leocarmo / circuit-breaker-php

Circuit Breaker Pattern for PHP

PHP implementation of Circuit Breaker Pattern

For more information about this pattern see this.

Starting with composer

composer require leocarmo/circuit-breaker-php

Adapters

• Redis
• Redis Cluster
• Swoole Table

Redis Adapter

The first argument is a redis connection, the second is your product name, for redis namespace avoid key conflicts with another product using the same redis.

use LeoCarmo\CircuitBreaker\CircuitBreaker;
use LeoCarmo\CircuitBreaker\Adapters\RedisAdapter;

// Connect to redis
$redis = new \Redis();
$redis->connect('localhost', 6379);

$adapter = new RedisAdapter($redis, 'my-product');

// Set redis adapter for CB
$circuit = new CircuitBreaker($adapter, 'my-service');

See this for full example

Redis Cluster Adapter

Without use of multi command. The first argument is a redis connection, the second is your product name, for redis namespace avoid key conflicts with another product using the same redis.

use LeoCarmo\CircuitBreaker\CircuitBreaker;
use LeoCarmo\CircuitBreaker\Adapters\RedisClusterAdapter;

// Connect to redis
$redis = new \Redis();
$redis->connect('localhost', 6379);

$adapter = new RedisClusterAdapter($redis, 'my-product');

// Set redis adapter for CB
$circuit = new CircuitBreaker($adapter, 'my-service');

See this for full example

SwooleTable Adapter

use LeoCarmo\CircuitBreaker\CircuitBreaker;

$circuit = new CircuitBreaker(new SwooleTableAdapter(), 'my-service');

Guzzle Middleware

use GuzzleHttp\Client;
use GuzzleHttp\HandlerStack;
use LeoCarmo\CircuitBreaker\GuzzleMiddleware;

$handler = new GuzzleMiddleware($circuit);

$handlers = HandlerStack::create();
$handlers->push($handler);

$client = new Client(['handler' => $handlers]);

$response = $client->get('leocarmo.dev');

Important: all status code between 200 and 299 will be recorded as a success, and other status will be recorded as a failure.

See this for full example

Customize success status code

If you need to specify a custom status code that is not a failure, you can use:

$handler = new GuzzleMiddleware($circuit);
$handler->setCustomSuccessCodes([400]);

Important: this configuration will record a success when a status code 400 is returned

See this for full example

Ignore status code

If you want to ignore the status code returned and not record a success or failure, use this:

$handler = new GuzzleMiddleware($circuit);
$handler->setCustomIgnoreCodes([412]);

Important

To use Customize success status code or Ignore status code you must set the Guzzle client config http_errors = false because the Guzzle Client throws a ClientException or ServerException when the status code is not in range >200 && <300.

Set circuit break settings

This is not required, default values will be set

$circuit->setSettings([
    'timeWindow' => 60, // Time for an open circuit (seconds)
    'failureRateThreshold' => 50, // Fail rate for open the circuit
    'intervalToHalfOpen' => 30,  // Half open time (seconds)
]);

Check if circuit is available (closed)

Each check is for a specific service. So you can have multiple services in the same application, and when one circuit is open, the other works normally.

// Check circuit status for service
if (! $circuit->isAvailable()) {
    die('Circuit is not available!');
}

Record success and failure

// Usage example for success and failure  
try {
    myService();
    $circuit->success();
} catch (RuntimeException $e) {
    // If an error occurred, it must be recorded as failure.
    $circuit->failure();
}

Development

Setup

make setup

Tests

make test 

Contributors