@@ -6,9 +6,12 @@ package gelf

 import (

 	"bytes"

+	"compress/flate"

+	"encoding/json"

 	"fmt"

 	"net"

 	"net/url"

+	"strconv"

 	"time"

 	"github.com/Graylog2/go-gelf/gelf"

@@ -24,7 +27,7 @@ type gelfLogger struct {

 	writer   *gelf.Writer

 	ctx      logger.Context

 	hostname string

-	extra    map[string]interface{}

+	rawExtra json.RawMessage

 }

 func init() {

@@ -81,17 +84,43 @@ func New(ctx logger.Context) (logger.Logger, error) {

 		extra[k] = v

 	}

+	rawExtra, err := json.Marshal(extra)

+	if err != nil {

+		return nil, err

+	}

+

 	// create new gelfWriter

 	gelfWriter, err := gelf.NewWriter(address)

 	if err != nil {

 		return nil, fmt.Errorf("gelf: cannot connect to GELF endpoint: %s %v", address, err)

 	}

+	if v, ok := ctx.Config["gelf-compression-type"]; ok {

+		switch v {

+		case "gzip":

+			gelfWriter.CompressionType = gelf.CompressGzip

+		case "zlib":

+			gelfWriter.CompressionType = gelf.CompressZlib

+		case "none":

+			gelfWriter.CompressionType = gelf.CompressNone

+		default:

+			return nil, fmt.Errorf("gelf: invalid compression type %q", v)

+		}

+	}

+

+	if v, ok := ctx.Config["gelf-compression-level"]; ok {

+		val, err := strconv.Atoi(v)

+		if err != nil {

+			return nil, fmt.Errorf("gelf: invalid compression level %s, err %v", v, err)

+		}

+		gelfWriter.CompressionLevel = val

+	}

+

 	return &gelfLogger{

 		writer:   gelfWriter,

 		ctx:      ctx,

 		hostname: hostname,

-		extra:    extra,

+		rawExtra: rawExtra,

 	}, nil

 }

@@ -107,7 +136,7 @@ func (s *gelfLogger) Log(msg *logger.Message) error {

 		Short:    string(msg.Line),

 		TimeUnix: float64(msg.Timestamp.UnixNano()/int64(time.Millisecond)) / 1000.0,

 		Level:    level,

-		Extra:    s.extra,

+		RawExtra: s.rawExtra,

 	}

 	if err := s.writer.WriteMessage(&m); err != nil {

@@ -127,15 +156,26 @@ func (s *gelfLogger) Name() string {

 // ValidateLogOpt looks for gelf specific log options gelf-address, &

 // gelf-tag.

 func ValidateLogOpt(cfg map[string]string) error {

-	for key := range cfg {

+	for key, val := range cfg {

 		switch key {

 		case "gelf-address":

 		case "gelf-tag":

 		case "tag":

 		case "labels":

 		case "env":

+		case "gelf-compression-level":

+			i, err := strconv.Atoi(val)

+			if err != nil || i < flate.DefaultCompression || i > flate.BestCompression {

+				return fmt.Errorf("unknown value %q for log opt %q for gelf log driver", val, key)

+			}

+		case "gelf-compression-type":

+			switch val {

+			case "gzip", "zlib", "none":

+			default:

+				return fmt.Errorf("unknown value %q for log opt %q for gelf log driver", val, key)

+			}

 		default:

-			return fmt.Errorf("unknown log opt '%s' for gelf log driver", key)

+			return fmt.Errorf("unknown log opt %q for gelf log driver", key)

 		}

 	}

@@ -146,6 +146,8 @@ The GELF logging driver supports the following options:

     --log-opt tag="database"

     --log-opt labels=label1,label2

     --log-opt env=env1,env2

+    --log-opt gelf-compression-type=gzip

+    --log-opt gelf-compression-level=1

 The `gelf-address` option specifies the remote GELF server address that the

 driver connects to. Currently, only `udp` is supported as the transport and you must

@@ -167,6 +169,14 @@ underscore (`_`).

     "_fizz": "buzz",

     // […]

+The `gelf-compression-type` option can be used to change how the GELF driver

+compresses each log message. The accepted values are `gzip`, `zlib` and `none`.

+`gzip` is chosen by default.

+

+The `gelf-compression-level` option can be used to change the level of compresssion

+when `gzip` or `zlib` is selected as `gelf-compression-type`. Accepted value

+must be from from -1 to 9 (BestCompression). Higher levels typically

+run slower but compress more. Default value is 1 (BestSpeed).

 ## fluentd options