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GraphQL APIs with Spring Boot · Leçon

Configurer et gérer la passerelle

Configurez et déployez une passerelle Apollo pour composer vos sous-graphes fédérés et les exposer sous la forme d'un graphe unifié unique.

Configurer et gérer la passerelle est une leçon GraphQL APIs with Spring Boot gratuite sur CoddyKit. Ceci est la leçon 3 sur 4. Tu peux lire la leçon complète ci-dessous gratuitement — puis la pratiquer en direct dans le navigateur avec un éditeur de code intégré et un tuteur IA 24/7. Elle fait partie du parcours d'apprentissage GraphQL APIs with Spring Boot, et ta progression se synchronise sur le web et l'application CoddyKit. Le cours GraphQL APIs with Spring Boot comprend 4 leçons au total.

Certaines parties de cette leçon n'ont pas encore été traduites et s'affichent en anglais.

Gateway: The Unified API

In GraphQL Federation, the Apollo Gateway acts as the central entry point for all client applications. Think of it as the brain that understands your entire supergraph.

It takes multiple independent GraphQL services (called subgraphs) and combines their schemas into one unified, client-facing schema.

Why a Gateway is Essential

With a microservices architecture, you might have many backend services, each with its own GraphQL API. Without a gateway, clients would need to know about and query each service individually.

  • Unified Endpoint: Clients interact with a single GraphQL API.
  • Schema Composition: The gateway automatically stitches together the schemas from all subgraphs.
  • Simplified Client Logic: Clients don't need to know which service owns which data.

How the Gateway Works

When a client sends a query to the gateway, here's what happens:

  1. The gateway receives the query.
  2. It analyzes the query against the composed supergraph schema.
  3. It breaks down the query into smaller parts, determining which subgraph owns which piece of data.
  4. It sends sub-queries to the relevant subgraphs.
  5. It then combines the results from these subgraphs into a single response for the client.

Gateway Implementations

While your subgraphs can be built with Spring Boot (or any other framework), the gateway itself is often implemented using Apollo's own tools.

The most common and robust implementation is the Apollo Server Gateway, which is a Node.js-based server designed specifically for federation. This lesson will focus on setting up this standard gateway.

Basic Gateway Setup (Node.js)

Let's set up a minimal Apollo Gateway. First, create a new Node.js project and install the necessary packages:

npm init -y
npm install @apollo/gateway apollo-server

Then, create an index.js file:

const { ApolloGateway, RemoteGraphQLDataSource } = require("@apollo/gateway");
const { ApolloServer } = require("apollo-server");

const gateway = new ApolloGateway({
  serviceList: [
    { name: "products", url: "http://localhost:4001/graphql" },
  ],
  buildService({ name, url }) {
    return new RemoteGraphQLDataSource({ url });
  },
});

const server = new ApolloServer({ gateway });

server.listen({
  port: process.env.PORT || 4000
}).then(({ url }) => {
  console.log(`🚀 Gateway ready at ${url}`);
});

Configuring Subgraphs

In the previous code, the serviceList array is crucial. It tells the gateway which subgraphs exist and where to find them. Each object in the array needs two properties:

  • name: A unique identifier for the subgraph (e.g., "products").
  • url: The endpoint where the subgraph's GraphQL API is running (e.g., "http://localhost:4001/graphql").

Adding More Subgraphs

As you develop more microservices with GraphQL APIs, you simply add them to the serviceList. The gateway will automatically compose their schemas into the unified graph.

