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Mojo-IOLoop-ReadWriteProcess-0.30
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/ Mojo::IOLoop::ReadWriteProcess::Container

NAME

Mojo::IOLoop::ReadWriteProcess::Container - (kinda) Pure Perl containers.

SYNOPSIS

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);

my $container = container(
  pid_isolation => 1,  # Best-effort, as depends on where you run it (you need CAP_SYS_ADMIN)
  subreaper => 1,
  group   => "my_org",
  name    => "my_process",
  process => process(
    sub {
      # Exec, fork ..
      process(sub { warn "\o/"; sleep 42;  })->start;
      process(sub { warn "\o/"; sleep 42; })->start;
      process(
        sub {
          process(
            sub {
              process(sub { warn "\o/"; sleep 42; })->start;
              warn "\o/";
              sleep 400;
              warn "\o/";
            })->start;
          warn "Hey";
          sleep 42;
          warn "\o/";
        })->start;
      sleep 42;
    }
  )->separate_err(0));

$container->start();
$container->is_running;
$container->stop;

my @procs = $container->cgroups->first->processes;
$container->cgroups->first->pid->max(300);

$container->process->on(stop => sub { print "Main container process stopped!" });

DESCRIPTION

Mojo::IOLoop::ReadWriteProcess::Container ties anonymous functions or a Mojo::IOLoop::ReadWriteProcess object to differents sets of Mojo::IOLoop::ReadWriteProcess::CGroup implementations.

When the pid_isolation attribute is set, it needs special permissions (CAP_SYS_ADMIN capabilities). This module uses features that are only available on Linux, and requires cgroups and capability (CAP_SYS_ADMIN) for unshare syscalls to achieve pid isolation.

EVENTS

Mojo::IOLoop::ReadWriteProcess inherits all events from Mojo::EventEmitter and can emit the following new ones.

start

$container->on(start => sub {
  my ($process) = @_;
   ...
});

Emitted when the container starts.

stop

$container->on(stop => sub {
  my ($container) = @_;
  ...
});

Emitted when the container stops.

process_error

$container->on(container_error => sub {
  my ($e) = @_;
  my @errors = @{$e};
});

Emitted when the container produce errors.

METHODS

Mojo::IOLoop::ReadWriteProcess::Container inherits all methods from Mojo::EventEmitter and implements the following new ones.

start

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);

my $c = container( name=>"test", process => sub { print "Hello!" });
$c->start();

Starts the container, it's main process is a Mojo::IOLoop::ReadWriteProcess, contained in the process() attribute. On stop it will terminate every process included in the cgroups attribute.

is_running

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);

my $c = container( name=>"test", process => sub { print "Hello!" });
$c->is_running();

Returns 1 if the container is running.

stop

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);

my $c = container( name=>"test", process => sub { print "Hello!" })->start;
$c->stop();

Stops the container and kill all the processes belonging to the cgroup. It also registers all the unknown processes to the current Mojo::IOLoop::ReadWriteProcess::Session.

wait_stop

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);

my $c = container( name=>"test", process => sub { print "Hello!" })->start;
$c->wait_stop();

Wait before stopping the container.

wait

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);

my $c = container( name=>"test", process => sub { print "Hello!" })->start;
$c->wait();

Wait the container to stop

migrate_process

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);

my $c = container( name=>"test", process => sub { print "Hello!" })->start;
$c->migrate_process(42);

Migrate the given process to the container cgroup.

ATTRIBUTES

Mojo::IOLoop::ReadWriteProcess::Container inherits all attributes from Mojo::EventEmitter and implements the following new ones.

name

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);
use Mojo::IOLoop::ReadWriteProcess::CGroup qw(cgroupv1);
use Mojo::Collection 'c';

my $container = container( name => "test", process => sub { print "Hello!" } );

$container->session->on(register => sub { ... });
$container->start();

Sets the container name. It creates in the indicated (or default) cgroups a sub-tree with the container name.

