Fix problems with wrapped errors in logrus

This vendors a fork of logrus with fixes to deal with errors generated
by the github.com/pkg/errors package. Without these fixes, the errors
are mishandled when passed to WithError:

- When printing to a terminal (colors enabled), stack traces are
  included in the error fields on a log line.

- When printing to a file (or with colors disabled), the error value is
  missing entirely.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>

hack/vendor.sh

@@ -50,7 +50,7 @@ esac
 clone git github.com/Azure/go-ansiterm 388960b655244e76e24c75f48631564eaefade62
 clone git github.com/Microsoft/hcsshim v0.5.1
 clone git github.com/Microsoft/go-winio v0.3.5
-clone git github.com/Sirupsen/logrus v0.10.0 # logrus is a common dependency among multiple deps
+clone git github.com/Sirupsen/logrus f76d643702a30fbffecdfe50831e11881c96ceb3 https://github.com/aaronlehmann/logrus
 clone git github.com/docker/libtrust 9cbd2a1374f46905c68a4eb3694a130610adc62a
 clone git github.com/go-check/check 4ed411733c5785b40214c70bce814c3a3a689609 https://github.com/cpuguy83/check.git
 clone git github.com/gorilla/context v1.1

vendor/src/github.com/Sirupsen/logrus/README.md

@@ -218,6 +218,7 @@ Note: Syslog hook also support connecting to local syslog (Ex. "/dev/log" or "/v
 | [Rollrus](https://github.com/heroku/rollrus) | Hook for sending errors to rollbar |
 | [Fluentd](https://github.com/evalphobia/logrus_fluent) | Hook for logging to fluentd |
 | [Mongodb](https://github.com/weekface/mgorus) | Hook for logging to mongodb |
+| [Influxus] (http://github.com/vlad-doru/influxus) | Hook for concurrently logging to [InfluxDB] (http://influxdata.com/) |
 | [InfluxDB](https://github.com/Abramovic/logrus_influxdb) | Hook for logging to influxdb |
 | [Octokit](https://github.com/dorajistyle/logrus-octokit-hook) | Hook for logging to github via octokit |
 | [DeferPanic](https://github.com/deferpanic/dp-logrus) | Hook for logging to DeferPanic |
@@ -226,6 +227,9 @@ Note: Syslog hook also support connecting to local syslog (Ex. "/dev/log" or "/v
 | [KafkaLogrus](https://github.com/goibibo/KafkaLogrus) | Hook for logging to kafka |
 | [Typetalk](https://github.com/dragon3/logrus-typetalk-hook) | Hook for logging to [Typetalk](https://www.typetalk.in/) |
 | [ElasticSearch](https://github.com/sohlich/elogrus) | Hook for logging to ElasticSearch|
+| [Sumorus](https://github.com/doublefree/sumorus) | Hook for logging to [SumoLogic](https://www.sumologic.com/)|
+| [Logstash](https://github.com/bshuster-repo/logrus-logstash-hook) | Hook for logging to [Logstash](https://www.elastic.co/products/logstash) |
+| [Logmatic.io](https://github.com/logmatic/logmatic-go) | Hook for logging to [Logmatic.io](http://logmatic.io/) |
 
 
 #### Level logging
@@ -304,14 +308,10 @@ The built-in logging formatters are:
     field to `true`.  To force no colored output even if there is a TTY  set the
     `DisableColors` field to `true`
 * `logrus.JSONFormatter`. Logs fields as JSON.
-* `logrus/formatters/logstash.LogstashFormatter`. Logs fields as [Logstash](http://logstash.net) Events.
-
-    ```go
-      logrus.SetFormatter(&logstash.LogstashFormatter{Type: "application_name"})
-    ```
 
 Third party logging formatters:
 
+* [`logstash`](https://github.com/bshuster-repo/logrus-logstash-hook). Logs fields as [Logstash](http://logstash.net) Events.
 * [`prefixed`](https://github.com/x-cray/logrus-prefixed-formatter). Displays log entry source along with alternative layout.
 * [`zalgo`](https://github.com/aybabtme/logzalgo). Invoking the P͉̫o̳̼̊w̖͈̰͎e̬͔̭͂r͚̼̹̲ ̫͓͉̳͈ō̠͕͖̚f̝͍̠ ͕̲̞͖͑Z̖̫̤̫ͪa͉̬͈̗l͖͎g̳̥o̰̥̅!̣͔̲̻͊̄ ̙̘̦̹̦.
 
