refactor; move logger to module

logger/go.mod

@@ -0,0 +1,5 @@
+module github.com/hrfee/jfa-go/logger
+
+go 1.16
+
+require github.com/fatih/color v1.10.0

logger/go.sum

@@ -0,0 +1,9 @@
+github.com/fatih/color v1.10.0 h1:s36xzo75JdqLaaWoiEHk767eHiwo0598uUxyfiPkDsg=
+github.com/fatih/color v1.10.0/go.mod h1:ELkj/draVOlAH/xkhN6mQ50Qd0MPOk5AAr3maGEBuJM=
+github.com/mattn/go-colorable v0.1.8 h1:c1ghPdyEDarC70ftn0y+A/Ee++9zz8ljHG1b13eJ0s8=
+github.com/mattn/go-colorable v0.1.8/go.mod h1:u6P/XSegPjTcexA+o6vUJrdnUu04hMope9wVRipJSqc=
+github.com/mattn/go-isatty v0.0.12 h1:wuysRhFDzyxgEmMf5xjvJ2M9dZoWAXNNr5LSBS7uHXY=
+github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
+golang.org/x/sys v0.0.0-20200116001909-b77594299b42/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200223170610-d5e6a3e2c0ae h1:/WDfKMnPU+m5M4xB+6x4kaepxRw6jWvR5iDRdvjHgy8=
+golang.org/x/sys v0.0.0-20200223170610-d5e6a3e2c0ae/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

logger/logger.go

@@ -0,0 +1,109 @@
+// Package logger provides a wrapper around log that adds color support with github.com/fatih/color.
+package logger
+
+import (
+	"io"
+	"log"
+	"runtime"
+	"strconv"
+
+	c "github.com/fatih/color"
+)
+
+type Logger interface {
+	Printf(format string, v ...interface{})
+	Print(v ...interface{})
+	Println(v ...interface{})
+	Fatal(v ...interface{})
+	Fatalf(format string, v ...interface{})
+}
+
+type logger struct {
+	logger    *log.Logger
+	shortfile bool
+	printer   *c.Color
+}
+
+func Lshortfile() string {
+	// 0 = This function, 1 = Print/Printf/Println, 2 = Caller of Print/Printf/Println
+	_, file, line, ok := runtime.Caller(2)
+	lineString := strconv.Itoa(line)
+	if !ok {
+		return ""
+	}
+	if file == "" {
+		return lineString
+	}
+	for i := len(file) - 1; i > 0; i-- {
+		if file[i] == '/' || file[i] == '\\' {
+			file = file[i+1:]
+			break
+		}
+	}
+	return file + ":" + lineString + ":"
+}
+
+func NewLogger(out io.Writer, prefix string, flag int, color c.Attribute) (l logger) {
+	// Use reimplemented Lshortfile since wrapping the log functions messes them up
+	if flag&log.Lshortfile != 0 {
+		flag -= log.Lshortfile
+		l.shortfile = true
+	}
+
+	l.logger = log.New(out, prefix, flag)
+	l.printer = c.New(color)
+	return l
+}
+
+func (l logger) Printf(format string, v ...interface{}) {
+	var out string
+	if l.shortfile {
+		out = Lshortfile()
+	}
+	out += " " + l.printer.Sprintf(format, v...)
+	l.logger.Print(out)
+}
+
+func (l logger) Print(v ...interface{}) {
+	var out string
+	if l.shortfile {
+		out = Lshortfile()
+	}
+	out += " " + l.printer.Sprint(v...)
+	l.logger.Print(out)
+}
+
+func (l logger) Println(v ...interface{}) {
+	var out string
+	if l.shortfile {
+		out = Lshortfile()
+	}
+	out += " " + l.printer.Sprintln(v...)
+	l.logger.Print(out)
+}
+
+func (l logger) Fatal(v ...interface{}) {
+	var out string
+	if l.shortfile {
+		out = Lshortfile()
+	}
+	out += " " + l.printer.Sprint(v...)
+	l.logger.Fatal(out)
+}
+
+func (l logger) Fatalf(format string, v ...interface{}) {
+	var out string
+	if l.shortfile {
+		out = Lshortfile()
+	}
+	out += " " + l.printer.Sprintf(format, v...)
+	l.logger.Fatal(out)
+}
+
+type EmptyLogger bool
+
+func (l EmptyLogger) Printf(format string, v ...interface{}) {}
+func (l EmptyLogger) Print(v ...interface{})                 {}
+func (l EmptyLogger) Println(v ...interface{})               {}
+func (l EmptyLogger) Fatal(v ...interface{})                 {}
+func (l EmptyLogger) Fatalf(format string, v ...interface{}) {}