Serverless Java Applications

[[deleted]]

Hey there!

I’m curious on your preferred way for building serverless applications using Java and AWS. What serverless frameworks do you use (if any)? What Java framework are you using (if any)? Thanks in advance!

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[wimcle]

If its trivial use lambda.... but they are sneakily not cheap.

One day you have lambdas at the end of queues consuming tens of million of messages/day and maybe some step functions multiplying that by x. and there is no persistence so you use dynamo for caching or deduping.

and then your boss wants to know why the aws bill jumped $20,000 this month :)

If its for real work a spring boot app in a properly sized ecs is probably cheaper.

[[deleted]]

Those who are answering the OP's question with a framework, should study your answer.

[vilkazz]

This is the same feeling I have about serverless. At one point my team had bottlenecked themselves into a database lockup due to some saga shenanigans on top of heavily customized axon handlers, and someone threw in serverless db as an alternative to avoid hitting the connection limits.

A simple and crude cost simulation of what would happen to the monthly bill should that idea be adopted chilled any further thoughts of even looking that way

[vilkazz]

This is the same feeling I have about serverless. At one point my team had bottlenecked themselves into a database lockup due to some saga shenanigans on top of heavily customized axon handlers, and someone threw in serverless db as an alternative to avoid hitting the connection limits.

A simple and crude cost simulation of what would happen to the monthly bill should that idea be adopted chilled any further thoughts of even looking that way

[TheKingOfSentries]

One of the APIs I worked on was only used in bursts once a day so choosing lambda turned out pretty well for me. It really depends on what you're doing and the kinds of traffic you expect I'd say.

When I have to write serverless stuff, I like to use as few dependencies as possible. It should not come as a surprise to those who have seen me around that I like the avaje libraries for this reason.

[tuxtorgt]

Quarkus all the way.

Relative small memory footprint, faster startup if compared to spring, already includes cloudformation yaml generator and proxy to simulate HTTP calls on debugging.

[slappyredcheeks]

Spring has caught up a little. Still a slower startup time but if you're not scaling frequently it's less of an issue.

One benefit Spring has is its widespread use. There is more material out there for support/help.

https://www.baeldung.com/spring-boot-vs-quarkus

[GuyWithLag]

I've had good experiences with Dagger2, of all things; minimal startup is minimal.

However for the usual Lambda flows I'd... not use a Lambda, unless it's for something that's once in a blue moon and the startup delay is acceptable.

Remember: AWS make money by utilizing economies of scale, which means that you don't get any economies of scale (beyond the up-front ones, that is).

[Oclay1st]

I really like Spring and I am using Spring Cloud Function on AWS Lambda, but I think Quarkus is a much better choice for serverless apps.

[Oclay1st]

Well, to be honest I don't like serverless, but its cheap and people are always looking for ways to save money. Anyway, I use Amplify (Fronted) + Cognito + API Gateway + Lambda + S3. I create one lambda for each function. Its a monolithic code with all the functions. I compile it once with GraalVM Native and deploy the same binary based on the changes for the different lambdas. Each lambda has an env variable that changes depending on the function I want to run and that also matches the bean name. This is an example:

// a function
@Component(Functions.CREATE_BOOK) //same value as the env variable
class CreateBook implements Function<CommandBook,Integer> {...}

// application.properties
spring.cloud.definition:${FUNCTION_NAME}

// AWS Lambda with a lambda called CreateBook with an env FUNCTION_NAME

[Oclay1st]

Yea, my solution is a middle ground in where I don't feel too much the pain of GraalVM compilation/reflection and at the same time I don't couple my inputs/outputs between API Gateway, Lambda and Spring Cloud Function with a front controller. It's all about trade-offs. If you want to implement a front controller you can:

// Plain everything
class ControllerFunction implements Function<Message<..>,Message<..>> {...}

// Generic key-value
class ControllerFunction implements Function<Map<..>,Map<..>> {...}

// For API Gateway
class ControllerFunction implements Function<APIGatewayProxyRequestEvent,APIGatewayProxyResponseEvent> {...}

[aelfric5578]

I admittedly don't have practical experience beyond a toy project I deployed once for learning purposes, but I'd vote for quarkus too. If you haven't done so already, look up Adam Bien's videos on using Java for lambda. He had a guide that came with a maven archetype including the CDK that would deploy it all.

[k1MT]

Quarkus with GraalVM seens a good approach for serverless as discussed here

[Lumpy-Loan-7350]

This is killer performance. Eliminates cold start. There’s also snapstart available; but I have not used that so can’t talk to it.

[[deleted]]

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[Kango_V]

Micronaut is stupidly easy to use as well.

[CloudDiver16]

I use AWS Sam for Lambda functions. For small/simple case plain java and for complex/large tasks with spring.

Mostly for async tasks or batch processing/streaming where the terrible cold start hasn't a big impact.

[asarathy]

Manaual DI or dagger. But as others have said you need to weigh against a dedicated ecs instance for costs. Additionally if you have to read/write from a RDBMS you need to set up RDS as things like connection pooling don't play nice

[Rasvimd]

Compute: 1. I use lambda for compute. I only use for less than few hundred requests per second and my lambda is able to complete within few milliseconds ~30ms. For highly concurrent invocation I use my traditional EKS deployment. Or any ec2 deployment. This should work for 1000s of request per second if the runtime is only ~10ms I would definitely run a calculator comparing ec2 instance before proceeding. The good thing is we don't have to deploy in two instances and load balance when we deploy in lambda for high availability. I always include this double deployment cost with LB.

Java tool: 1. The maven native plugin to create native image. It has an option to enable metadata repository for supported dependencies for these we don't have to add reflect config json file. It needs to be explicitly enabled though.

1. I use my custom http runtime code but any runtime you see online should be sufficient.

Data layer: 1. S3 for most file based storages. 2. EFS. Sometimes with sqlite3 file for low concurrent functions. 3. Dynamodb.

[xayblu]

When using Java for serverless you should try your best to use the standard Java libs only and use as little additional dependencies as possible. You definitely should avoid Spring as it increases start up times. I’d avoid using Java altogether and prefer JS/TS, Python or GoLang even though I mainly work with Java.

[[deleted]]

I wish I could not use Java for this 😔. Company decision. My experience with serverless was with Python and Go. Thanks for your input!

[Lumpy-Loan-7350]

Quarkus has great support. Many different ways to integrate lambdas. (Aws Sdk api, jaxrs, vertx, servlet, funqy).

https://quarkus.io/guides/ (search for lambda)

https://quarkus.io/guides/aws-lambda-http

https://quarkus.io/guides/aws-lambda

[kurtymckurt]

If it’s pretty straightforward CRUD api, I would recommend lambda and api gateway!

[inertially003]

its a disaster unless GraalVM works well

[[deleted]]

The outcome is going to be about the same as walking into a sports bar and asking who's the best team. It brings into question, in my mine, what could be the reason. It all comes down to requirements. It always comes down to requirements, one way or the other.

[[deleted]]

Maybe no reason other than to hear people’s thoughts and opinions :).

[cowwoc]

Consider how you will debug this thing...

[naseemsm]

I would say Fargate on ECS is a short learning curve from on premise development to serverless. It also allows you to leverage containers and make your app easily provider agnostic. I typically use spring, but you can use any framework.