From 5738ead5fb4c46ef78614abffa0a13564626d0b2 Mon Sep 17 00:00:00 2001
From: Alexandru Gologan <alexandru.gologan@gmail.com>
Date: Sat, 28 Oct 2023 10:19:09 +0300
Subject: [PATCH] Cache supegraph in memory

---
 src/helpers/middleware.ts | 43 +++++++++++++++++++++++++++++++++++++++
 src/logger.ts             |  6 +++++-
 src/router/index.ts       | 18 ++++++++++++----
 3 files changed, 62 insertions(+), 5 deletions(-)

diff --git a/src/helpers/middleware.ts b/src/helpers/middleware.ts
index 38627940..6e30ac57 100644
--- a/src/helpers/middleware.ts
+++ b/src/helpers/middleware.ts
@@ -1,5 +1,48 @@
+import { logger } from '../logger';
+
 export function asyncWrap(fn) {
 	return (req, res, next) => {
 		Promise.resolve(fn(req, res, next)).catch(next);
 	};
 }
+
+export function cache(key) {
+	return (req, res, next) => {
+		const locals = req.app.locals;
+		if (!locals.cache) {
+			locals.cache = {};
+		}
+
+		const cached = locals.cache[key];
+		if (cached) {
+			logger.info(`Sending cached: ${key}`);
+			res.set(cached.headers);
+			return res.send(cached.body);
+		} else {
+			res.__send = res.send;
+			res.send = (body) => {
+				locals.cache[key] = {
+					body,
+					headers: res.getHeaders(),
+				};
+				res.__send(body);
+				logger.info(`Cached: ${key}`);
+			};
+		}
+		next();
+	};
+}
+
+export function invalidate(key) {
+	return (req, res, next) => {
+		const locals = req.app.locals;
+		if (!locals.cache) {
+			return next();
+		}
+
+		logger.info(`Invalidating: ${key}`);
+		delete locals.cache[key];
+
+		return next();
+	};
+}
diff --git a/src/logger.ts b/src/logger.ts
index 26f1a3bd..7de299c2 100644
--- a/src/logger.ts
+++ b/src/logger.ts
@@ -31,10 +31,14 @@ export const logger = createLogger({
 
 function buildPrettyFormat() {
 	return format.combine(
+		format.errors({ stack: true }),
 		format.colorize(),
 		format.timestamp(),
 		format.printf(({ timestamp, level, message, stack }) => {
-			return `[${timestamp}] ${level}: ${message} ${stack}`;
+			if (stack) {
+				return `[${timestamp}] ${level}: ${message} ${stack}`;
+			}
+			return `[${timestamp}] ${level}: ${message}`;
 		})
 	);
 }
diff --git a/src/router/index.ts b/src/router/index.ts
index 96e3d4fc..cd7c2ddb 100644
--- a/src/router/index.ts
+++ b/src/router/index.ts
@@ -2,7 +2,7 @@ import express from 'express';
 // eslint-disable-next-line new-cap
 const router = express.Router();
 import { json } from 'body-parser';
-import { asyncWrap } from '../helpers/middleware';
+import { asyncWrap, cache, invalidate } from '../helpers/middleware';
 
 import parseMiddleware from '../middleware/parse-request';
 import { indexHtml, assetRouter } from './assets';
@@ -46,18 +46,28 @@ router.get(
 router.get('/', indexHtml());
 assetRouter(router);
 
+const supergraphKey = 'supergraph';
+
 router.get('/persisted_query', asyncWrap(persistedQuery.get));
 router.post('/persisted_query', asyncWrap(persistedQuery.create));
 
 router.get('/schema/latest', asyncWrap(schema.composeLatest));
-router.get('/schema/supergraph', asyncWrap(schema.supergraph));
+router.get(
+	'/schema/supergraph',
+	cache(supergraphKey),
+	asyncWrap(schema.supergraph)
+);
 router.post('/schema/compose', asyncWrap(schema.compose));
-router.post('/schema/push', asyncWrap(schema.push));
+router.post('/schema/push', invalidate(supergraphKey), asyncWrap(schema.push));
 router.post('/schema/diff', asyncWrap(schema.diff));
 
 router.delete('/schema/:schemaId', asyncWrap(schema.remove));
 router.post('/schema/validate', asyncWrap(schema.validate));
 
-router.delete('/service/:name', asyncWrap(service.remove));
+router.delete(
+	'/service/:name',
+	invalidate(supergraphKey),
+	asyncWrap(service.remove)
+);
 
 export default router;