worker.md

Configuration

To use a worker, you should resolve its dependencies (e.g. through DI container) and define handlers for each message which will be consumed by this worker;

Handlers are callables indexed by payload names. When a message is consumed from the queue, a callable associated with its payload name is called.

Handler format

Handler can be any callable with a couple of additions:

• If handler is provided as an array of two strings, it will be treated as a DI container service id and its method. E.g. [ClassName::class, 'handle'] will be resolved to:

  $container
      ->get(ClassName::class)
      ->handle();

• An Injector is used to call the handlers. This means you can define handlers as closures with their own dependencies which will be resolved with DI container. In the example below you can see a closure in which message will be taken from the queue and ClientInterface will be resolved via DI container.

  'payloadName' => fn (MessageInterface $message, ClientInterface $client) => $client->send($message->getPayloadData()),

  $handlers = [
      'simple' => fn() => 'someWork',
      'anotherHandler' => [QueueHandlerCollection::class, 'methodName']
  ];
  $worker = new Worker(
      $handlers,
      new \Psr\Log\NullLogger(),
      new \Yiisoft\Injector\Injector($DIContainer),
      $DIContainer
  );

Starting Workers

Supervisor

Supervisor is a process monitor for Linux. It automatically starts console processes. On Ubuntu or Debian it can be installed with the following command:

sudo apt-get install supervisor

Supervisor config files are usually available in /etc/supervisor/conf.d. You can create any number of config files there.

Here's an example:

[program:yii-queue-worker]
process_name=%(program_name)s_%(process_num)02d
command=/usr/bin/php /var/www/my_project/yii queue:listen --verbose=1 --color=0
autostart=true
autorestart=true
user=www-data
numprocs=4
redirect_stderr=true
stdout_logfile=/var/www/my_project/log/yii-queue-worker.log

In this case Supervisor should start 4 queue:listen workers. The worker output will be written to the specified log file.

For more info about Supervisor's configuration and usage see its documentation.

Systemd

Systemd is another init system used on Linux to bootstrap the user space. To configure workers startup using systemd, create a config file named [email protected] in /etc/systemd/system with the following content:

[Unit]
Description=Yii Queue Worker %I
After=network.target
# the following two lines only apply if your queue backend is mysql
# replace this with the service that powers your backend
After=mysql.service
Requires=mysql.service

[Service]
User=www-data
Group=www-data
ExecStart=/usr/bin/php /var/www/my_project/yii queue:listen --verbose
Restart=on-failure

[Install]
WantedBy=multi-user.target

You need to reload systemd in order to re-read its configuration:

systemctl daemon-reload

Set of commands to control workers:

# To start two workers
systemctl start yii-queue@1 yii-queue@2

# To get the status of running workers
systemctl status "yii-queue@*"

# To stop a specific worker
systemctl stop yii-queue@2

# To stop all running workers
systemctl stop "yii-queue@*"

# To start two workers at system boot
systemctl enable yii-queue@1 yii-queue@2

To learn all features of systemd, check its documentation.

Cron

You can also start workers using cron that executes queue:run command.

Config example:

* * * * * /usr/bin/php /var/www/my_project/yii queue:run

In this case cron will run the command every minute.