Query: fix exemplarsServer data race (#4777)

Signed-off-by: Jimmiehan <hanjinming@outlook.com>
thanos-io · Oct 28, 2021 · 3a5450f · 3a5450f
1 parent 5eacdf0
commit 3a5450f
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Showing 2 changed files with 8 additions and 3 deletions.
diff --git a/pkg/exemplars/exemplars.go b/pkg/exemplars/exemplars.go
@@ -6,6 +6,7 @@ package exemplars
 import (
 	"context"
 	"sort"
+	"sync"
 
 	"github.com/pkg/errors"
 	"github.com/prometheus/prometheus/storage"
@@ -37,10 +38,13 @@ type exemplarsServer struct {
 
 	warnings []error
 	data     []*exemplarspb.ExemplarData
+	mu       sync.Mutex
 }
 
 func (srv *exemplarsServer) Send(res *exemplarspb.ExemplarsResponse) error {
 	if res.GetWarning() != "" {
+		srv.mu.Lock()
+		defer srv.mu.Unlock()
 		srv.warnings = append(srv.warnings, errors.New(res.GetWarning()))
 		return nil
 	}
@@ -49,6 +53,8 @@ func (srv *exemplarsServer) Send(res *exemplarspb.ExemplarsResponse) error {
 		return errors.New("empty exemplars data")
 	}
 
+	srv.mu.Lock()
+	defer srv.mu.Unlock()
 	srv.data = append(srv.data, res.GetData())
 	return nil
 }

diff --git a/pkg/exemplars/proxy_test.go b/pkg/exemplars/proxy_test.go
@@ -292,8 +292,7 @@ func TestProxy(t *testing.T) {
 	}
 }
 
-// TestProxyDataRace find the concurrent data race bug.
-// go test -race -run TestProxyDataRace -v
+// TestProxyDataRace find the concurrent data race bug ( go test -race -run TestProxyDataRace -v ).
 func TestProxyDataRace(t *testing.T) {
 	logger := log.NewLogfmtLogger(os.Stderr)
 	p := NewProxy(logger, func() []*exemplarspb.ExemplarStore {
@@ -318,4 +317,4 @@ func TestProxyDataRace(t *testing.T) {
 		ctx: context.Background(),
 	}
 	_ = p.Exemplars(req, s)
-}
+}