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=head1 NAME |
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1.4 |
AnyEvent::Fork - everything you wanted to use fork() for, but couldn't |
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=head1 SYNOPSIS |
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use AnyEvent::Fork; |
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AnyEvent::Fork |
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->new |
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->require ("MyModule") |
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->run ("MyModule::server", my $cv = AE::cv); |
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my $fh = $cv->recv; |
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=head1 DESCRIPTION |
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This module allows you to create new processes, without actually forking |
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them from your current process (avoiding the problems of forking), but |
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preserving most of the advantages of fork. |
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It can be used to create new worker processes or new independent |
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subprocesses for short- and long-running jobs, process pools (e.g. for use |
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in pre-forked servers) but also to spawn new external processes (such as |
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CGI scripts from a web server), which can be faster (and more well behaved) |
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than using fork+exec in big processes. |
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Special care has been taken to make this module useful from other modules, |
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while still supporting specialised environments such as L<App::Staticperl> |
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or L<PAR::Packer>. |
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1.39 |
=head2 WHAT THIS MODULE IS NOT |
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This module only creates processes and lets you pass file handles and |
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strings to it, and run perl code. It does not implement any kind of RPC - |
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there is no back channel from the process back to you, and there is no RPC |
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or message passing going on. |
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If you need some form of RPC, you could use the L<AnyEvent::Fork::RPC> |
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companion module, which adds simple RPC/job queueing to a process created |
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by this module. |
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And if you need some automatic process pool management on top of |
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L<AnyEvent::Fork::RPC>, you can look at the L<AnyEvent::Fork::Pool> |
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companion module. |
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Or you can implement it yourself in whatever way you like: use some |
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message-passing module such as L<AnyEvent::MP>, some pipe such as |
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L<AnyEvent::ZeroMQ>, use L<AnyEvent::Handle> on both sides to send |
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e.g. JSON or Storable messages, and so on. |
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1.39 |
=head2 COMPARISON TO OTHER MODULES |
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There is an abundance of modules on CPAN that do "something fork", such as |
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L<Parallel::ForkManager>, L<AnyEvent::ForkManager>, L<AnyEvent::Worker> |
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or L<AnyEvent::Subprocess>. There are modules that implement their own |
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process management, such as L<AnyEvent::DBI>. |
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The problems that all these modules try to solve are real, however, none |
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of them (from what I have seen) tackle the very real problems of unwanted |
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memory sharing, efficiency, not being able to use event processing or |
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similar modules in the processes they create. |
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This module doesn't try to replace any of them - instead it tries to solve |
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the problem of creating processes with a minimum of fuss and overhead (and |
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also luxury). Ideally, most of these would use AnyEvent::Fork internally, |
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except they were written before AnyEvent:Fork was available, so obviously |
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had to roll their own. |
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=head2 PROBLEM STATEMENT |
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There are two traditional ways to implement parallel processing on UNIX |
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like operating systems - fork and process, and fork+exec and process. They |
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have different advantages and disadvantages that I describe below, |
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together with how this module tries to mitigate the disadvantages. |
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=over 4 |
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=item Forking from a big process can be very slow. |
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A 5GB process needs 0.05s to fork on my 3.6GHz amd64 GNU/Linux box. This |
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overhead is often shared with exec (because you have to fork first), but |
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in some circumstances (e.g. when vfork is used), fork+exec can be much |
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faster. |
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This module can help here by telling a small(er) helper process to fork, |
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which is faster then forking the main process, and also uses vfork where |
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possible. This gives the speed of vfork, with the flexibility of fork. |
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=item Forking usually creates a copy-on-write copy of the parent |
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process. |
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For example, modules or data files that are loaded will not use additional |
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memory after a fork. When exec'ing a new process, modules and data files |
