NAME

       Test2::Manual::Anatomy::IPC - Manual for the IPC system.

DESCRIPTION

       This document describes the IPC system.

WHAT IS THE IPC SYSTEM

       The IPC system is activated by loading Test2::IPC. This makes hubs process/thread aware,
       and makes them forward events along to the parent process/thread as necessary.

HOW DOES THE IPC SYSTEM EFFECT EVERYTHING?

       Test2::API and Test2::API::Instance have some behaviors that trigger if Test2::IPC is
       loaded before the global state is initialized. Mainly an IPC driver will be initiated and
       stored in the global state.

       If an IPC driver is initialized then all hubs will be initialized with a reference to the
       driver instance. If a hub has an IPC driver instance it will use it to forward events to
       parent processes and threads.

WHAT DOES AN IPC DRIVER DO?

       An Test2::IPC::Driver provides a way to send event data to a destination
       process+thread+hub (or to all globally). The driver must also provide a way for a
       process/thread/hub to read in any pending events that have been sent to it.

HOW DOES THE DEFAULT IPC DRIVER WORK?

       The default IPC driver is Test2::API::Driver::Files. This default driver, when
       initialized, starts by creating a temporary directory. Any time an event needs to be sent
       to another process/thread/hub, the event will be written to a file using Storable. The
       file is written with the destination process, thread, and hub as part of the filename. All
       hubs will regularly check for pending IPC events and will process them.

       This driver is further optimized using a small chunk of SHM. Any time a new event is sent
       via IPC the shm is updated to have a new value. Hubs will not bother checking for new IPC
       events unless the shm value has changed since their last poll. A result of this is that
       the IPC system is surprisingly fast, and does not waste time polling the hard drive when
       there are no pending events.

SEE ALSO

       Test2::Manual - Primary index of the manual.

SOURCE

       The source code repository for Test2-Manual can be found at
       https://github.com/Test-More/Test2-Suite/.

MAINTAINERS

       Chad Granum <exodist@cpan.org>

AUTHORS

       Chad Granum <exodist@cpan.org>

COPYRIGHT

       Copyright 2018 Chad Granum <exodist@cpan.org>.

       This program is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.

       See http://dev.perl.org/licenses/