Improve application responsiveness and background processing

src/lib/server/reports/worker.ts

@@ -0,0 +1,33 @@
+import { parentPort } from 'node:worker_threads';
+import { db } from '../db/index.js';
+import { readMetrics } from '../fleet/metrics.js';
+import { getLeaderboard, getPlayerLeaderboardEntry } from '../fleet/leaderboard.js';
+import { getPlayerProfile } from '../fleet/player-profile.js';
+
+const cache = new Map<string, { value: unknown; bytes: number }>();
+let bytes = 0;
+parentPort!.on('message', ({ id, kind, input }) => {
+    const started = performance.now();
+    try {
+        const result = db().transaction(() => {
+            const topic = kind === 'metrics' ? 'metrics' : 'leaderboard';
+            const { revision } = db().prepare('SELECT revision FROM report_revisions WHERE topic=?').get(topic) as { revision: number };
+            const now = kind === 'metrics' ? input.now : Date.now();
+            const key = JSON.stringify([kind, revision, kind === 'metrics' ? Math.floor(now / 30_000) : 0, kind === 'metrics' ? input.query : input]);
+            const saved = cache.get(key);
+            if (saved) { cache.delete(key); cache.set(key, saved); return { value: saved.value, cached: true }; }
+            const value = kind === 'metrics' ? readMetrics(input.query, now)
+                : kind === 'leaderboard' ? getLeaderboard(input)
+                : { profile: getPlayerProfile(input.guid, input.offset, input.options), entry: getPlayerLeaderboardEntry(input.guid, input.options) };
+            const size = Buffer.byteLength(JSON.stringify(value));
+            if (size < 16 * 1024 * 1024) {
+                cache.set(key, { value, bytes: size }); bytes += size;
+                while (cache.size > 64 || bytes > 32 * 1024 * 1024) {
+                    const oldest = cache.keys().next().value!; bytes -= cache.get(oldest)!.bytes; cache.delete(oldest);
+                }
+            }
+            return { value, cached: false };
+        })();
+        parentPort!.postMessage({ id, ...result, elapsedMs: performance.now() - started });
+    } catch (cause) { parentPort!.postMessage({ id, error: cause instanceof Error ? cause.message : 'Report failed' }); }
+});