add log util

log/formatter.go

@@ -0,0 +1,20 @@
+/*
+   Copyright (c) 2016 VMware, Inc. All Rights Reserved.
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package log
+
+type Formatter interface {
+	Format(*Record) ([]byte, error)
+}

log/level.go

@@ -0,0 +1,45 @@
+/*
+   Copyright (c) 2016 VMware, Inc. All Rights Reserved.
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package log
+
+type Level int
+
+const (
+	DebugLevel Level = iota
+	InfoLevel
+	WarningLevel
+	ErrorLevel
+	FatalLevel
+)
+
+func (l Level) string() string {
+	switch l {
+	case DebugLevel:
+		return "DEBUG"
+	case InfoLevel:
+		return "INFO"
+	case WarningLevel:
+		return "WARNING"
+	case ErrorLevel:
+		return "ERROR"
+	case FatalLevel:
+		return "FATAL"
+	}
+
+	return "unknown"
+}
+
+//DEBUG, INFO, WARNING, ERROR, and FATAL

log/logger.go

@@ -0,0 +1,265 @@
+/*
+   Copyright (c) 2016 VMware, Inc. All Rights Reserved.
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package log
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"runtime"
+	"sync"
+	"time"
+)
+
+var logger = New(os.Stdout, NewTextFormatter(""), WarningLevel)
+
+// Logger provides a struct with fields that describe the details of logger.
+type Logger struct {
+	out    io.Writer
+	fmtter Formatter
+	lvl    Level
+	mu     sync.Mutex
+}
+
+func New(out io.Writer, fmtter Formatter, lvl Level) *Logger {
+	return &Logger{
+		out:    out,
+		fmtter: fmtter,
+		lvl:    lvl,
+	}
+}
+
+func (l *Logger) SetOutput(out io.Writer) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
+	l.out = out
+}
+
+func (l *Logger) SetFormatter(fmtter Formatter) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
+	l.fmtter = fmtter
+}
+
+func (l *Logger) SetLevel(lvl Level) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
+	l.lvl = lvl
+}
+
+func SetOutput(out io.Writer) {
+	logger.mu.Lock()
+	defer logger.mu.Unlock()
+
+	logger.out = out
+}
+
+func SetFormatter(fmtter Formatter) {
+	logger.mu.Lock()
+	defer logger.mu.Unlock()
+
+	logger.fmtter = fmtter
+}
+
+func SetLevel(lvl Level) {
+	logger.mu.Lock()
+	defer logger.mu.Unlock()
+
+	logger.lvl = lvl
+}
+
+func (l *Logger) output(record *Record) (err error) {
+	b, err := l.fmtter.Format(record)
+	if err != nil {
+		return
+	}
+
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
+	_, err = l.out.Write(b)
+
+	return
+}
+
+func (l *Logger) Debug(v ...interface{}) {
+	if l.lvl <= DebugLevel {
+		line := line(2)
+		record := NewRecord(time.Now(), fmt.Sprint(v...), line, DebugLevel)
+		l.output(record)
+	}
+}
+
+func (l *Logger) Debugf(format string, v ...interface{}) {
+	if l.lvl <= DebugLevel {
+		line := line(2)
+		record := NewRecord(time.Now(), fmt.Sprintf(format, v...), line, DebugLevel)
+		l.output(record)
+	}
+}
+
+func (l *Logger) Info(v ...interface{}) {
+	if l.lvl <= InfoLevel {
+		record := NewRecord(time.Now(), fmt.Sprint(v...), "", InfoLevel)
+		l.output(record)
+	}
+}
+
+func (l *Logger) Infof(format string, v ...interface{}) {
+	if l.lvl <= InfoLevel {
+		record := NewRecord(time.Now(), fmt.Sprintf(format, v...), "", InfoLevel)
+		l.output(record)
+	}
+}
+
+func (l *Logger) Warning(v ...interface{}) {
+	if l.lvl <= WarningLevel {
+		record := NewRecord(time.Now(), fmt.Sprint(v...), "", WarningLevel)
+		l.output(record)
+	}
+}
+
+func (l *Logger) Warningf(format string, v ...interface{}) {
+	if l.lvl <= WarningLevel {
+		record := NewRecord(time.Now(), fmt.Sprintf(format, v...), "", WarningLevel)
+		l.output(record)
+	}
+}
+
+func (l *Logger) Error(v ...interface{}) {
+	if l.lvl <= ErrorLevel {
+		line := line(2)
+		record := NewRecord(time.Now(), fmt.Sprint(v...), line, ErrorLevel)
+		l.output(record)
+	}
+}
+
+func (l *Logger) Errorf(format string, v ...interface{}) {
+	if l.lvl <= ErrorLevel {
+		line := line(2)
+		record := NewRecord(time.Now(), fmt.Sprintf(format, v...), line, ErrorLevel)
+		l.output(record)
+	}
+}
+
+func (l *Logger) Fatal(v ...interface{}) {
+	if l.lvl <= FatalLevel {
+		line := line(2)
+		record := NewRecord(time.Now(), fmt.Sprint(v...), line, FatalLevel)
+		l.output(record)
+	}
+	os.Exit(1)
+}
+
+func (l *Logger) Fatalf(format string, v ...interface{}) {
+	if l.lvl <= FatalLevel {
+		line := line(2)
+		record := NewRecord(time.Now(), fmt.Sprintf(format, v...), line, FatalLevel)
+		l.output(record)
+	}
+	os.Exit(1)
+}
+
+func Debug(v ...interface{}) {
+	if logger.lvl <= DebugLevel {
+		line := line(2)
+		record := NewRecord(time.Now(), fmt.Sprint(v...), line, DebugLevel)
+		logger.output(record)
+	}
+}
+
+func Debugf(format string, v ...interface{}) {
+	if logger.lvl <= DebugLevel {
+		line := line(2)
+		record := NewRecord(time.Now(), fmt.Sprintf(format, v...), line, DebugLevel)
+		logger.output(record)
+	}
+}
+
+func Info(v ...interface{}) {
+	if logger.lvl <= InfoLevel {
+		record := NewRecord(time.Now(), fmt.Sprint(v...), "", InfoLevel)
+		logger.output(record)
+	}
+}
+
+func Infof(format string, v ...interface{}) {
+	if logger.lvl <= InfoLevel {
+		record := NewRecord(time.Now(), fmt.Sprintf(format, v...), "", InfoLevel)
+		logger.output(record)
+	}
+}
+
+func Warning(v ...interface{}) {
+	if logger.lvl <= WarningLevel {
+		record := NewRecord(time.Now(), fmt.Sprint(v...), "", WarningLevel)
+		logger.output(record)
+	}
+}
+
+func Warningf(format string, v ...interface{}) {
+	if logger.lvl <= WarningLevel {
+		record := NewRecord(time.Now(), fmt.Sprintf(format, v...), "", WarningLevel)
+		logger.output(record)
+	}
+}
+
+func Error(v ...interface{}) {
+	if logger.lvl <= ErrorLevel {
+		line := line(2)
+		record := NewRecord(time.Now(), fmt.Sprint(v...), line, ErrorLevel)
+		logger.output(record)
+	}
+}
+
+func Errorf(format string, v ...interface{}) {
+	if logger.lvl <= ErrorLevel {
+		line := line(2)
+		record := NewRecord(time.Now(), fmt.Sprintf(format, v...), line, ErrorLevel)
+		logger.output(record)
+	}
+}
+
+func Fatal(v ...interface{}) {
+	if logger.lvl <= FatalLevel {
+		line := line(2)
+		record := NewRecord(time.Now(), fmt.Sprint(v...), line, FatalLevel)
+		logger.output(record)
+	}
+	os.Exit(1)
+}
+
+func Fatalf(format string, v ...interface{}) {
+	if logger.lvl <= FatalLevel {
+		line := line(2)
+		record := NewRecord(time.Now(), fmt.Sprintf(format, v...), line, FatalLevel)
+		logger.output(record)
+	}
+	os.Exit(1)
+}
+
+func line(calldepth int) string {
+	_, file, line, ok := runtime.Caller(calldepth)
+	if !ok {
+		file = "???"
+		line = 0
+	}
+
+	return fmt.Sprintf("%s:%d", file, line)
+}

