Implement checkVersion middleware

Checks version on each request, terminating the application if version 
mdoes not match

src/app.ts

@@ -8,6 +8,7 @@ import session from "express-session";
 import pg from "pg";
 import pgSessionStore from "connect-pg-simple";
 import fetch, { Response as FetchResponse } from "node-fetch";
+import { log, LogLevel } from "./logging"
 import cron from "./cron";
 import db from "./db";
 import errorHandler from "./errors";
@@ -26,6 +27,7 @@ async function validateApiToken(session: Express.Session) {
 }
 
 const app = express();
+app.use(version.checkVersionMiddleware);
 app.use(express.static('public'));
 app.use(express.urlencoded({extended: false}));
 app.use(session({
@@ -340,4 +342,8 @@ version.checkVersion().then(_ => app.listen(config.port, () => {
 	cron.run();
 	setInterval(cron.run,config.cronInterval);
   console.log(`Listening on port ${config.port}`);
-}));
+}))
+.catch((e) => {
+	log(LogLevel.ERROR,e)
+	process.exit(1);
+});

src/version.ts

@@ -1,4 +1,6 @@
 import * as queries from "./queries";
+import { log, LogLevel } from "./logging"
+import express from "express";
 import pg from "pg";
 import db from "./db";
 
@@ -10,6 +12,19 @@ export function getVersion() {
 	return `${versionMajor}.${versionMinor}.${versionPatch}`
 }
 
+export async function checkVersionMiddleware(_req: express.Request, _res: express.Response, next: express.NextFunction) {
+	try {
+		await checkVersion();
+	} catch (e) {
+		log(LogLevel.ERROR,e)
+		// Terminate the nodejs process with error. If restarted, the app will
+		// never start listening for new requests so this will not result in a
+		// restart loop.
+		process.exit(1);
+	}
+	next();
+}
+
 export async function checkVersion() {
 	var dbver = await db.query(queries.getDbVersion).then((result: pg.QueryResult) => result.rows[0]['get_version']);
 	if (dbver != `${versionMajor}.${versionMinor}`) {