Adding upstream version 2.1.2.

Signed-off-by: Daniel Baumann <daniel@debian.org>

logger.go

@@ -0,0 +1,148 @@
+package chart
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"time"
+)
+
+var (
+	_ Logger = (*StdoutLogger)(nil)
+)
+
+// NewLogger returns a new logger.
+func NewLogger(options ...LoggerOption) Logger {
+	stl := &StdoutLogger{
+		TimeFormat: time.RFC3339Nano,
+		Stdout:     os.Stdout,
+		Stderr:     os.Stderr,
+	}
+	for _, option := range options {
+		option(stl)
+	}
+	return stl
+}
+
+// Logger is a type that implements the logging interface.
+type Logger interface {
+	Info(...interface{})
+	Infof(string, ...interface{})
+	Debug(...interface{})
+	Debugf(string, ...interface{})
+	Err(error)
+	FatalErr(error)
+	Error(...interface{})
+	Errorf(string, ...interface{})
+}
+
+// Info logs an info message if the logger is set.
+func Info(log Logger, arguments ...interface{}) {
+	if log == nil {
+		return
+	}
+	log.Info(arguments...)
+}
+
+// Infof logs an info message if the logger is set.
+func Infof(log Logger, format string, arguments ...interface{}) {
+	if log == nil {
+		return
+	}
+	log.Infof(format, arguments...)
+}
+
+// Debug logs an debug message if the logger is set.
+func Debug(log Logger, arguments ...interface{}) {
+	if log == nil {
+		return
+	}
+	log.Debug(arguments...)
+}
+
+// Debugf logs an debug message if the logger is set.
+func Debugf(log Logger, format string, arguments ...interface{}) {
+	if log == nil {
+		return
+	}
+	log.Debugf(format, arguments...)
+}
+
+// LoggerOption mutates a stdout logger.
+type LoggerOption = func(*StdoutLogger)
+
+//OptLoggerStdout sets the Stdout writer.
+func OptLoggerStdout(wr io.Writer) LoggerOption {
+	return func(stl *StdoutLogger) {
+		stl.Stdout = wr
+	}
+}
+
+// OptLoggerStderr sets the Stdout writer.
+func OptLoggerStderr(wr io.Writer) LoggerOption {
+	return func(stl *StdoutLogger) {
+		stl.Stderr = wr
+	}
+}
+
+// StdoutLogger is a basic logger.
+type StdoutLogger struct {
+	TimeFormat string
+	Stdout     io.Writer
+	Stderr     io.Writer
+}
+
+// Info writes an info message.
+func (l *StdoutLogger) Info(arguments ...interface{}) {
+	l.Println(append([]interface{}{"[INFO]"}, arguments...)...)
+}
+
+// Infof writes an info message.
+func (l *StdoutLogger) Infof(format string, arguments ...interface{}) {
+	l.Println(append([]interface{}{"[INFO]"}, fmt.Sprintf(format, arguments...))...)
+}
+
+// Debug writes an debug message.
+func (l *StdoutLogger) Debug(arguments ...interface{}) {
+	l.Println(append([]interface{}{"[DEBUG]"}, arguments...)...)
+}
+
+// Debugf writes an debug message.
+func (l *StdoutLogger) Debugf(format string, arguments ...interface{}) {
+	l.Println(append([]interface{}{"[DEBUG]"}, fmt.Sprintf(format, arguments...))...)
+}
+
+// Error writes an error message.
+func (l *StdoutLogger) Error(arguments ...interface{}) {
+	l.Println(append([]interface{}{"[ERROR]"}, arguments...)...)
+}
+
+// Errorf writes an error message.
+func (l *StdoutLogger) Errorf(format string, arguments ...interface{}) {
+	l.Println(append([]interface{}{"[ERROR]"}, fmt.Sprintf(format, arguments...))...)
+}
+
+// Err writes an error message.
+func (l *StdoutLogger) Err(err error) {
+	if err != nil {
+		l.Println(append([]interface{}{"[ERROR]"}, err.Error())...)
+	}
+}
+
+// FatalErr writes an error message and exits.
+func (l *StdoutLogger) FatalErr(err error) {
+	if err != nil {
+		l.Println(append([]interface{}{"[FATAL]"}, err.Error())...)
+		os.Exit(1)
+	}
+}
+
+// Println prints a new message.
+func (l *StdoutLogger) Println(arguments ...interface{}) {
+	fmt.Fprintln(l.Stdout, append([]interface{}{time.Now().UTC().Format(l.TimeFormat)}, arguments...)...)
+}
+
+// Errorln prints a new message.
+func (l *StdoutLogger) Errorln(arguments ...interface{}) {
+	fmt.Fprintln(l.Stderr, append([]interface{}{time.Now().UTC().Format(l.TimeFormat)}, arguments...)...)
+}