From 98dba52131f58761d117fb3283f14e143f9511b7 Mon Sep 17 00:00:00 2001
From: dtfiedler <dylan@ar.io>
Date: Mon, 8 Jan 2024 18:06:58 -0700
Subject: [PATCH] fix(healthcheck): make healthcheck dependent on result of
 prefetching contracts

---
 src/router.ts |  3 ++-
 src/system.ts | 20 ++++++++++++++++++--
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/src/router.ts b/src/router.ts
index b4bdba8..3d6e034 100644
--- a/src/router.ts
+++ b/src/router.ts
@@ -30,6 +30,7 @@ import {
 } from './routes';
 import { swaggerDocs } from './routes/swagger';
 import { KoaContext } from './types';
+import { getPrefetchStatusCode } from './system';
 
 const router: Router = new Router();
 
@@ -37,7 +38,7 @@ const router: Router = new Router();
 router.get('/healthcheck', (ctx) => {
   ctx.body = {
     timestamp: new Date(),
-    status: 200,
+    status: getPrefetchStatusCode(),
     message: 'Hello world.',
   };
 });
diff --git a/src/system.ts b/src/system.ts
index 4827815..748082f 100644
--- a/src/system.ts
+++ b/src/system.ts
@@ -20,9 +20,15 @@ import { prefetchContractTxIds } from './config';
 import logger from './logger';
 import { warp } from './middleware';
 
-export const prefetchContracts = () => {
+let successfullyPrefetchedContracts = false;
+
+export const getPrefetchStatusCode = () => {
+  return successfullyPrefetchedContracts ? 200 : 503;
+};
+
+export const prefetchContracts = async () => {
   // don't wait - just fire and forget
-  Promise.all(
+  const prefetchResults = await Promise.all(
     prefetchContractTxIds.map((contractTxId: string) => {
       const startTimestamp = Date.now();
       logger.info('Pre-fetching contract state...', {
@@ -42,6 +48,7 @@ export const prefetchContracts = () => {
             endTimestamp,
             durationMs: endTimestamp - startTimestamp,
           });
+          return true;
         })
         .catch((error: unknown) => {
           const endTimestamp = Date.now();
@@ -53,7 +60,16 @@ export const prefetchContracts = () => {
             endTimestamp,
             durationMs: endTimestamp - startTimestamp,
           });
+          return false;
         });
     }),
   );
+  // update our healthcheck flag
+  successfullyPrefetchedContracts = prefetchResults.every(
+    (result) => result === true,
+  );
+  logger.info('Finished pre-fetching contracts', {
+    success: successfullyPrefetchedContracts,
+    contractTxIds: prefetchContractTxIds,
+  });
 };