From f9a0055e78a582e26e88458bdc8ba1f5eaa6c798 Mon Sep 17 00:00:00 2001
From: Alex Gleason <alex@alexgleason.me>
Date: Fri, 17 May 2024 19:00:56 -0500
Subject: [PATCH] stats: add a Semaphore when refreshing author stats

---
 deno.json    |  1 +
 src/stats.ts | 15 +++++++++++----
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/deno.json b/deno.json
index e8719a4..84d5351 100644
--- a/deno.json
+++ b/deno.json
@@ -20,6 +20,7 @@
     "@bradenmacdonald/s3-lite-client": "jsr:@bradenmacdonald/s3-lite-client@^0.7.4",
     "@db/sqlite": "jsr:@db/sqlite@^0.11.1",
     "@isaacs/ttlcache": "npm:@isaacs/ttlcache@^1.4.1",
+    "@lambdalisue/async": "jsr:@lambdalisue/async@^2.1.1",
     "@noble/secp256k1": "npm:@noble/secp256k1@^2.0.0",
     "@nostrify/nostrify": "jsr:@nostrify/nostrify@^0.20.0",
     "@sentry/deno": "https://deno.land/x/sentry@7.112.2/index.mjs",
diff --git a/src/stats.ts b/src/stats.ts
index 9f0d257..7112496 100644
--- a/src/stats.ts
+++ b/src/stats.ts
@@ -1,3 +1,4 @@
+import { Semaphore } from '@lambdalisue/async';
 import { NKinds, NostrEvent, NStore } from '@nostrify/nostrify';
 import Debug from '@soapbox/stickynotes/debug';
 import { InsertQueryBuilder, Kysely } from 'kysely';
@@ -253,13 +254,19 @@ async function countAuthorStats(
   };
 }
 
-const lru = new LRUCache<string, true>({ max: 1000 });
+const authorStatsSemaphore = new Semaphore(10);
+const refreshedAuthors = new LRUCache<string, true>({ max: 1000 });
 
 /** Calls `refreshAuthorStats` only once per author. */
 function refreshAuthorStatsDebounced(pubkey: string): void {
-  if (lru.get(pubkey)) return;
-  lru.set(pubkey, true);
-  refreshAuthorStats(pubkey).catch(() => {});
+  if (refreshedAuthors.get(pubkey)) {
+    return;
+  }
+
+  refreshedAuthors.set(pubkey, true);
+
+  authorStatsSemaphore
+    .lock(() => refreshAuthorStats(pubkey).catch(() => {}));
 }
 
 export { refreshAuthorStats, refreshAuthorStatsDebounced, updateStats };