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might need to be loaded again, at extra CPU and memory cost. But when |
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forking, literally all data structures are copied - if the program frees |
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them and replaces them by new data, the child processes will retain the |
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old version even if it isn't used, which can suddenly and unexpectedly |
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increase memory usage when freeing memory. |
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The trade-off is between more sharing with fork (which can be good or |
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bad), and no sharing with exec. |
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This module allows the main program to do a controlled fork, and allows |
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modules to exec processes safely at any time. When creating a custom |
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process pool you can take advantage of data sharing via fork without |
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risking to share large dynamic data structures that will blow up child |
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memory usage. |
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In other words, this module puts you into control over what is being |
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shared and what isn't, at all times. |
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=item Exec'ing a new perl process might be difficult. |
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For example, it is not easy to find the correct path to the perl |
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interpreter - C<$^X> might not be a perl interpreter at all. |
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This module tries hard to identify the correct path to the perl |
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interpreter. With a cooperative main program, exec'ing the interpreter |
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might not even be necessary, but even without help from the main program, |
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it will still work when used from a module. |
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=item Exec'ing a new perl process might be slow, as all necessary modules |
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have to be loaded from disk again, with no guarantees of success. |
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Long running processes might run into problems when perl is upgraded |
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and modules are no longer loadable because they refer to a different |
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perl version, or parts of a distribution are newer than the ones already |
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loaded. |
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This module supports creating pre-initialised perl processes to be used as |
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a template for new processes. |
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=item Forking might be impossible when a program is running. |
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For example, POSIX makes it almost impossible to fork from a |
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multi-threaded program while doing anything useful in the child - in |
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fact, if your perl program uses POSIX threads (even indirectly via |
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e.g. L<IO::AIO> or L<threads>), you cannot call fork on the perl level |
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anymore without risking corruption issues on a number of operating |
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systems. |
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This module can safely fork helper processes at any time, by calling |
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fork+exec in C, in a POSIX-compatible way (via L<Proc::FastSpawn>). |
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=item Parallel processing with fork might be inconvenient or difficult |
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to implement. Modules might not work in both parent and child. |
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For example, when a program uses an event loop and creates watchers it |
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becomes very hard to use the event loop from a child program, as the |
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watchers already exist but are only meaningful in the parent. Worse, a |
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module might want to use such a module, not knowing whether another module |
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or the main program also does, leading to problems. |
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1.26 |
Apart from event loops, graphical toolkits also commonly fall into the |
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"unsafe module" category, or just about anything that communicates with |
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the external world, such as network libraries and file I/O modules, which |
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usually don't like being copied and then allowed to continue in two |
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processes. |
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1.25 |
With this module only the main program is allowed to create new processes |
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by forking (because only the main program can know when it is still safe |
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to do so) - all other processes are created via fork+exec, which makes it |
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possible to use modules such as event loops or window interfaces safely. |
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=back |
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1.24 |
=head1 EXAMPLES |
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=head2 Create a single new process, tell it to run your worker function. |
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AnyEvent::Fork |
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->new |
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->require ("MyModule") |
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->run ("MyModule::worker, sub { |
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my ($master_filehandle) = @_; |
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# now $master_filehandle is connected to the |
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# $slave_filehandle in the new process. |
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}); |
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1.32 |
C<MyModule> might look like this: |
