From 054cf5c5f5bb35b8b0bf05dc2e4a6b05a916ef5e Mon Sep 17 00:00:00 2001
From: Calle Pettersson <carlpett@users.noreply.github.com>
Date: Sat, 30 Jan 2021 11:14:23 +0100
Subject: [PATCH] Include log from prometheus/common/log

Signed-off-by: Calle Pettersson <carlpett@users.noreply.github.com>
---
 log/eventlog_formatter.go |  91 ++++++++++
 log/log.go                | 367 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 458 insertions(+)
 create mode 100644 log/eventlog_formatter.go
 create mode 100644 log/log.go

diff --git a/log/eventlog_formatter.go b/log/eventlog_formatter.go
new file mode 100644
index 00000000..9ad9e31d
--- /dev/null
+++ b/log/eventlog_formatter.go
@@ -0,0 +1,91 @@
+// 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.
+//
+// Implementation forked from github.com/prometheus/common
+//
+// +build windows
+
+package log
+
+import (
+	"fmt"
+	"os"
+
+	"golang.org/x/sys/windows/svc/eventlog"
+
+	"github.com/sirupsen/logrus"
+)
+
+func init() {
+	setEventlogFormatter = func(l logger, name string, debugAsInfo bool) error {
+		if name == "" {
+			return fmt.Errorf("missing name parameter")
+		}
+
+		fmter, err := newEventlogger(name, debugAsInfo, l.entry.Logger.Formatter)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "error creating eventlog formatter: %v\n", err)
+			l.Errorf("can't connect logger to eventlog: %v", err)
+			return err
+		}
+		l.entry.Logger.Formatter = fmter
+		return nil
+	}
+}
+
+type eventlogger struct {
+	log         *eventlog.Log
+	debugAsInfo bool
+	wrap        logrus.Formatter
+}
+
+func newEventlogger(name string, debugAsInfo bool, fmter logrus.Formatter) (*eventlogger, error) {
+	logHandle, err := eventlog.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	return &eventlogger{log: logHandle, debugAsInfo: debugAsInfo, wrap: fmter}, nil
+}
+
+func (s *eventlogger) Format(e *logrus.Entry) ([]byte, error) {
+	data, err := s.wrap.Format(e)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "eventlogger: can't format entry: %v\n", err)
+		return data, err
+	}
+
+	switch e.Level {
+	case logrus.PanicLevel:
+		fallthrough
+	case logrus.FatalLevel:
+		fallthrough
+	case logrus.ErrorLevel:
+		err = s.log.Error(102, e.Message)
+	case logrus.WarnLevel:
+		err = s.log.Warning(101, e.Message)
+	case logrus.InfoLevel:
+		err = s.log.Info(100, e.Message)
+	case logrus.DebugLevel:
+		if s.debugAsInfo {
+			err = s.log.Info(100, e.Message)
+		}
+	default:
+		err = s.log.Info(100, e.Message)
+	}
+
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "eventlogger: can't send log to eventlog: %v\n", err)
+	}
+
+	return data, err
+}
diff --git a/log/log.go b/log/log.go
new file mode 100644
index 00000000..7a8b4b33
--- /dev/null
+++ b/log/log.go
@@ -0,0 +1,367 @@
+// 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.
+
+// Package log implements logging via logrus.
+// Implementation forked from github.com/prometheus/common
+
+package log
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net/url"
+	"os"
+	"runtime"
+	"strconv"
+	"strings"
+
+	"github.com/sirupsen/logrus"
+	"gopkg.in/alecthomas/kingpin.v2"
+)
+
+// setSyslogFormatter is nil if the target architecture does not support syslog.
+var setSyslogFormatter func(logger, string, string) error
+
+// setEventlogFormatter is nil if the target OS does not support Eventlog (i.e., is not Windows).
+var setEventlogFormatter func(logger, string, bool) error
+
+func setJSONFormatter() {
+	origLogger.Formatter = &logrus.JSONFormatter{}
+}
+
+type loggerSettings struct {
+	level  string
+	format string
+}
+
+func (s *loggerSettings) apply(ctx *kingpin.ParseContext) error {
+	err := baseLogger.SetLevel(s.level)
+	if err != nil {
+		return err
+	}
+	err = baseLogger.SetFormat(s.format)
+	return err
+}
+
+// AddFlags adds the flags used by this package to the Kingpin application.
+// To use the default Kingpin application, call AddFlags(kingpin.CommandLine)
+func AddFlags(a *kingpin.Application) {
+	s := loggerSettings{}
+	a.Flag("log.level", "Only log messages with the given severity or above. Valid levels: [debug, info, warn, error, fatal]").
+		Default(origLogger.Level.String()).
+		StringVar(&s.level)
+	defaultFormat := url.URL{Scheme: "logger", Opaque: "stderr"}
+	a.Flag("log.format", `Set the log target and format. Example: "logger:syslog?appname=bob&local=7" or "logger:stdout?json=true"`).
