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<?php declare(strict_types=1); |
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namespace HolidayPirates\CircuitBreaker; |
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use HolidayPirates\CircuitBreaker\Service\ServiceInterface; |
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use HolidayPirates\CircuitBreaker\Storage\StorageInterface; |
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class CircuitBreaker implements CircuitBreakerInterface |
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{ |
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private $storage; |
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private $services = []; |
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public function __construct(StorageInterface $storage) |
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{ |
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$this->storage = $storage; |
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} |
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public function registerService(ServiceInterface $service): void |
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{ |
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$this->services[$service->getIdentifier()] = $service; |
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} |
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public function isServiceAvailable(string $serviceName): bool |
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{ |
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$service = $this->getService($serviceName); |
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if ($this->isCircuitOpen($service)) { |
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return false; |
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} |
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/** |
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* If we wanted a full 3-state CircuitBreaker implementation as described by Fowler, it is in here |
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* that we can add the logic for the "Half-open circuit", which would allow a smaller number of requests |
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* to go through before we really close the circuit. |
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*/ |
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return true; |
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} |
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public function reportFailure(string $serviceName): void |
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{ |
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$service = $this->getService($serviceName); |
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$amountOfFailures = $this->storage->getAmountOfFailures($service); |
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if ($amountOfFailures >= $service->getMaxFailures()) { |
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$this->setOpenCircuit($service); |
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return; |
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} |
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$this->storage->incrementAmountOfFailures($service); |
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} |
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public function reportSuccess(string $serviceName): void |
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{ |
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$service = $this->getService($serviceName); |
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$this->storage->incrementAmountOfSuccess($service); |
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} |
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public function areAllServicesAvailable(): bool |
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{ |
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foreach ($this->getRegisteredServiceNames() as $serviceName) { |
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if (!$this->isServiceAvailable($serviceName)) { |
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return false; |
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} |
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} |
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return true; |
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} |
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public function getRegisteredServiceNames(): array |
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{ |
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return array_keys($this->services); |
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} |
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private function getService(string $serviceName): ServiceInterface |
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{ |
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if (false === isset($this->services[$serviceName])) { |
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throw new \LogicException( |
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sprintf( |
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'Service not found. Did you forgot to call registerService(%s) ?', |
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$serviceName |
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) |
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); |
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} |
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return $this->services[$serviceName]; |
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} |
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private function setOpenCircuit(ServiceInterface $service): void |
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{ |
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$this->storage->setOpenCircuit($service); |
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} |
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private function isCircuitOpen(ServiceInterface $service): bool |
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{ |
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return $this->storage->isCircuitOpen($service); |
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} |
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} |
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holidaypirates /
pirate-circuit-breaker