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1.30 |
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1.31 |
package MyModule; |
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sub worker { |
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my ($slave_filehandle) = @_; |
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# now $slave_filehandle is connected to the $master_filehandle |
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# in the original prorcess. have fun! |
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} |
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1.24 |
=head2 Create a pool of server processes all accepting on the same socket. |
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# create listener socket |
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my $listener = ...; |
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# create a pool template, initialise it and give it the socket |
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my $pool = AnyEvent::Fork |
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->new |
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->require ("Some::Stuff", "My::Server") |
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->send_fh ($listener); |
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# now create 10 identical workers |
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for my $id (1..10) { |
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$pool |
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->fork |
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->send_arg ($id) |
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->run ("My::Server::run"); |
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} |
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# now do other things - maybe use the filehandle provided by run |
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# to wait for the processes to die. or whatever. |
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1.32 |
C<My::Server> might look like this: |
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package My::Server; |
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1.31 |
sub run { |
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my ($slave, $listener, $id) = @_; |
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close $slave; # we do not use the socket, so close it to save resources |
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# we could go ballistic and use e.g. AnyEvent here, or IO::AIO, |
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# or anything we usually couldn't do in a process forked normally. |
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while (my $socket = $listener->accept) { |
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# do sth. with new socket |
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} |
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} |
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1.24 |
=head2 use AnyEvent::Fork as a faster fork+exec |
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1.23 |
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1.44 |
This runs C</bin/echo hi>, with standard output redirected to F</tmp/log> |
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1.32 |
and standard error redirected to the communications socket. It is usually |
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faster than fork+exec, but still lets you prepare the environment. |
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1.23 |
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open my $output, ">/tmp/log" or die "$!"; |
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AnyEvent::Fork |
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->new |
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->eval (' |
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1.40 |
# compile a helper function for later use |
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1.23 |
sub run { |
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my ($fh, $output, @cmd) = @_; |
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# perl will clear close-on-exec on STDOUT/STDERR |
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open STDOUT, ">&", $output or die; |
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open STDERR, ">&", $fh or die; |
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exec @cmd; |
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} |
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') |
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->send_fh ($output) |
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->send_arg ("/bin/echo", "hi") |
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->run ("run", my $cv = AE::cv); |
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my $stderr = $cv->recv; |
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1.51 |
=head2 For stingy users: put the worker code into a C<DATA> section. |
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When you want to be stingy with files, you cna put your code into the |
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C<DATA> section of your module (or program): |
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use AnyEvent::Fork; |
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AnyEvent::Fork |
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->new |
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->eval (do { local $/; <DATA> }) |
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->run ("doit", sub { ... }); |
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__DATA__ |
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sub doit { |
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... do something! |
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} |
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=head2 For stingy standalone programs: do not rely on external files at |
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all. |
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For single-file scripts it can be inconvenient to rely on external |
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files - even when using < C<DATA> section, you still need to C<exec> |
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an external perl interpreter, which might not be available when using |
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L<App::Staticperl>, L<Urlader> or L<PAR::Packer> for example. |
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Two modules help here - L<AnyEvent::Fork::Early> forks a template process |
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for all further calls to C<new_exec>, and L<AnyEvent::Fork::Template> |
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forks the main program as a template process. |
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Here is how your main program should look like: |
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#! perl |
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# optional, as the very first thing. |
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# in case modules want to create their own processes. |
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use AnyEvent::Fork::Early; |
