class CachePreWarmer

Prewarms caches for services that implement PreWarmableInterface.

Takes a list of prewarmable services and prewarms them at random. Randomization is used because whenever two or more requests are building caches, the most benefit is gained by minimizing duplication. For example two requests rely on the same six services but these services are requested at different times, one request builds caches for the other and vice versa.

No randomization:

ABCDEF ABCDEF

Randomization:

ABCDEF FCDABE

Randomization and three requests:

ABCDEF FCDABE BEDAFC

@internal

Hierarchy

Expanded class hierarchy of CachePreWarmer

See also

Drupal\Core\PreWarm\PreWarmableInterface

Drupal\Core\DrupalKernel::handle()

Drupal\Core\LockBackendAbstract::wait()

Drupal\Core\Routing\RouteProvider::preLoadRoutes()

1 file declares its use of CachePreWarmer
CachePreWarmerTest.php in core/tests/Drupal/Tests/Core/PreWarm/CachePreWarmerTest.php

File

core/lib/Drupal/Core/PreWarm/CachePreWarmer.php, line 41

Namespace

Drupal\Core\PreWarm
View source 
class CachePreWarmer implements CachePreWarmerInterface {
    
    /**
     * Whether to prewarm caches at the end of the request.
     */
    protected bool $needsPreWarming = FALSE;
    public function __construct(ClassResolverInterface $classResolver, array $serviceIds) {
        // Ensure the serviceId order is random to reduce chances of conflicts.
        shuffle($this->serviceIds);
    }
    
    /**
     * {@inheritdoc}
     */
    public function preWarmOneCache() : bool {
        $candidate = array_pop($this->serviceIds);
        if ($candidate === NULL) {
            return FALSE;
        }
        $service = $this->classResolver
            ->getInstanceFromDefinition($candidate);
        $service->preWarm();
        return TRUE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function preWarmAllCaches() : bool {
        $prewarmed = FALSE;
        while ($this->preWarmOneCache()) {
            $prewarmed = TRUE;
        }
        return $prewarmed;
    }

}

Members

Title Modifiers Object type Summary Overriden Title
CachePreWarmer::$needsPreWarming protected property Whether to prewarm caches at the end of the request.
CachePreWarmer::preWarmAllCaches public function Prewarms all PreWarmable services. Overrides CachePreWarmerInterface::preWarmAllCaches
CachePreWarmer::preWarmOneCache public function Prewarms one PreWarmable service. Overrides CachePreWarmerInterface::preWarmOneCache
CachePreWarmer::__construct public function

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