logrus_support_windows.go

package windows

import (
	"bytes"
	"errors"
	"fmt"
	"os"

	"github.com/sirupsen/logrus"
	"golang.org/x/sys/windows"
	"golang.org/x/sys/windows/svc/eventlog"
)

// see https://github.com/docker/engine/blob/8e610b2b55bfd1bfa9436ab110d311f5e8a74dcb/cmd/dockerd/service_windows.go#L64-L149

const (
	// These should match the values in event_messages.mc.
	eventInfo  = 1
	eventWarn  = 1
	eventError = 1
	eventDebug = 2
	eventPanic = 3
	eventFatal = 4

	eventExtraOffset = 10 // Add this to any event to get a string that supports extended data
)

type ETWHook struct {
	log *eventlog.Log
}

func (h *ETWHook) Levels() []logrus.Level {
	return []logrus.Level{
		logrus.PanicLevel,
		logrus.FatalLevel,
		logrus.ErrorLevel,
		logrus.WarnLevel,
		logrus.InfoLevel,
		logrus.DebugLevel,
	}
}

func (h *ETWHook) Fire(e *logrus.Entry) error {
	var (
		etype uint16
		eid   uint32
	)

	switch e.Level {
	case logrus.PanicLevel:
		etype = windows.EVENTLOG_ERROR_TYPE
		eid = eventPanic
	case logrus.FatalLevel:
		etype = windows.EVENTLOG_ERROR_TYPE
		eid = eventFatal
	case logrus.ErrorLevel:
		etype = windows.EVENTLOG_ERROR_TYPE
		eid = eventError
	case logrus.WarnLevel:
		etype = windows.EVENTLOG_WARNING_TYPE
		eid = eventWarn
	case logrus.InfoLevel:
		etype = windows.EVENTLOG_INFORMATION_TYPE
		eid = eventInfo
	case logrus.DebugLevel:
		etype = windows.EVENTLOG_INFORMATION_TYPE
		eid = eventDebug
	default:
		return errors.New("unknown level")
	}

	// If there is additional data, include it as a second string.
	exts := ""
	if len(e.Data) > 0 {
		fs := bytes.Buffer{}
		for k, v := range e.Data {
			fs.WriteString(k)
			fs.WriteByte('=')
			fmt.Fprint(&fs, v)
			fs.WriteByte(' ')
		}

		exts = fs.String()[:fs.Len()-1]
		eid += eventExtraOffset
	}

	if h.log == nil {
		fmt.Fprintf(os.Stderr, "%s [%s]\n", e.Message, exts)
		return nil
	}

	var (
		ss  [2]*uint16
		err error
	)

	ss[0], err = windows.UTF16PtrFromString(e.Message)
	if err != nil {
		return err
	}

	count := uint16(1)
	if exts != "" {
		ss[1], err = windows.UTF16PtrFromString(exts)
		if err != nil {
			return err
		}

		count++
	}

	return windows.ReportEvent(h.log.Handle, etype, 0, eid, 0, count, 0, &ss[0], nil)
}