@@ -386,3 +386,36 @@ assert.Equal("Hello error", hook.LastEntry().Message)
 hook.Reset()
 assert.Nil(hook.LastEntry())
 ```
+
+#### Fatal handlers
+
+Logrus can register one or more functions that will be called when any `fatal`
+level message is logged. The registered handlers will be executed before
+logrus performs a `os.Exit(1)`. This behavior may be helpful if callers need
+to gracefully shutdown. Unlike a `panic("Something went wrong...")` call which can be intercepted with a deferred `recover` a call to `os.Exit(1)` can not be intercepted.
+
+```
+...
+handler := func() {
+  // gracefully shutdown something...
+}
+logrus.RegisterExitHandler(handler)
+...
+```
+
+#### Thread safty
+
+By default Logger is protected by mutex for concurrent writes, this mutex is invoked when calling hooks and writing logs.
+If you are sure such locking is not needed, you can call logger.SetNoLock() to disable the locking.
+
+Situation when locking is not needed includes:
+
+* You have no hooks registered, or hooks calling is already thread-safe.
+
+* Writing to logger.Out is already thread-safe, for example:
+
+  1) logger.Out is protected by locks.
+
+  2) logger.Out is a os.File handler opened with `O_APPEND` flag, and every write is smaller than 4k. (This allow multi-thread/multi-process writing)
+
+     (Refer to http://www.notthewizard.com/2014/06/17/are-files-appends-really-atomic/)

vendor/src/github.com/Sirupsen/logrus/alt_exit.go

@@ -0,0 +1,64 @@
+package logrus
+
+// The following code was sourced and modified from the
+// https://bitbucket.org/tebeka/atexit package governed by the following license:
+//
+// Copyright (c) 2012 Miki Tebeka <miki.tebeka@gmail.com>.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy of
+// this software and associated documentation files (the "Software"), to deal in
+// the Software without restriction, including without limitation the rights to
+// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+// the Software, and to permit persons to whom the Software is furnished to do so,
+// subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+import (
+	"fmt"
+	"os"
+)
+
+var handlers = []func(){}
+
+func runHandler(handler func()) {
+	defer func() {
+		if err := recover(); err != nil {
+			fmt.Fprintln(os.Stderr, "Error: Logrus exit handler error:", err)
+		}
+	}()
+
+	handler()
+}
+
+func runHandlers() {
+	for _, handler := range handlers {
+		runHandler(handler)
+	}
+}
+
+// Exit runs all the Logrus atexit handlers and then terminates the program using os.Exit(code)
+func Exit(code int) {
+	runHandlers()
+	os.Exit(code)
+}
+
+// RegisterExitHandler adds a Logrus Exit handler, call logrus.Exit to invoke
+// all handlers. The handlers will also be invoked when any Fatal log entry is
+// made.
+//
+// This method is useful when a caller wishes to use logrus to log a fatal
+// message but also needs to gracefully shutdown. An example usecase could be
+// closing database connections, or sending a alert that the application is
+// closing.
+func RegisterExitHandler(handler func()) {
+	handlers = append(handlers, handler)
+}

vendor/src/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"
 
@@ -29,6 +39,9 @@ type Entry struct {
 
