*switch app to using fastify

src/modules/app.ts

@@ -1,60 +1,24 @@
-import express, { Express } from "express";
-import http from "http";
 import { AddressInfo } from "net";
 import log from "loglevel";
+import fastify from "fastify";
+import type { FastifyInstance } from "fastify";
 import { getKeyPair } from "../lib/seed.js";
 
-let app: Express;
-let router = express.Router();
-let server: http.Server;
-
-export function getRouter(): express.Router {
-  return router;
-}
-
-export function setRouter(newRouter: express.Router): void {
-  router = newRouter;
-}
+let app: FastifyInstance;
 
 export async function start() {
-  app = express();
-  server = http.createServer(app);
-  resetRouter();
-  await new Promise((resolve) => {
-    server.listen(80, "0.0.0.0", function () {
-      const address = server.address() as AddressInfo;
-      log.info(
-        "HTTP/App Server started on ",
-        `${address.address}:${address.port}`
-      );
-      resolve(null);
-    });
+  const keyPair = getKeyPair();
+  app = fastify({
+    logger: true,
   });
 
-  app.use(function (req, res, next) {
-    router(req, res, next);
-  });
-}
+  await app.listen({ port: 80, host: "0.0.0.0" });
 
-export function getApp(): Express {
-  return app;
-}
-export function getServer(): http.Server {
-  return server;
-}
-
-export function resetRouter(): void {
-  setRouter(newRouter());
-}
-
-function newRouter(): express.Router {
-  const router = express.Router();
-
-  let keyPair = getKeyPair();
-
-  router.get("/", (req, res) => {
+  app.get("/", (req, res) => {
     res.send(Buffer.from(keyPair.publicKey).toString("hex"));
   });
 
-  return router;
+  const address = app.server.address() as AddressInfo;
+
+  log.info("HTTP/App Server started on ", `${address.address}:${address.port}`);
 }