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# next, load all modules you need in your template process |
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use Example::My::Module |
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use Example::Whatever; |
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# next, put your run function definition and anything else you |
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# need, but do not use code outside of BEGIN blocks. |
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sub worker_run { |
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my ($fh, @args) = @_; |
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... |
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} |
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# now preserve everything so far as AnyEvent::Fork object |
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# in §TEMPLATE. |
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use AnyEvent::Fork::Template; |
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# do not put code outside of BEGIN blocks until here |
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# now use the $TEMPLATE process in any way you like |
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# for example: create 10 worker processes |
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my @worker; |
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my $cv = AE::cv; |
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for (1..10) { |
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$cv->begin; |
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$TEMPLATE->fork->send_arg ($_)->run ("worker_run", sub { |
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push @worker, shift; |
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$cv->end; |
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}); |
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} |
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$cv->recv; |
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root |
1.52 |
=head1 CONCEPTS |
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1.3 |
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This module can create new processes either by executing a new perl |
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process, or by forking from an existing "template" process. |
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1.45 |
All these processes are called "child processes" (whether they are direct |
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children or not), while the process that manages them is called the |
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"parent process". |
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1.3 |
Each such process comes with its own file handle that can be used to |
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communicate with it (it's actually a socket - one end in the new process, |
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one end in the main process), and among the things you can do in it are |
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load modules, fork new processes, send file handles to it, and execute |
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functions. |
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There are multiple ways to create additional processes to execute some |
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jobs: |
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=over 4 |
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=item fork a new process from the "default" template process, load code, |
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run it |
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This module has a "default" template process which it executes when it is |
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needed the first time. Forking from this process shares the memory used |
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for the perl interpreter with the new process, but loading modules takes |
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time, and the memory is not shared with anything else. |
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This is ideal for when you only need one extra process of a kind, with the |
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1.17 |
option of starting and stopping it on demand. |
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1.3 |
|
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1.9 |
Example: |
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AnyEvent::Fork |
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->new |
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->require ("Some::Module") |
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->run ("Some::Module::run", sub { |
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my ($fork_fh) = @_; |
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}); |
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root |
1.3 |
=item fork a new template process, load code, then fork processes off of |
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it and run the code |
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When you need to have a bunch of processes that all execute the same (or |
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very similar) tasks, then a good way is to create a new template process |
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for them, loading all the modules you need, and then create your worker |
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processes from this new template process. |
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This way, all code (and data structures) that can be shared (e.g. the |
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modules you loaded) is shared between the processes, and each new process |
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consumes relatively little memory of its own. |
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|
|
The disadvantage of this approach is that you need to create a template |
381 |
|
|
process for the sole purpose of forking new processes from it, but if you |
382 |
root |
1.17 |
only need a fixed number of processes you can create them, and then destroy |
383 |
root |
1.3 |
the template process. |
384 |
|
|
|
385 |
root |
1.9 |
Example: |
386 |
|
|
|
387 |
|
|
my $template = AnyEvent::Fork->new->require ("Some::Module"); |
388 |
|
|
|
389 |
|
|
for (1..10) { |
390 |
|
|
$template->fork->run ("Some::Module::run", sub { |
391 |
|
|
my ($fork_fh) = @_; |
392 |
|
|
}); |
393 |
|
|
} |
394 |
|
|
|
395 |
|
|
# at this point, you can keep $template around to fork new processes |
396 |
|
|
# later, or you can destroy it, which causes it to vanish. |
397 |
|
|
|
398 |
root |
1.3 |
=item execute a new perl interpreter, load some code, run it |
399 |
|
|
|
400 |
|
|
This is relatively slow, and doesn't allow you to share memory between |
401 |
|
|
multiple processes. |
402 |
|
|
|
403 |
|
|
The only advantage is that you don't have to have a template process |
404 |
|
|
hanging around all the time to fork off some new processes, which might be |
405 |
|
|
an advantage when there are long time spans where no extra processes are |
406 |
|
|
needed. |
407 |
|
|
|
408 |
root |
1.9 |
Example: |
409 |
|
|
|
410 |
|
|
AnyEvent::Fork |
411 |
|
|
->new_exec |
412 |
|
|
->require ("Some::Module") |
413 |
|
|
->run ("Some::Module::run", sub { |
414 |
|
|
my ($fork_fh) = @_; |
415 |
|
|
}); |
416 |
|
|
|
417 |
root |
1.3 |
=back |
418 |
|
|
|
419 |
root |
1.27 |
=head1 THE C<AnyEvent::Fork> CLASS |
420 |
|
|
|
421 |
|
|
This module exports nothing, and only implements a single class - |
422 |
|
|
C<AnyEvent::Fork>. |
423 |
|
|
|
424 |
root |
1.28 |
There are two class constructors that both create new processes - C<new> |
425 |
|
|
and C<new_exec>. The C<fork> method creates a new process by forking an |
426 |
root |
1.27 |
existing one and could be considered a third constructor. |
427 |
|
|
|
428 |
|
|
Most of the remaining methods deal with preparing the new process, by |
429 |
|
|
loading code, evaluating code and sending data to the new process. They |
430 |
|
|
usually return the process object, so you can chain method calls. |
431 |
|
|
|
432 |
|
|
If a process object is destroyed before calling its C<run> method, then |
433 |
|
|
the process simply exits. After C<run> is called, all responsibility is |
434 |
|
|
passed to the specified function. |
435 |
root |
1.3 |
|
436 |
root |
1.29 |
As long as there is any outstanding work to be done, process objects |
437 |
|
|
resist being destroyed, so there is no reason to store them unless you |
438 |
|
|
need them later - configure and forget works just fine. |
439 |
|
|
|
440 |
root |
1.1 |
=over 4 |
441 |
|
|
|
442 |
|
|
=cut |
443 |
|
|
|
444 |
root |
1.4 |
package AnyEvent::Fork; |
445 |
root |
1.1 |
|
446 |
|
|
use common::sense; |
447 |
|
|
|
448 |
root |
1.18 |
use Errno (); |
449 |
root |
1.1 |
|
450 |
|
|
use AnyEvent; |
451 |
|
|
use AnyEvent::Util (); |
452 |
|
|
|
453 |
root |
1.15 |
use IO::FDPass; |
454 |
|
|
|
455 |
root |
1.60 |
our $VERSION = 1.2; |
456 |
root |
1.12 |
|
457 |
root |
1.5 |
# the early fork template process |
458 |
|
|
our $EARLY; |
459 |
|
|
|
460 |
root |
1.4 |
# the empty template process |
461 |
|
|
our $TEMPLATE; |
462 |
|
|
|
463 |
root |
1.42 |
sub QUEUE() { 0 } |
464 |
|
|
sub FH() { 1 } |
465 |
|
|
sub WW() { 2 } |
466 |
|
|
sub PID() { 3 } |
467 |
|
|
sub CB() { 4 } |
468 |
|
|
|
469 |
|
|
sub _new { |
470 |
|
|
my ($self, $fh, $pid) = @_; |
471 |
|
|
|
472 |
|
|
AnyEvent::Util::fh_nonblocking $fh, 1; |
473 |
|
|
|
474 |
|
|
$self = bless [ |
475 |
|
|
[], # write queue - strings or fd's |
476 |
|
|
$fh, |
477 |
|
|
undef, # AE watcher |
478 |
|
|
$pid, |
479 |
|
|
], $self; |
480 |
|
|
|
481 |
|
|
$self |
482 |
|
|
} |
483 |
|
|
|
484 |
root |
1.4 |
sub _cmd { |
485 |
|
|
my $self = shift; |
486 |
|
|
|
487 |
root |
1.18 |
# ideally, we would want to use "a (w/a)*" as format string, but perl |
488 |
|
|
# versions from at least 5.8.9 to 5.16.3 are all buggy and can't unpack |
489 |
|
|
# it. |
490 |
root |
1.55 |
push @{ $self->[QUEUE] }, pack "a L/a*", $_[0], $_[1]; |
491 |
root |
1.4 |
|
492 |
root |
1.42 |
$self->[WW] ||= AE::io $self->[FH], 1, sub { |
493 |
root |
1.19 |
do { |
494 |
|
|
# send the next "thing" in the queue - either a reference to an fh, |
495 |
|
|
# or a plain string. |
496 |
|
|
|
497 |
root |
1.42 |
if (ref $self->[QUEUE][0]) { |
498 |
root |
1.19 |
# send fh |
499 |
root |
1.42 |
unless (IO::FDPass::send fileno $self->[FH], fileno ${ $self->[QUEUE][0] }) { |
500 |
root |
1.19 |
return if $! == Errno::EAGAIN || $! == Errno::EWOULDBLOCK; |
501 |
root |
1.42 |
undef $self->[WW]; |
502 |
root |
1.19 |
die "AnyEvent::Fork: file descriptor send failure: $!"; |
503 |
root |
1.18 |
} |
504 |
root |
1.4 |
|
505 |
root |
1.42 |
shift @{ $self->[QUEUE] }; |
506 |
root |
1.18 |
|
507 |
root |
1.19 |
} else { |
508 |
|
|
# send string |
509 |
root |
1.42 |
my $len = syswrite $self->[FH], $self->[QUEUE][0]; |
510 |
root |
1.19 |
|
511 |
|
|
unless ($len) { |
512 |
|
|
return if $! == Errno::EAGAIN || $! == Errno::EWOULDBLOCK; |
513 |
root |
1.50 |
undef $self->[WW]; |
514 |
root |
1.19 |
die "AnyEvent::Fork: command write failure: $!"; |
515 |
|
|
} |
516 |
root |
1.18 |
|
517 |
root |
1.42 |
substr $self->[QUEUE][0], 0, $len, ""; |
518 |
|
|
shift @{ $self->[QUEUE] } unless length $self->[QUEUE][0]; |
519 |
root |
1.19 |
} |
520 |
root |
1.42 |
} while @{ $self->[QUEUE] }; |
521 |
root |
1.19 |
|
522 |
|
|
# everything written |
523 |
root |
1.42 |
undef $self->[WW]; |
524 |
root |
1.19 |
|
525 |
|
|
# invoke run callback, if any |
526 |
root |
1.48 |
if ($self->[CB]) { |
527 |
|
|
$self->[CB]->($self->[FH]); |
528 |
|
|
@$self = (); |
529 |
|
|
} |
530 |
root |
1.19 |
}; |
531 |
root |
1.14 |
|
532 |
|
|
() # make sure we don't leak the watcher |
533 |
root |
1.4 |
} |
534 |
root |
1.1 |
|
535 |
root |
1.6 |
# fork template from current process, used by AnyEvent::Fork::Early/Template |
536 |
|
|
sub _new_fork { |
537 |
|
|
my ($fh, $slave) = AnyEvent::Util::portable_socketpair; |
538 |
root |
1.7 |
my $parent = $$; |
539 |
|
|
|
540 |
root |
1.6 |
my $pid = fork; |
541 |
|
|
|
542 |
|
|
if ($pid eq 0) { |
543 |
|
|
require AnyEvent::Fork::Serve; |
544 |
root |
1.7 |
$AnyEvent::Fork::Serve::OWNER = $parent; |
545 |
root |
1.6 |
close $fh; |
546 |
root |
1.7 |
$0 = "$_[1] of $parent"; |
547 |
root |
1.6 |
AnyEvent::Fork::Serve::serve ($slave); |
548 |
root |
1.15 |
exit 0; |
549 |
root |
1.6 |
} elsif (!$pid) { |
550 |
|
|
die "AnyEvent::Fork::Early/Template: unable to fork template process: $!"; |
551 |
|
|
} |
552 |
|
|
|
553 |
root |
1.19 |
AnyEvent::Fork->_new ($fh, $pid) |
554 |
root |
1.6 |
} |
555 |
|
|
|
556 |
root |
1.4 |
=item my $proc = new AnyEvent::Fork |
557 |
root |
1.1 |
|
558 |
root |
1.4 |
Create a new "empty" perl interpreter process and returns its process |
559 |
|
|
object for further manipulation. |
560 |
root |
1.1 |
|
561 |
root |
1.4 |
The new process is forked from a template process that is kept around |
562 |
|
|
for this purpose. When it doesn't exist yet, it is created by a call to |
563 |
root |
1.29 |
C<new_exec> first and then stays around for future calls. |
564 |
root |
1.9 |
|
565 |
root |
1.4 |
=cut |
566 |
|
|
|
567 |
|
|
sub new { |
568 |
|
|
my $class = shift; |
569 |
root |
1.1 |
|
570 |
root |
1.4 |
$TEMPLATE ||= $class->new_exec; |
571 |
|
|
$TEMPLATE->fork |
572 |
root |
1.1 |
} |
573 |
|
|
|
574 |
root |
1.4 |
=item $new_proc = $proc->fork |
575 |
|
|
|
576 |
|
|
Forks C<$proc>, creating a new process, and returns the process object |
577 |
|
|
of the new process. |
578 |
|
|
|
579 |
|
|
If any of the C<send_> functions have been called before fork, then they |
580 |
|
|
will be cloned in the child. For example, in a pre-forked server, you |
581 |
|
|
might C<send_fh> the listening socket into the template process, and then |
582 |
|
|
keep calling C<fork> and C<run>. |
583 |
|
|
|
584 |
|
|
=cut |
585 |
|
|
|
586 |
|
|
sub fork { |
587 |
|
|
my ($self) = @_; |
588 |
root |
1.1 |
|
589 |
|
|
my ($fh, $slave) = AnyEvent::Util::portable_socketpair; |
590 |
root |
1.4 |
|
591 |
|
|
$self->send_fh ($slave); |
592 |
|
|
$self->_cmd ("f"); |
593 |
|
|
|
594 |
|
|
AnyEvent::Fork->_new ($fh) |
595 |
|
|
} |
596 |
|
|
|
597 |
|
|
=item my $proc = new_exec AnyEvent::Fork |
598 |
|
|
|
599 |
|
|
Create a new "empty" perl interpreter process and returns its process |
600 |