 	// 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 +52,15 @@ 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
 	}
-
+	str := string(serialized)
-	return reader.String(), err
+	return str, nil
 }
 
 // Add an error as single field (using the key defined in ErrorKey) to the Entry.
@@ -81,6 +88,7 @@ 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
@@ -90,20 +98,23 @@ func (entry Entry) log(level Level, msg string) {
 		fmt.Fprintf(os.Stderr, "Failed to fire hook: %v\n", err)
 		entry.Logger.mu.Unlock()
 	}
-
+	buffer = bufferPool.Get().(*bytes.Buffer)
-	reader, err := entry.Reader()
+	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()
-	}
+	} else {
-
+		entry.Logger.mu.Lock()
-	entry.Logger.mu.Lock()
+		_, err = entry.Logger.Out.Write(serialized)
-	defer entry.Logger.mu.Unlock()
+		if err != nil {
-
+			fmt.Fprintf(os.Stderr, "Failed to write to log, %v\n", err)
-	_, err = io.Copy(entry.Logger.Out, reader)
+		}
-	if err != nil {
+		entry.Logger.mu.Unlock()
-		fmt.Fprintf(os.Stderr, "Failed to write to log, %v\n", err)
 	}
 
 	// To avoid Entry#log() returning a value that only would make sense for
@@ -150,7 +161,7 @@ func (entry *Entry) Fatal(args ...interface{}) {
 	if entry.Logger.Level >= FatalLevel {
 		entry.log(FatalLevel, fmt.Sprint(args...))
 	}
-	os.Exit(1)
+	Exit(1)
 }
 
 func (entry *Entry) Panic(args ...interface{}) {
@@ -198,7 +209,7 @@ func (entry *Entry) Fatalf(format string, args ...interface{}) {
 	if entry.Logger.Level >= FatalLevel {
 		entry.Fatal(fmt.Sprintf(format, args...))
 	}
-	os.Exit(1)
+	Exit(1)
 }
 
 func (entry *Entry) Panicf(format string, args ...interface{}) {
@@ -245,7 +256,7 @@ func (entry *Entry) Fatalln(args ...interface{}) {
 	if entry.Logger.Level >= FatalLevel {
 		entry.Fatal(entry.sprintlnn(args...))
 	}
-	os.Exit(1)
+	Exit(1)
 }
 
 func (entry *Entry) Panicln(args ...interface{}) {

vendor/src/github.com/Sirupsen/logrus/formatter.go

@@ -31,18 +31,15 @@ type Formatter interface {
 // It's not exported because it's still using Data in an opinionated way. It's to
 // avoid code duplication between the two default formatters.
 func prefixFieldClashes(data Fields) {
-	_, ok := data["time"]
+	if t, ok := data["time"]; ok {
-	if ok {
+		data["fields.time"] = t
-		data["fields.time"] = data["time"]
 	}
 
-	_, ok = data["msg"]
+	if m, ok := data["msg"]; ok {
-	if ok {
+		data["fields.msg"] = m
-		data["fields.msg"] = data["msg"]
 	}
 
-	_, ok = data["level"]
+	if l, ok := data["level"]; ok {
-	if ok {
+		data["fields.level"] = l
-		data["fields.level"] = data["level"]
 	}
 }

vendor/src/github.com/Sirupsen/logrus/logger.go

@@ -26,8 +26,31 @@ type Logger struct {
 	// to) `logrus.Info`, which allows Info(), Warn(), Error() and Fatal() to be
 	// logged. `logrus.Debug` is useful in
 	Level Level
-	// Used to sync writing to the log.
+	// Used to sync writing to the log. Locking is enabled by Default
-	mu sync.Mutex
+	mu MutexWrap
+	// Reusable empty entry
+	entryPool sync.Pool
+}
+
+type MutexWrap struct {
+	lock     sync.Mutex
+	disabled bool
+}
+
+func (mw *MutexWrap) Lock() {
+	if !mw.disabled {
+		mw.lock.Lock()
+	}
+}
+
+func (mw *MutexWrap) Unlock() {
+	if !mw.disabled {
+		mw.lock.Unlock()
+	}
+}
+
+func (mw *MutexWrap) Disable() {
