thanos-io/thanos · error

get object attributes of

Error message

get object attributes of %s

What it means

newChunkedIndexReader starts WriteBinary by fetching object-storage attributes (size) of the block's index file at <block-id>/index. This error wraps a failure of bkt.Attributes(ctx, indexFilepath): the object could not be stat'ed in the bucket (does not exist, no permission, or the object-store request failed).

Solutions

1. Verify the object <block-id>/index exists in the bucket (aws s3 ls / gsutil ls on the exact path).
2. Check the Thanos objstore config (bucket name, endpoint, prefix) for typos.
3. Verify the credentials/IAM role allow Head/Get on the bucket objects.
4. If the block was deleted by compaction/retention, remove it from the store-gateway's bucket index / meta.json state and re-sync.
5. Check network connectivity and object-store service status; retry on transient 5xx.

Example fix

// before: assume attributes always available
attrs, err := bkt.Attributes(ctx, indexFilepath)
// after: caller-side preflight
var exists bool
err := bkt.Iter(ctx, id.String()+"/", func(string) error { exists = true; return nil })
if err != nil || !exists {
    return nil, errors.New("block missing from bucket; re-sync or restore")
}

// Go: verify block object presence before WriteBinary
func blockIndexExists(ctx context.Context, bkt objstore.BucketReader, id ulid.ULID) error {
    exists, err := bkt.Exists(ctx, path.Join(id.String(), block.IndexFilename))
    if err != nil { return err }
    if !exists { return errors.Errorf("block %s index object missing from bucket", id) }
    return nil
}

// Go
_, err := indexheader.WriteBinary(ctx, bkt, id, dst)
if err != nil && strings.Contains(err.Error(), "get object attributes of") {
    var nf objstoreNotFoundError // or check errors.Is on provider SDK error
    if errors.As(err, &nf) {
        log.Warn("block index vanished from bucket; dropping local reference", "block", id)
        return ErrBlockMissing // handle upstream instead of crash-looping
    }
    return err
}

When it happens

Trigger: WriteBinary -> newChunkedIndexReader -> bkt.Attributes(ctx, "<ulid>/index") failing: the block's index object is missing from the bucket (block deleted/partially uploaded), the bucket credentials lack s3:GetObject/HeadObject, the bucket name is wrong, or the object store is unreachable (DNS, 403, 5xx).

Common situations: Store Gateway pointed at a bucket where the block was garbage-collected; misconfigured bucket/prefix in the Thanos objstore config; IAM policies stripped HeadObject permission; network outage or wrong endpoint in the objstore provider config.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

• index header PostingsOffset
• read postings range
• compaction
• sync before first pass of downsampling
• sync before second pass of downsampling

AI-assisted analysis of thanos-io/thanos@35b8b99117 (2026-09-07). Data as JSON: /api/errors/3dbf60a0ce52ab74. Report an issue: GitHub.

Appendix: source

Thrown at pkg/block/indexheader/binary_reader.go:185

		return nil, os.Rename(tmpFilename, filename)
	}

	return bw.Buffer(), nil
}

type chunkedIndexReader struct {
	ctx  context.Context
	path string
	size uint64
	bkt  objstore.BucketReader
	toc  *index.TOC
}

func newChunkedIndexReader(ctx context.Context, bkt objstore.BucketReader, id ulid.ULID) (*chunkedIndexReader, int, error) {
	indexFilepath := filepath.Join(id.String(), block.IndexFilename)
	attrs, err := bkt.Attributes(ctx, indexFilepath)
	if err != nil {
		return nil, 0, errors.Wrapf(err, "get object attributes of %s", indexFilepath)
	}

	rc, err := bkt.GetRange(ctx, indexFilepath, 0, index.HeaderLen)
	if err != nil {
		return nil, 0, errors.Wrapf(err, "get TOC from object storage of %s", indexFilepath)
	}

	b, err := io.ReadAll(rc)
	if err != nil {
		runutil.CloseWithErrCapture(&err, rc, "close reader")
		return nil, 0, errors.Wrapf(err, "get header from object storage of %s", indexFilepath)
	}

	if err := rc.Close(); err != nil {
		return nil, 0, errors.Wrap(err, "close reader")
	}

	if m := binary.BigEndian.Uint32(b[0:4]); m != index.MagicIndex {

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