Add influxdb gzip support

plugins/outputs/influxdb/README.md

@@ -43,6 +43,9 @@ This plugin writes to [InfluxDB](https://www.influxdb.com) via HTTP or UDP.
 
   ## HTTP Proxy Config
   # http_proxy = "http://corporate.proxy:3128"
+
+  ## Compress each HTTP request payload using GZIP, defaults to false.
+  # gzip = false
 ```
 
 ### Required parameters:
@@ -67,3 +70,4 @@ to write to. Each URL should start with either `http://` or `udp://`
 * `ssl_key`: SSL key
 * `insecure_skip_verify`: Use SSL but skip chain & host verification (default: false)
 * `http_proxy`: HTTP Proxy URI
+* `gzip`: Compress each HTTP request payload using gzip (default: false)

plugins/outputs/influxdb/client/http.go

@@ -2,6 +2,7 @@ package client
 
 import (
 	"bytes"
+	"compress/gzip"
 	"crypto/tls"
 	"encoding/json"
 	"fmt"
@@ -95,8 +96,7 @@ type HTTPConfig struct {
 	HTTPProxy string
 
 	// Gzip, if true, compresses each payload using gzip.
-	// TODO
-	// Gzip bool
+	Gzip bool
 }
 
 // Response represents a list of statement results.
@@ -233,15 +233,27 @@ func (c *httpClient) makeWriteRequest(
 		return nil, err
 	}
 	req.Header.Set("Content-Length", fmt.Sprint(contentLength))
-	// TODO
-	// if gzip {
-	// 	req.Header.Set("Content-Encoding", "gzip")
-	// }
+	if c.config.Gzip {
+		req.Header.Set("Content-Encoding", "gzip")
+	}
 	return req, nil
 }
 
 func (c *httpClient) makeRequest(uri string, body io.Reader) (*http.Request, error) {
-	req, err := http.NewRequest("POST", uri, body)
+	var req *http.Request
+	var err error
+	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())
+		if err != nil {
+			return nil, err
+		}
+		body = bytes.NewBuffer(compressed)
+	}
+	req, err = http.NewRequest("POST", uri, body)
 	if err != nil {
 		return nil, err
 	}
@@ -253,6 +265,18 @@ 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 (c *httpClient) Close() error {
 	// Nothing to do.
 	return nil

plugins/outputs/influxdb/influxdb.go

@@ -34,6 +34,7 @@ type InfluxDB struct {
 	Timeout          internal.Duration
 	UDPPayload       int    `toml:"udp_payload"`
 	HTTPProxy        string `toml:"http_proxy"`
+	Gzip             bool
 
 	// Path to CA file
 	SSLCA string `toml:"ssl_ca"`
@@ -87,6 +88,9 @@ var sampleConfig = `
 
   ## HTTP Proxy Config
   # http_proxy = "http://corporate.proxy:3128"
+
+  ## Compress each HTTP request payload using GZIP, defaults to false.
+  # gzip = false
 `
 
 // Connect initiates the primary connection to the range of provided URLs
@@ -128,6 +132,7 @@ func (i *InfluxDB) Connect() error {
 				Username:  i.Username,
 				Password:  i.Password,
 				HTTPProxy: i.HTTPProxy,
+				Gzip:      i.Gzip,
 			}
 			wp := client.WriteParams{
 				Database:        i.Database,