Use io.Pipe() to minimize internal buffering

Fix lint

Mop

plugins/outputs/influxdb/client/http.go

@@ -245,13 +245,10 @@ func (c *httpClient) makeRequest(uri string, body io.Reader) (*http.Request, err
 	if c.config.Gzip {
 		// If gzip is set to true, then compress
 		// the payload.
-		buf := new(bytes.Buffer)
-		buf.ReadFrom(body)
-		compressed, err := compressWithGzip(buf.Bytes())
+		body, err = compressWithGzip(body)
 		if err != nil {
 			return nil, err
 		}
-		body = bytes.NewBuffer(compressed)
 	}
 	req, err = http.NewRequest("POST", uri, body)
 	if err != nil {
@@ -265,16 +262,18 @@ func (c *httpClient) makeRequest(uri string, body io.Reader) (*http.Request, err
 	return req, nil
 }
 
-func compressWithGzip(data []byte) ([]byte, error) {
-	var buf bytes.Buffer
-	gz := gzip.NewWriter(&buf)
-	if _, err := gz.Write(data); err != nil {
-		return nil, err
-	}
-	if err := gz.Close(); err != nil {
-		return nil, err
-	}
-	return buf.Bytes(), nil
+func compressWithGzip(data io.Reader) (io.Reader, error) {
+	pr, pw := io.Pipe()
+	gw := gzip.NewWriter(pw)
+	var err error
+
+	go func() {
+		_, err = io.Copy(gw, data)
+		gw.Close()
+		pw.Close()
+	}()
+
+	return pr, err
 }
 
 func (c *httpClient) Close() error {

plugins/outputs/influxdb/client/http_test.go

@@ -344,20 +344,22 @@ func TestHTTPClient_Query_JSONDecodeError(t *testing.T) {
 }
 
 func TestGzipCompression(t *testing.T) {
+	influxLine := "cpu value=99\n"
+
 	// Compress the payload using GZIP.
-	payload := []byte("cpu value=99\n")
+	payload := bytes.NewReader([]byte(influxLine))
 	compressed, err := compressWithGzip(payload)
 	assert.Nil(t, err)
 
-	// GUNZIP the compressed payload and make sure
+	// Decompress the compressed payload and make sure
 	// that its original value has not changed.
-	r, err := gzip.NewReader(bytes.NewReader(compressed))
+	gr, err := gzip.NewReader(compressed)
 	assert.Nil(t, err)
-	r.Close()
+	gr.Close()
 
 	var uncompressed bytes.Buffer
-	_, err = uncompressed.ReadFrom(r)
+	_, err = uncompressed.ReadFrom(gr)
 	assert.Nil(t, err)
 
-	assert.Equal(t, payload, uncompressed.Bytes())
+	assert.Equal(t, []byte(influxLine), uncompressed.Bytes())
 }