Increasing maxHeaderSize for downstream requests

[mxku]

I have a use case where spring-cloud-gateway injects some headers in the request for authentication/authorization purpose. In some case, the size of these headers is going beyond 8KB which make gateway throw http 400 in those cases.

I did go through issue #402 and tried that option. But this seems related to changing the header size that gateway itself will accept and not what it will be routing to downstream services.

The downstream services in my case have max-http-headers-size as 0, tomcat based spring-boot applications, hence they aren't rejecting. Is there any configuration option or component that I can add to customize this behaviour?

[ryanjbaxter]

This is really a Netty/Spring Boot question and not a Spring Cloud Gateway question.

Try

	@Configuration
	public class ServerConfiguration {

		@Bean
		public NettyServerCustomizer serverCustomizer() {
			return options -> options.maxHeaderSize(1000);
		}
	}

See spring-projects/spring-boot#9955 (comment)

[mxku]

@ryanjbaxter Thanks. But wouldn't customizing through NettyServerConfiguration will alter the header size that cloud gateway will accept. I have issue when header size in downstream request exceeds 8KB. As in my case, cloud gateway injects some authentication related headers before forwarding the request to downstream services.

I couldn't find any way to customize the HttpClient.

[spencergibb]

We have support for the server side, @MANISHONLINE is this specifically for the client side? Can you share the exception?

[tony-clarke-amdocs]

@MANISHONLINE DId you find a way to adjust the max size?

[spencergibb]

@violetagg or @smaldini?

[violetagg]

Currently we do not provide a way for changing these settings for the client.
If you need that, please create a GitHub issue. Also once we add it, Gateway has to provide also a way for changing these settings.

[tony-clarke-amdocs]

Thanks reactor/reactor-netty#531

[Fraser-Chapman]

Did @mxku find a fix for this in the end? I'm struggling with this in my app and raised an issue: #3418