logging (#1)

Promoting branch to master

Co-authored-by: grumbulon <grumbulon@dismail.de>
Reviewed-on: #1

awl.go

@@ -3,9 +3,13 @@ package main
 import (
 	"fmt"
 	"os"
+
+	"git.froth.zone/sam/awl/logawl"
 )
 
 func main() {
+	logger := logawl.New()
+	logger.Println("Test PLEASE WORK")
 	app := prepareCLI()
 	err := app.Run(os.Args)
 	if err != nil {

cli.go

@@ -186,7 +186,7 @@ func parseArgs(args []string) (util.Answers, error) {
 			// TODO: Actually find where windows stuffs its dns resolvers
 			resp.Answers.Server = "8.8.4.4"
 		} else {
-			resp.Answers.Server = resolv.Servers[rand.Intn(len(resolv.Servers)-1)]
+			resp.Answers.Server = resolv.Servers[rand.Intn(len(resolv.Servers))]
 		}
 	}
 

logawl/logawl.go

@@ -0,0 +1,44 @@
+package logawl
+
+import "fmt"
+
+type Lvl int
+
+type Level struct {
+	lvl    int
+	Prefix string
+}
+
+func (l *Level) GetLevel(i int) (string, error) {
+	switch i {
+	case int(FatalLevel):
+		return "FATAL ", nil
+	case int(ErrorLevel):
+		return "ERROR ", nil
+	case int(InfoLevel):
+		return "INFO ", nil
+	case int(DebugLevel):
+		return "DEBUG ", nil
+	}
+	return "", fmt.Errorf("Invalid log level choice")
+}
+
+var AllLevels = []Lvl{
+	FatalLevel,
+	ErrorLevel,
+	InfoLevel,
+	DebugLevel,
+}
+
+const (
+	// Fatal logs (will call exit(1))
+	FatalLevel Lvl = iota
+
+	// Error logs
+	ErrorLevel
+
+	// What is going on level
+	InfoLevel
+	// Verbose log level.
+	DebugLevel
+)

logawl/logger.go

@@ -0,0 +1,113 @@
+package logawl
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+type Logger struct {
+	Mu        sync.Mutex
+	Level     Lvl
+	Prefix    string
+	Out       io.Writer
+	buf       []byte
+	isDiscard int32
+}
+
+// Calling New instantiates Logger
+//
+// Level can be changed to one of the other log levels (FatalLevel, ErrorLevel, InfoLevel, DebugLevel)
+func New() *Logger {
+	return &Logger{
+		Out: os.Stderr,
+		//TODO: Make cli.go change this value when calling logawl.New()
+		Level: InfoLevel, //Default value is InfoLevel
+	}
+}
+
+// Takes any and prints it out to Logger -> Out (io.Writer (default is std.Err))
+func (l *Logger) Println(v ...any) {
+	if atomic.LoadInt32(&l.isDiscard) != 0 {
+		return
+	}
+	switch l.Level { //Goes through log levels and does stuff based on them (Fatal os.Exit...etc)
+	case 0:
+		l.Printer(0, fmt.Sprintln(v...)) //Fatal level
+		os.Exit(1)
+	case 1:
+		l.Printer(1, fmt.Sprintln(v...)) //Error level
+	case 2:
+		l.Printer(2, fmt.Sprintln(v...)) //Info level
+	case 3:
+		l.Printer(3, fmt.Sprintln(v...)) //Debug level
+	}
+
+}
+
+// Formats the log header as such <LogLevel> YYYY/MM/DD HH:MM:SS (local time) <the message to log>
+func (l *Logger) formatHeader(buf *[]byte, t time.Time, level int, line int) {
+	var lv Level
+	if logLvl, err := lv.GetLevel(level); err != nil {
+		fmt.Printf("Invalid log level %s. Error: %v", logLvl, err)
+		os.Exit(1)
+	} else {
+		*buf = append(*buf, logLvl...)
+		year, month, day := t.Date()
+		formatter(buf, year, 4)
+		*buf = append(*buf, '/')
+		formatter(buf, int(month), 2)
+		*buf = append(*buf, '/')
+		formatter(buf, day, 2)
+		*buf = append(*buf, ' ')
+		hour, min, sec := t.Clock()
+		formatter(buf, hour, 2)
+		*buf = append(*buf, ':')
+		formatter(buf, min, 2)
+		*buf = append(*buf, ':')
+		formatter(buf, sec, 2)
+		*buf = append(*buf, ' ')
+	}
+
+}
+
+// Printer prints the formatted message directly to stdErr
+func (l *Logger) Printer(level int, s string) error {
+	now := time.Now()
+	var line int
+	l.Mu.Lock()
+	defer l.Mu.Unlock()
+
+	l.buf = l.buf[:0]
+	l.formatHeader(&l.buf, now, level, line)
+	l.buf = append(l.buf, s...)
+	if len(s) == 0 || s[len(s)-1] != '\n' {
+		l.buf = append(l.buf, '\n')
+	}
+	_, err := l.Out.Write(l.buf)
+	return err
+}
+
+// Some line formatting stuff from Golang log stdlib file
+//
+// Please view https://cs.opensource.google/go/go/+/refs/tags/go1.18.3:src/log/log.go;drc=41e1d9075e428c2fc32d966b3752a3029b620e2c;l=96
+//
+// Cheap integer to fixed-width decimal ASCII. Give a negative width to avoid zero-padding.
+func formatter(buf *[]byte, i int, wid int) {
+	// Assemble decimal in reverse order.
+	var b [20]byte
+	bp := len(b) - 1
+	for i >= 10 || wid > 1 {
+		wid--
+		q := i / 10
+		b[bp] = byte('0' + i - q*10)
+		bp--
+		i = q
+	}
+	// i < 10
+	b[bp] = byte('0' + i)
+	*buf = append(*buf, b[bp:]...)
+}