improve /version api route to only call git once on startup

src/index.ts

@@ -67,6 +67,10 @@ Sentry.init({
 	environment: config.global.debug ? 'development' : 'production'
 });
 
+app.locals.versionRev = require('child_process')
+.execSync('git rev-parse --short HEAD')
+.toString().trim()
+
 // RequestHandler creates a separate execution context using domains, so that every
 // transaction/span/breadcrumb is attached to its own Hub instance
 app.use(Sentry.Handlers.requestHandler());

src/routes/api/v1/version.ts

@@ -1,9 +1,7 @@
 import express, { Request, Response } from 'express';
 
 function get(req: Request, res: Response) {
-	const revision = require('child_process')
-		.execSync('git rev-parse --short HEAD')
-		.toString().trim()
+	const revision = req.app.locals.versionRev;
 	res.status(200).send({ version: '1.0.0', commit: revision });
 };