Ensuring a number of servers | laravel-dynamic-servers | Spatie

 SPATIE

  Laravel Dynamic Servers
==========================

spatie.be/open-source

  [Docs](https://spatie.be/docs)  [Laravel-dynamic-servers](https://spatie.be/docs/laravel-dynamic-servers/v1)  Basic-usage  Ensuring a number of servers

 Version   v1

 Other versions for crawler [v1](https://spatie.be/docs/laravel-dynamic-servers/v1)

- [ Introduction ](https://spatie.be/docs/laravel-dynamic-servers/v1/introduction)
- [ Support us ](https://spatie.be/docs/laravel-dynamic-servers/v1/support-us)
- [ Requirements ](https://spatie.be/docs/laravel-dynamic-servers/v1/requirements)
- [ Installation & setup ](https://spatie.be/docs/laravel-dynamic-servers/v1/installation-setup)
- [ Questions and issues ](https://spatie.be/docs/laravel-dynamic-servers/v1/questions-issues)
- [ Changelog ](https://spatie.be/docs/laravel-dynamic-servers/v1/changelog)
- [ About us ](https://spatie.be/docs/laravel-dynamic-servers/v1/about-us)

Basic usage
-----------

- [ Getting started ](https://spatie.be/docs/laravel-dynamic-servers/v1/basic-usage/getting-started)
- [ Configuring your first server type ](https://spatie.be/docs/laravel-dynamic-servers/v1/basic-usage/configuring-your-first-server-type)
- [ Ensuring a number of servers ](https://spatie.be/docs/laravel-dynamic-servers/v1/basic-usage/ensuring-a-number-of-servers)
- [ Rebooting servers ](https://spatie.be/docs/laravel-dynamic-servers/v1/basic-usage/rebooting-servers)
- [ Using multiple server types ](https://spatie.be/docs/laravel-dynamic-servers/v1/basic-usage/using-multiple-server-types)
- [ Manually increasing and decreasing servers ](https://spatie.be/docs/laravel-dynamic-servers/v1/basic-usage/manually-increasing-and-decreasing-servers)

Advanced usage
--------------

- [ Creating your own server provider ](https://spatie.be/docs/laravel-dynamic-servers/v1/advanced-usage/creating-your-own-server-provider)
- [ How servers are managed under the hood ](https://spatie.be/docs/laravel-dynamic-servers/v1/advanced-usage/how-servers-are-managed-under-the-hood)
- [ Dealing with erroring servers ](https://spatie.be/docs/laravel-dynamic-servers/v1/advanced-usage/dealing-with-erroring-servers)
- [ Dealing with hanging servers ](https://spatie.be/docs/laravel-dynamic-servers/v1/advanced-usage/dealing-with-hanging-servers)
- [ Fired Events ](https://spatie.be/docs/laravel-dynamic-servers/v1/advanced-usage/fired-events)
- [ Overriding actions and jobs ](https://spatie.be/docs/laravel-dynamic-servers/v1/advanced-usage/overriding-actions)
- [ Setting a server limit ](https://spatie.be/docs/laravel-dynamic-servers/v1/advanced-usage/setting-a-server-limit)

 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);
});
```