test-spring-boot-reactive-netty

This repository tests an appearing issue when using Netty to serve a Spring Boot-enabled Reactive Web application.

This application is very simple: it was created at http://start.spring.io and the following modification was made to its pom.xml in order to disable the Tomcat starter and use Netty instead:

<dependency>
    <groupId>org.springframework.boot.experimental</groupId>
    <artifactId>spring-boot-starter-web-reactive</artifactId>
    <exclusions>
        <!-- Excluded because we will be using netty -->
        <exclusion>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
        </exclusion>
    </exclusions>
</dependency>

<dependency>
    <groupId>io.projectreactor.ipc</groupId>
    <artifactId>reactor-netty</artifactId>
</dependency>

The controller is very simple:

@RestController
public class TestSpringBootReactiveNettyController {

	@RequestMapping(value = "/")
	public Mono<SomeBean> root() {
		return Mono.just(new SomeBean("Ola mundo", "Hola mundo"));
	}

}

How to replicate

Requirements: Java 8, Maven 3, git client, web browser (Chrome or Firefox). Tested on several Operating Systems: Mac OS 10.11 El Capitan, Windows 10, Ubuntu 16.

Clone this repository
cd to the project's folder
Start the app with mvn -U clean compile spring-boot:run
Open browser and go to http://localhost:8080 (it is important that localhost is used)
If a small piece of JSON loads OK the first time, hit refresh several times until some of those refreshes stop responding at all

Issue description

Environments in which this has been replicated:

Chrome 52, Postman (Chrome-based), Firefox 49 and Safari 9.1.3 on Mac OS X 10.11 El Capitan (server + browsers, all local).
Chrome 52 and Firefox 49 on Windows 10 (server + browsers, all local).

Symptoms: only alternate requests have response: 1. Response, 2. No response, 3. Response, 4. No response…

By means of debugging it has been determined that Netty does receive an HTTP request in every case. But no HTTP response is sent half of the times.

By means of network sniffing it has been determined that the HTTP request looks alright, and exactly the same both when there is HTTP response and when there isn't. Example:

GET / HTTP/1.1
Host: localhost:8080
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:45.0) Gecko/20100101 Firefox/45.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Connection: keep-alive

This cannot be replicated using curl, httpie or wget. Only browsers seem to show this behaviour (or Postman, which works on the Chrome engine).

Also, this behaviour also happens when the application is configured to return HTML (actually this issue initially appeared at the Thymeleaf + Spring Reactive sandbox application).

IMPORTANT: This issue, in the same systems and setups, cannot be replicated when accessing the server using its IP (e.g. 192.168.0.20). So this seems somehow related to the use of localhost.

danielfernandez/test-spring-boot-reactive-netty

test-spring-boot-reactive-netty

How to replicate

Issue description