CircuitBreakerRegistry

CircuitBreakerRegistry is a component of the Resilience4j library that serves as a central registry for CircuitBreaker instances. It provides a name-based repository where circuit breakers can be created, configured, and reused across an application. The registry is designed to ensure that a single CircuitBreaker instance is associated with a given name, promoting consistent behavior and reducing duplication.

Construction and configuration

The registry can be created with a default configuration or with a custom global configuration. When a circuit breaker is requested by name, the registry either returns an existing instance or creates a new one using the provided configuration (default or per-breaker). This enables both uniform global settings and per-breaker customization when needed.

Operations and behavior

The registry maintains an internal storage, typically a thread-safe map, linking names to CircuitBreaker instances. It supports retrieval by name and, in many versions, creation with an explicit CircuitBreakerConfig. It can also provide access to all registered breakers and, depending on the version, may support removal of breakers from the registry.

Usage

A typical usage pattern is to create a registry and obtain breakers by name, reusing them across modules. For example, a registry created with defaults can supply a CircuitBreaker for a service by name, and a custom configuration can be supplied to a specific breaker if different behavior is required.

Context

CircuitBreakerRegistry is part of the Resilience4j circuit breaker module. It complements the per-breaker state machine (closed, open, half-open) by providing centralized management, reuse, and consistent configuration across an application.