startServer

#!/usr/bin/env node

const { spawn } = require("child_process");
const http = require("http");
const httpProxy = require("http-proxy");
const services = [
  { route: "/billing/*", path: "services/billing-api", port: 3001 },
  { route: "/notes/*", path: "services/notes-api", port: 3002 }
];

// Start `sls offline` for each service
services.forEach(service => {
  const child = spawn(
    "sls",
    ["offline", "start", "--stage", "dev", "--port", service.port],
    { cwd: service.path }
  );
  child.stdout.setEncoding("utf8");
  child.stdout.on("data", chunk => console.log(chunk));
  child.stderr.on("data", chunk => console.log(chunk));
  child.on("close", code => console.log(`child exited with code ${code}`));
});

// Start a proxy server on port 8080 forwarding based on url path
const proxy = httpProxy.createProxyServer({});
const server = http.createServer(function(req, res) {
  const service = services.find(per => urlMatchRoute(req.url, per.route));
  // Case 1: matching service FOUND => forward request to the service
  if (service) {
    proxy.web(req, res, { target: `http://localhost:${service.port}` });
  }
  // Case 2: matching service NOT found => display available routes
  else {
    res.writeHead(200, { "Content-Type": "text/plain" });
    res.write(
      `Url path "${req.url}" does not match routes defined in services\n\n`
    );
    res.write(`Available routes are:\n`);
    services.map(service => res.write(`- ${service.route}\n`));
    res.end();
  }
});
server.listen(8080);

// Check match route
// - ie. url is '/notes/123'
// - ie. route is '/notes/*'
function urlMatchRoute(url, route) {
  const urlParts = url.split("/");
  const routeParts = route.split("/");
  for (let i = 0, l = routeParts.length; i < l; i++) {
    const urlPart = urlParts[i];
    const routePart = routeParts[i];

    // Case 1: If either part is undefined => not match
    if (urlPart === undefined || routePart === undefined) {
      return false;
    }

    // Case 2: If route part is match all => match
    if (routePart === "*") {
      return true;
    }

    // Case 3: Exact match => keep checking
    if (urlPart === routePart) {
      continue;
    }

    // Case 4: route part is variable => keep checking
    if (routePart.startsWith("{")) {
      continue;
    }
  }

  return true;
}