|
|
object for further manipulation. |
601 |
|
|
|
602 |
|
|
Unlike the C<new> method, this method I<always> spawns a new perl process |
603 |
|
|
(except in some cases, see L<AnyEvent::Fork::Early> for details). This |
604 |
|
|
reduces the amount of memory sharing that is possible, and is also slower. |
605 |
|
|
|
606 |
|
|
You should use C<new> whenever possible, except when having a template |
607 |
|
|
process around is unacceptable. |
608 |
|
|
|
609 |
root |
1.17 |
The path to the perl interpreter is divined using various methods - first |
610 |
root |
1.57 |
C<$^X> is investigated to see if the path ends with something that looks |
611 |
root |
1.4 |
as if it were the perl interpreter. Failing this, the module falls back to |
612 |
|
|
using C<$Config::Config{perlpath}>. |
613 |
|
|
|
614 |
root |
1.56 |
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 |
|
|
|
618 |
root |
1.4 |
=cut |
619 |
|
|
|
620 |
root |
1.56 |
our $PERL; |
621 |
|
|
|
622 |
root |
1.4 |
sub new_exec { |
623 |
|
|
my ($self) = @_; |
624 |
|
|
|
625 |
root |
1.5 |
return $EARLY->fork |
626 |
|
|
if $EARLY; |
627 |
|
|
|
628 |
root |
1.56 |
unless (defined $PERL) { |
629 |
|
|
# first find path of perl |
630 |
|
|
my $perl = $; |
631 |
|
|
|
632 |
|
|
# first we try $^X, but the path must be absolute (always on win32), and end in sth. |
633 |
|
|
# that looks like perl. this obviously only works for posix and win32 |
634 |
|
|
unless ( |
635 |
|
|
($^O eq "MSWin32" || $perl =~ m%^/%) |
636 |
|
|
&& $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i |
637 |
|
|
) { |
638 |
|
|
# if it doesn't look perlish enough, try Config |
639 |
|
|
require Config; |
640 |
|
|
$perl = $Config::Config{perlpath}; |
641 |
|
|
$perl =~ s/(?:\Q$Config::Config{_exe}\E)?$/$Config::Config{_exe}/; |
642 |
|
|
} |
643 |
root |
1.4 |
|
644 |
root |
1.56 |
$PERL = $perl; |
645 |
root |
1.4 |
} |
646 |
|
|
|
647 |
|
|
require Proc::FastSpawn; |
648 |
|
|
|
649 |
|
|
my ($fh, $slave) = AnyEvent::Util::portable_socketpair; |
650 |
|
|
Proc::FastSpawn::fd_inherit (fileno $slave); |
651 |
|
|
|
652 |
root |
1.10 |
# new fh's should always be set cloexec (due to $^F), |
653 |
|
|
# but hey, not on win32, so we always clear the inherit flag. |
654 |
|
|
Proc::FastSpawn::fd_inherit (fileno $fh, 0); |
655 |
|
|
|
656 |
root |
1.4 |
# quick. also doesn't work in win32. of course. what did you expect |
657 |
|
|
#local $ENV{PERL5LIB} = join ":", grep !ref, @INC; |
658 |
root |
1.1 |
my %env = %ENV; |
659 |
root |
1.15 |
$env{PERL5LIB} = join +($^O eq "MSWin32" ? ";" : ":"), grep !ref, @INC; |
660 |
root |
1.1 |
|
661 |
root |
1.19 |
my $pid = Proc::FastSpawn::spawn ( |
662 |
root |
1.56 |
$PERL, |
663 |
root |
1.7 |
["perl", "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$], |
664 |
root |
1.4 |
[map "$_=$env{$_}", keys %env], |
665 |
|
|
) or die "unable to spawn AnyEvent::Fork server: $!"; |
666 |
|
|
|
667 |
root |
1.19 |
$self->_new ($fh, $pid) |
668 |
root |
1.4 |
} |
669 |
|
|
|
670 |
root |
1.20 |
=item $pid = $proc->pid |
671 |
|
|
|
672 |
|
|
Returns the process id of the process I<iff it is a direct child of the |
673 |
root |
1.59 |
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. |
677 |
|
|
|
678 |
|
|
Or in other words, you do not normally have to take care of zombies for |
679 |
|
|
processes created via C<new>, but when in doubt, or zombies are a problem, |
680 |
|
|
you need to check whether a process is a diretc child by calling this |
681 |
|
|
method, and possibly creating a child watcher or reap it manually. |
682 |
root |
1.20 |
|
683 |
|
|
=cut |
684 |
|
|
|
685 |
|
|
sub pid { |
686 |
root |
1.42 |
$_[0][PID] |
687 |
root |
1.20 |
} |
688 |
|
|
|
689 |
root |
1.9 |
=item $proc = $proc->eval ($perlcode, @args) |
690 |
|
|
|
691 |
root |
1.44 |
Evaluates the given C<$perlcode> as ... Perl code, while setting C<@_> to |
692 |
root |
1.23 |
the strings specified by C<@args>, in the "main" package. |
693 |
root |
1.9 |
|
694 |
|
|
This call is meant to do any custom initialisation that might be required |
695 |
|
|
(for example, the C<require> method uses it). It's not supposed to be used |
696 |
|
|
to completely take over the process, use C<run> for that. |
697 |
|
|
|
698 |
|
|
The code will usually be executed after this call returns, and there is no |
699 |
|
|
way to pass anything back to the calling process. Any evaluation errors |
700 |
|
|
will be reported to stderr and cause the process to exit. |
701 |
|
|
|
702 |
root |
1.33 |
If you want to execute some code (that isn't in a module) to take over the |
703 |
|
|
process, you should compile a function via C<eval> first, and then call |
704 |
|
|
it via C<run>. This also gives you access to any arguments passed via the |
705 |
|
|
C<send_xxx> methods, such as file handles. See the L<use AnyEvent::Fork as |
706 |
root |
1.34 |
a faster fork+exec> example to see it in action. |
707 |
root |
1.23 |
|
708 |
root |
1.9 |
Returns the process object for easy chaining of method calls. |
709 |
|
|
|
710 |
|
|
=cut |
711 |
|
|
|
712 |
|
|
sub eval { |
713 |
|
|
my ($self, $code, @args) = @_; |
714 |
|
|
|
715 |
root |
1.19 |
$self->_cmd (e => pack "(w/a*)*", $code, @args); |
716 |
root |
1.9 |
|
717 |
|
|
$self |
718 |
|
|
} |
719 |
|
|
|
720 |
root |
1.4 |
=item $proc = $proc->require ($module, ...) |
721 |
root |
1.1 |
|
722 |
root |
1.9 |
Tries to load the given module(s) into the process |
723 |
root |
1.1 |
|
724 |
root |
1.4 |
Returns the process object for easy chaining of method calls. |
725 |
root |
1.1 |
|
726 |
root |
1.9 |
=cut |
727 |
|
|
|
728 |
|
|
sub require { |
729 |
|
|
my ($self, @modules) = @_; |
730 |
|
|
|
731 |
|
|
s%::%/%g for @modules; |
732 |
|
|
$self->eval ('require "$_.pm" for @_', @modules); |
733 |
|
|
|
734 |
|
|
$self |
735 |
|
|
} |
736 |
|
|
|
737 |
root |
1.4 |
=item $proc = $proc->send_fh ($handle, ...) |
738 |
root |
1.1 |
|
739 |
root |
1.4 |
Send one or more file handles (I<not> file descriptors) to the process, |
740 |
|
|
to prepare a call to C<run>. |
741 |
root |
1.1 |
|
742 |
root |
1.35 |
The process object keeps a reference to the handles until they have |
743 |
|
|
been passed over to the process, so you must not explicitly close the |
744 |
|
|
handles. This is most easily accomplished by simply not storing the file |
745 |
|
|
handles anywhere after passing them to this method - when AnyEvent::Fork |
746 |
|
|
is finished using them, perl will automatically close them. |
747 |
root |
1.4 |
|
748 |
|
|
Returns the process object for easy chaining of method calls. |
749 |
|
|
|
750 |
root |
1.17 |
Example: pass a file handle to a process, and release it without |
751 |
|
|
closing. It will be closed automatically when it is no longer used. |
752 |
root |
1.9 |
|
753 |
|
|
$proc->send_fh ($my_fh); |
754 |
|
|
undef $my_fh; # free the reference if you want, but DO NOT CLOSE IT |
755 |
|
|
|
756 |
root |
1.4 |
=cut |
757 |
|
|
|
758 |
|
|
sub send_fh { |
759 |
|
|
my ($self, @fh) = @_; |
760 |
|
|
|
761 |
|
|
for my $fh (@fh) { |
762 |
|
|
$self->_cmd ("h"); |
763 |
root |
1.42 |
push @{ $self->[QUEUE] }, \$fh; |
764 |
root |
1.4 |
} |
765 |
|
|
|
766 |
|
|
$self |
767 |
root |
1.1 |
} |
768 |
|
|
|
769 |
root |
1.4 |
=item $proc = $proc->send_arg ($string, ...) |
770 |
|
|
|
771 |
|
|
Send one or more argument strings to the process, to prepare a call to |
772 |
root |
