Ensure that a nil Matrix is not encoded as null but empty list.

grafana · Nov 9, 2023 · 54976d2 · 54976d2
1 parent 7ab40e0
commit 54976d2
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Showing 2 changed files with 28 additions and 0 deletions.
diff --git a/pkg/querier/queryrange/codec_test.go b/pkg/querier/queryrange/codec_test.go
@@ -911,6 +911,28 @@ func Test_codec_EncodeResponse(t *testing.T) {
 				},
 			}, seriesVolumeString, false, nil,
 		},
+		{
+			"empty matrix", "/loki/api/v1/query_range",
+			&LokiPromResponse{
+				Response: &queryrangebase.PrometheusResponse{
+					Status: loghttp.QueryStatusSuccess,
+					Data: queryrangebase.PrometheusData{
+						ResultType: loghttp.ResultTypeMatrix,
+						Result:     nil,
+					},
+				},
+				Statistics: statsResult,
+			},
+			`{
+				"data": {
+				  ` + statsResultString + `
+	              "resultType": "matrix",
+	              "result": []
+	            },
+	            "status": "success"
+		     }`,
+			false, nil,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {

diff --git a/pkg/querier/queryrange/prometheus.go b/pkg/querier/queryrange/prometheus.go
@@ -125,6 +125,12 @@ func (p *LokiPromResponse) marshalVector() ([]byte, error) {
 }
 
 func (p *LokiPromResponse) marshalMatrix() ([]byte, error) {
+
+	// Make sure nil is not encoded as null.
+	if p.Response.Data.Result == nil {
+		p.Response.Data.Result = []queryrangebase.SampleStream{}
+	}
+
 	// embed response and add statistics.
 	return jsonStd.Marshal(struct {
 		Status string `json:"status"`