Here's how you'd add a reviews subgraph running on port 4002:

const { ApolloGateway, RemoteGraphQLDataSource } = require("@apollo/gateway");
const { ApolloServer } = require("apollo-server");

const gateway = new ApolloGateway({
  serviceList: [
    { name: "products", url: "http://localhost:4001/graphql" },
    { name: "reviews", url: "http://localhost:4002/graphql" },
  ],
  buildService({ name, url }) {
    return new RemoteGraphQLDataSource({ url });
  },
});

const server = new ApolloServer({ gateway });

server.listen({
  port: process.env.PORT || 4000
}).then(({ url }) => {
  console.log(`🚀 Gateway ready at ${url}`);
});

Running and Accessing the Gateway

Once your index.js is set up, you can start the gateway:

node index.js

The console will output the URL where your gateway is running, typically http://localhost:4000/. Open this URL in your browser to access the GraphQL Playground or GraphiQL interface provided by Apollo Server.

Querying the Unified Graph

Clients will send their GraphQL queries directly to the gateway's URL. The gateway handles all the internal routing and data fetching from the subgraphs.

For example, a query combining data from both a products and reviews subgraph might look like this:

query GetProductDetails {
  product(id: "prod-1") {
    name
    price
    reviews {
      id
      rating
      comment
    }
  }
}

Gateway Management Tips

Beyond initial setup, managing your gateway involves several best practices:

  • Deployment: Deploy the gateway as a standalone service, often alongside your subgraphs.
  • Monitoring: Use tools to monitor its performance, error rates, and latency.
  • Scaling: The gateway can be scaled horizontally to handle increased client traffic.
  • Schema Changes: Ensure your gateway is configured to pick up schema updates from subgraphs reliably (e.g., via Apollo Studio or a local schema registry).

Quick Check: Gateway Role

You've learned about the Apollo Gateway and its role in federation.

Recap: Gateway Essentials

Congratulations! You've learned about the Apollo Gateway, a crucial component in GraphQL Federation. It provides a unified API endpoint for clients, seamlessly composing schemas from various subgraphs and routing queries effectively.

By configuring the serviceList, your gateway becomes the single source of truth for your entire supergraph, simplifying client interactions and enabling a robust microservices architecture.

Questions Fréquemment Posées

La leçon « Configurer et gérer la passerelle » est-elle gratuite ?

Oui — le texte complet de « Configurer et gérer la passerelle » est gratuit à lire ici sur le web. Pour la pratiquer de manière interactive (un éditeur de code intégré et un tuteur IA 24/7) et déverrouiller le reste du cours GraphQL APIs with Spring Boot, passe à CoddyKit PRO. Le cours GraphQL APIs with Spring Boot comprend 4 leçons au total.

Qu'est-ce que j'apprendrai dans « Configurer et gérer la passerelle » ?

Configurez et déployez une passerelle Apollo pour composer vos sous-graphes fédérés et les exposer sous la forme d'un graphe unifié unique. Tu pratiques GraphQL APIs with Spring Boot avec du code pratique que tu exécutes directement dans le navigateur, et un tuteur IA 24/7 répond à tes questions au fur et à mesure que tu avances dans la leçon.

Dois-je avoir de l'expérience pour commencer GraphQL APIs with Spring Boot ?

Aucune expérience préalable n'est requise. GraphQL APIs with Spring Boot sur CoddyKit est structuré pour les débutants jusqu'aux apprenants avancés, donc tu peux commencer ici ou depuis le début et avancer à ton rythme. Ceci est la leçon 3 sur 4.

Combien de temps prend la leçon « Configurer et gérer la passerelle » ?

La plupart des leçons CoddyKit prennent environ 5–10 minutes. Chacune est courte et interactive, tu progresses régulièrement et tu repiques exactement où tu t'es arrêté sur le web et l'app.

Peux-tu écrire et exécuter du code dans cette leçon GraphQL APIs with Spring Boot ?

Oui. Chaque leçon GraphQL APIs with Spring Boot inclut un éditeur de code intégré, tu écris et exécutes du vrai code directement dans ton navigateur et tu reçois des retours IA instantanés — aucune configuration locale requise.

Toutes les leçons de ce cours

  1. Introduction à la fédération Apollo
  2. Construire des sous-graphes fédérés
  3. Configurer et gérer la passerelle
  4. Références d’entités et directive @key
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