circuitBreaker.php

<?php

class CircuitBreaker
{
  private $maxFailures;
  private $service;
  private $redisClient;
  
  public function __construct(int $maxFailures, callable $service)
  {
    $this->maxFailures = $maxFailures;
    $this->service = $service;
    $this->redisClient = new RedisClient();
  }

  private function isUp(string $key)
  {
    return (int)$this->redisClient->get($key) < $this->maxFailures;
  }

  private function fail(string $key, int $ttl)
  {
    $this->redisClient->incr($key, 1);
    $this->redisClient->expire($key, $ttl);
  }
  
  public function __invoke()
  {
    [$arguments, $defaultResponse] = func_get_args();
    $key = md5($arguments);

    if (!$this->isUp($key)) {
        return $defaultResponse;
    }

    try {
      $result = call_user_func_array($this->service, $arguments);
      
      return $result;
    } catch (\Throwable $e) {
      $this->fail($key, 10);
      
      return $defaultResponse;
    }
  }
}