fastify rest-gateway

Description

This plugin for fastify 4.x allows you to expose REST APIs for your REST microservices starting from OpenApi contracts hosted into same microservice.

Routes to be exposed by the gateway must be tagged with the appropriate tags; by default "public-api" for public APIs, "private-api" for hidden APIs.

Note
To distribute open-api compliant contracts I recommend using the plugins for fastify @fastify/swagger and @fastify/swagger-ui

Warning
The plugin mandatorily requires the @fastify/reply-from plugin.

Install

npm i @fgiova/fastify-rest-gateway @fastify/reply-from

Usage

const app = require("fastify")();
const replyFrom = require("@fastify/reply-from");
const fastifyRestGateway = require("@fgiova/fastify-rest-gateway");
app.register(replyFrom);
app.register(fastifyRestGateway, {
    services: [
        {
            host: "https://petstore.test.com",
            openApiUrl: "/open-api/json",
            remoteBaseUrl: "/v1/test/public-api/",
            gwBaseUrl: "/v1/test/",
            
        }
    ]
});

The plugin can be used in conjunction with @fastify/swagger and @fastify/swagger-ui to produce an open-api contract of the routes exposed by the fastify-rest-gateway plugin.

npm i @fgiova/fastify-rest-gateway @fastify/reply-from @fastify/swagger @fastify/swagger-ui

const app = require("fastify")();
const fastifyRestGateway = require("@fgiova/fastify-rest-gateway");

await app.register(require("@fastify/reply-from"));
await app.register(fastifyRestGateway, {
    services: [
        {
            host: "https://petstore.test.com",
            openApiUrl: "/open-api/json",
            remoteBaseUrl: "/v1/test/public-api/",
            gwBaseUrl: "/v1/test/",
            
        }
    ]
});

await app.register(require("@fastify/swagger"), {
    mode: "dynamic",
    openapi: {
        ...
    }
});
await app.register(require("@fastify/swagge-ui"), {
    routePrefix: "/open-api",
});

The plugin can be used in conjunction with @fastify/rate-limit to restrict upstream accesses to the target microservice.

npm i @fgiova/fastify-rest-gateway @fastify/reply-from @fastify/rate-limit

const app = require("fastify")();
const fastifyRestGateway = require("@fgiova/fastify-rest-gateway");

await app.register(require("@fastify/reply-from"));
await app.register(require("@fastify/rate-limit"));
await app.register(fastifyRestGateway, {
    services: [
        {
            host: "https://petstore.test.com",
            openApiUrl: "/open-api/json",
            remoteBaseUrl: "/v1/test/public-api/",
            gwBaseUrl: "/v1/test/",
            hitLimit: {
                max: (req: FastifyRequest) => {
                    return 10;
                },
                keyGenerator: (req: FastifyRequest) => {
                    return `${req.ip}_test`;
                },
                timeWindow: 5000
            }
        }
    ]
});

await app.register(require("@fastify/swagger"), {
    mode: "dynamic",
    openapi: {
        ...
    }
});
await app.register(require("@fastify/swagge-ui"), {
    routePrefix: "/open-api",
});

This plugin can be used in conjunction with @fastify/restartable to reload the routes when open-api contracts of microservices are changed.

npm i @fgiova/fastify-rest-gateway @fastify/reply-from @fastify/rate-limit @fastify/restartable

const app = require("fastify")();
const fastifyRestGateway = require("@fgiova/fastify-rest-gateway");
const restartable = require("@fastify/restartable");


async function createApp (fastify, opts) {
    const app = fastify(opts)

    await app.register(require("@fastify/reply-from"));
    await app.register(require("@fastify/rate-limit"));
    await app.register(fastifyRestGateway, {
        services: [
            {
                host: "https://petstore.test.com",
                openApiUrl: "/open-api/json",
                remoteBaseUrl: "/v1/test/public-api/",
                gwBaseUrl: "/v1/test/",
                refreshTimeout: 60000, // each 60s reload open-api contract from host if are changed, restart fastify
                hitLimit: {
                    max: (req: FastifyRequest) => {
                        return 10;
                    },
                    keyGenerator: (req: FastifyRequest) => {
                        return `${req.ip}_test`;
                    },
                    timeWindow: 5000
                }
            }
        ]
    });

    await app.register(require("@fastify/swagger"), {
        mode: "dynamic",
        openapi: {
            ...
        }
    });
    await app.register(require("@fastify/swagge-ui"), {
        routePrefix: "/open-api",
    });

    return app;
}

const app = await restartable(createApp, { logger: true });
const host = await app.listen({ port: 3000 });

Options

Option	Type	Description
services	array	The list of services to expose.
services[].host	string	The host of the service.
services[].openApiUrl	string	The URL of the OpenApi JSON contract (default: /open-api/json).
services[].remoteBaseUrl	string	The baseUrl of the remote service.
services[].gwBaseUrl	string	The baseUrl where the service will be connected on the gateway
services[].tag	string	Optional tag for selecting target routes to expose (default: public-api)
services[].hiddenTag	string	Optional tag for selecting target routes to expose, but hidden on fastify-swagger (default: private-api)
services[].preHandler	FastifyHandler	Optional Fastify Pre Handler function to add to each service route
services[].hooks	object	Optional hooks for each route exposed
services[].hitLimit	object	Optional limit configuration for each route exposed
defaultLimit	object	Optional default limit configuration
gwTag	string	Optional default tag for select target routes to expose (default: public-api)
gwHiddenTag	string	Optional default tag for select target routes to expose, but hidden on fastify-swagger (default: X-HIDDEN)
ignoreHidden	boolean	Optional flag to ignore hidden routes
refreshTimeout	number	Optional interval in ms for watching open-api contracts and reload through Fastify restartable

Service Hooks

Option	Type	Description
onRequest	FastifyHandler	Optional Fastify OnRoute Handler function to add to each service route
onResponse	FastifyHandler	Optional Fastify OnResponse Handler function to add to each service route
onError	FastifyHandler	Optional Fastify OnError Handler function to add to each service route

Service limit options

Option	Type	Description
max	number \| function	Optional sync/async Function or number maximum hit per timeWindow (default: 1000)
keyGenerator	function	Optional sync/async function to generate a unique identifier for each incoming request (default: req.ip)
timeWindow	number	Optional the duration of the time window in ms (default: 60000)

License

Licensed under MIT.

Acknowledgements

This project is kindly sponsored by: isendu Srl www.isendu.com