| Mojo::IOLoop::ReadWriteProcess::Shared::Lock(3pm) | User Contributed Perl Documentation | Mojo::IOLoop::ReadWriteProcess::Shared::Lock(3pm) |
Mojo::IOLoop::ReadWriteProcess::Shared::Lock - IPC Lock
use Mojo::IOLoop::ReadWriteProcess qw(process queue lock);
my $q = queue; # Create a Queue
$q->pool->maximum_processes(10); # 10 Concurrent processes at maximum
$q->queue->maximum_processes(50); # 50 is maximum total to be allowed in the queue
$q->add(
process(
sub {
my $l = lock(key => 42); # IPC Lock
my $e = 1;
if ($l->lock) { # Blocking lock acquire
# Critical section
$e = 0;
$l->unlock;
}
exit($e);
}
)->set_pipes(0)->internal_pipes(0)) for 1 .. 20; # Fill with 20 processes
$q->consume(); # Consume the processes
Mojo::IOLoop::ReadWriteProcess::Shared::Lock uses IPC::Semaphore internally and creates a Lock from a semaphore that is available across different processes.
Mojo::IOLoop::ReadWriteProcess::Shared::Lock inherits all events from Mojo::IOLoop::ReadWriteProcess::Shared::Semaphore and implements the following new ones.
use Mojo::IOLoop::ReadWriteProcess qw(lock);
my $l = lock(key => "42"); # Create Lock with key 42
if ($l->lock) { # Blocking call
# Critical section
...
$l->unlock; # Release the lock
}
Acquire access to the lock and unlocks it.
"lock()" has the same arguments as Mojo::IOLoop::ReadWriteProcess::Shared::Semaphore "acquire()".
use Mojo::IOLoop::ReadWriteProcess qw(lock);
my $l = lock(key => "42"); # Create Lock with key 42
if ($l->try_lock) { # Non Blocking call
# Critical section
...
$l->unlock; # Release the lock
}
Try to acquire lock in a non-blocking way.
use Mojo::IOLoop::ReadWriteProcess qw(lock);
my $l = lock(key => 3331);
my $e = 1;
$l->lock_section(sub { $e = 0; die; }); # or also $l->section(sub { $e = 0 });
$l->locked; # is 0
Executes a function inside a locked section. Errors are caught so lock is released in case of failures.
Mojo::IOLoop::ReadWriteProcess::Shared::Lock inherits all attributes from Mojo::IOLoop::ReadWriteProcess::Shared::Semaphore and provides the following new ones.
use Mojo::IOLoop::ReadWriteProcess qw(lock);
use IPC::SysV qw(IPC_CREAT IPC_EXCL S_IRUSR S_IWUSR);
my $l = lock(flags=> IPC_CREAT | IPC_EXCL | S_IRUSR | S_IWUSR);
Sets flag for the lock. In such way you can limit the access to the lock, e.g. to specific user/group process.
use Mojo::IOLoop::ReadWriteProcess qw(lock);
my $l = lock(key => 42);
Sets the lock key that is used to retrieve the lock among different processes, must be an integer.
use Mojo::IOLoop::ReadWriteProcess qw(lock);
my $l = lock(key => 42);
$l->lock_section(sub {
$l->locked; # 1
});
$l->locked; # 0
Returns the lock status
You can set MOJO_PROCESS_DEBUG environment variable to get diagnostics about the process execution.
MOJO_PROCESS_DEBUG=1
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.
Ettore Di Giacinto <edigiacinto@suse.com>
| 2022-12-30 | perl v5.36.0 |