README

Circuits declared in configuration, their states shared by the workers, and HTTP clients behind their circuits.

phil/circuit-breaker-bundle brings phil/circuit-breaker into a Symfony application. The circuits are declared in the phil_circuit_breaker configuration, one policy per key — an HTTP client, or a destination such as one webhook endpoint — and checked when the container is built. Their states live in a PSR-6 cache pool shared by the workers, so that a circuit open in one is open in all, or in a store of the application's. A circuit with http_client puts that client behind it: while the circuit is open, a request is refused before it leaves, and its answers are counted — a server error or a transport error as a failure, anything else as a success.

It is for any Symfony application that calls third parties it does not control: a payment provider, the partners its webhooks reach, a geocoding API. An operator forces a circuit open through any service implementing CircuitOverride, tagged by autoconfiguration; phil/feature-flags-bundle provides one that reads a flag per circuit. The profiler shows the state of each circuit at the end of the request.

It is built on the components Symfony already ships: Config and DependencyInjection for the configuration, Cache for the store, HttpClient for the decorated clients, HttpKernel for the profiler.

Status

Part	State
Circuits from configuration, each checked at build time	Implemented and tested
States in a PSR-6 cache pool, or a store of the application's	Implemented and tested
An HTTP client behind its circuit, per client or destination	Implemented and tested
Overrides tagged and asked together, autoconfigured	Implemented and tested
A profiler panel of the circuits	Implemented, its collector tested
Console commands to inspect or reset a circuit	Not started

Documentation

Document	What it covers
Installation	Requirements, installing, the cache pool.
Configuration	Every key of `phil_circuit_breaker`, and the errors of a bad circuit.
HTTP clients	A client behind its circuit: what is refused, what counts as a failure.
Extension points	The store of states, the overrides, the parameter of the circuit keys.
Testing	The bundle's tests, and how to test an application with circuits.
Reference	Every class, service, tag, parameter and template of the bundle.

Quick start

composer require phil/circuit-breaker-bundle

# config/packages/phil_circuit_breaker.yaml
phil_circuit_breaker:
    circuits:
        http.payments:
            failure_rate_percent: 50
            minimum_calls: 10
            window_seconds: 60
            open_seconds: 30
            http_client: payments.client

use Phil\CircuitBreakerBundle\Infrastructure\HttpClient\Exception\CircuitOpen;

try {
    $response = $paymentsClient->request('POST', '/charges', ['json' => $charge]);
} catch (CircuitOpen) {
    // the circuit is open: the request was not sent
}

Requirements

PHP 8.5 or later, Symfony 8.2 or later, and phil/circuit-breaker. psr/cache for the default store, symfony/http-client for the clients behind their circuits, symfony/web-profiler-bundle for the panel — each only when used.

Contributing

Contributions are welcome on the PHIL monorepo: read the contribution guide and the code of conduct. Report a vulnerability privately, as the security policy explains, never in a public issue.

phil / circuit-breaker-bundle

Package info

Security

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