How to configure netty in spring boot 2 - spring-boot

Question

By default spring web flux uses netty which is single threaded event loop. How to configure spring boot so that a thread will be created for each core.
Thanks,
Lokesh

Answer 1

As described in the Spring Boot reference documentation, you can customize the Reactor Netty web server with a NettyServerCustomizer.
Here's an example with Spring Boot 2.1:
#Component
public class MyNettyWebServerCustomizer
implements WebServerFactoryCustomizer<NettyReactiveWebServerFactory> {
#Override
public void customize(NettyReactiveWebServerFactory factory) {
factory.addServerCustomizers(new EventLoopNettyCustomizer());
}
}
class EventLoopNettyCustomizer implements NettyServerCustomizer {
#Override
public HttpServer apply(HttpServer httpServer) {
LoopResources loopResources = LoopResources.create(...);
return httpServer.runOn(loopResources);
}
}

Answer 2

You can change your dependencies:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<!-- Exclude the Tomcat dependency -->
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</dependency>
<!-- Use Jetty instead -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jetty</artifactId>
</dependency>
https://docs.spring.io/spring-boot/docs/current/reference/html/howto-embedded-web-servers.html