Steps to follow for creating Queue Listener:

1. Install Supervisor

   Supervisor will automatically restart the queue if fails or stop working. To install Supervisor on Linux based system, use below command:

   sudo apt-get install supervisor

    

2. Create ‘/etc/supervisor/conf.d/laravel-worker.conf‘ and paste the below code into it

   [program:laravel-worker]
   user=user_name
   process_name=%(program_name)s_%(process_num)02d
   command=php application_path/artisan queue:listen --sleep=3 --tries=3
   directory=application_path
   autostart=true
   autorestart=true
   numprocs=10
   redirect_stderr=true
   stdout_logfile=application_path/storage/logs/worker.log

   where,
   user_name: Your machine user
   application_path: Full path to your application

3. Start the processes using following commands

   sudo supervisorctl reread
   sudo supervisorctl update
   sudo supervisorctl start laravel-worker:*

Now your queue listener is ready, let’s configure Laravel by following steps:

Step 1:
Set QUEUE_DRIVER=database in ‘.env‘ file

Step 2:
Navigate to ‘queue.php‘ file and check whether the table name and other settings for queue are present in database section

Step 3:
Run this command to migrate queue table in database

php artisan queue:table
php artisan queue:failed-table
php artisan migrate

You are ready for sending email through queue. Just replace Mail::send with Mail::queue or Mail::later

Final Steps:
Start and stop the following processes one by one to make Supervisor listen everytime (perform only if Supervisor doesn’t start listening automatically)

php artisan queue:listen
php artisan queue:work --daemon

*Note:

1. Add ‘APP_URL‘ in .env file as per the accessible domain for application. If you’re using ‘url()‘ function in email which is queued, not adding ‘APP_URL‘ will generate a localhost URL.

2. While passing data to views when using Mail::queue or Mail::later the data isn’t accessible as expected. This happens when you’re passing an object or eloquent object and not as arrays. To make this work with queue you have to serialize the $eloquentObject first and later unserialize it in the view.

Mail::queue('emails.hello', serialize($data), function($message) {
...
});

Add this on top of view file:

{{-- */unserialize($data);/* --}}