0Pricing
API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) · Aula

Definição de Rotas e Predicados

Aprenda a definir rotas dinâmicas usando predicados, como Path, Host e Method, para direcionar requisições a serviços específicos.

Definição de Rotas e Predicados é uma aula grátis de API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) no CoddyKit. Esta é a aula 3 de 4. Você pode ler a aula completa abaixo gratuitamente — depois pratica ao vivo no navegador com um editor de código integrado e um tutor de IA 24/7. Faz parte do caminho de aprendizado de API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway), e seu progresso é sincronizado entre a web e o app CoddyKit. O curso de API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) inclui 4 aulas no total.

Partes desta aula ainda não foram traduzidas e aparecem em inglês.

Routing with API Gateways

Welcome! In a microservices architecture, clients don't talk directly to every service. Instead, they interact with an API Gateway.

This gateway acts as a single entry point, directing incoming requests to the correct backend service. This process is called routing.

What Are Predicates?

In Spring Cloud Gateway, predicates are key to routing. Think of them as 'conditions' or 'rules'.

  • A predicate evaluates to true or false.
  • If a predicate (or set of predicates) for a route evaluates to true, the gateway forwards the request using that route.
  • If false, the gateway tries the next route.

Gateway Project Foundation

Routes are typically configured in your Spring Boot application's application.yml or application.properties file. Here's a minimal Spring Boot application that *could* host our gateway configuration. The routing logic itself will go into the YAML.

You can run this basic app to see it working:

package com.coddykit.gateway;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@RestController
public class GatewayApplication {

  public static void main(String[] args) {
    SpringApplication.run(GatewayApplication.class, args);
  }

  @GetMapping("/test-gateway")
  public String testGateway() {
    return "Hello from Gateway!";
  }
}

Basic Route Structure

A route in Spring Cloud Gateway needs three main things:

  • id: A unique identifier for the route.
  • uri: The URI of the backend service to which requests will be forwarded.
  • predicates: A list of conditions that must be met for this route to activate.

We'll primarily define these in application.yml.

The Path Predicate

The Path predicate is one of the most common. It matches the request URI path against a specified pattern.

  • You can use wildcards like * (matches one path segment) and ** (matches multiple path segments).
  • For example, /users/* matches /users/1 but not /users/admin/1.
  • /users/** matches both /users/1 and /users/admin/1.

Path Predicate in Action

Here's how you'd configure a route using the Path predicate to send all requests starting with /api/users to a backend user-service:

spring:
  cloud:
    gateway:
      routes:
        - id: user_service_route
          uri: http://localhost:8081 # Your backend user service
          predicates:
            - Path=/api/users/**

The Host Predicate

The Host predicate matches requests based on the hostname in the request header.

  • This is useful for routing requests from different domains or subdomains to specific services.
  • You can also use wildcards here, like *.example.com to match any subdomain of example.com.

Host Predicate Example

Let's say you want to route all requests coming from api.mycompany.com to a specific backend service. Here's how:

spring:
  cloud:
    gateway:
      routes:
        - id: api_domain_route
          uri: http://localhost:8082 # Your backend API service
          predicates:
            - Host=api.mycompany.com

The Method Predicate

The Method predicate matches requests based on their HTTP method (also known as HTTP verb).

  • Common methods include GET, POST, PUT, DELETE, and PATCH.
  • This allows you to direct different types of operations (e.g., reading vs. creating data) to distinct backend endpoints or services.

Method Predicate Example

To ensure only POST requests to /products are routed to a specific service, and other methods are handled elsewhere:

spring:
  cloud:
    gateway:
      routes:
        - id: create_product_route
          uri: http://localhost:8083 # Service for creating products
          predicates:
            - Path=/products
            - Method=POST

Predicate Power Check

You've learned about Path, Host, and Method predicates. Now, let's test your understanding!

Recap: Routes & Predicates

Great job! You've learned the fundamentals of defining routes and using predicates in Spring Cloud Gateway.

  • Routes direct traffic to backend services.
  • Predicates are the conditions (like Path, Host, Method) that determine if a route matches.
  • Multiple predicates on a single route act as an AND condition.

This powerful combination allows for flexible and intelligent traffic management in your microservices.

Perguntas Frequentes

A aula “Definição de Rotas e Predicados” é grátis?

Sim — o texto completo de “Definição de Rotas e Predicados” é grátis para ler aqui na web. Para praticá-la interativamente (um editor de código integrado e um tutor de IA 24/7) e desbloquear o restante do curso de API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway), atualize para CoddyKit PRO. O curso de API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) inclui 4 aulas no total.

O que vou aprender em “Definição de Rotas e Predicados”?

Aprenda a definir rotas dinâmicas usando predicados, como Path, Host e Method, para direcionar requisições a serviços específicos. Você pratica API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) com código prático que executa diretamente no navegador, e um tutor de IA 24/7 responde suas dúvidas enquanto trabalha na aula.

Preciso ter experiência prévia para começar API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway)?

Nenhuma experiência prévia é necessária. API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) no CoddyKit é estruturado para alunos iniciantes até avançados, então você pode começar aqui ou desde o início e aprender no seu ritmo. Esta é a aula 3 de 4.

Quanto tempo leva a aula “Definição de Rotas e Predicados”?

A maioria das aulas CoddyKit leva cerca de 5–10 minutos. Cada uma é compacta e interativa, então você faz progresso constante e retoma exatamente de onde parou entre web e app.

Posso escrever e executar código nesta aula de API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway)?

Sim. Cada aula de API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) inclui um editor de código integrado, então você escreve e executa código real direto no navegador e recebe feedback de IA instantaneamente — nenhuma configuração local necessária.

Todas as aulas deste curso

  1. Gateway versus Microsserviços Tradicionais
  2. Configuração de um Projeto Básico de Gateway
  3. Definição de Rotas e Predicados
  4. Compreendendo a base reativa
← Voltar para API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway)