Vercel

A Swift runtime and SDK for Vercel Serverless Functions.

How does this work?

There's two important pieces to this package that make everything work:

An SDK that wraps the AWSLambdaRuntime and provides access to Vercel specific API like EdgeConfig
A Swift Package Plugin which builds your code and produces a directory structure compliant with Vercel's Build Output API

Usage

Request Handler

import Vercel

@main
struct App: RequestHandler {

    func onRequest(_ req: Request, context: Context) async throws -> Response {
        let greeting = EdgeConfig.default.get("greeting").string!
        return .status(.ok).send("Hello, \(greeting)")
    }
}

Express Handler

import Vercel

@main
struct App: ExpressHandler {

    static let router = Router()
        .get("/") { req, res in
            res.status(.ok).send("Hello, Swift")
        }
        .get("/api/me") { req, res in
            try res.cors().send(["name": "Andrew"])
        }
        .get("/hello/:name") { req, res in
            res.send("Hello, " + req.pathParams["name"]!)
        }
}

Data Fetching

You can use any popular library to fetch data such as Alamofire or async-http-client but we also provide a convenient fetch() method directly in this package:

let obj = try await fetch("https://httpbin.org/json").json()

Edge Config

This package provides full access to Vercel's Edge Config API. You can access the default edge config store or any additinoal store assigned to your project:

// Default edge config
let str = EdgeConfig.default.get("some-string-key").string

// Edge config assigned to an environment variable
let num = EdgeConfig("EDGE_CONFIG_2").get("some-int-key").int

Static Files

You can add a top level public folder that will be deployed statically to Vercel's CDN.

Deploy

Locally

To deploy your project locally you need to install Docker and the Vercel CLI. Once installed you can you must link your Vercel project:

vercel link

After linking your project you can deploy it via Swift package manager:

swift package --disable-sandbox vercel

Deploy Options

swift package --disable-sandbox vercel --product MyApp --memory 1024 --duration 60 --regions iad1,sfo1

--product - The product you want to deploy. Default: first target in Package.swift with the Vercel dependency
--memory - The amount of memory in megabytes to allocate to your function. Default 512mb
--duration - The maximum duration in seconds that your function will run. Default: 10s
--regions - Comma separated list of regions to deploy your function to. Default: iad1

GitHub Actions

Use the following GitHub actions workflow to continuiously deploy your project to Vercel:

name: Vercel

on:
  push:
    branches:
      - main

env:
  VERCEL_ORG_ID: ${{ secrets.VERCEL_ORG_ID }}
  VERCEL_PROJECT_ID: ${{ secrets.VERCEL_PROJECT_ID }}
  VERCEL_TOKEN: ${{ secrets.VERCEL_TOKEN }}

jobs:
  deploy:
    runs-on: ubuntu-latest
    container: swift:5.7-amazonlinux2

    steps:
      - uses: actions/checkout@v3

      - uses: actions/cache@v3
        with:
          path: .build
          key: ${{ runner.os }}-spm-${{ hashFiles('Package.resolved') }}
          restore-keys: |
            ${{ runner.os }}-spm-

      - uses: actions/setup-node@v3
        with:
          node-version: 16

      - name: Install
        run: npm install -g vercel@latest

      - name: Deploy
        run: swift package --disable-sandbox vercel --prod

TooTallNate / Vercel