You can manage message queues from the command line using cron jobs or an external process manager to ensure that consumers are retrieving messages.
Cron jobs are the default mechanism to restart consumers. Processes started by
cron consume the specified number of messages and then terminate. Re-running
cron restarts the consumer.
The following example shows the Magento
crontab configuration for running consumers:
1 2 3 4 5 ... <job name="consumers_runner" instance="Magento\MessageQueue\Model\Cron\ConsumersRunner" method="run"> <schedule>* * * * *</schedule> </job> ...
How often you check message queues depends on your business logic and available system resources. In general, you’ll probably want to check for newly created customers and send welcome emails more frequently than a more resource intensive process (e.g., updating your catalog). You should define
cron schedules according to your business needs.
It can be configured in Admin Panel Stores > Settings > Configuration > Advanced > System > Cron configuration options for group: consumers
See Configure and run cron for more information about using
cron with Magento.
You can also use a process manager such as Supervisor to monitor the status of processes. The manager can use the command line to restart the processes as needed.
Behavior by default
- Cron job
- Cron job
consumers_runnerruns all defined consumers
- Each consumer processes 10000 messages and then terminates
If your Magento Commerce store is hosted on the Cloud platform, use the
CRON_CONSUMERS_RUNNER to configure the
consumers_runner cron job.
/app/etc/env.php file to configure the cron job
1 2 3 4 5 6 7 8 9 10 ... 'cron_consumers_runner' => array( 'cron_run' => false, 'max_messages' => 20000, 'consumers' => array( 'consumer1', 'consumer2', ) ), ...
cron_run- A boolean value that enables or disables the
consumers_runnercron job (default =
max_messages- The maximum number of messages each consumer must process before terminating (default =
10000). Although we do not recommend it, you can use 0 to prevent the consumer from terminating.
consumers- An array of strings specifying which consumer(s) to run. An empty array runs all consumers.
View a list of available message queue consumers
To view a list of all consumers:
1 bin/magento queue:consumers:list
Start message queue consumers
To start message queue consumers:
1 bin/magento queue:consumers:start [--max-messages=<value>] [--batch-size=<value>] [--single-thread] [--area-code=<value>] <consumer_name>
The following table explains this command’s options, parameters, and values.
||The maximum number of messages to consume per invocation. If the number of queued messages is less than the specified max, the consumer polls for new messages until it has processed the max. If you don’t specify
||Specifies whether consumers should continue polling for messages if the number of processed messages is less than the
On Magento Commerce Cloud projects, this variable is set by default using the
||The number of messages to consume per batch. If specified, messages in a queue are consumed in batches of
||This option is deprecated. Use the
||This option prevents running multiple copies of a consumer simultaneously.||No|
||The area code preferred for consumer process.||No||global|
||The consumer to start.||Yes|
After consuming all available messages, the command terminates. You can run the command again manually or with a cron job. You can also run multiple instances of the
magento queue:consumers:start command to process large message queues. For example, you can append
& to the command to run it in the background, return to a prompt, and continue running commands:
1 bin/magento queue:consumers:start <consumer_name> &