+		Default(defaultFormat.String()).
+		StringVar(&s.format)
+	a.Action(s.apply)
+}
+
+// Logger is the interface for loggers used in the Prometheus components.
+type Logger interface {
+	Debug(...interface{})
+	Debugln(...interface{})
+	Debugf(string, ...interface{})
+
+	Info(...interface{})
+	Infoln(...interface{})
+	Infof(string, ...interface{})
+
+	Warn(...interface{})
+	Warnln(...interface{})
+	Warnf(string, ...interface{})
+
+	Error(...interface{})
+	Errorln(...interface{})
+	Errorf(string, ...interface{})
+
+	Fatal(...interface{})
+	Fatalln(...interface{})
+	Fatalf(string, ...interface{})
+
+	With(key string, value interface{}) Logger
+
+	SetFormat(string) error
+	SetLevel(string) error
+}
+
+type logger struct {
+	entry *logrus.Entry
+}
+
+func (l logger) With(key string, value interface{}) Logger {
+	return logger{l.entry.WithField(key, value)}
+}
+
+// Debug logs a message at level Debug on the standard logger.
+func (l logger) Debug(args ...interface{}) {
+	l.sourced().Debug(args...)
+}
+
+// Debug logs a message at level Debug on the standard logger.
+func (l logger) Debugln(args ...interface{}) {
+	l.sourced().Debugln(args...)
+}
+
+// Debugf logs a message at level Debug on the standard logger.
+func (l logger) Debugf(format string, args ...interface{}) {
+	l.sourced().Debugf(format, args...)
+}
+
+// Info logs a message at level Info on the standard logger.
+func (l logger) Info(args ...interface{}) {
+	l.sourced().Info(args...)
+}
+
+// Info logs a message at level Info on the standard logger.
+func (l logger) Infoln(args ...interface{}) {
+	l.sourced().Infoln(args...)
+}
+
+// Infof logs a message at level Info on the standard logger.
+func (l logger) Infof(format string, args ...interface{}) {
+	l.sourced().Infof(format, args...)
+}
+
+// Warn logs a message at level Warn on the standard logger.
+func (l logger) Warn(args ...interface{}) {
+	l.sourced().Warn(args...)
+}
+
+// Warn logs a message at level Warn on the standard logger.
+func (l logger) Warnln(args ...interface{}) {
+	l.sourced().Warnln(args...)
+}
+
+// Warnf logs a message at level Warn on the standard logger.
+func (l logger) Warnf(format string, args ...interface{}) {
+	l.sourced().Warnf(format, args...)
+}
+
+// Error logs a message at level Error on the standard logger.
+func (l logger) Error(args ...interface{}) {
+	l.sourced().Error(args...)
+}
+
+// Error logs a message at level Error on the standard logger.
+func (l logger) Errorln(args ...interface{}) {
+	l.sourced().Errorln(args...)
+}
+
+// Errorf logs a message at level Error on the standard logger.
+func (l logger) Errorf(format string, args ...interface{}) {
+	l.sourced().Errorf(format, args...)
+}
+
+// Fatal logs a message at level Fatal on the standard logger.
+func (l logger) Fatal(args ...interface{}) {
+	l.sourced().Fatal(args...)
+}
+
+// Fatal logs a message at level Fatal on the standard logger.
+func (l logger) Fatalln(args ...interface{}) {
+	l.sourced().Fatalln(args...)
+}
+
+// Fatalf logs a message at level Fatal on the standard logger.
+func (l logger) Fatalf(format string, args ...interface{}) {
+	l.sourced().Fatalf(format, args...)
+}
+
+func (l logger) SetLevel(level string) error {
+	lvl, err := logrus.ParseLevel(level)
+	if err != nil {
+		return err
+	}
+
+	l.entry.Logger.Level = lvl
+	return nil
+}
+
+func (l logger) SetFormat(format string) error {
+	u, err := url.Parse(format)
+	if err != nil {
+		return err
+	}
+	if u.Scheme != "logger" {
+		return fmt.Errorf("invalid scheme %s", u.Scheme)
+	}
+	jsonq := u.Query().Get("json")
+	if jsonq == "true" {
+		setJSONFormatter()
+	}
+
+	switch u.Opaque {
+	case "syslog":
+		if setSyslogFormatter == nil {
+			return fmt.Errorf("system does not support syslog")
+		}
+		appname := u.Query().Get("appname")
+		facility := u.Query().Get("local")
+		return setSyslogFormatter(l, appname, facility)
+	case "eventlog":
+		if setEventlogFormatter == nil {
+			return fmt.Errorf("system does not support eventlog")
+		}
+		name := u.Query().Get("name")
+		debugAsInfo := false
+		debugAsInfoRaw := u.Query().Get("debugAsInfo")
+		if parsedDebugAsInfo, err := strconv.ParseBool(debugAsInfoRaw); err == nil {
+			debugAsInfo = parsedDebugAsInfo
+		}
+		return setEventlogFormatter(l, name, debugAsInfo)
+	case "stdout":
+		l.entry.Logger.Out = os.Stdout
+	case "stderr":
+		l.entry.Logger.Out = os.Stderr
+	default:
+		return fmt.Errorf("unsupported logger %q", u.Opaque)
+	}
+	return nil
+}
+
+// sourced adds a source field to the logger that contains
+// the file name and line where the logging happened.
