785	2079 new processes per second, using manual socketpair + fork	954	2079 new processes per second, using manual socketpair + fork
786		955
787	Then I did the same thing, but instead of calling fork, I called	956	Then I did the same thing, but instead of calling fork, I called
788	AnyEvent::Fork->new->run ("CORE::exit") and then again waited for the	957	AnyEvent::Fork->new->run ("CORE::exit") and then again waited for the
789	socket form the child to close on exit. This does the same thing as manual	958	socket from the child to close on exit. This does the same thing as manual
790	socket pair + fork, except that what is forked is the template process	959	socket pair + fork, except that what is forked is the template process
791	(2440kB), and the socket needs to be passed to the server at the other end	960	(2440kB), and the socket needs to be passed to the server at the other end
792	of the socket first.	961	of the socket first.
793		962
794	2307 new processes per second, using AnyEvent::Fork->new	963	2307 new processes per second, using AnyEvent::Fork->new
…		…
901	to make it so, mostly due to the bloody broken perl that nobody seems to	1070	to make it so, mostly due to the bloody broken perl that nobody seems to
902	care about. The fork emulation is a bad joke - I have yet to see something	1071	care about. The fork emulation is a bad joke - I have yet to see something
903	useful that you can do with it without running into memory corruption	1072	useful that you can do with it without running into memory corruption
904	issues or other braindamage. Hrrrr.	1073	issues or other braindamage. Hrrrr.
905		1074
		1075	Since fork is endlessly broken on win32 perls (it doesn't even remotely
		1076	work within it's documented limits) and quite obviously it's not getting
		1077	improved any time soon, the best way to proceed on windows would be to
		1078	always use C<new_exec> and thus never rely on perl's fork "emulation".
		1079
906	Cygwin perl is not supported at the moment due to some hilarious	1080	Cygwin perl is not supported at the moment due to some hilarious
907	shortcomings of its API - see L<IO::FDPoll> for more details.	1081	shortcomings of its API - see L<IO::FDPoll> for more details. If you never
		1082	use C<send_fh> and always use C<new_exec> to create processes, it should
		1083	work though.
908		1084
909	=head1 SEE ALSO	1085	=head1 SEE ALSO
910		1086
911	L<AnyEvent::Fork::Early> (to avoid executing a perl interpreter),	1087	L<AnyEvent::Fork::Early>, to avoid executing a perl interpreter at all
		1088	(part of this distribution).
		1089
912	L<AnyEvent::Fork::Template> (to create a process by forking the main	1090	L<AnyEvent::Fork::Template>, to create a process by forking the main
913	program at a convenient time), L<AnyEvent::Fork::RPC> (for simple RPC to	1091	program at a convenient time (part of this distribution).
914	child processes).	1092
		1093	L<AnyEvent::Fork::Remote>, for another way to create processes that is
		1094	mostly compatible to this module and modules building on top of it, but
		1095	works better with remote processes.
		1096
		1097	L<AnyEvent::Fork::RPC>, for simple RPC to child processes (on CPAN).
		1098
		1099	L<AnyEvent::Fork::Pool>, for simple worker process pool (on CPAN).
915		1100
916	=head1 AUTHOR AND CONTACT INFORMATION	1101	=head1 AUTHOR AND CONTACT INFORMATION
917		1102
918	Marc Lehmann <schmorp@schmorp.de>	1103	Marc Lehmann <schmorp@schmorp.de>
919	http://software.schmorp.de/pkg/AnyEvent-Fork	1104	http://software.schmorp.de/pkg/AnyEvent-Fork

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Comparing AnyEvent-Fork/Fork.pm (file contents): Revision 1.44 by root, Thu Apr 18 10:49:59 2013 UTC vs. Revision 1.61 by root, Wed Nov 20 15:24:28 2013 UTC

Diff Legend

Comparing AnyEvent-Fork/Fork.pm (file contents):
Revision 1.44 by root, Thu Apr 18 10:49:59 2013 UTC vs.
Revision 1.61 by root, Wed Nov 20 15:24:28 2013 UTC