vmware-go-kcl-v2/logger/logger.go

/*
 * Copyright (c) 2019 VMware, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
 * associated documentation files (the "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is furnished to do
 * so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or substantial
 * portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
 * NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
// Note: The implementation comes from https://www.mountedthoughts.com/golang-logger-interface/
// https://github.com/amitrai48/logger

package logger

import (
	"github.com/sirupsen/logrus"
)

// Fields Type to pass when we want to call WithFields for structured logging
type Fields map[string]interface{}

const (
	//Debug has verbose message
	Debug = "debug"
	//Info is default log level
	Info = "info"
	//Warn is for logging messages about possible issues
	Warn = "warn"
	//Error is for logging errors
	Error = "error"
	//Fatal is for logging fatal messages. The sytem shutsdown after logging the message.
	Fatal = "fatal"
)

// Logger is the common interface for logging.
type Logger interface {
	Debugf(format string, args ...interface{})

	Infof(format string, args ...interface{})

	Warnf(format string, args ...interface{})

	Errorf(format string, args ...interface{})

	Fatalf(format string, args ...interface{})

	Panicf(format string, args ...interface{})

	WithFields(keyValues Fields) Logger
}

// Configuration stores the config for the logger
// For some loggers there can only be one level across writers, for such the level of Console is picked by default
type Configuration struct {
	EnableConsole     bool
	ConsoleJSONFormat bool
	ConsoleLevel      string
	EnableFile        bool
	FileJSONFormat    bool
	FileLevel         string

	// Filename is the file to write logs to.  Backup log files will be retained
	// in the same directory.  It uses <processname>-lumberjack.log in
	// os.TempDir() if empty.
	Filename string

	// MaxSize is the maximum size in megabytes of the log file before it gets
	// rotated. It defaults to 100 megabytes.
	MaxSizeMB int

	// MaxAge is the maximum number of days to retain old log files based on the
	// timestamp encoded in their filename.  Note that a day is defined as 24
	// hours and may not exactly correspond to calendar days due to daylight
	// savings, leap seconds, etc. The default is 7 days.
	MaxAgeDays int

	// MaxBackups is the maximum number of old log files to retain.  The default
	// is to retain all old log files (though MaxAge may still cause them to get
	// deleted.)
	MaxBackups int

	// LocalTime determines if the time used for formatting the timestamps in
	// backup files is the computer's local time.  The default is to use UTC
	// time.
	LocalTime bool
}

// GetDefaultLogger creates a default logger.
func GetDefaultLogger() Logger {
	return NewLogrusLogger(logrus.StandardLogger())
}

// normalizeConfig to enforce default value in configuration.
func normalizeConfig(config *Configuration) {
	if config.MaxSizeMB <= 0 {
		config.MaxSizeMB = 100
	}

	if config.MaxAgeDays <= 0 {
		config.MaxAgeDays = 7
	}

	if config.MaxBackups < 0 {
		config.MaxBackups = 0
	}
}