Switch to snappy framing

output/cloud/expv2/metrics_client.go

@@ -65,7 +65,7 @@ func (mc *metricsClient) push(referenceID string, samples *pbcloud.MetricSet) er
 	}
 
 	req.Header.Set("Content-Type", "application/x-protobuf")
-	req.Header.Set("Content-Encoding", "snappy")
+	req.Header.Set("Content-Encoding", "x-snappy-framed")
 	req.Header.Set("K6-Metrics-Protocol-Version", "2.0")
 
 	err = mc.httpClient.Do(req, nil)
@@ -81,13 +81,37 @@ func newRequestBody(data *pbcloud.MetricSet) ([]byte, error) {
 	if err != nil {
 		return nil, fmt.Errorf("encoding metrics as Protobuf write request failed: %w", err)
 	}
-	// TODO: use the framing format
-	// https://github.com/google/snappy/blob/main/framing_format.txt
-	// It can be done replacing the encode with
-	// https://pkg.go.dev/github.com/klauspost/compress/snappy#NewBufferedWriter
+
 	if snappy.MaxEncodedLen(len(b)) < 0 {
 		return nil, fmt.Errorf("the Protobuf message is too large to be handled by Snappy encoder; "+
 			"size: %d, limit: %d", len(b), 0xffffffff)
 	}
-	return snappy.Encode(nil, b), nil
+
+	b, err = encodeWithSnappyFraming(b)
+	if err != nil {
+		return nil, fmt.Errorf("metrics request compression failed: %w", err)
+	}
+
+	return b, nil
+}
+
+// encodeWithSnappyFraming encodes the given data with Snappy framing.
+// See https://github.com/google/snappy/blob/main/framing_format.txt
+func encodeWithSnappyFraming(data []byte) ([]byte, error) {
+	var buf bytes.Buffer
+	writer := snappy.NewBufferedWriter(&buf)
+
+	_, err := writer.Write(data)
+	if err != nil {
+		_ = writer.Close()
+
+		return nil, err
+	}
+
+	err = writer.Close()
+	if err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
 }

output/cloud/expv2/metrics_client_test.go

@@ -24,8 +24,7 @@ func TestMetricsClientPush(t *testing.T) {
 		assert.Equal(t, http.MethodPost, r.Method)
 		assert.Equal(t, "Token fake-token", r.Header.Get("Authorization"))
 		assert.Contains(t, r.Header.Get("User-Agent"), "k6cloud/v0.4")
-		assert.Equal(t, "application/x-protobuf", r.Header.Get("Content-Type"))
-		assert.Equal(t, "snappy", r.Header.Get("Content-Encoding"))
+		assert.Equal(t, "x-snappy-framed", r.Header.Get("Content-Encoding"))
 		assert.Equal(t, "2.0", r.Header.Get("K6-Metrics-Protocol-Version"))
 		b, err := io.ReadAll(r.Body)
 		require.NoError(t, err)
@@ -39,7 +38,15 @@ func TestMetricsClientPush(t *testing.T) {
 	mc, err := newMetricsClient(c)
 	require.NoError(t, err)
 
-	mset := pbcloud.MetricSet{}
+	mset := pbcloud.MetricSet{
+		Metrics: []*pbcloud.Metric{
+			{
+				Name:       "http_reqs",
+				Type:       pbcloud.MetricType_METRIC_TYPE_COUNTER,
+				TimeSeries: []*pbcloud.TimeSeries{},
+			},
+		},
+	}
 	err = mc.push("test-ref-id", &mset)
 	require.NoError(t, err)
 	assert.Equal(t, 1, reqs)