Reactive system

As explained in Quarkus in Action

A reactive system is a distributed software system designed to remain responsive through resiliency, elasticity, and asynchronous message-driven communication.

A reactive system is a distributed system designed to remain responsive under demand and failure. It combines responsiveness, resiliency, elasticity, and asynchronous message passing. In microservices, message-driven communication lets services exchange information without blocking threads or coupling their implementations too closely. section 9.2 section 9.0

Its properties reinforce one another:

• Responsiveness handles user requests in a timely fashion and includes identifying and dealing with failures. section 9.2
• Resiliency keeps the system responsive during failures through isolated, highly available services and fast transitions to backups. section 9.2
• Elasticity scales service instances horizontally up or down according to demand, including scaling services down when unused. section 9.2
• Message-driven communication provides asynchronous service interactions that support the other properties. section 9.0 section 9.2

In Quarkus, MicroProfile Reactive Messaging supplies a unified API for propagating asynchronous messages between services. Connectors integrate that API with messaging providers, while Reactive Streams and Mutiny support reactive pipelines. section 9.0 section 9.9

Car-rental services

A Billing service communicates asynchronously with a Reservation service through RabbitMQ using AMQP 0-9-1 and exchanges messages with a Rental service through Apache Kafka. In Quarkus, a reactive connection can be assembled with @Incoming and @Outgoing, configuration, and Dev Services. section 9.9

Figure 9.2 The reactive system architecture

Use the architecture figure to relate responsiveness, resiliency, elasticity, and message-driven communication. section 9.2

How Quarkus in Action covers it

How deep it goes

Defines four properties, explains their roles, and applies them through Quarkus messaging without detailing broker internals.

Examples

Uses a car-rental Billing service with Reservation and Rental services, RabbitMQ, Kafka, AMQP, and Quarkus messaging annotations.

What it assumes

Builds on reactive programming, asynchronous execution, nonblocking I/O, and microservice architecture.

What you can do after

Apply it via MicroProfile Reactive Messaging by connecting Quarkus services to Kafka or RabbitMQ with annotations and configuration.

How it connects

Connects reactive programming, microservices, asynchronous messaging, Reactive Streams, Kafka, RabbitMQ, resiliency, and elasticity.

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Related concepts

• resiliencehas part · Resilience is the capacity of a system or organization to withstand disruption, adapt, recover, or continue functioning acceptably.
• message passinghas part · A communication or computation technique in which entities exchange messages to transmit or propagate information, coordinate work, or update state.
• cloud elasticityhas part · Cloud elasticity is the ability of cloud infrastructure or services to dynamically increase or decrease resource capacity in response to changing workload demand.
• reactive applicationincludes · A reactive application is a software application that responds to events or other stimuli while coordinating asynchronous, nonblocking processing of data and tasks.

This explainer was generated by Manning's knowledge graph from the text of Quarkus in Action. The section links point to the parts of the book it draws on.