frankdejonge/locked-console-command

A symfony/console command decorator which locks.

3.1.1 2016-06-30 12:12 UTC

README

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In some cases, you'll want only one process of a certain command to be able to run at a time. The Command decorator supplied in this package makes this possible by using the LockHandler class from Symfony's Filesystem Component.

Credits

The idea wasn't initially mine, I stole it from @Seldaek.

Installation

composer require frankdejonge/locked-console-command

Usage

All you have to do, is wrap the command:

<?php

use FrankDeJonge\LockedConsoleCommand\LockedCommandDecorator;
use Symfony\Component\Console\Application;

$application = new Application;
$app->add(new LockedCommandDecorator(new YourConsoleCommand()));
$app->run();

Laravel Usage

use FrankDeJonge\LockedConsoleCommand\LockedCommandDecorator;
Artisan::add(new LockedCommandDecorator(new SomeCommand()));

How does the locking work?

The decorator uses a file lock (supplied by Symfony's LockHandler) to ensure a lock is set before and released after executing the command.

If a lock is already set for a given task, an info message is shown and the decorated command is prevented from running.

Configuration

There are two configurable parts to influence locking.

  1. The lock name
  2. The lock path

Through __constructor argument injection

$command = new LockedCommandDecorator($yourCommand, 'lock-name', '/lock/path'));

Through interface implementations in the wrapper Command

  • Implement FrankDeJonge\LockedConsoleCommand\SpecifiesLockName (::getLockName())
  • Implement FrankDeJonge\LockedConsoleCommand\SpecifiesLockPath (::getLockPath())

The SpecifiesLockName interface is especially handy with dynamic lock names, for example:


class SomeQueueWorker extends Command implements SpecifiesLockName
{
    public function getLockName(InputInterface $input)
    {
        return 'root:name:'.$input->getArgument('worker-id');
    }
}