This means that cgroups settings can be done also outside of the container object:

use Mojo::IOLoop::ReadWriteProcess::CGroup qw(cgroupv1);
use Mojo::IOLoop::ReadWriteProcess::Container qw(container);

my $container = container( name => "test", process => sub { print "Hello!" } );

cgroupv1->from($continer->cgroups->first->_group)->pid->max(100);

As cgroups are represented by path, you can set options directly from controllers objects that are pointing to the same cgroup slice.

group

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);
use Mojo::IOLoop::ReadWriteProcess::CGroup qw(cgroupv2);
use Mojo::Collection 'c';

my $container = container( name => "bar", group => "foo", process => sub { print "Hello!" } );
my $container2 = container( name => "bar2", group => "foo", process => sub { print "Hello!" } );

$container->start();
$container2->start();

my $group_cgroup = cgroupv2->from($container2->cgroups->first->parent);

$group_cgroup->pid->max(200);

Sets the container group. If containers are sharing the same group they will inherit the same CGroup parent path, in such way it is possible to create controllers pointing to it and set specific options for the whole group.

pid_isolation

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);
use Mojo::IOLoop::ReadWriteProcess::CGroup qw(cgroupv1);
use Mojo::Collection 'c';

my $container = container( pid_isolation => 1, process => sub { print "Hello!" } );

$container->session->on(register => sub { ... });
$container->start();

If set, the process will see itself as PID 1. It needs CAP_SYS_ADMIN capabilities set on the executable (or run as root).

pre_migrate

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);

my $container = container( pre_migrate => 1, process => sub { print "Hello!" } );

$container->session->on(register => sub { ... });
$container->start();

If set, the process will migrate itself into the cgroup.

clean_cgroup

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);

my $container = container( clean_cgroup => 1, process => sub { print "Hello!" });

$container->session->on(register => sub { ... });
$container->start();

If set, attempts to destroy the cgroup after the process terminated its execution.

subreaper

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);

my $c = container(subreaper => 1, name=>"test", process => sub { print "Hello!" });
$c->start();

Enable subreaper mode inside the child process.

process

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);

my $c = container(process => sub { print "Hello!" });
my $c = container(process => sub { print "Hello!" });

$c->start();

The process to run. It can be an anonymous function or a Mojo::IOLoop::ReadWriteProcess object.

namespace

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);

my $c = container(process => sub { print "Hello!" });
$c->namespace->unshare(0); # All
$c->start();

Set/Return Mojo::IOLoop::ReadWriteProcess::Namespace object. It's main use is to invoke syscalls.

session

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);

my $c = container(process => process(sub { print "Hello!" }));
$c->session->on(register => sub { ... });
$c->start();

Returns/Set the Mojo::IOLoop::ReadWriteProcess::Session singleton object.

unshare

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);
use Mojo::IOLoop::ReadWriteProcess::Namespace qw( CLONE_NEWPID CLONE_NEWNS );

my $c = container( unshare=> CLONE_NEWPID | CLONE_NEWNS, process => sub { print "Hello!" } );
$c->session->on(register => sub { ... });
$c->start();

Returns/Set the unshare syscall options. See man unshare(2) for further documentation.

cgroups

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);
use Mojo::IOLoop::ReadWriteProcess::CGroup qw(cgroupv1);
use Mojo::Collection 'c';

my $container = container(process => sub { print "Hello!" });
$container->cgroups( c(cgroupv1(controller => 'pids'), cgroupv1(controller => 'memory')) );

$container->session->on(register => sub { ... });
$container->start();

Returns/Set a Mojo::Collection collection of CGroups where the process should belong to. If used with a single CGroup, you don't need to pass the Mojo::Collection object:

use Mojo::IOLoop::ReadWriteProcess::Container qw(container);
use Mojo::IOLoop::ReadWriteProcess qw(process);
use Mojo::IOLoop::ReadWriteProcess::CGroup qw(cgroupv1);
use Mojo::Collection 'c';

my $container = container(cgroups=> cgroupv1(controller => 'pids'), process => sub { print "Hello!" });

$container->session->on(register => sub { ... });
$container->start();

DEBUGGING

You can set the MOJO_EVENTEMITTER_DEBUG environment variable to get some advanced diagnostics information printed to STDERR.

MOJO_EVENTEMITTER_DEBUG=1

Also, you can set MOJO_PROCESS_DEBUG environment variable to get diagnostics about the process execution.

MOJO_PROCESS_DEBUG=1

LICENSE

Copyright (C) Ettore Di Giacinto.

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

AUTHOR

Ettore Di Giacinto <edigiacinto@suse.com>