How to debug feign client read time out exception or error?

Feb 5, 2025

Purpose

In this post, I will demonstrate how to debug the following error when using Feign:

2022-02-18 15:29:38.417 ERROR 44793 --- [nio-8086-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is feign.RetryableException: Read timed out executing GET http://nacos-provider-bswencw1/hello] with root cause

java.net.SocketTimeoutException: Read timed out
        at java.net.SocketInputStream.socketRead0(Native Method) ~[na:1.8.0_121]
        at java.net.SocketInputStream.socketRead(SocketInputStream.java:116) ~[na:1.8.0_121]
        at java.net.SocketInputStream.read(SocketInputStream.java:171) ~[na:1.8.0_121]
        at java.net.SocketInputStream.read(SocketInputStream.java:141) ~[na:1.8.0_121]
        at java.io.BufferedInputStream.fill(BufferedInputStream.java:246) ~[na:1.8.0_121]
        at java.io.BufferedInputStream.read1(BufferedInputStream.java:286) ~[na:1.8.0_121]
        at java.io.BufferedInputStream.read(BufferedInputStream.java:345) ~[na:1.8.0_121]
        at sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:704) ~[na:1.8.0_121]
        at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:647) ~[na:1.8.0_121]
        at

2. The solution

2.1 The details of the problem

➜  nacos-feign ./start.sh 8086
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building nacos-feign 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-clean-plugin:3.1.0:clean (default-clean) @ nacos-feign ---
[INFO]
[INFO] >>> spring-boot-maven-plugin:2.1.18.RELEASE:run (default-cli) > test-compile @ nacos-feign >>>
[INFO]
[INFO] --- maven-resources-plugin:3.1.0:resources (default-resources) @ nacos-feign ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 1 resource
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ nacos-feign ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 4 source files to /Users/bswencaiwen/JavaProjects/SpringCloudLearning202202/nacos-feign/target/classes
[INFO]
[INFO] --- maven-resources-plugin:3.1.0:testResources (default-testResources) @ nacos-feign ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /Users/bswencaiwen/JavaProjects/SpringCloudLearning202202/nacos-feign/src/test/resources
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:testCompile (default-testCompile) @ nacos-feign ---
[INFO] Changes detected - recompiling the module!
[INFO]
[INFO] <<< spring-boot-maven-plugin:2.1.18.RELEASE:run (default-cli) < test-compile @ nacos-feign <<<
[INFO]
[INFO] --- spring-boot-maven-plugin:2.1.18.RELEASE:run (default-cli) @ nacos-feign ---

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::       (v2.1.18.RELEASE)

2022-02-18 15:28:49.521  INFO 44793 --- [           main] c.e.nacosfeign.NacosFeignApplication     : No active profile set, falling back to default profiles: default
2022-02-18 15:28:52.439  INFO 44793 --- [           main] c.e.nacosfeign.NacosFeignApplication     : Started NacosFeignApplication in 5.934 seconds (JVM running for 10.224)
2022-02-18 15:29:38.417 ERROR 44793 --- [nio-8086-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is feign.RetryableException: Read timed out executing GET http://nacos-provider-bswencw1/hello] with root cause

java.net.SocketTimeoutException: Read timed out
        at java.net.SocketInputStream.socketRead0(Native Method) ~[na:1.8.0_121]
        at java.net.SocketInputStream.socketRead(SocketInputStream.java:116) ~[na:1.8.0_121]
        at java.net.SocketInputStream.read(SocketInputStream.java:171) ~[na:1.8.0_121]
        at java.net.SocketInputStream.read(SocketInputStream.java:141) ~[na:1.8.0_121]
        at java.lang.Thread.run(Thread.java:745) [na:1.8.0_121]

2.2 The debug process

We know that spring boot use feign(ribbon) to access remote services registered in a service registry.

But if some errors occur, how to debug this process?

