Fixed the color output on Windows

Colored output seems to be broken on Windows Command Prompt
#8

cmd/go-log/main.go

@@ -5,6 +5,7 @@ import (
 )
 
 func main() {
+
 	log.DebugMode = true
 	log.DebugSQLMode = true
 	log.PrintTimestamp = true

go.mod

@@ -5,7 +5,7 @@ go 1.13
 require (
 	github.com/fatih/color v1.7.0
 	github.com/go-errors/errors v1.0.1
-	github.com/mattn/go-colorable v0.1.4 // indirect
+	github.com/mattn/go-colorable v0.1.4
 	github.com/mgutz/ansi v0.0.0-20170206155736-9520e82c474b
 	github.com/pieterclaerhout/go-formatter v1.0.2
 	github.com/pkg/errors v0.8.1

logger.go

@@ -2,7 +2,6 @@ package log
 
 import (
 	"fmt"
-	"io"
 	"os"
 	"strings"
 	"time"
@@ -32,10 +31,10 @@ var DebugSQLMode = false
 var TimeZone *time.Location
 
 // Stdout is the writer to where the stdout messages should be written (defaults to os.Stdout)
-var Stdout io.Writer = os.Stdout
+var Stdout *os.File = os.Stdout
 
 // Stderr is the writer to where the stderr messages should be written (defaults to os.Stderr)
-var Stderr io.Writer = os.Stderr
+var Stderr *os.File = os.Stderr
 
 // DefaultTimeFormat is the default format to use for the timestamps
 var DefaultTimeFormat = "2006-01-02 15:04:05.000"

logger_internal.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/fatih/color"
+	"github.com/mattn/go-colorable"
 )
 
 var logMutex = &sync.Mutex{}
@@ -48,8 +49,6 @@ func formatSeparator(message string, separator string, length int) string {
 
 func printMessage(level string, message string) {
 
-	logMutex.Lock()
-
 	level = strings.ToUpper(level)
 
 	if PrintTimestamp {
@@ -60,20 +59,21 @@ func printMessage(level string, message string) {
 		formattedTime := tstamp.Format(TimeFormat)
 		message = formattedTime + " | " + level + " | " + message
 	}
-	if PrintColors {
-		if color, ok := colors[level]; ok {
-			message = color.Sprint(message)
-		}
-	}
 
 	w := Stdout
 	if level == "ERROR" || level == "FATAL" {
 		w = Stderr
 	}
 
-	w.Write([]byte(message + "\n"))
+	if PrintColors {
+		cw := colorable.NewColorable(w)
+		if c, ok := colors[level]; ok {
+			c.Fprintln(cw, message)
+			return
+		}
+	}
 
-	logMutex.Unlock()
+	w.Write([]byte(message + "\n"))
 
 }