Update all dependencies.

* Switch to using kingpin for CLI interface as upstream Prometheus has moved
  that way too.

vendor/github.com/Sirupsen/logrus/entry.go

@@ -3,11 +3,21 @@ package logrus
 import (
 	"bytes"
 	"fmt"
-	"io"
 	"os"
+	"sync"
 	"time"
 )
 
+var bufferPool *sync.Pool
+
+func init() {
+	bufferPool = &sync.Pool{
+		New: func() interface{} {
+			return new(bytes.Buffer)
+		},
+	}
+}
+
 // Defines the key when adding errors using WithError.
 var ErrorKey = "error"
 
@@ -25,10 +35,14 @@ type Entry struct {
 	Time time.Time
 
 	// Level the log entry was logged at: Debug, Info, Warn, Error, Fatal or Panic
+	// This field will be set on entry firing and the value will be equal to the one in Logger struct field.
 	Level Level
 
 	// Message passed to Debug, Info, Warn, Error, Fatal or Panic
 	Message string
+
+	// When formatter is called in entry.log(), an Buffer may be set to entry
+	Buffer *bytes.Buffer
 }
 
 func NewEntry(logger *Logger) *Entry {
@@ -39,21 +53,15 @@ func NewEntry(logger *Logger) *Entry {
 	}
 }
 
-// Returns a reader for the entry, which is a proxy to the formatter.
-func (entry *Entry) Reader() (*bytes.Buffer, error) {
-	serialized, err := entry.Logger.Formatter.Format(entry)
-	return bytes.NewBuffer(serialized), err
-}
-
 // Returns the string representation from the reader and ultimately the
 // formatter.
 func (entry *Entry) String() (string, error) {
-	reader, err := entry.Reader()
+	serialized, err := entry.Logger.Formatter.Format(entry)
 	if err != nil {
 		return "", err
 	}
-
-	return reader.String(), err
+	str := string(serialized)
+	return str, nil
 }
 
 // Add an error as single field (using the key defined in ErrorKey) to the Entry.
@@ -68,7 +76,7 @@ func (entry *Entry) WithField(key string, value interface{}) *Entry {
 
 // Add a map of fields to the Entry.
 func (entry *Entry) WithFields(fields Fields) *Entry {
-	data := Fields{}
+	data := make(Fields, len(entry.Data)+len(fields))
 	for k, v := range entry.Data {
 		data[k] = v
 	}
@@ -81,29 +89,36 @@ func (entry *Entry) WithFields(fields Fields) *Entry {
 // This function is not declared with a pointer value because otherwise
 // race conditions will occur when using multiple goroutines
 func (entry Entry) log(level Level, msg string) {
+	var buffer *bytes.Buffer
 	entry.Time = time.Now()
 	entry.Level = level
 	entry.Message = msg
 
-	if err := entry.Logger.Hooks.Fire(level, &entry); err != nil {
+	entry.Logger.mu.Lock()
+	err := entry.Logger.Hooks.Fire(level, &entry)
+	entry.Logger.mu.Unlock()
+	if err != nil {
 		entry.Logger.mu.Lock()
 		fmt.Fprintf(os.Stderr, "Failed to fire hook: %v\n", err)
 		entry.Logger.mu.Unlock()
 	}
-
-	reader, err := entry.Reader()
+	buffer = bufferPool.Get().(*bytes.Buffer)
+	buffer.Reset()
+	defer bufferPool.Put(buffer)
+	entry.Buffer = buffer
+	serialized, err := entry.Logger.Formatter.Format(&entry)
+	entry.Buffer = nil
 	if err != nil {
 		entry.Logger.mu.Lock()
 		fmt.Fprintf(os.Stderr, "Failed to obtain reader, %v\n", err)
 		entry.Logger.mu.Unlock()
-	}
-
-	entry.Logger.mu.Lock()
-	defer entry.Logger.mu.Unlock()
-
-	_, err = io.Copy(entry.Logger.Out, reader)
-	if err != nil {
-		fmt.Fprintf(os.Stderr, "Failed to write to log, %v\n", err)
+	} else {
+		entry.Logger.mu.Lock()
+		_, err = entry.Logger.Out.Write(serialized)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Failed to write to log, %v\n", err)
+		}
+		entry.Logger.mu.Unlock()
 	}
 
 	// To avoid Entry#log() returning a value that only would make sense for
@@ -115,7 +130,7 @@ func (entry Entry) log(level Level, msg string) {
 }
 
 func (entry *Entry) Debug(args ...interface{}) {
-	if entry.Logger.Level >= DebugLevel {
+	if entry.Logger.level() >= DebugLevel {
 		entry.log(DebugLevel, fmt.Sprint(args...))
 	}
 }
@@ -125,13 +140,13 @@ func (entry *Entry) Print(args ...interface{}) {
 }
 
 func (entry *Entry) Info(args ...interface{}) {
-	if entry.Logger.Level >= InfoLevel {
+	if entry.Logger.level() >= InfoLevel {
 		entry.log(InfoLevel, fmt.Sprint(args...))
 	}
 }
 
