Examples with ApplicationEventListener io.micronaut.context.event.ApplicationEventListener used on opensource projects

Example 1 with ApplicationEventListener

use of io.micronaut.context.event.ApplicationEventListener in project micronaut-core by micronaut-projects.

the class ServiceHttpClientFactory method healthCheckStarter.

/**
 * Creates a {@link ApplicationEventListener} that listens to {@link ServerStartupEvent} for each configured HTTP client
 * in order to register a health check if necessary.
 *
 * @param configuration The configuration
 * @param instanceList  The instance list
 * @return The event listener
 */
@EachBean(ServiceHttpClientConfiguration.class)
@Requires(condition = ServiceHttpClientCondition.class)
ApplicationEventListener<ServerStartupEvent> healthCheckStarter(@Parameter ServiceHttpClientConfiguration configuration, @Parameter StaticServiceInstanceList instanceList) {
    if (configuration.isHealthCheck()) {
        return event -> {
            final List<URI> originalURLs = configuration.getUrls();
            Collection<URI> loadBalancedURIs = instanceList.getLoadBalancedURIs();
            final HttpClient httpClient = clientFactory.get().getClient(configuration.getHttpVersion(), configuration.getServiceId(), configuration.getPath().orElse(null));
            final Duration initialDelay = configuration.getHealthCheckInterval();
            Duration delay = configuration.getHealthCheckInterval();
            taskScheduler.scheduleWithFixedDelay(initialDelay, delay, () -> Flux.fromIterable(originalURLs).flatMap(originalURI -> {
                URI healthCheckURI = originalURI.resolve(configuration.getHealthCheckUri());
                return Flux.from(httpClient.exchange(HttpRequest.GET(healthCheckURI))).onErrorResume(throwable -> {
                    if (throwable instanceof HttpClientResponseException) {
                        HttpClientResponseException responseException = (HttpClientResponseException) throwable;
                        return Flux.just((HttpResponse<ByteBuffer>) responseException.getResponse());
                    }
                    return Flux.just(HttpResponse.serverError());
                }).map(response -> Collections.singletonMap(originalURI, response.getStatus()));
            }).subscribe(uriToStatusMap -> {
                Map.Entry<URI, HttpStatus> entry = uriToStatusMap.entrySet().iterator().next();
                URI uri = entry.getKey();
                HttpStatus status = entry.getValue();
                if (status.getCode() >= 300) {
                    loadBalancedURIs.remove(uri);
                } else if (!loadBalancedURIs.contains(uri)) {
                    loadBalancedURIs.add(uri);
                }
            }));
        };
    }
    throw new DisabledBeanException("HTTP Client Health Check not enabled");
}