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<?php |
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namespace Ackintosh; |
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use Ackintosh\Ganesha\Exception\StorageException; |
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use Ackintosh\Ganesha\StrategyInterface; |
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class Ganesha |
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{ |
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/** |
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* @var string |
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*/ |
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const EVENT_TRIPPED = 'tripped'; |
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/** |
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* @var string |
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*/ |
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const EVENT_CALMED_DOWN = 'calmed_down'; |
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/** |
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* @var string |
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*/ |
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const EVENT_STORAGE_ERROR = 'storage_error'; |
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/** |
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* the status between failure count 0 and trip. |
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* @var int |
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*/ |
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const STATUS_CALMED_DOWN = 1; |
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/** |
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* the status between trip and calm down. |
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* @var int |
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*/ |
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const STATUS_TRIPPED = 2; |
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/** |
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* @var StrategyInterface |
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*/ |
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private $strategy; |
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/** |
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* @var callable[] |
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*/ |
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private $subscribers = []; |
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/** |
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* @var bool |
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*/ |
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private static $disabled = false; |
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/** |
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* Ganesha constructor. |
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* |
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* @param StrategyInterface $strategy |
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*/ |
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public function __construct($strategy) |
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{ |
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$this->strategy = $strategy; |
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} |
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/** |
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* records failure |
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* |
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* @param string $service |
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* @return void |
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*/ |
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public function failure($service): void |
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{ |
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try { |
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if ($this->strategy->recordFailure($service) === self::STATUS_TRIPPED) { |
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$this->notify(self::EVENT_TRIPPED, $service, ''); |
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} |
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} catch (StorageException $e) { |
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$this->notify(self::EVENT_STORAGE_ERROR, $service, 'failed to record failure : ' . $e->getMessage()); |
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} |
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} |
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/** |
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* records success |
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* |
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* @param string $service |
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* @return void |
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*/ |
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public function success($service): void |
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{ |
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try { |
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if ($this->strategy->recordSuccess($service) === self::STATUS_CALMED_DOWN) { |
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$this->notify(self::EVENT_CALMED_DOWN, $service, ''); |
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} |
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} catch (StorageException $e) { |
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$this->notify(self::EVENT_STORAGE_ERROR, $service, 'failed to record success : ' . $e->getMessage()); |
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} |
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} |
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/** |
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* @param string $service |
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* @return bool |
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*/ |
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public function isAvailable($service): bool |
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{ |
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if (self::$disabled) { |
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return true; |
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} |
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try { |
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return $this->strategy->isAvailable($service); |
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} catch (StorageException $e) { |
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$this->notify(self::EVENT_STORAGE_ERROR, $service, 'failed to isAvailable : ' . $e->getMessage()); |
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// fail-silent |
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return true; |
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} |
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} |
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/** |
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* @param callable $callable |
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* @return void |
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*/ |
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public function subscribe(callable $callable): void |
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{ |
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$this->subscribers[] = $callable; |
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} |
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/** |
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* @param string $event |
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* @param string $service |
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* @param string $message |
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* @return void |
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*/ |
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private function notify(string $event, string $service, string $message): void |
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{ |
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foreach ($this->subscribers as $s) { |
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call_user_func_array($s, [$event, $service, $message]); |
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} |
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} |
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/** |
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* disable |
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* |
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* @return void |
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140
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*/ |
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public static function disable(): void |
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{ |
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self::$disabled = true; |
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} |
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/** |
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147
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* enable |
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148
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* |
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149
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* @return void |
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150
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*/ |
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public static function enable(): void |
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{ |
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self::$disabled = false; |
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} |
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156
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/** |
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157
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* resets all counts |
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158
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* |
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159
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* @return void |
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160
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*/ |
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public function reset(): void |
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162
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{ |
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$this->strategy->reset(); |
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164
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} |
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165
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} |
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