fix: warm homepage metrics cache on first read

.github/workflows/deploy-homepage-metrics.yml

@@ -106,3 +106,9 @@ jobs:
         env:
           CLOUDFLARE_ACCOUNT_ID: ${{ secrets.CLOUDFLARE_ACCOUNT_ID }}
           CLOUDFLARE_API_TOKEN: ${{ secrets.CLOUDFLARE_API_TOKEN }}
+
+      - name: Warm homepage metrics cache
+        run: >-
+          curl --fail --silent --show-error --retry 5 --retry-all-errors
+          --retry-delay 2 --max-time 45 --output /dev/null
+          https://rustfs.com/api/homepage-metrics

workers/homepage-metrics/src/index.test.ts

@@ -1,7 +1,7 @@
 import assert from "node:assert/strict";
 import test from "node:test";
 import type { HomepageMetrics } from "../../../lib/homepage-metrics.ts";
-import { mergeHomepageMetrics } from "./index.ts";
+import { loadOrRefreshHomepageMetrics, mergeHomepageMetrics } from "./index.ts";
 
 const current: HomepageMetrics = {
   schemaVersion: 1,
@@ -67,3 +67,43 @@ test("updates Docker without overwriting failed GitHub values", () => {
   assert.equal(result.githubRefreshed, false);
   assert.equal(result.dockerRefreshed, true);
 });
+
+test("returns valid cached metrics without refreshing", async () => {
+  let refreshCalls = 0;
+  const result = await loadOrRefreshHomepageMetrics(
+    async () => current,
+    async () => {
+      refreshCalls += 1;
+      return {
+        metrics: { ...current, schemaVersion: 1 },
+        githubRefreshed: true,
+        dockerRefreshed: true,
+      };
+    },
+  );
+
+  assert.deepEqual(result, current);
+  assert.equal(refreshCalls, 0);
+});
+
+test("refreshes metrics when the cache is empty", async () => {
+  let refreshCalls = 0;
+  const refreshed = {
+    ...current,
+    github: { ...current.github, stars: 120, updatedAt: refreshedAt },
+  } satisfies HomepageMetrics;
+  const result = await loadOrRefreshHomepageMetrics(
+    async () => null,
+    async () => {
+      refreshCalls += 1;
+      return {
+        metrics: refreshed,
+        githubRefreshed: true,
+        dockerRefreshed: false,
+      };
+    },
+  );
+
+  assert.deepEqual(result, refreshed);
+  assert.equal(refreshCalls, 1);
+});

workers/homepage-metrics/src/index.ts

@@ -156,11 +156,23 @@ export function mergeHomepageMetrics(
 }
 
 async function readCachedMetrics(env: Env): Promise<HomepageMetrics> {
-  const cached = await env.HOMEPAGE_METRICS.get<unknown>(CACHE_KEY, {
+  const cached = await readStoredMetrics(env);
+  return isHomepageMetrics(cached) ? cached : fallbackMetrics;
+}
+
+async function readStoredMetrics(env: Env): Promise<unknown> {
+  return env.HOMEPAGE_METRICS.get<unknown>(CACHE_KEY, {
     type: "json",
     cacheTtl: 300,
   });
-  return isHomepageMetrics(cached) ? cached : fallbackMetrics;
+}
+
+export async function loadOrRefreshHomepageMetrics(
+  read: () => Promise<unknown>,
+  refresh: () => Promise<RefreshResult>,
+): Promise<HomepageMetrics> {
+  const cached = await read();
+  return isHomepageMetrics(cached) ? cached : (await refresh()).metrics;
 }
 
 export async function refreshHomepageMetrics(env: Env): Promise<RefreshResult> {
@@ -212,7 +224,11 @@ export default {
     }
 
     try {
-      return metricsResponse(await readCachedMetrics(env), request.method);
+      const metrics = await loadOrRefreshHomepageMetrics(
+        () => readStoredMetrics(env),
+        () => refreshHomepageMetrics(env),
+      );
+      return metricsResponse(metrics, request.method);
     } catch (error) {
       console.error(JSON.stringify({
         event: "homepage_metrics_read_failed",