1.35 |
C<run>. The strings can be any octet strings. |
773 |
root |
1.4 |
|
774 |
root |
1.18 |
The protocol is optimised to pass a moderate number of relatively short |
775 |
|
|
strings - while you can pass up to 4GB of data in one go, this is more |
776 |
|
|
meant to pass some ID information or other startup info, not big chunks of |
777 |
|
|
data. |
778 |
|
|
|
779 |
root |
1.17 |
Returns the process object for easy chaining of method calls. |
780 |
root |
1.4 |
|
781 |
|
|
=cut |
782 |
root |
1.1 |
|
783 |
root |
1.4 |
sub send_arg { |
784 |
|
|
my ($self, @arg) = @_; |
785 |
root |
1.1 |
|
786 |
root |
1.19 |
$self->_cmd (a => pack "(w/a*)*", @arg); |
787 |
root |
1.1 |
|
788 |
|
|
$self |
789 |
|
|
} |
790 |
|
|
|
791 |
root |
1.4 |
=item $proc->run ($func, $cb->($fh)) |
792 |
|
|
|
793 |
root |
1.23 |
Enter the function specified by the function name in C<$func> in the |
794 |
|
|
process. The function is called with the communication socket as first |
795 |
root |
1.4 |
argument, followed by all file handles and string arguments sent earlier |
796 |
|
|
via C<send_fh> and C<send_arg> methods, in the order they were called. |
797 |
|
|
|
798 |
root |
1.35 |
The process object becomes unusable on return from this function - any |
799 |
|
|
further method calls result in undefined behaviour. |
800 |
|
|
|
801 |
root |
1.23 |
The function name should be fully qualified, but if it isn't, it will be |
802 |
root |
1.35 |
looked up in the C<main> package. |
803 |
root |
1.4 |
|
804 |
root |
1.23 |
If the called function returns, doesn't exist, or any error occurs, the |
805 |
|
|
process exits. |
806 |
root |
1.4 |
|
807 |
root |
1.23 |
Preparing the process is done in the background - when all commands have |
808 |
|
|
been sent, the callback is invoked with the local communications socket |
809 |
|
|
as argument. At this point you can start using the socket in any way you |
810 |
|
|
like. |
811 |
|
|
|
812 |
root |
1.4 |
If the communication socket isn't used, it should be closed on both sides, |
813 |
|
|
to save on kernel memory. |
814 |
|
|
|
815 |
|
|
The socket is non-blocking in the parent, and blocking in the newly |
816 |
root |
1.23 |
created process. The close-on-exec flag is set in both. |
817 |
|
|
|
818 |
|
|
Even if not used otherwise, the socket can be a good indicator for the |
819 |
|
|
existence of the process - if the other process exits, you get a readable |
820 |
|
|
event on it, because exiting the process closes the socket (if it didn't |
821 |
|
|
create any children using fork). |
822 |
root |
1.4 |
|
823 |
root |
1.58 |
=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 |
848 |
|
|
|
849 |
root |
1.9 |
Example: create a template for a process pool, pass a few strings, some |
850 |
|
|
file handles, then fork, pass one more string, and run some code. |
851 |
|
|
|
852 |
|
|
my $pool = AnyEvent::Fork |
853 |
|
|
->new |
854 |
|
|
->send_arg ("str1", "str2") |
855 |
|
|
->send_fh ($fh1, $fh2); |
856 |
|
|
|
857 |
|
|
for (1..2) { |
858 |
|
|
$pool |
859 |
|
|
->fork |
860 |
|
|
->send_arg ("str3") |
861 |
|
|
->run ("Some::function", sub { |
862 |
|
|
my ($fh) = @_; |
863 |
|
|
|
864 |
|
|
# fh is nonblocking, but we trust that the OS can accept these |
865 |
root |
1.22 |
# few octets anyway. |
866 |
root |
1.9 |
syswrite $fh, "hi #$_\n"; |
867 |
|
|
|
868 |
|
|
# $fh is being closed here, as we don't store it anywhere |
869 |
|
|
}); |
870 |
|
|
} |
871 |
|
|
|
872 |
|
|
# Some::function might look like this - all parameters passed before fork |
873 |
|
|
# and after will be passed, in order, after the communications socket. |
874 |
|
|
sub Some::function { |
875 |
|
|
my ($fh, $str1, $str2, $fh1, $fh2, $str3) = @_; |
876 |
|
|
|
877 |
root |
1.22 |
print scalar <$fh>; # prints "hi #1\n" and "hi #2\n" in any order |
878 |
root |
1.9 |
} |
879 |
|
|
|
880 |
root |
1.4 |
=cut |
881 |
|
|
|
882 |
|
|
sub run { |
883 |
|
|
my ($self, $func, $cb) = @_; |
884 |
|
|
|
885 |
root |
1.42 |
$self->[CB] = $cb; |
886 |
root |
1.9 |
$self->_cmd (r => $func); |
887 |
root |
1.4 |
} |
888 |
|
|
|
889 |
root |
1.53 |
=back |
890 |
|
|
|
891 |
|
|
=head2 EXPERIMENTAL METHODS |
892 |
|
|
|
893 |
root |
1.55 |
These methods might go away completely or change behaviour, at any time. |
894 |
root |
1.53 |
|
895 |
|
|
=over 4 |
896 |
|
|
|
897 |
root |
1.50 |
=item $proc->to_fh ($cb->($fh)) # EXPERIMENTAL, MIGHT BE REMOVED |
898 |
root |
1.48 |
|
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 |
root |
1.58 |
The point of this method is to give you a file handle that you can pass |
906 |
root |
1.48 |
to another process. In that other process, you can call C<new_from_fh |
907 |
root |
1.58 |
AnyEvent::Fork $fh> to create a new C<AnyEvent::Fork> object from it, |
908 |
|
|
thereby effectively passing a fork object to another process. |
909 |
root |
1.48 |
|
910 |
|
|
=cut |
911 |
|
|
|
912 |
|
|
sub to_fh { |
913 |
|
|
my ($self, $cb) = @_; |
914 |
|
|
|
915 |
|
|
$self->[CB] = $cb; |
916 |
|
|
|
917 |
|
|
unless ($self->[WW]) { |
918 |
|
|
$self->[CB]->($self->[FH]); |
919 |
|
|
@$self = (); |
920 |
|
|
} |
921 |
|
|
} |
922 |
|
|
|
923 |
root |
1.50 |
=item new_from_fh AnyEvent::Fork $fh # EXPERIMENTAL, MIGHT BE REMOVED |
924 |
root |
1.48 |
|
925 |
|
|
Takes a file handle originally rceeived by the C<to_fh> method and creates |
926 |
|
|
a new C<AnyEvent:Fork> object. The child process itself will not change in |
927 |
|
|
any way, i.e. it will keep all the modifications done to it before calling |
928 |
|
|
C<to_fh>. |
929 |
|
|
|
930 |
|
|
The new object is very much like the original object, except that the |
931 |
|
|
C<pid> method will return C<undef> even if the process is a direct child. |
932 |
|
|
|
933 |
|
|
=cut |
934 |
|
|
|
935 |
|
|
sub new_from_fh { |
936 |
|
|
my ($class, $fh) = @_; |
937 |
|
|
|
938 |
|
|
$class->_new ($fh) |
939 |
|
|
} |
940 |
|
|
|
941 |
root |
1.1 |
=back |
942 |
|
|
|
943 |
root |
1.16 |
=head1 PERFORMANCE |
944 |
|
|
|
945 |
|
|
Now for some unscientific benchmark numbers (all done on an amd64 |
946 |
|
|
GNU/Linux box). These are intended to give you an idea of the relative |
947 |
root |
1.18 |
performance you can expect, they are not meant to be absolute performance |
948 |
|
|
numbers. |
949 |
root |
1.16 |
|
950 |
root |
1.17 |
OK, so, I ran a simple benchmark that creates a socket pair, forks, calls |
951 |
root |
1.16 |
exit in the child and waits for the socket to close in the parent. I did |
952 |
root |
1.18 |
load AnyEvent, EV and AnyEvent::Fork, for a total process size of 5100kB. |
953 |
root |
1.16 |
|
954 |
root |
1.18 |
2079 new processes per second, using manual socketpair + fork |
955 |
root |
1.16 |
|
956 |
|
|
Then I did the same thing, but instead of calling fork, I called |
957 |
|
|
AnyEvent::Fork->new->run ("CORE::exit") and then again waited for the |
958 |
root |
1.48 |
socket from the child to close on exit. This does the same thing as manual |
959 |
root |
1.17 |
socket pair + fork, except that what is forked is the template process |
960 |
root |
1.16 |
(2440kB), and the socket needs to be passed to the server at the other end |
961 |
|
|
of the socket first. |
962 |
|
|
|
963 |
|
|
2307 new processes per second, using AnyEvent::Fork->new |
964 |
|
|
|
965 |
|
|
And finally, using C<new_exec> instead C<new>, using vforks+execs to exec |
966 |
|
|
