switch to go-kit/log (#1575)

Signed-off-by: yeya24 <yb532204897@gmail.com>

vendor/github.com/prometheus/common/promlog/flag/flag.go

@@ -0,0 +1,45 @@
+// Copyright 2017 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 flag
+
+import (
+	"github.com/prometheus/common/promlog"
+	kingpin "gopkg.in/alecthomas/kingpin.v2"
+)
+
+// LevelFlagName is the canonical flag name to configure the allowed log level
+// within Prometheus projects.
+const LevelFlagName = "log.level"
+
+// LevelFlagHelp is the help description for the log.level flag.
+const LevelFlagHelp = "Only log messages with the given severity or above. One of: [debug, info, warn, error]"
+
+// FormatFlagName is the canonical flag name to configure the log format
+// within Prometheus projects.
+const FormatFlagName = "log.format"
+
+// FormatFlagHelp is the help description for the log.format flag.
+const FormatFlagHelp = "Output format of log messages. One of: [logfmt, json]"
+
+// 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, config *promlog.Config) {
+	config.Level = &promlog.AllowedLevel{}
+	a.Flag(LevelFlagName, LevelFlagHelp).
+		Default("info").SetValue(config.Level)
+
+	config.Format = &promlog.AllowedFormat{}
+	a.Flag(FormatFlagName, FormatFlagHelp).
+		Default("logfmt").SetValue(config.Format)
+}

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

@@ -0,0 +1,106 @@
+// Copyright 2017 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 promlog defines standardised ways to initialize Go kit loggers
+// across Prometheus components.
+// It should typically only ever be imported by main packages.
+package promlog
+
+import (
+	"os"
+	"time"
+
+	"github.com/go-kit/kit/log"
+	"github.com/go-kit/kit/log/level"
+	"github.com/pkg/errors"
+)
+
+var (
+	// This timestamp format differs from RFC3339Nano by using .000 instead
+	// of .999999999 which changes the timestamp from 9 variable to 3 fixed
+	// decimals (.130 instead of .130987456).
+	timestampFormat = log.TimestampFormat(
+		func() time.Time { return time.Now().UTC() },
+		"2006-01-02T15:04:05.000Z07:00",
+	)
+)
+
+// AllowedLevel is a settable identifier for the minimum level a log entry
+// must be have.
+type AllowedLevel struct {
+	s string
+	o level.Option
+}
+
+func (l *AllowedLevel) String() string {
+	return l.s
+}
+
+// Set updates the value of the allowed level.
+func (l *AllowedLevel) Set(s string) error {
+	switch s {
+	case "debug":
+		l.o = level.AllowDebug()
+	case "info":
+		l.o = level.AllowInfo()
+	case "warn":
+		l.o = level.AllowWarn()
+	case "error":
+		l.o = level.AllowError()
+	default:
+		return errors.Errorf("unrecognized log level %q", s)
+	}
+	l.s = s
+	return nil
+}
+
+// AllowedFormat is a settable identifier for the output format that the logger can have.
+type AllowedFormat struct {
+	s string
+}
+
+func (f *AllowedFormat) String() string {
+	return f.s
+}
+
+// Set updates the value of the allowed format.
+func (f *AllowedFormat) Set(s string) error {
+	switch s {
+	case "logfmt", "json":
+		f.s = s
+	default:
+		return errors.Errorf("unrecognized log format %q", s)
+	}
+	return nil
+}
+
+// Config is a struct containing configurable settings for the logger
+type Config struct {
+	Level  *AllowedLevel
+	Format *AllowedFormat
+}
+
+// New returns a new leveled oklog logger. Each logged line will be annotated
+// with a timestamp. The output always goes to stderr.
+func New(config *Config) log.Logger {
+	var l log.Logger
+	if config.Format.s == "logfmt" {
+		l = log.NewLogfmtLogger(log.NewSyncWriter(os.Stderr))
+	} else {
+		l = log.NewJSONLogger(log.NewSyncWriter(os.Stderr))
+	}
+
+	l = level.NewFilter(l, config.Level.o)
+	l = log.With(l, "ts", timestampFormat, "caller", log.DefaultCaller)
+	return l
+}