Merge branch '25-enhanced-logging' into 'develop'

Resolve "Enhanced Logging"

See merge request cocsn/gosdn!41

log/logger.go

@@ -3,7 +3,12 @@ package log
 import (
 	"fmt"
 	"io"
+	"log/syslog"
 	"os"
+	"reflect"
+	"runtime"
+	"strconv"
+	"strings"
 	"sync"
 	"time"
 )
@@ -14,15 +19,38 @@ var once sync.Once
 // Logger is a wrapper for log.Logger and provides
 // methods to enable and disable logging.
 type Logger struct {
-	Out      io.Writer
+	DefaultWriter  io.Writer
+	LoglevelWriter map[Level]io.Writer
+	toSyslog       map[Level]bool
 	Loglevel       Level
 	lock           sync.Mutex
+	builder        strings.Builder
+}
+
+func (l *Logger) buildMessage(level Level, syslog bool, args ...interface{}) {
+	if !syslog {
+		l.builder.WriteString(time.Now().Format(time.RFC3339))
+	}
+	l.builder.WriteRune('\t')
+	l.builder.WriteString(prefix(level))
+	l.builder.WriteRune('\t')
+	function, line := callers()
+	functionSplitted := strings.SplitAfter(function, "/")
+	function = functionSplitted[len(functionSplitted)-1]
+	l.builder.WriteString(function)
+	l.builder.WriteRune(':')
+	l.builder.WriteString(strconv.Itoa(line))
+	l.builder.WriteRune('\t')
+	l.builder.WriteString(fmt.Sprint(args...))
+	l.builder.WriteRune('\n')
 }
 
 func get() *Logger {
 	once.Do(func() {
 		logger = &Logger{
-			Out:      os.Stdout,
+			DefaultWriter:  os.Stderr,
+			LoglevelWriter: make(map[Level]io.Writer),
+			toSyslog:       make(map[Level]bool),
 			Loglevel:       INFO,
 			lock:           sync.Mutex{},
 		}
@@ -30,6 +58,8 @@ func get() *Logger {
 	return logger
 }
 
+//Loglevel sets the verbosity of the logger
+//Defaults to INFO
 func Loglevel(level Level) {
 	l := get()
 	l.lock.Lock()
@@ -37,47 +67,100 @@ func Loglevel(level Level) {
 	l.Loglevel = level
 }
 
+//Output defines the output of the logger
+//Defaults to os.Stderr
 func Output(out io.Writer) {
 	l := get()
 	l.lock.Lock()
 	defer l.lock.Unlock()
-	l.Out = out
+	l.DefaultWriter = out
+}
+
+//LoglevelOutput defines a special output
+//for a certain log level
+func LoglevelOutput(level Level, out io.Writer) {
+	l := get()
+	l.lock.Lock()
+	defer l.lock.Unlock()
+	l.LoglevelWriter[level] = out
+	if reflect.TypeOf(out) ==  reflect.TypeOf(&syslog.Writer{}) {
+		l.toSyslog[level] = true
+	}
 }
 
+//Debug passes the DEBUG flag and a
+//message to the logger
 func Debug(args ...interface{}) {
 	log(DEBUG, args...)
 }
 
+//Debug passes the DEBUG flag and a
+//message to the logger
 func Info(args ...interface{}) {
 	log(INFO, args...)
 }
 
+//Warn passes the WARNING flag and a
+//message to the logger
 func Warn(args ...interface{}) {
 	log(WARNING, args...)
 }
 
+//Error passes the ERROR flag and a
+//message to the logger
 func Error(args ...interface{}) {
 	log(ERROR, args...)
 }
 
+//Fatal passes the FATAL flag and a
+//message to the logger and calls
+//os.Exit(1)
 func Fatal(args ...interface{}) {
 	log(FATAL, args...)
+	os.Exit(1)
 }
 
+//Panic passes the PANIC flag and a
+//message to the logger
+//Also calls builtin.panic()
 func Panic(args ...interface{}) {
 	log(PANIC, args...)
+	panic(args)
 }
 
 func log(level Level, args ...interface{}) {
+	defer func() {
+		if r := recover(); r != nil {
+			fmt.Println("Recovered in f", r)
+		}
+	}()
 	l := get()
 	l.lock.Lock()
 	defer l.lock.Unlock()
+	defer l.builder.Reset()
 	if level <= l.Loglevel {
-		msg := fmt.Sprint(args...)
-		logMessage := time.Now().Format(time.RFC3339) + "\t" + prefix(level) + "\t" + msg + "\n"
-		l.Out.Write([]byte(logMessage))
+		l.buildMessage(level, l.toSyslog[level], args...)
+		msg := []byte(l.builder.String())
+		writer, ok := l.LoglevelWriter[level]
+		var err error
+		if !ok {
+			_, err = l.DefaultWriter.Write(msg)
+		} else {
+			_, err = writer.Write(msg)
+		}
+		if err != nil {
+			panic(err)
 		}
 	}
+}
+
+func callers() (string, int) {
+	pc := make([]uintptr, 15)
+	n := runtime.Callers(5, pc)
+	frames := runtime.CallersFrames(pc[:n])
+	frame, _ := frames.Next()
+	return frame.Function, frame.Line
+}
 
 func prefix(level Level) string {
 	switch level {

main.go

@@ -4,6 +4,7 @@ import (
 	"code.fbi.h-da.de/cocsn/gosdn/log"
 	"code.fbi.h-da.de/cocsn/gosdn/nucleus"
 	"flag"
+	"log/syslog"
 )
 
 func main() {
@@ -17,6 +18,16 @@ func main() {
 	cliSocket := *cliListenAddr + ":" + *cliListenPort
 
 	log.Loglevel(log.DEBUG)
+	syslogWriter, err := syslog.New(syslog.LOG_ALERT, "gosdn")
+	defer func() {
+		if err := syslogWriter.Close(); err != nil {
+			log.Fatal(err)
+		}
+	}()
+	if err != nil {
+		log.Fatal(err)
+	}
+	log.LoglevelOutput(log.INFO, syslogWriter)
 
 	// Setup a channel to communicate if goSDN should shutdown.
 	IsRunningChannel := make(chan bool)

nucleus/nucleus-core.go

@@ -7,10 +7,7 @@ import (
 	"time"
 )
 
-/*
- * This function is used to start the core of the controller and any auxiliary services.
- */
-
+//StartAndRun is used to start the core of the controller and any auxiliary services.
 func StartAndRun(socket, filename string, IsRunningChannel chan bool) {
 	log.Info("This is the network superintendent...")
 	log.Info("Starting my ducks")