+func (l logger) sourced() *logrus.Entry {
+	_, file, line, ok := runtime.Caller(2)
+	if !ok {
+		file = "<???>"
+		line = 1
+	} else {
+		slash := strings.LastIndex(file, "/")
+		file = file[slash+1:]
+	}
+	return l.entry.WithField("source", fmt.Sprintf("%s:%d", file, line))
+}
+
+var origLogger = logrus.New()
+var baseLogger = logger{entry: logrus.NewEntry(origLogger)}
+
+// Base returns the default Logger logging to
+func Base() Logger {
+	return baseLogger
+}
+
+// NewLogger returns a new Logger logging to out.
+func NewLogger(w io.Writer) Logger {
+	l := logrus.New()
+	l.Out = w
+	return logger{entry: logrus.NewEntry(l)}
+}
+
+// NewNopLogger returns a logger that discards all log messages.
+func NewNopLogger() Logger {
+	l := logrus.New()
+	l.Out = ioutil.Discard
+	return logger{entry: logrus.NewEntry(l)}
+}
+
+// With adds a field to the logger.
+func With(key string, value interface{}) Logger {
+	return baseLogger.With(key, value)
+}
+
+// Debug logs a message at level Debug on the standard logger.
+func Debug(args ...interface{}) {
+	baseLogger.sourced().Debug(args...)
+}
+
+// Debugln logs a message at level Debug on the standard logger.
+func Debugln(args ...interface{}) {
+	baseLogger.sourced().Debugln(args...)
+}
+
+// Debugf logs a message at level Debug on the standard logger.
+func Debugf(format string, args ...interface{}) {
+	baseLogger.sourced().Debugf(format, args...)
+}
+
+// Info logs a message at level Info on the standard logger.
+func Info(args ...interface{}) {
+	baseLogger.sourced().Info(args...)
+}
+
+// Infoln logs a message at level Info on the standard logger.
+func Infoln(args ...interface{}) {
+	baseLogger.sourced().Infoln(args...)
+}
+
+// Infof logs a message at level Info on the standard logger.
+func Infof(format string, args ...interface{}) {
+	baseLogger.sourced().Infof(format, args...)
+}
+
+// Warn logs a message at level Warn on the standard logger.
+func Warn(args ...interface{}) {
+	baseLogger.sourced().Warn(args...)
+}
+
+// Warnln logs a message at level Warn on the standard logger.
+func Warnln(args ...interface{}) {
+	baseLogger.sourced().Warnln(args...)
+}
+
+// Warnf logs a message at level Warn on the standard logger.
+func Warnf(format string, args ...interface{}) {
+	baseLogger.sourced().Warnf(format, args...)
+}
+
+// Error logs a message at level Error on the standard logger.
+func Error(args ...interface{}) {
+	baseLogger.sourced().Error(args...)
+}
+
+// Errorln logs a message at level Error on the standard logger.
+func Errorln(args ...interface{}) {
+	baseLogger.sourced().Errorln(args...)
+}
+
+// Errorf logs a message at level Error on the standard logger.
+func Errorf(format string, args ...interface{}) {
+	baseLogger.sourced().Errorf(format, args...)
+}
+
+// Fatal logs a message at level Fatal on the standard logger.
+func Fatal(args ...interface{}) {
+	baseLogger.sourced().Fatal(args...)
+}
+
+// Fatalln logs a message at level Fatal on the standard logger.
+func Fatalln(args ...interface{}) {
+	baseLogger.sourced().Fatalln(args...)
+}
+
+// Fatalf logs a message at level Fatal on the standard logger.
+func Fatalf(format string, args ...interface{}) {
+	baseLogger.sourced().Fatalf(format, args...)
+}
+
+// AddHook adds hook to Prometheus' original logger.
+func AddHook(hook logrus.Hook) {
+	origLogger.Hooks.Add(hook)
+}
+
+type errorLogWriter struct{}
+
+func (errorLogWriter) Write(b []byte) (int, error) {
+	baseLogger.sourced().Error(string(b))
+	return len(b), nil
+}
+
+// NewErrorLogger returns a log.Logger that is meant to be used
+// in the ErrorLog field of an http.Server to log HTTP server errors.
+func NewErrorLogger() *log.Logger {
+	return log.New(&errorLogWriter{}, "", 0)
+}