Spring WebClient – How to set timeouts

Learn to set connection timeout, read timeout and write timeout periods for WebClient interface available in Spring WebFlux for making synchronous and asynchronous HTTP requests.

1. Set timeouts globally via HTTPClient

We can configure the various timeouts easily at the underlying HTTP client library. It is the most easy and efficient way to configure timeout values globally for the whole application.

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.client.reactive.ClientHttpConnector;
import org.springframework.http.client.reactive.ReactorClientHttpConnector;
import org.springframework.web.reactive.config.EnableWebFlux;
import org.springframework.web.reactive.config.WebFluxConfigurer;
import org.springframework.web.reactive.function.client.WebClient;

import io.netty.channel.ChannelOption;
import io.netty.handler.timeout.ReadTimeoutHandler;
import io.netty.handler.timeout.WriteTimeoutHandler;
import reactor.netty.http.client.HttpClient;

@Configuration
@EnableWebFlux
public class WebFluxConfig implements WebFluxConfigurer
{  
	Logger logger = LoggerFactory.getLogger(WebFluxConfig.class);
	
	@Bean
	public WebClient getWebClient()
	{
		HttpClient httpClient = HttpClient.create()
		        .tcpConfiguration(client ->
		                client.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 10000)
		                .doOnConnected(conn -> conn
		                        .addHandlerLast(new ReadTimeoutHandler(10))
		                        .addHandlerLast(new WriteTimeoutHandler(10))));
		
		ClientHttpConnector connector = new ReactorClientHttpConnector(httpClient.wiretap(true));	    

		return WebClient.builder()
		        .baseUrl("http://localhost:3000")
		        .clientConnector(connector)
		        .defaultHeader(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE)
		        .build();
	}
}

2. Set timeout specific to request

To set the timeout specific to a request, its better to use timeout() methods e.g. Mono.timeout(duration) and Flux.timeout(duration).

The timeout() method in both classes is overloaded with many options. Checkout spring docs for Mono and Flux for more details.

public Flux<Employee> findAll() 
{
	return webClient.get()
		.uri("/employees")
		.retrieve()
		.bodyToFlux(Employee.class)
		.timeout(Duration.ofMillis(10_000));
}

public Mono<Employee> create(Employee empl)
{
	return webClient.post()
			.uri("/employees")
			.body(Mono.just(empl), Employee.class)
			.retrieve()
			.bodyToMono(Employee.class)
			.timeout(Duration.ofMillis(10_000));
}

Drop me your questions related to setting timeouts in Spring 5 WebClient.

Happy Learning !!

Reference : Spring boot doc