Multi tenant circuit breaker with resilience4j & spring

! Multi tenant circuit breaker with resilience4j & spring

.

_README.md

updated usage of @CircuitBreaker annotation

- @CircuitBreaker(name = "backend", fallbackMethod = "exampleFallbackMethod")
+ @CircuitBreaker(name = "@tenantCircuitBreakerResolver.resolveName('backend')", fallbackMethod = "exampleFallbackMethod")

whats happening in background:

• CB configuration is duplicated during spring context startup
• for each registered CB in CBregistry configuration is extracted and copypasted for all supported tenants
• only possible drawback: multitenant setup/configuration is created for all registered CBs (even for those without multitenant resolving

CircuitBreakerAutoConfiguration.java

import io.github.resilience4j.circuitbreaker.CircuitBreakerRegistry;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.context.event.ApplicationReadyEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Component;

@Slf4j
@Component
@RequiredArgsConstructor
public class CircuitBreakerAutoConfiguration implements ApplicationListener<ApplicationReadyEvent> {

    private final CircuitBreakerRegistry circuitBreakerRegistry;
    private final MultiTenantConfiguration multiTenantConfiguration;
    private final TenantCircuitBreakerResolver multiTenantCircuitBreakerResolver;

    @Override
    public void onApplicationEvent(final ApplicationReadyEvent event) {
        for (var cb : circuitBreakerRegistry.getAllCircuitBreakers()) {
            for (var tenant : multiTenantConfiguration.getSupportedTenants()) {
                TenantContext.setTenantId(tenant);
                var cbTenantName = multiTenantCircuitBreakerResolver.resolveName(cb.getName());
                var config = cb.getCircuitBreakerConfig();

                circuitBreakerRegistry.circuitBreaker(cbTenantName, config);
                log.debug("Configuring new Circuit breaker: {}", cbTenantName);
                TenantContext.clear();
            }
        }
    }
}

TenantCircuitBreakerResolver.java

import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

@Component("tenantCircuitBreakerResolver")
public class TenantCircuitBreakerResolver {

    public String resolveName(final String circuitBreakerName) {
        if (TenantContext.getTenantId() != null) {
            return circuitBreakerName + "__" + TenantContext.getTenantId();
        }

        return circuitBreakerName;
    }
}