feat: initial commit

Author: jacob-ebey

.github/workflows/ci.yaml

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+name: Node.js CI
+
+on: [push]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Use Node.js
+        uses: actions/setup-node@v1
+      - run: yarn
+      - run: yarn build
+      - run: yarn test
+        env:
+          CI: true

package.json

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+{
+  "name": "apollo-gateway",
+  "version": "1.0.0",
+  "main": "dist/cjs/index.js",
+  "module": "dist/esm/index.js",
+  "repository": "https://github.com/module-federation/apollo-gateway.git",
+  "license": "MIT",
+  "scripts": {
+    "build": "rollup -c",
+    "dev": "rollup -c -w",
+    "test": "jest --coverage"
+  },
+  "peerDependencies": {
+    "@apollo/federation": ">= 0.21.0",
+    "@apollo/gateway": ">= 0.23.0"
+  },
+  "devDependencies": {
+    "@apollo/federation": "^0.21.0",
+    "@apollo/gateway": "^0.23.0",
+    "apollo-graphql": "^0.6.0",
+    "apollo-server": "^2.21.0",
+    "apollo-server-testing": "^2.21.0",
+    "cz-conventional-changelog": "^3.3.0",
+    "graphql": "^15.5.0",
+    "jest": "^26.6.3",
+    "rollup": "^2.39.0"
+  },
+  "config": {
+    "commitizen": {
+      "path": "cz-conventional-changelog"
+    }
+  }
+}

rollup.config.js

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+import pkg from "./package.json";
+
+export default [
+  // CommonJS (for Node) and ES module (for bundlers) build.
+  // (We could have three entries in the configuration array
+  // instead of two, but it's quicker to generate multiple
+  // builds from a single configuration where possible, using
+  // an array for the `output` option, where we can specify
+  // `file` and `format` for each target)
+  {
+    input: "src/index.js",
+    external: ["@apollo/federation", "@apollo/gateway"],
+    output: [
+      { file: pkg.main, format: "cjs" },
+      { file: pkg.module, format: "es" },
+    ],
+  },
+];

src/federated-gateway.js

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+import { buildFederatedSchema } from "@apollo/federation";
+import {
+  ApolloGateway,
+  LocalGraphQLDataSource,
+  RemoteGraphQLDataSource,
+} from "@apollo/gateway";
+
+/**
+ * @typedef {import("graphql").DocumentNode} DocumentNode
+ * @typedef {import("apollo-graphql").GraphQLSchemaModule} GraphQLSchemaModule
+ * @typedef {import("apollo-graphql").GraphQLResolverMap} GraphQLResolverMap
+ * @typedef {import("@apollo/gateway").ServiceEndpointDefinition} ServiceEndpointDefinition
+ */
+
+/**
+ * @typedef {object} LegacySchemaModule
+ * @property {DocumentNode | DocumentNode[]} typeDefs
+ * @property {GraphQLResolverMap} resolvers
+ * {
+  typeDefs: DocumentNode | DocumentNode[];
+  resolvers?: GraphQLResolverMap<any>;
+ */
+
+/**
+ * @typedef {object} FederatedServiceDefinition
+ * @property {string} name
+ * @property {DocumentNode | (GraphQLSchemaModule | DocumentNode)[] | LegacySchemaModule} schema
+ */
+
+/**
+ * @typedef {import("@apollo/gateway").GatewayConfig} FederatedGatewayConfig
+ * @property {Array<FederatedServiceDefinition | ServiceEndpointDefinition>} serviceList
+ */
+
+const DUMMY_URL = "https://";
+
+export class FederatedGateway extends ApolloGateway {
+  /**
+   * @param {FederatedGatewayConfig} config
+   */
+  constructor(config) {
+    if (config.serviceList) {
+      config.serviceList = config.serviceList.map((service) => {
+        if (!service.url) {
+          return {
+            url: DUMMY_URL,
+            ...service,
+          };
+        }
+
+        return service;
+      });
+    }
+
+    super(config);
+  }
+
+  /**
+   * @param {import("@apollo/gateway").ServiceEndpointDefinition} serviceDef
+   */
+  createDataSource(serviceDef) {
+    if (serviceDef.url !== DUMMY_URL) {
+      return new RemoteGraphQLDataSource({ url: serviceDef.url });
+    }
+
+    if (!serviceDef.schema) {
+      throw new Error(`Invalid service definition for ${serviceDef.name}`);
+    }
+
+    return new LocalGraphQLDataSource(buildFederatedSchema(serviceDef.schema));
+  }
+}

src/federated-gateway.test.js

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+const { ApolloServer, gql } = require("apollo-server");
+const { createTestClient } = require("apollo-server-testing");
+
+const { FederatedGateway } = require("..");
+
+describe("federated-gateway", () => {
+  let aSchema;
+  let bSchema;
+  let gateway;
+  let server;
+  beforeEach(() => {
+    aSchema = {
+      typeDefs: gql`
+        type Query {
+          aPing: String
+        }
+      `,
+      resolvers: {
+        Query: {
+          aPing: () => "apong",
+        },
+      },
+    };
+
+    bSchema = {
+      typeDefs: gql`
+        type Query {
+          bPing: String
+        }
+      `,
+      resolvers: {
+        Query: {
+          bPing: () => "bpong",
+        },
+      },
+    };
+
+    gateway = new FederatedGateway({
+      serviceList: [
+        {
+          name: "a",
+          schema: aSchema,
+        },
+        {
+          name: "b",
+          schema: bSchema,
+        },
+      ],
+    });
+    server = new ApolloServer({
+      gateway,
+      subscriptions: false,
+      playground: false,
+      introspection: true,
+    });
+  });
+
+  it("executes federated service", async () => {
+    const { query } = createTestClient(server);
+
+    const response = await query({
+      query: `#graphql
+        {
+          aPing
+          bPing
+        }
+      `,
+    });
+
+    expect(response.data.aPing).toEqual("apong");
+    expect(response.data.bPing).toEqual("bpong");
+  });
+});

src/index.js

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+export { FederatedGateway } from "./federated-gateway";