Ensuring a number of servers

You can use the ensure($numberOfServerNeeded) method to make sure that the given number of servers are available.

use Spatie\DynamicServers\Facades\DynamicServers;

/*
 * The package will make sure that 5 servers are available.
 * 
 * If there currently are less than 5, more servers will be started
 * If there currently are more than 5, some servers will be deleted
 */
DynamicServers::ensure(5);

There's also a determineServerCount function that accepts a callable. That callable will be executed each minute by the MonitorDynamicServersCommand you scheduled when configuring the package.

Here's how you could use ensure with the callable passed to determineServerCount.

// typically, in the `DynamicServersProvider` or a service provider of your own

use Laravel\Horizon\WaitTimeCalculator;
use Spatie\DynamicServers\Facades\DynamicServers;
use Spatie\DynamicServers\Support\DynamicServersManager;

/*
 * The package will call the closure passed to `determineServerCount` every minute
 */
DynamicServers::determineServerCount(function(DynamicServersManager $servers) {
   /*
    * First, we'll calculate the number of servers needed. 
    * 
    * In this example, we will take a look at Horizon's reported waiting time.
    * Of course, in your project you can calculate the number of servers needed however you want.    
    */
    $waitTimeInMinutes = app(WaitTimeCalculator::class)->calculate('default');
    
    $numberOfServersNeeded = round($waitTimeInMinutes / 10);

   /*
    * Next, we will pass the number of servers needed to the `ensure` method.
    */
    $servers->ensure($numberOfServersNeeded);
});

In addition to using determineServerCount, you could also listen for Horizon's LongWaitDetected event. This way, servers will be started immediately when your queue grows long, and we don't have to wait until the schedule is called.

use Illuminate\Support\Facades\Event;
use Laravel\Horizon\Events\LongWaitDetected;
use Spatie\DynamicServers\Facades\DynamicServers;

Event::listen(function (LongWaitDetected $event) {
    $waitTimeInMinutes = app(WaitTimeCalculator::class)->calculate('default');
    
    $numberOfServersNeeded = round($waitTimeInMinutes / 10);
    
    DynamicServers::ensure($numberOfServersNeeded);
});