Laravel Job and Queue – My memo Wall

This post shows the steps on how to run queue in database using background worker process.

Useful tutorials:
Queue Connections
- In env file, there’s a variable called QUEUE_CONNECTION. If it is set to `sync’, any jobs scheduled will be executed as soon as they are dispatched. This is done synchronously. This needs to be changed to QUEUE_CONNECTION=database
- Don’t forget to run php artisan config:cache after for it to take effect if the env is cached
Some jobs running synchronous, some running async:
- UsedispatchNow for synchronous jobs, use dispatch for async jobs.

Create a job

php artisan make:job JobName

A module will be created in

App\Jobs\JobName

Add what you want to accomplish by the job to the handle() function of the generated module
Queue a job in database, add this to the .env file and restart the server
```
QUEUE_CONNECTION=database
```
Create queue table in the database:
```
php artisan queue:table
```
then run migration
```
php artisan migrate
```
Jobs will queue in this table
To start a process that performs a task using the job information in the queue table
```
php artisan queue:work
```
Multiple processes can take jobs from the queue and run in parallel. Just call
```
php artisan queue:work
```
again from another cmd or terminal. For more processes, here’s an sample bash script
```
for i in {1..20} do
    artisan do-command $i &
done
```
queue:work also takes a –tries option that will indicate how many time the process will try before it was declared failed. Default value for tries is 1.
Failed jobs go to failed job table. The table must be created as follows:
```
php artisan queue:failed-table
```
Don’t forget to run migration.
Retry all jobs in failed-table:
```
php artisan queue:retry all
```
Please note that queue workers are long-lived processes and store the booted application state in memory. As a result, they will not notice changes in your codebase after they have been started. So, during your deployment process, be sure to restart your queue workers.
To avoid having to restart after each code change:
```
php artisan queue:listen
```

According to Laravel documentation: Alternatively, you may run the queue:listen command. When using the queue:listen command, you don’t have to manually restart the worker when you want to reload your updated code or reset the application state; however, this command is significantly less efficient than the queue:work command: