feat: zero-downtime using lightship

.kontinuous/values.yaml

@@ -17,7 +17,18 @@ app:
   host: "{{.Values.global.host}}"
   imagePackage: app
   containerPort: 3000
-  probesPath: "/healthz"
+  livenessProbe:
+    httpGet:
+      path: /live
+      port: 9000
+  startupProbe:
+    httpGet:
+      path: /live
+      port: 9000
+  readinessProbe:
+    httpGet:
+      path: /ready
+      port: 9000
   envFrom:
     - configMapRef:
         name: app

package.json

@@ -8,7 +8,7 @@
     "only-include-used-icons": "node node_modules/@codegouvfr/react-dsfr/bin/only-include-used-icons.js",
     "dev": "next dev",
     "build": "next build",
-    "start": "next start",
+    "start": "NEXT_MANUAL_SIG_HANDLE=true next start",
     "lint": "next lint",
     "prepare": "husky install",
     "lint-staged": "lint-staged",
@@ -38,6 +38,7 @@
     "@sentry/nextjs": "^7.60.1",
     "@socialgouv/matomo-next": "^1.6.1",
     "dayjs": "^1.11.9",
+    "lightship": "^9.0.2",
     "next": "13.4.12",
     "next-auth": "^4.22.3",
     "react": "18.2.0",

src/lib/graceful-shutdown.ts

@@ -0,0 +1,6 @@
+import { createLightship } from "lightship";
+
+export default async function handleGracefulShutdown() {
+  const lightship = await createLightship();
+  lightship.signalReady();
+}

src/pages/_document.tsx

@@ -1,4 +1,5 @@
 import { Html, Head, Main, NextScript, DocumentProps } from "next/document";
+import handleGracefulShutdown from "../lib/graceful-shutdown";
 import { dsfrDocumentApi, augmentDocumentWithEmotionCache } from "./_app";
 
 const { getColorSchemeHtmlAttributes, augmentDocumentForDsfr } =
@@ -26,3 +27,5 @@ export default function Document(props: DocumentProps) {
 augmentDocumentForDsfr(Document);
 
 augmentDocumentWithEmotionCache(Document);
+
+handleGracefulShutdown();