 func (entry *Entry) Warn(args ...interface{}) {
-	if entry.Logger.Level >= WarnLevel {
+	if entry.Logger.level() >= WarnLevel {
 		entry.log(WarnLevel, fmt.Sprint(args...))
 	}
 }
@@ -141,20 +156,20 @@ func (entry *Entry) Warning(args ...interface{}) {
 }
 
 func (entry *Entry) Error(args ...interface{}) {
-	if entry.Logger.Level >= ErrorLevel {
+	if entry.Logger.level() >= ErrorLevel {
 		entry.log(ErrorLevel, fmt.Sprint(args...))
 	}
 }
 
 func (entry *Entry) Fatal(args ...interface{}) {
-	if entry.Logger.Level >= FatalLevel {
+	if entry.Logger.level() >= FatalLevel {
 		entry.log(FatalLevel, fmt.Sprint(args...))
 	}
-	os.Exit(1)
+	Exit(1)
 }
 
 func (entry *Entry) Panic(args ...interface{}) {
-	if entry.Logger.Level >= PanicLevel {
+	if entry.Logger.level() >= PanicLevel {
 		entry.log(PanicLevel, fmt.Sprint(args...))
 	}
 	panic(fmt.Sprint(args...))
@@ -163,13 +178,13 @@ func (entry *Entry) Panic(args ...interface{}) {
 // Entry Printf family functions
 
 func (entry *Entry) Debugf(format string, args ...interface{}) {
-	if entry.Logger.Level >= DebugLevel {
+	if entry.Logger.level() >= DebugLevel {
 		entry.Debug(fmt.Sprintf(format, args...))
 	}
 }
 
 func (entry *Entry) Infof(format string, args ...interface{}) {
-	if entry.Logger.Level >= InfoLevel {
+	if entry.Logger.level() >= InfoLevel {
 		entry.Info(fmt.Sprintf(format, args...))
 	}
 }
@@ -179,7 +194,7 @@ func (entry *Entry) Printf(format string, args ...interface{}) {
 }
 
 func (entry *Entry) Warnf(format string, args ...interface{}) {
-	if entry.Logger.Level >= WarnLevel {
+	if entry.Logger.level() >= WarnLevel {
 		entry.Warn(fmt.Sprintf(format, args...))
 	}
 }
@@ -189,20 +204,20 @@ func (entry *Entry) Warningf(format string, args ...interface{}) {
 }
 
 func (entry *Entry) Errorf(format string, args ...interface{}) {
-	if entry.Logger.Level >= ErrorLevel {
+	if entry.Logger.level() >= ErrorLevel {
 		entry.Error(fmt.Sprintf(format, args...))
 	}
 }
 
 func (entry *Entry) Fatalf(format string, args ...interface{}) {
-	if entry.Logger.Level >= FatalLevel {
+	if entry.Logger.level() >= FatalLevel {
 		entry.Fatal(fmt.Sprintf(format, args...))
 	}
-	os.Exit(1)
+	Exit(1)
 }
 
 func (entry *Entry) Panicf(format string, args ...interface{}) {
-	if entry.Logger.Level >= PanicLevel {
+	if entry.Logger.level() >= PanicLevel {
 		entry.Panic(fmt.Sprintf(format, args...))
 	}
 }
@@ -210,13 +225,13 @@ func (entry *Entry) Panicf(format string, args ...interface{}) {
 // Entry Println family functions
 
 func (entry *Entry) Debugln(args ...interface{}) {
-	if entry.Logger.Level >= DebugLevel {
+	if entry.Logger.level() >= DebugLevel {
 		entry.Debug(entry.sprintlnn(args...))
 	}
 }
 
 func (entry *Entry) Infoln(args ...interface{}) {
-	if entry.Logger.Level >= InfoLevel {
+	if entry.Logger.level() >= InfoLevel {
 		entry.Info(entry.sprintlnn(args...))
 	}
 }
@@ -226,7 +241,7 @@ func (entry *Entry) Println(args ...interface{}) {
 }
 
 func (entry *Entry) Warnln(args ...interface{}) {
-	if entry.Logger.Level >= WarnLevel {
+	if entry.Logger.level() >= WarnLevel {
 		entry.Warn(entry.sprintlnn(args...))
 	}
 }
@@ -236,20 +251,20 @@ func (entry *Entry) Warningln(args ...interface{}) {
 }
 
 func (entry *Entry) Errorln(args ...interface{}) {
-	if entry.Logger.Level >= ErrorLevel {
+	if entry.Logger.level() >= ErrorLevel {
 		entry.Error(entry.sprintlnn(args...))
 	}
 }
 
 func (entry *Entry) Fatalln(args ...interface{}) {
-	if entry.Logger.Level >= FatalLevel {
+	if entry.Logger.level() >= FatalLevel {
 		entry.Fatal(entry.sprintlnn(args...))
 	}
-	os.Exit(1)
+	Exit(1)
 }
 
 func (entry *Entry) Panicln(args ...interface{}) {
-	if entry.Logger.Level >= PanicLevel {
+	if entry.Logger.level() >= PanicLevel {
 		entry.Panic(entry.sprintlnn(args...))
 	}
 }