a new perl interpreter and compile the small server each time, I get: |
967 |
|
|
|
968 |
|
|
479 vfork+execs per second, using AnyEvent::Fork->new_exec |
969 |
|
|
|
970 |
root |
1.17 |
So how can C<< AnyEvent->new >> be faster than a standard fork, even |
971 |
|
|
though it uses the same operations, but adds a lot of overhead? |
972 |
root |
1.16 |
|
973 |
root |
1.36 |
The difference is simply the process size: forking the 5MB process takes |
974 |
|
|
so much longer than forking the 2.5MB template process that the extra |
975 |
root |
1.43 |
overhead is canceled out. |
976 |
root |
1.16 |
|
977 |
|
|
If the benchmark process grows, the normal fork becomes even slower: |
978 |
|
|
|
979 |
root |
1.36 |
1340 new processes, manual fork of a 20MB process |
980 |
|
|
731 new processes, manual fork of a 200MB process |
981 |
|
|
235 new processes, manual fork of a 2000MB process |
982 |
|
|
|
983 |
|
|
What that means (to me) is that I can use this module without having a bad |
984 |
|
|
conscience because of the extra overhead required to start new processes. |
985 |
root |
1.16 |
|
986 |
root |
1.15 |
=head1 TYPICAL PROBLEMS |
987 |
|
|
|
988 |
|
|
This section lists typical problems that remain. I hope by recognising |
989 |
|
|
them, most can be avoided. |
990 |
|
|
|
991 |
|
|
=over 4 |
992 |
|
|
|
993 |
root |
1.36 |
=item leaked file descriptors for exec'ed processes |
994 |
root |
1.15 |
|
995 |
|
|
POSIX systems inherit file descriptors by default when exec'ing a new |
996 |
|
|
process. While perl itself laudably sets the close-on-exec flags on new |
997 |
|
|
file handles, most C libraries don't care, and even if all cared, it's |
998 |
|
|
often not possible to set the flag in a race-free manner. |
999 |
|
|
|
1000 |
|
|
That means some file descriptors can leak through. And since it isn't |
1001 |
root |
1.17 |
possible to know which file descriptors are "good" and "necessary" (or |
1002 |
|
|
even to know which file descriptors are open), there is no good way to |
1003 |
root |
1.15 |
close the ones that might harm. |
1004 |
|
|
|
1005 |
|
|
As an example of what "harm" can be done consider a web server that |
1006 |
|
|
accepts connections and afterwards some module uses AnyEvent::Fork for the |
1007 |
|
|
first time, causing it to fork and exec a new process, which might inherit |
1008 |
|
|
the network socket. When the server closes the socket, it is still open |
1009 |
|
|
in the child (which doesn't even know that) and the client might conclude |
1010 |
|
|
that the connection is still fine. |
1011 |
|
|
|
1012 |
|
|
For the main program, there are multiple remedies available - |
1013 |
|
|
L<AnyEvent::Fork::Early> is one, creating a process early and not using |
1014 |
|
|
C<new_exec> is another, as in both cases, the first process can be exec'ed |
1015 |
|
|
well before many random file descriptors are open. |
1016 |
|
|
|
1017 |
|
|
In general, the solution for these kind of problems is to fix the |
1018 |
|
|
libraries or the code that leaks those file descriptors. |
1019 |
|
|
|
1020 |
root |
1.17 |
Fortunately, most of these leaked descriptors do no harm, other than |
1021 |
root |
1.15 |
sitting on some resources. |
1022 |
|
|
|
1023 |
root |
1.36 |
=item leaked file descriptors for fork'ed processes |
1024 |
root |
1.15 |
|
1025 |
|
|
Normally, L<AnyEvent::Fork> does start new processes by exec'ing them, |
1026 |
|
|
which closes file descriptors not marked for being inherited. |
1027 |
|
|
|
1028 |
|
|
However, L<AnyEvent::Fork::Early> and L<AnyEvent::Fork::Template> offer |
1029 |
|
|
a way to create these processes by forking, and this leaks more file |
1030 |
|
|
descriptors than exec'ing them, as there is no way to mark descriptors as |
1031 |
|
|
"close on fork". |
1032 |
|
|
|
1033 |
|
|
An example would be modules like L<EV>, L<IO::AIO> or L<Gtk2>. Both create |
1034 |
|
|
pipes for internal uses, and L<Gtk2> might open a connection to the X |
1035 |
|
|
server. L<EV> and L<IO::AIO> can deal with fork, but Gtk2 might have |
1036 |
|
|
trouble with a fork. |
1037 |
|
|
|
1038 |
|
|
The solution is to either not load these modules before use'ing |
1039 |
|
|
L<AnyEvent::Fork::Early> or L<AnyEvent::Fork::Template>, or to delay |
1040 |
|
|
initialising them, for example, by calling C<init Gtk2> manually. |
1041 |
|
|
|
1042 |
root |
1.37 |
=item exiting calls object destructors |
1043 |
root |
1.19 |
|
1044 |
root |
1.38 |
This only applies to users of L<AnyEvent::Fork:Early> and |
1045 |
root |
1.44 |
L<AnyEvent::Fork::Template>, or when initialising code creates objects |
1046 |
root |
1.38 |
that reference external resources. |
1047 |
root |
1.19 |
|
1048 |
|
|
When a process created by AnyEvent::Fork exits, it might do so by calling |
1049 |
|
|
exit, or simply letting perl reach the end of the program. At which point |
1050 |
|
|
Perl runs all destructors. |
1051 |
|
|
|
1052 |
|
|
Not all destructors are fork-safe - for example, an object that represents |
1053 |
|
|
the connection to an X display might tell the X server to free resources, |
1054 |
|
|
which is inconvenient when the "real" object in the parent still needs to |
1055 |
|
|
use them. |
1056 |
|
|
|
1057 |
|
|
This is obviously not a problem for L<AnyEvent::Fork::Early>, as you used |
1058 |
|
|
it as the very first thing, right? |
1059 |
|
|
|
1060 |
|
|
It is a problem for L<AnyEvent::Fork::Template> though - and the solution |
1061 |
|
|
is to not create objects with nontrivial destructors that might have an |
1062 |
|
|
effect outside of Perl. |
1063 |
|
|
|
1064 |
root |
1.15 |
=back |
1065 |
|
|
|
1066 |
root |
1.8 |
=head1 PORTABILITY NOTES |
1067 |
|
|
|
1068 |
root |
1.10 |
Native win32 perls are somewhat supported (AnyEvent::Fork::Early is a nop, |
1069 |
|
|
and ::Template is not going to work), and it cost a lot of blood and sweat |
1070 |
|
|
to make it so, mostly due to the bloody broken perl that nobody seems to |
1071 |
|
|
care about. The fork emulation is a bad joke - I have yet to see something |
1072 |
root |
1.17 |
useful that you can do with it without running into memory corruption |
1073 |
root |
1.10 |
issues or other braindamage. Hrrrr. |
1074 |
|
|
|
1075 |
root |
1.49 |
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 |
|
|
|
1080 |
root |
1.36 |
Cygwin perl is not supported at the moment due to some hilarious |
1081 |
root |
1.49 |
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. |
1084 |
root |
1.8 |
|
1085 |
root |
1.13 |
=head1 SEE ALSO |
1086 |
|
|
|
1087 |
root |
1.46 |
L<AnyEvent::Fork::Early>, to avoid executing a perl interpreter at all |
1088 |
|
|
(part of this distribution). |
1089 |
|
|
|
1090 |
|
|
L<AnyEvent::Fork::Template>, to create a process by forking the main |
1091 |
|
|
program at a convenient time (part of this distribution). |
1092 |
|
|
|
1093 |
root |
1.57 |
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 |
root |
1.46 |
L<AnyEvent::Fork::RPC>, for simple RPC to child processes (on CPAN). |
1098 |
root |
1.13 |
|
1099 |
root |
1.51 |
L<AnyEvent::Fork::Pool>, for simple worker process pool (on CPAN). |
1100 |
|
|
|
1101 |
root |
1.43 |
=head1 AUTHOR AND CONTACT INFORMATION |
1102 |
root |
1.1 |
|
1103 |
|
|
Marc Lehmann <schmorp@schmorp.de> |
1104 |
root |
1.43 |
http://software.schmorp.de/pkg/AnyEvent-Fork |
1105 |
root |
1.1 |
|
1106 |
|
|
=cut |
1107 |
|
|
|
1108 |
|
|
1 |
1109 |
|
|
|