TUN-528: Move cloudflared into a separate repo

vendor/github.com/prometheus/common/log/syslog_formatter.go

@@ -0,0 +1,126 @@
+// Copyright 2015 The Prometheus Authors
+// 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.
+
+// +build !windows,!nacl,!plan9
+
+package log
+
+import (
+	"fmt"
+	"log/syslog"
+	"os"
+
+	"github.com/sirupsen/logrus"
+)
+
+var _ logrus.Formatter = (*syslogger)(nil)
+
+func init() {
+	setSyslogFormatter = func(l logger, appname, local string) error {
+		if appname == "" {
+			return fmt.Errorf("missing appname parameter")
+		}
+		if local == "" {
+			return fmt.Errorf("missing local parameter")
+		}
+
+		fmter, err := newSyslogger(appname, local, l.entry.Logger.Formatter)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "error creating syslog formatter: %v\n", err)
+			l.entry.Errorf("can't connect logger to syslog: %v", err)
+			return err
+		}
+		l.entry.Logger.Formatter = fmter
+		return nil
+	}
+}
+
+var prefixTag []byte
+
+type syslogger struct {
+	wrap logrus.Formatter
+	out  *syslog.Writer
+}
+
+func newSyslogger(appname string, facility string, fmter logrus.Formatter) (*syslogger, error) {
+	priority, err := getFacility(facility)
+	if err != nil {
+		return nil, err
+	}
+	out, err := syslog.New(priority, appname)
+	_, isJSON := fmter.(*logrus.JSONFormatter)
+	if isJSON {
+		// add cee tag to json formatted syslogs
+		prefixTag = []byte("@cee:")
+	}
+	return &syslogger{
+		out:  out,
+		wrap: fmter,
+	}, err
+}
+
+func getFacility(facility string) (syslog.Priority, error) {
+	switch facility {
+	case "0":
+		return syslog.LOG_LOCAL0, nil
+	case "1":
+		return syslog.LOG_LOCAL1, nil
+	case "2":
+		return syslog.LOG_LOCAL2, nil
+	case "3":
+		return syslog.LOG_LOCAL3, nil
+	case "4":
+		return syslog.LOG_LOCAL4, nil
+	case "5":
+		return syslog.LOG_LOCAL5, nil
+	case "6":
+		return syslog.LOG_LOCAL6, nil
+	case "7":
+		return syslog.LOG_LOCAL7, nil
+	}
+	return syslog.LOG_LOCAL0, fmt.Errorf("invalid local(%s) for syslog", facility)
+}
+
+func (s *syslogger) Format(e *logrus.Entry) ([]byte, error) {
+	data, err := s.wrap.Format(e)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "syslogger: can't format entry: %v\n", err)
+		return data, err
+	}
+	// only append tag to data sent to syslog (line), not to what
+	// is returned
+	line := string(append(prefixTag, data...))
+
+	switch e.Level {
+	case logrus.PanicLevel:
+		err = s.out.Crit(line)
+	case logrus.FatalLevel:
+		err = s.out.Crit(line)
+	case logrus.ErrorLevel:
+		err = s.out.Err(line)
+	case logrus.WarnLevel:
+		err = s.out.Warning(line)
+	case logrus.InfoLevel:
+		err = s.out.Info(line)
+	case logrus.DebugLevel:
+		err = s.out.Debug(line)
+	default:
+		err = s.out.Notice(line)
+	}
+
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "syslogger: can't send log to syslog: %v\n", err)
+	}
+
+	return data, err
+}