Move locks to their own DB collection

lib/cache.ts

@@ -52,45 +52,3 @@ export async function pop(key: string): Promise<string> {
   const res = await collections.cache.findOneAndDelete({ _id: key });
   return res.value?.value;
 }
-
-export async function acquireLock(
-  lockName: string,
-  ttl: number,
-  timeout = 0,
-  token = Math.random().toString(36).slice(2)
-): Promise<string> {
-  try {
-    const now = Date.now();
-    const r = await collections.cache.findOneAndUpdate(
-      { _id: lockName, value: token },
-      {
-        $set: {
-          expire: new Date(now + ttl + CLOCK_SKEW_TOLERANCE),
-        },
-        $currentDate: { timestamp: true },
-      },
-      { upsert: true, returnDocument: "after" }
-    );
-    if (Math.abs(r.value.timestamp.getTime() - now) > CLOCK_SKEW_TOLERANCE)
-      throw new Error("Database clock skew too great");
-  } catch (err) {
-    if (err.code !== 11000) throw err;
-    if (!(timeout > 0)) return null;
-    const w = 50 + Math.random() * 50;
-    await new Promise((resolve) => setTimeout(resolve, w));
-    return acquireLock(lockName, ttl, timeout - w, token);
-  }
-
-  return token;
-}
-
-export async function releaseLock(
-  lockName: string,
-  token: string
-): Promise<void> {
-  const res = await collections.cache.deleteOne({
-    _id: lockName,
-    value: token,
-  });
-  if (res.deletedCount !== 1) throw new Error("Lock expired");
-}