2.3 The solution

We can create a config class to configure feign:

import feign.Logger;
import org.springframework.context.annotation.Bean;

public class FeignConfig {
    @Bean
    Logger.Level feignLoggerLevel() {
        return Logger.Level.FULL;
    }
}

Notice the Logger is instance of the class feign.Logger. There are 4 levels :

NONE, No logging (DEFAULT).
BASIC, Log only the request method and URL and the response status code and execution time.
HEADERS, Log the basic information along with request and response headers.
FULL, Log the headers, body, and metadata for both requests and responses.

If you want to show the request URL(including host of the URL) , you can use BASIC:

import feign.Logger;
import org.springframework.context.annotation.Bean;

public class FeignConfig {
    @Bean
    Logger.Level feignLoggerLevel() {
        return Logger.Level.BASIC;
    }
}

Then we can configure FeignClient to use the config:

import com.example.nacosfeign.config.FeignConfig;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;

import java.util.Map;

@FeignClient(name="nacos-provider-bswencw1", configuration = FeignConfig.class)
public interface DemoClient {
    @GetMapping("hello")
    Map<String, Object> hello();
}

At last, we should change our app logging level to DEBUG to show the logs:

Say our app’s package is prefixed by com.example:

server:
  port: 8086
spring:
  application:
    name: nacos-feign
  cloud:
    nacos:
      discovery:
        server-addr: 10.1.1.1:8848
logging:
  level:
    root: ERROR
    org.springframework.web: ERROR
    com.example: DEBUG

Then run the test again, we got this debug info:

2022-02-18 15:35:45.000  INFO 45588 --- [           main] c.e.nacosfeign.NacosFeignApplication     : No active profile set, falling back to default profiles: default
2022-02-18 15:35:47.732  INFO 45588 --- [           main] c.e.nacosfeign.NacosFeignApplication     : Started NacosFeignApplication in 4.065 seconds (JVM running for 8.322)
2022-02-18 15:36:16.404 DEBUG 45588 --- [nio-8086-exec-1] c.example.nacosfeign.clients.DemoClient  : [DemoClient#hello] ---> GET http://nacos-provider-/hello HTTP/1.1
2022-02-18 15:36:16.405 DEBUG 45588 --- [nio-8086-exec-1] c.example.nacosfeign.clients.DemoClient  : [DemoClient#hello] Content-Length: 2
2022-02-18 15:36:16.405 DEBUG 45588 --- [nio-8086-exec-1] c.example.nacosfeign.clients.DemoClient  : [DemoClient#hello] Content-Type: text/plain;charset=UTF-8
2022-02-18 15:36:16.405 DEBUG 45588 --- [nio-8086-exec-1] c.example.nacosfeign.clients.DemoClient  : [DemoClient#hello]
2022-02-18 15:36:16.405 DEBUG 45588 --- [nio-8086-exec-1] c.example.nacosfeign.clients.DemoClient  : [DemoClient#hello] aa
2022-02-18 15:36:16.405 DEBUG 45588 --- [nio-8086-exec-1] c.example.nacosfeign.clients.DemoClient  : [DemoClient#hello] ---> END HTTP (2-byte body)
2022-02-18 15:36:19.253 DEBUG 45588 --- [nio-8086-exec-1] c.example.nacosfeign.clients.DemoClient  : [DemoClient#hello] <--- ERROR SocketTimeoutException: Read timed out (2847ms)
2022-02-18 15:36:19.254 DEBUG 45588 --- [nio-8086-exec-1] c.example.nacosfeign.clients.DemoClient  : [DemoClient#hello] java.net.SocketTimeoutException: Read timed out

It works!

3. Summary

In this post, I demonstrated how to debug the application that is using feign to access remote servcies, the key point is to change the logging level of feign using spring configuration class . That’s it, thanks for your reading.

Final Words + More Resources

My intention with this article was to help others share my knowledge and experience. If you want to contact me, you can contact by email: Email me

Here are also the most important links from this article along with some further resources that will help you in this scope:

👨‍💻 Spring Boot Guide

Oh, and if you found these resources useful, don’t forget to support me by starring the repo on GitHub!