From c954e09667fdd0869b3a6888f64d77a91e9e81b2 Mon Sep 17 00:00:00 2001
From: Thomas Flament <thomas.flament@scality.com>
Date: Tue, 3 Mar 2026 18:01:00 +0100
Subject: [PATCH] S3UTILS-224: pre-seed zero-value metrics for empty buckets
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When all buckets are empty (0 objects), count-items produces no
bucket metric documents in __infostore. This is because
getObjectMDStats() only populates dataMetrics.bucket entries when
the MongoDB cursor yields objects — with 0 objects, the cursor
yields nothing, _processEntryData() is never called, and
dataMetrics.bucket remains {}. The flatMap in
updateStorageConsumptionMetrics() then produces zero documents,
and the atomic collection rename leaves __infostore with only
the countitems marker.

Downstream, Scuba's deep health check queries __infostore for any
metric document and crashes when it finds none, causing CloudServer
to mark the quota service as unavailable (ARTESCA-17063).

Pre-seed dataMetrics.bucket with zero-value entries for every known
bucket in CountManager.addWork(), using consolidateDataMetrics() to
create the canonical zero structure. When workers return results for
non-empty buckets, consolidation adds on top of these zeros. For
empty buckets, the zero entries survive through to
updateStorageConsumptionMetrics, ensuring every bucket gets a
document in __infostore.

Issue: S3UTILS-224
---
 CountItems/CountManager.js            |  4 +++
 tests/unit/CountItems/CountManager.js | 45 +++++++++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/CountItems/CountManager.js b/CountItems/CountManager.js
index 34f0fc3e..e5646f22 100644
--- a/CountItems/CountManager.js
+++ b/CountItems/CountManager.js
@@ -180,6 +180,10 @@ class CountManager {
         this.store.bucketList = this.store.bucketList.concat(transformedInfos);
         bucketInfos.forEach(bucketInfo => {
             this.q.push(bucketInfo);
+            const key = `${bucketInfo.getName()}_${new Date(bucketInfo.getCreationDate()).getTime()}`;
+            if (!this.dataMetrics.bucket[key]) {
+                this.dataMetrics.bucket[key] = consolidateDataMetrics(null, null);
+            }
         });
         this.log.debug('added work', {
             workInQueue: this.q.length(),
diff --git a/tests/unit/CountItems/CountManager.js b/tests/unit/CountItems/CountManager.js
index 53fbed41..a8e8f149 100644
--- a/tests/unit/CountItems/CountManager.js
+++ b/tests/unit/CountItems/CountManager.js
@@ -974,6 +974,51 @@ describe('CountItems::CountManager', () => {
         expect(m.q.paused).toBeTruthy();
     });
 
+    test('should pre-seed dataMetrics.bucket with zero-value entries for all buckets', () => {
+        const workers = createWorkers(1);
+        const m = new CountManager({
+            log: new DummyLogger(),
+            workers,
+            maxConcurrent: 1,
+        });
+        const bucketInfos = [
+            BucketInfo.deSerialize(stringifiedBucketMD),
+        ];
+        const bucketList = {
+            bucketCount: bucketInfos.length,
+            bucketInfos,
+        };
+        m.addWork(bucketList);
+        const expectedKey = `${bucketInfos[0].getName()}_${new Date(bucketInfos[0].getCreationDate()).getTime()}`;
+        expect(m.dataMetrics.bucket[expectedKey]).toBeDefined();
+        expect(m.dataMetrics.bucket[expectedKey].usedCapacity.current).toEqual(0n);
+        expect(m.dataMetrics.bucket[expectedKey].usedCapacity.nonCurrent).toEqual(0n);
+        expect(m.dataMetrics.bucket[expectedKey].objectCount.current).toEqual(0n);
+        expect(m.dataMetrics.bucket[expectedKey].objectCount.nonCurrent).toEqual(0n);
+        expect(m.dataMetrics.bucket[expectedKey].objectCount.deleteMarker).toEqual(0n);
+    });
+
+    test('should not overwrite existing dataMetrics.bucket entries on addWork', () => {
+        const workers = createWorkers(1);
+        const m = new CountManager({
+            log: new DummyLogger(),
+            workers,
+            maxConcurrent: 1,
+        });
+        const bucketInfo = BucketInfo.deSerialize(stringifiedBucketMD);
+        const key = `${bucketInfo.getName()}_${new Date(bucketInfo.getCreationDate()).getTime()}`;
+        m.dataMetrics.bucket[key] = {
+            usedCapacity: { current: 100n, nonCurrent: 50n },
+            objectCount: { current: 10n, nonCurrent: 5n, deleteMarker: 0n },
+        };
+        m.addWork({
+            bucketCount: 1,
+            bucketInfos: [bucketInfo],
+        });
+        expect(m.dataMetrics.bucket[key].usedCapacity.current).toEqual(100n);
+        expect(m.dataMetrics.bucket[key].objectCount.current).toEqual(10n);
+    });
+
     test('should only allow queue to be started once', done => {
         const workers = createWorkers(1);
         const m = new CountManager({