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package FCGI::Spawn;

use vars qw($VERSION);

BEGIN {
    $VERSION              = '0.16.7';
    $FCGI::Spawn::Default = 'FCGI::Spawn';
}

=pod

=head1 NAME

 FCGI::Spawn - FastCGI server for CGI-like applications effective multiprocessing

=head1 SYNOPSIS

Minimum unrecommended way to illustrate it working:

	FCGI::Spawn->new->spawn;

Never put this in production use. The C<fcgi_spawn> script supplied should care about sadly mandatory whistles and bells, at least the security is a king in sight of this:

FCGI::Spawn code should be run as its own user id, and the web server should be configured to request its FastCGI; in the case the local socket file is used, the web server should have the read and write permissions on it, the default name is /tmp/sp...
Consider about sock_chmod/sock_chown parameters for this, too.


In the case if you request via TCP care should be taken on network security like DMZ/VPN/firewalls setup instead of sock_* parameters.

About the ready to run applications compatibility refer to C<fcgi_spawn> docs.

Every other thing is explained in L<FCGI::ProcManager|FCGI::ProcManager> docs.

=head1 DESCRIPTION

The overall idea is to make Perl server-side scripts as convinient for newbies and server administrators as PHP in FastCGI mode.

FCGI::Spawn is used to serve as a FastCGI process manager.
Besides  the features the FCGI::ProcManager posess itself, the FCGI::Spawn is targeted as web server admin understandable instance for building the own fastcgi server with copy-on-write memory sharing among forks and with single input parameters like...

Another thing to mention is that it is able to execute any file pointed by Web server ( FastCGI requester ).
So we have the daemon that is hot ready for hosting providing :-)

The definitive care is taken in FCGI::Spawn on security.
Besides the inode settings on local UNIX socket taken as input parameter, it is aware to avoid hosting users from changing the max_requests parameter meant correspondent to MaxRequests Apache's forked MPM parameter, and the respective current request...

The aforementioned max_requests parameter takes also care about the performance to avoid forks' memory leaks to consume all the RAM accounted on your hardware.

For shared hosting it is assumed that system administrator controls the process manager daemon script contents with those user hardware consumption limits and executes it with a user's credentials.
E. g., the user should be able to send signal to the daemon to initiate graceful restart on his/her demand ( this is yet to be done ) or change the settings those administrator can specifically allow in the daemon starter script without restart ( bot...

The call stack lets you set up your own code reference for your scripts execution. Also, feature exists that you can cache some object, like the template or XSLT processor and the recompilation to happen only on the template or xsl file(s) change. En...

Seeking for convention between high preformance needs that the perl compile cache possess and the convinience of debugging with recompilation on every request that php provides, the C<stats> feature allows you not to recompile the tested source like ...
This may be useful in both development environment to make the recompilation yet faster and on a production host to make the details of code adaptaion to hosting clear in a much less time needed.

=head1 Behind the scenes of fcgi_spawn

Here are the details for those unsatisfied with C<fcgi_spawn> but trying with FCGI::Spawn anyway:

=over

=item * You must configure socket

with %ENV or shell and tweak the CGI.pm with the patch supplied, if need, at early before use FCGI::Spawn.  

%ENV and @INC can be tweaked in the special BEGIN block or you can eval "use FCGI::Spawn;" otherwise.
This is because of setting up the socket communication in the CGI::Fast, which is the part of Perl core distribution, right in the BEGIN block, e. g. right before the compilation.

=item * You should beware about CGI::Fast IS NOT included

at the moment this module is being used, e. g. IS ABSENT in the %INC global hash.

=item * CGI scripts ( if not CGI.pm ) must be tweaked to use $FCGI::Spawn::fcgi instead of new CGI or CGI->new.

In other case they will not be able to process HTTP POST.

In some caeses ( e. g. Bugzilla that derives CGI.pm ) the sources should be changed, too.
Hope your code obfuscators are not that complex to allow such a tweak. ;-)
FastCGI scripts do take the FastCGI object as a parameter, so it is obviously supplied in the callout code reference ( see below ).

=back

=head2 Why not mod_perl/mod_perl2/mod_fcgid?

=over

=item * Memory consumption

With FCGI::Spawn every fork weghts less in your "top".
Thus it is less hard to see the system load while forks' memory being swapped out and losing its copy-on-write kernel facility.
Every fork stops sharing its memory in this case.

=item * Memory sharing

With mod_fcgid, the compiled Perl code is not being shared among forks by far.

=item * Too much need for root

The startup.pl providing the memory sharing among forks is aimed to be run as root, at least when you need to listen binded to ports numbered less than 1024, for example, 80.
And, the root user ( the human ) is often too busy to check if that massive code is secure enough to be run as root system user ( the effective UID ) Thus, it's no much deal to accelerate Perl on mod_perl steroids if the startup.pl includes rather sm...

Root is needed to recompile the Perl sources, at least with the useful Registry handler.
It is obvious to gracefully restart Apache once per N minutes and this is what several hosting panel use to do but it is not convinient to debug code that is migrated from developer's hosting to production's  as it is needed to be recompiled on webma...
And, with no ( often proprietary ) hosting panel software onboard, Apache doesn't even gracefully restart on a regular basis without special admin care taken at server setup time.
On the uptime had gone till the need of restart after launch it is not an admin favor to do this, even gracefully.
Apache::Reload can save from this but it's not a production feature, too.

=item * File serving speed loss