logging.go

// Copyright © 2020 Weald Technology Trading
// 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 util

import (
	"os"
	"strings"

	"github.com/pkg/errors"
	"github.com/rs/zerolog"
	zerologger "github.com/rs/zerolog/log"
	"github.com/spf13/viper"
)

// Log is the ethdo global logger.
var Log zerolog.Logger

// InitLogging initialises logging.
func InitLogging() error {
	// Change the output file.
	if viper.GetString("log-file") != "" {
		f, err := os.OpenFile(viper.GetString("log-file"), os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o600)
		if err != nil {
			return errors.Wrap(err, "failed to open log file")
		}
		zerologger.Logger = zerologger.Logger.Output(f)
	}

	// Set the log level.
	Log = zerologger.Logger.With().Logger().Level(logLevel(viper.GetString("log-level")))

	return nil
}

// logLevel converts a string to a log level.
// It returns the user-supplied level by default.
func logLevel(input string) zerolog.Level {
	switch strings.ToLower(input) {
	case "none":
		return zerolog.Disabled
	case "trace":
		return zerolog.TraceLevel
	case "debug":
		return zerolog.DebugLevel
	case "warn", "warning":
		return zerolog.WarnLevel
	case "info", "information":
		return zerolog.InfoLevel
	case "err", "error":
		return zerolog.ErrorLevel
	case "fatal":
		return zerolog.FatalLevel
	default:
		return Log.GetLevel()
	}
}