portainer/portainer

package main

import (
    "fmt"
    stdlog "log"
    "os"

    "github.com/rs/zerolog"
    "github.com/rs/zerolog/log"
    "github.com/rs/zerolog/pkgerrors"
)

func configureLogger() {
    zerolog.ErrorStackFieldName = "stack_trace"
    zerolog.ErrorStackMarshaler = pkgerrors.MarshalStack
    zerolog.TimeFieldFormat = zerolog.TimeFormatUnix

    stdlog.SetFlags(0)
    stdlog.SetOutput(log.Logger)

    log.Logger = log.Logger.With().Caller().Stack().Logger()
}

func setLoggingLevel(level string) {
    switch level {
    case "ERROR":
        zerolog.SetGlobalLevel(zerolog.ErrorLevel)
    case "WARN":
        zerolog.SetGlobalLevel(zerolog.WarnLevel)
    case "INFO":
        zerolog.SetGlobalLevel(zerolog.InfoLevel)
    case "DEBUG":
        zerolog.SetGlobalLevel(zerolog.DebugLevel)
    }
}

func setLoggingMode(mode string) {
    switch mode {
    case "PRETTY":
        log.Logger = log.Output(zerolog.ConsoleWriter{
            Out:           os.Stderr,
            TimeFormat:    "2006/01/02 03:04PM",
            FormatMessage: formatMessage,
        })
    case "NOCOLOR":
        log.Logger = log.Output(zerolog.ConsoleWriter{
            Out:           os.Stderr,
            TimeFormat:    "2006/01/02 03:04PM",
            FormatMessage: formatMessage,
            NoColor:       true,
        })
    case "JSON":
        log.Logger = log.Output(os.Stderr)
    }
}

func formatMessage(i interface{}) string {
    if i == nil {
        return ""
    }

    return fmt.Sprintf("%s |", i)
}