log/record.go

@@ -0,0 +1,36 @@
+/*
+   Copyright (c) 2016 VMware, Inc. All Rights Reserved.
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package log
+
+import (
+	"time"
+)
+
+type Record struct {
+	Time time.Time
+	Msg  string
+	Line string
+	Lvl  Level
+}
+
+func NewRecord(time time.Time, msg, line string, lvl Level) *Record {
+	return &Record{
+		Time: time,
+		Msg:  msg,
+		Line: line,
+		Lvl:  lvl,
+	}
+}

log/text_formatter.go

@@ -0,0 +1,58 @@
+/*
+   Copyright (c) 2016 VMware, Inc. All Rights Reserved.
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package log
+
+import (
+	"fmt"
+	"time"
+)
+
+var defaultTimeFormat string = time.RFC3339
+
+type TextFormatter struct {
+	timeFormat string
+}
+
+func NewTextFormatter(timeFormat string) *TextFormatter {
+	if len(timeFormat) == 0 {
+		timeFormat = defaultTimeFormat
+	}
+
+	return &TextFormatter{
+		timeFormat: timeFormat,
+	}
+}
+
+// Format formats the logs as "time [level] line message"
+func (t *TextFormatter) Format(r *Record) (b []byte, err error) {
+	s := fmt.Sprintf("%s [%s] ", r.Time.Format(t.timeFormat), r.Lvl.string())
+
+	if len(r.Line) != 0 {
+		s = s + r.Line + " "
+	}
+
+	if len(r.Msg) != 0 {
+		s = s + r.Msg
+	}
+
+	b = []byte(s)
+
+	if len(b) == 0 || b[len(b)-1] != '\n' {
+		b = append(b, '\n')
+	}
+
+	return
+}