spring webflux + serverless

[jayasai470]

• Framework version: 1.3
• Implementations: Spring boot 2.1.2 + web-react

Scenario

just wanted to check if there is a support for spring webflux without server sent events ?

Expected behavior

Actual behavior

Steps to reproduce

Full log output

[sapessi]

I have not tested with WebFlux. I will mark this as a feature request and look into it for the next minor release.

[renecairo]

Hi, is there any feedback on this?
I'm trying to deploy a lambda function using Spring Boot 2.x + webflux and I'm having the following issue:
Error loading class com.everymundo.openair.farenet.processor.StreamLambdaHandler: org/springframework/web/servlet/DispatcherServlet: java.lang.NoClassDefFoundError java.lang.NoClassDefFoundError: org/springframework/web/servlet/DispatcherServlet

@sapessi was the webflux support added at some point to any release?

Thanks in advance

[sapessi]

Hi @renecairo - I have not worked on Webflux yet. I'm assuming you have tested with the latest version of this library? The error indicates that it cannot load org/springframework/web/servlet/DispatcherServlet, which I'd expected to be bundled in the jar/zip every time. Do you have a repo that I can use to replicate?

[renecairo]

Hi @sapessi

We are building fully reactive micro-services using Spring Boot 2.x and Webflux with Reactor Netty (non-servlet). Spring web-mvc is the one including the missing class and we can't have both dependencies in the same project.

[khakiout]

Would like to comment that we've experience the same thing. It seems SpringBootLambdaContainerHandler contains a dispatcherServlet field by default. However, this is not included for Webflux.

[sapessi]

I spent some time looking into this. I see two possible path forward:

1. Spring-spefici: Sounds like this should be a separate SpringWebfluxLambdaContainerHandler that interfaces with an WebHandler object instead of the classic DispatcherServlet. We should also provide implementations of the ServerHttpRequest and response interfaces. This is relatively low effort but cannot be used with other frameworks
2. Create an implementation of the reactor core APIs and integrate with Spring effectively pretending to be a server such as Netty. This is more generic and will likely scale better to other frameworks. However, it is considerably more effort.

To be clear, AWS Lambda itself enforces that each sandbox only processes one event at a time. So you won't see any performance gain by using the reactor API. Adding support for this in the library simply gives you the ability to port your code between compute platforms.

Do you use any other framework for "reactor" development other than Spring @jayasai470, @renecairo, @khakiout?

[jayasai470]

@sapessi right now no.

[khakiout]

@sapessi At the moment no, we only use 'reactor' with Spring.

To be clear, AWS Lambda itself enforces that each sandbox only processes one event at a time. So you won't see any performance gain by using the reactor API.

We'll take note of this. If Serverless doesn't benefit much from Reactor maybe we can go back to the usual way.

[sapessi]

I'd say it's still worth testing @khakiout, especially if your function performs multiple, network-bound operations all at once. I'm hoping to find some time to work on this soon.

We'll take note of this. If Serverless doesn't benefit much from Reactor maybe we can go back to the usual way.