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Bootiful RSocket with Coroutines

github.com/renatomrcosta

@renatomrcosta

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Bootiful RSocket with Coroutines

  • Intro
  • Spring
  • Kotlin Coroutines
  • Why Reactive?
  • RSocket
  • Demo

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Intro

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The goal for today

  • Understand the tools available:
    • Introduce the Concepts we will explore;

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  • Make deliberate choices:
    • Let’s look at our options, and understand if our technological choices fit the problem we are trying to solve;

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  • Be Productive:
    • Let’s code a small demo.

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Spring

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Spring Boot

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Coroutines

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Coroutines

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Why are Coroutines?

  • It is still important to care about individual blocking of Threads even when you can use many of them:
    • UI Threads
    • Process intensive operations that may overload the Threads pools and make the entire thing go unresponsive.

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  • In this interconnected world of services, waiting efficiently can be more important than raw computing.

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What are Coroutines?

  • They are devices that allow the non-blocking execution of code.
  • This code, in turn, can be suspended and later resumed.
  • In Kotlin, they are essentially State Machine Objects

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What are (Kotlin) Coroutines?

  • A library provided that aims to give tools to help developers to write non-blocking code with coroutine primitives;
  • The three main aspects (in my opinion) are:
    • Providing an inexpensive substitute for threads, both in terms of application resources and developer mental model;
      • Threads are expensive, whereas Coroutines are very lightweight.
    • Helping to simplify code:
      • Avoiding things as callback hell / operator hell code when using Callbacks or typical Futures / Promise library implementations;
    • Helping to make it EASIER to write idiomatic code that can behave asynchronously.

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Coroutines Sample

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Why Reactive?

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Servlet Based Approach

Requests

Endpoint /

Servlet

Request #1

Request #2

Request #3

Thread #1

Thread #2

Thread #3

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Spring Web - Controller Sample

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Spring Web - Controller Sample

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Spring Web - Reference

  • Spring Web Reference Docs

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Servlet Based Approach

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  • Do you need asynchronous or reactive programming?
  • Do you need to scale sensibly, or handle bursts of requests?
  • Do you require backpressure support?

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  • Spring Web
    • Spring Data
      • JPA
      • JDBC
      • Redis
      • Mongo
      • ...

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NO

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Backpressure

  • “Resistance or force opposing the desired flow of data through software” - Jay Phelps

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  • Classic Example: Reading from a Hard Drive
    • Read Speeds: 150MB/s
    • Write Speeds: 100MB/s
    • 50MB/s in the buffer!

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Reactive approach

Requests

Request #1

Response (Immediate) #1

Request #2

Response (Immediate) #2

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Spring Webflux - Controller Sample

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Spring Webflux - Controller Sample

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Spring Webflux - Controller Sample

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Spring Webflux - Controller Sample

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Reactive approach

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  • Do you need asynchronous or reactive programming?
  • Do you need to scale sensibly, or handle bursts of requests?
  • Do you require backpressure support?

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  • Spring Webflux
    • Spring Data Reactive
      • R2DBC
      • Redis
      • Mongo
    • Reactor / Coroutines
  • RSocket

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Yes

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What is RSocket then?

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RSocket

  • A protocol that enables high-performance, fault-tolerant messaging over a multiplexed, duplex connection.
  • Is Transport, Message Format, and Language agnostic
  • Built on top of the Reactive Streams specification

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Multiplexed

  • Multiple requests and responses in the same connection

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Duplex

  • Requester / Receiver instead of Client / Server

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Agnostic

  • Transport: TCP, Websocket, HTTP/2, Aeron…

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  • Client Implementation: Kotlin, C++, Java, Javascript, .NET, Go, Python

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  • Payload: Binary (so it can essentially be anything: CBOR, Protobuf, JSON, XML)

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Interaction Models

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Request / Response

  • Single request that may contain a payload, that may yield a response
  • Maps to the normal request / response semantics in HTTP / REST

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Fire-and-Forget

  • A Request that may contain a payload, but does not wait for a response

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Request / Stream

  • The requester sends a single request and the responder returns a stream of results.

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Request / Channel

  • A requester may send multiple values and the responder may return multiple values
  • Bi-directional stream of messages

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RSocket Server

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The Spring Boot approach

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Spring Boot + RSocket

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Spring Boot + RSocket

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Demo Time

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References - Coroutines

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References - RSocket / Spring

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Questions

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Thank you!

github.com/renatomrcosta

@renatomrcosta