go-gelf Custom Message Example

main.go

/*
This is a very basic example of sending custom messages to Graylog with the go-gelf package
GELF Spec https://docs.graylog.org/en/3.2/pages/gelf.html#gelf-via-udp
*/

package main

import (
	"fmt"
	"gopkg.in/Graylog2/go-gelf.v2/gelf"
	"os"
	"runtime"
	"time"
)

// GelfWriter is a pointer to a gelf.UPDWriter
var GelfWriter *gelf.UDPWriter

// GelfHostname is used across GELF messages to provide the source field
var GelfHostname string

func main() {
	fmt.Println("Starting tests")
	GelfHostname, _ = os.Hostname()
	createLogger()
	logMsg()
}

func createLogger() {
	GelfWriter, _ = gelf.NewUDPWriter("172.28.253.58:11589")

}

func wrapBuildMessage(s string, f string, l int32, ex map[string]interface{}) *gelf.Message {
	/*
		Level is a stanard syslog level
		Facility is deprecated
		Line is deprecated
		File is deprecated
	*/

	m := &gelf.Message{
		Version:  "1.1",
		Host:     GelfHostname,
		Short:    s,
		Full:     f,
		TimeUnix: float64(time.Now().Unix()),
		Level:    l,
		Extra:    ex,
	}

	return m
}

func LogMsg() {

	var level int32

	shortMsg := "Error"
	fullMsg := "Stack trace here"
	level = 3 // https://success.trendmicro.com/solution/TP000086250-What-are-Syslog-Facilities-and-Levels
	_, file, line, _ := runtime.Caller(1)
	customExtras := map[string]interface{}{"file": file, "line": line, "job_name": "testJob"}

	customMessage := wrapBuildMessage(shortMsg, fullMsg, level, customExtras)

	e := GelfWriter.WriteMessage(customMessage)

	if e != nil {
		fmt.Println("Received error when sending GELF message:", e.Error())
	} else {
		fmt.Println("Sent message")
	}

}