feat: add health check endpoints for application status and GraphQL API readiness

Author: rbjornstad

src/routes/isAlive/+server.ts

@@ -0,0 +1,5 @@
+import { json } from '@sveltejs/kit';
+
+export function GET() {
+	return json({ status: 'ok' });
+}

src/routes/isReady/+server.ts

@@ -0,0 +1,36 @@
+import { json } from '@sveltejs/kit';
+
+const GRAPHQL_API_URL = process.env.VITE_GRAPHQL_ENDPOINT || 'http://localhost:3000/graphql';
+
+async function checkGraphQLAPI() {
+	try {
+		const response = await fetch(GRAPHQL_API_URL, {
+			method: 'POST'
+		});
+
+		if (response.status === 401) {
+			return true;
+		}
+
+		return response.ok;
+	} catch (error) {
+		console.log(error);
+		return false;
+	}
+}
+
+let isAppReady = false;
+
+async function ready() {
+	isAppReady = await checkGraphQLAPI();
+	setTimeout(ready, 1000);
+}
+
+ready();
+
+export async function GET() {
+	return json(
+		{ status: isAppReady ? 'ready' : 'waiting-for-api' },
+		{ status: isAppReady ? 200 : 503 }
+	);
+}