Simple Reverse Proxy with Spring Boot and Netflix Zuul

Question

I'm looking to implement a simple reverse proxy with Spring Boot that is:

• Easy to add routes
• Ability to add custom authentication on a per route basis
• Add additional headers as needed

I've looked at the facilities provided by the @EnableZuulProxy annotation but it seems too heavyweight as I don't have a desire to use Eureka, Ribbon, or Hystrix. However, @EnableZuulServer is a bit light on configuration.

Would anyone be able to provide an example of what I'm after? Is Netflix Zuul the right choice for this or is there another library I should be looking at?

Thanks!

Answer 1

Simple Reverse Proxy Server

It's easy to set up a simple proxy reverse using Spring Boot without Ribbon, Eureka, or Hystrix.

Simply annotate your main application class with @EnableZuulProxy and set the following property in your configuration:

ribbon.eureka.enabled=false

Then define your routes in your configuration like such:

zuul.routes.<route_name>.path=<route_path>    
zuul.routes.<route_name>.url=http://<url_to_host>/

where <route_name> is an arbitrary name for your route and <route_path> is a path using Ant-style path matching.

So a concrete example would be something like this

zuul.routes.userservice.path=users/**
zuul.routes.userservice.url=http://localhost:9999/

Custom Filters

You can also implement your custom authentication and any additional headers by extending and implementing the ZuulFilter class and adding it as an @Bean to your @Configuration class.

So another concrete example:

public class MyFilter extends ZuulFilter {

  @Override
  public String filterType() {
    // can be pre, route, post, and error
    return "pre";
  }

  @Override
  public int filterOrder() {
    return 0;
  }

  @Override
  public boolean shouldFilter() {
    return true;
  }

  @Override
  public Object run() {
    // RequestContext is shared by all ZuulFilters
    RequestContext ctx = RequestContext.getCurrentContext();
    HttpServletRequest request = ctx.getRequest();

    // add custom headers
    ctx.addZuulRequestHeader("x-custom-header", "foobar");    

    // additional custom logic goes here

    // return isn't used in current impl, null is fine
    return null;
  }

}

and then

@Configuration
public class GatewayApplication {

  @Bean
  public MyFilter myFilter() {
    return new myFilter();
  }

}