RestTemplate.postForObject() java.net.SocketTimeoutException: Read timed out EVEN THOUGH SUCCESSFUL

Question

I have two Java Spring Boot web service apps on the same server calling each other via REST. Service A calls Service B and the latter successfully acts upon the notfication. THE PROBLEM is that Service A never receives the acknowlegement from Service B, so it thinks it has failed, and in accordance with its looping recovery logic, it tries again…and again…and again. Service B ends up doing 3 times the work for no added benefit.

The relevant code (stripped down and falsified to protect the guilty) is as follows:

Service A:

public void giveOrderToServiceB(@RequestBody CustomClass message) {
...    
org.springframework.web.client.RestTemplate template = new RestTemplate(clientHttpRequestFactory());
com.mycompany.CustomReply reply = template.postForObject(serviceBUrl, message, CustomReply.class);

Service B REST Controller:

@PostMapping(value="ExecuteTheWork", produces=org.springframework.http.MediaType.APPLICATION_JSON_VALUE, consumes=MediaType.APPLICATION_JSON_VALUE)
public @ResponseBody CustomReply executeTheWork(@RequestBody CustomClass thing) {
    // do something with the thing...
   CustomReply reply = new CustomReply();
    reply.setReply("Successfully executed the work.");
    return reply;
}

The actual exception caught by Service A after calling RestTemplate.postForObject() is

java.net.SocketTimeoutException: Read timed out

Please advise.

Answer 1

OK, I think I got it. I don't send the response back from Service B until after the method has completed all of its work, which can take several seconds to several minutes. If I immediately answer (and skip the processing), it works consistently. Need to spin off the actual work to a separate thread. Cheeers

Answer 2

When you are registering the bean of rest template in your application it must then configure it with a timeout. Following is the Spring application config file

package com.temp.project.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;

@Configuration
public class TempProjectConfig {

    /**
     * Set Timeout for HTTP requests
     * @return
     */
    @Bean
    public ClientHttpRequestFactory getClientHttpRequestFactory() {
        int timeout = 1200000; // here is the timeout property set for rest template
        HttpComponentsClientHttpRequestFactory clientHttpRequestFactory
                = new HttpComponentsClientHttpRequestFactory();
        clientHttpRequestFactory.setConnectTimeout(timeout);
        return clientHttpRequestFactory;
    }

    /**
     * RestTemplate to call REST endpoints
     * @param clientHttpRequestFactory
     * @return
     */
    @Bean
    public RestTemplate getRestTemplate(ClientHttpRequestFactory clientHttpRequestFactory) {
        return new RestTemplate(clientHttpRequestFactory);
    }

}