tests and new -> original proto mapping util

Signed-off-by: Nicolás Pazos <npazosmendez@gmail.com>

storage/remote/codec.go

@@ -888,3 +888,37 @@ func DecodeReducedWriteRequest(r io.Reader) (*prompb.WriteRequestWithRefs, error
 
 	return &req, nil
 }
+
+func ReducedWriteRequestToWriteRequest(redReq *prompb.WriteRequestWithRefs) (*prompb.WriteRequest, error) {
+	req := &prompb.WriteRequest{
+		Timeseries: make([]prompb.TimeSeries, len(redReq.Timeseries)),
+		Metadata:   redReq.Metadata,
+	}
+
+	for i, rts := range redReq.Timeseries {
+
+		lbls := make([]prompb.Label, len(rts.Labels))
+		for j, l := range rts.Labels {
+			lbls[j].Name = redReq.StringSymbolTable[l.NameRef]
+			lbls[j].Value = redReq.StringSymbolTable[l.ValueRef]
+		}
+
+		exemplars := make([]prompb.Exemplar, len(rts.Exemplars))
+		for j, e := range rts.Exemplars {
+			exemplars[j].Value = e.Value
+			exemplars[j].Timestamp = e.Timestamp
+			exemplars[j].Labels = make([]prompb.Label, len(e.Labels))
+			for k, l := range e.Labels {
+				exemplars[j].Labels[k].Name = redReq.StringSymbolTable[l.NameRef]
+				exemplars[j].Labels[k].Value = redReq.StringSymbolTable[l.ValueRef]
+			}
+		}
+
+		req.Timeseries[i].Labels = lbls
+		req.Timeseries[i].Samples = rts.Samples
+		req.Timeseries[i].Exemplars = exemplars
+		req.Timeseries[i].Histograms = rts.Histograms
+
+	}
+	return req, nil
+}

storage/remote/codec_test.go

@@ -74,6 +74,59 @@ var writeRequestFixture = &prompb.WriteRequest{
 	},
 }
 
+// writeRequestWithRefsFixture represents the same request as writeRequestFixture, but using the reduced representation.
+var writeRequestWithRefsFixture = &prompb.WriteRequestWithRefs{
+	StringSymbolTable: map[uint64]string{
+		// Names
+		0:  "__name__",
+		2:  "b",
+		4:  "baz",
+		6:  "d",
+		8:  "foo",
+		10: "f",
+		12: "h",
+		// Values
+		1:  "test_metric1",
+		3:  "c",
+		5:  "qux",
+		7:  "e",
+		9:  "bar",
+		11: "g",
+		13: "i",
+	},
+
+	Timeseries: []prompb.ReducedTimeSeries{
+		{
+			Labels: []prompb.LabelRef{
+				{NameRef: 0, ValueRef: 1},
+				{NameRef: 2, ValueRef: 3},
+				{NameRef: 4, ValueRef: 5},
+				{NameRef: 6, ValueRef: 7},
+				{NameRef: 8, ValueRef: 9},
+			},
+			Samples: []prompb.Sample{{Value: 1, Timestamp: 0}},
+			Exemplars: []prompb.ExemplarRef{{Labels: []prompb.LabelRef{
+				{NameRef: 10, ValueRef: 11},
+			}, Value: 1, Timestamp: 0}},
+			Histograms: []prompb.Histogram{HistogramToHistogramProto(0, &testHistogram)},
+		},
+		{
+			Labels: []prompb.LabelRef{
+				{NameRef: 0, ValueRef: 1},
+				{NameRef: 2, ValueRef: 3},
+				{NameRef: 4, ValueRef: 5},
+				{NameRef: 6, ValueRef: 7},
+				{NameRef: 8, ValueRef: 9},
+			},
+			Samples: []prompb.Sample{{Value: 2, Timestamp: 1}},
+			Exemplars: []prompb.ExemplarRef{{Labels: []prompb.LabelRef{
+				{NameRef: 12, ValueRef: 13},
+			}, Value: 2, Timestamp: 1}},
+			Histograms: []prompb.Histogram{HistogramToHistogramProto(1, &testHistogram)},
+		},
+	},
+}
+
 func TestValidateLabelsAndMetricName(t *testing.T) {
 	tests := []struct {
 		input       []prompb.Label
@@ -525,7 +578,24 @@ func TestDecodeWriteRequest(t *testing.T) {
 	require.Equal(t, writeRequestFixture, actual)
 }
 
-func TestNilHistogramProto(*testing.T) {
+func TestDecodeReducedWriteRequest(t *testing.T) {
+	buf, _, err := buildReducedWriteRequest(writeRequestWithRefsFixture.Timeseries, writeRequestWithRefsFixture.StringSymbolTable, nil, nil)
+
+	require.NoError(t, err)
+
+	actual, err := DecodeReducedWriteRequest(bytes.NewReader(buf))
+	require.NoError(t, err)
+	require.Equal(t, writeRequestWithRefsFixture, actual)
+}
+
+func TestReducedWriteRequestToWriteRequest(t *testing.T) {
+	actual, err := ReducedWriteRequestToWriteRequest(writeRequestWithRefsFixture)
+	require.NoError(t, err)
+
+	require.Equal(t, writeRequestFixture, actual)
+}
+
+func TestNilHistogramProto(t *testing.T) {
 	// This function will panic if it impromperly handles nil
 	// values, causing the test to fail.
 	HistogramProtoToHistogram(prompb.Histogram{})