From 368b69b4c49bacba33c48a7ecea45506a3917eb7 Mon Sep 17 00:00:00 2001
From: Aliaksandr Valialkin <valyala@gmail.com>
Date: Thu, 5 Nov 2020 01:36:13 +0200
Subject: [PATCH] app/vmselect: properly handle errors in GetLabelsOnTimeRange
 and GetLabelValuesOnTimeRange

---
 app/vmselect/prometheus/prometheus.go | 22 ++++++++++++++--------
 lib/storage/index_db_test.go          |  2 +-
 lib/storage/merge.go                  |  2 +-
 3 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/app/vmselect/prometheus/prometheus.go b/app/vmselect/prometheus/prometheus.go
index f43517e61e..cdee46c671 100644
--- a/app/vmselect/prometheus/prometheus.go
+++ b/app/vmselect/prometheus/prometheus.go
@@ -512,9 +512,12 @@ func LabelValuesHandler(startTime time.Time, labelName string, w http.ResponseWr
 	}
 	var labelValues []string
 	if len(r.Form["match[]"]) == 0 {
-		var err error
 		if len(r.Form["start"]) == 0 && len(r.Form["end"]) == 0 {
+			var err error
 			labelValues, err = netstorage.GetLabelValues(labelName, deadline)
+			if err != nil {
+				return fmt.Errorf(`cannot obtain label values for %q: %w`, labelName, err)
+			}
 		} else {
 			ct := startTime.UnixNano() / 1e6
 			end, err := searchutils.GetTime(r, "end", ct)
@@ -530,9 +533,9 @@ func LabelValuesHandler(startTime time.Time, labelName string, w http.ResponseWr
 				MaxTimestamp: end,
 			}
 			labelValues, err = netstorage.GetLabelValuesOnTimeRange(labelName, tr, deadline)
-		}
-		if err != nil {
-			return fmt.Errorf(`cannot obtain label values for %q: %w`, labelName, err)
+			if err != nil {
+				return fmt.Errorf(`cannot obtain label values on time range for %q: %w`, labelName, err)
+			}
 		}
 	} else {
 		// Extended functionality that allows filtering by label filters and time range
@@ -710,9 +713,12 @@ func LabelsHandler(startTime time.Time, w http.ResponseWriter, r *http.Request)
 	}
 	var labels []string
 	if len(r.Form["match[]"]) == 0 {
-		var err error
 		if len(r.Form["start"]) == 0 && len(r.Form["end"]) == 0 {
+			var err error
 			labels, err = netstorage.GetLabels(deadline)
+			if err != nil {
+				return fmt.Errorf("cannot obtain labels: %w", err)
+			}
 		} else {
 			ct := startTime.UnixNano() / 1e6
 			end, err := searchutils.GetTime(r, "end", ct)
@@ -728,9 +734,9 @@ func LabelsHandler(startTime time.Time, w http.ResponseWriter, r *http.Request)
 				MaxTimestamp: end,
 			}
 			labels, err = netstorage.GetLabelsOnTimeRange(tr, deadline)
-		}
-		if err != nil {
-			return fmt.Errorf("cannot obtain labels: %w", err)
+			if err != nil {
+				return fmt.Errorf("cannot obtain labels on time range: %w", err)
+			}
 		}
 	} else {
 		// Extended functionality that allows filtering by label filters and time range
diff --git a/lib/storage/index_db_test.go b/lib/storage/index_db_test.go
index 3d12eb7da0..eecf1b64f5 100644
--- a/lib/storage/index_db_test.go
+++ b/lib/storage/index_db_test.go
@@ -1577,7 +1577,7 @@ func TestSearchTSIDWithTimeRange(t *testing.T) {
 
 	// Check SearchTagValuesOnTimeRange.
 	tvs, err := db.SearchTagValuesOnTimeRange([]byte(""), TimeRange{
-		MinTimestamp: int64(now)-msecPerDay,
+		MinTimestamp: int64(now) - msecPerDay,
 		MaxTimestamp: int64(now),
 	}, 10000, noDeadline)
 	if err != nil {
diff --git a/lib/storage/merge.go b/lib/storage/merge.go
index 433b2fc4e6..073361064e 100644
--- a/lib/storage/merge.go
+++ b/lib/storage/merge.go
@@ -182,7 +182,7 @@ func skipSamplesOutsideRetention(b *Block, retentionDeadline int64, rowsDeleted
 	for nextIdx < len(timestamps) && timestamps[nextIdx] < retentionDeadline {
 		nextIdx++
 	}
-	atomic.AddUint64(rowsDeleted, uint64(nextIdx - b.nextIdx))
+	atomic.AddUint64(rowsDeleted, uint64(nextIdx-b.nextIdx))
 	b.nextIdx = nextIdx
 }