+	mw.disabled = true
 }
 
 // Creates a new logger. Configuration should be set by changing `Formatter`,
@@ -51,162 +74,235 @@ func New() *Logger {
 	}
 }
 
-// Adds a field to the log entry, note that you it doesn't log until you call
+func (logger *Logger) newEntry() *Entry {
+	entry, ok := logger.entryPool.Get().(*Entry)
+	if ok {
+		return entry
+	}
+	return NewEntry(logger)
+}
+
+func (logger *Logger) releaseEntry(entry *Entry) {
+	logger.entryPool.Put(entry)
+}
+
+// Adds a field to the log entry, note that it doesn't log until you call
 // Debug, Print, Info, Warn, Fatal or Panic. It only creates a log entry.
 // If you want multiple fields, use `WithFields`.
 func (logger *Logger) WithField(key string, value interface{}) *Entry {
-	return NewEntry(logger).WithField(key, value)
+	entry := logger.newEntry()
+	defer logger.releaseEntry(entry)
+	return entry.WithField(key, value)
 }
 
 // Adds a struct of fields to the log entry. All it does is call `WithField` for
 // each `Field`.
 func (logger *Logger) WithFields(fields Fields) *Entry {
-	return NewEntry(logger).WithFields(fields)
+	entry := logger.newEntry()
+	defer logger.releaseEntry(entry)
+	return entry.WithFields(fields)
 }
 
 // Add an error as single field to the log entry.  All it does is call
 // `WithError` for the given `error`.
 func (logger *Logger) WithError(err error) *Entry {
-	return NewEntry(logger).WithError(err)
+	entry := logger.newEntry()
+	defer logger.releaseEntry(entry)
+	return entry.WithError(err)
 }
 
 func (logger *Logger) Debugf(format string, args ...interface{}) {
 	if logger.Level >= DebugLevel {
-		NewEntry(logger).Debugf(format, args...)
+		entry := logger.newEntry()
+		entry.Debugf(format, args...)
+		logger.releaseEntry(entry)
 	}
 }
 
 func (logger *Logger) Infof(format string, args ...interface{}) {
 	if logger.Level >= InfoLevel {
-		NewEntry(logger).Infof(format, args...)
+		entry := logger.newEntry()
+		entry.Infof(format, args...)
+		logger.releaseEntry(entry)
 	}
 }
 
 func (logger *Logger) Printf(format string, args ...interface{}) {
-	NewEntry(logger).Printf(format, args...)
+	entry := logger.newEntry()
+	entry.Printf(format, args...)
+	logger.releaseEntry(entry)
 }
 
 func (logger *Logger) Warnf(format string, args ...interface{}) {
 	if logger.Level >= WarnLevel {
-		NewEntry(logger).Warnf(format, args...)
+		entry := logger.newEntry()
+		entry.Warnf(format, args...)
+		logger.releaseEntry(entry)
 	}
 }
 
 func (logger *Logger) Warningf(format string, args ...interface{}) {
 	if logger.Level >= WarnLevel {
-		NewEntry(logger).Warnf(format, args...)
+		entry := logger.newEntry()
+		entry.Warnf(format, args...)
+		logger.releaseEntry(entry)
 	}
 }
 
 func (logger *Logger) Errorf(format string, args ...interface{}) {
 	if logger.Level >= ErrorLevel {
-		NewEntry(logger).Errorf(format, args...)
+		entry := logger.newEntry()
+		entry.Errorf(format, args...)
+		logger.releaseEntry(entry)
 	}
 }
 
 func (logger *Logger) Fatalf(format string, args ...interface{}) {
 	if logger.Level >= FatalLevel {
-		NewEntry(logger).Fatalf(format, args...)
+		entry := logger.newEntry()
+		entry.Fatalf(format, args...)
+		logger.releaseEntry(entry)
 	}
-	os.Exit(1)
+	Exit(1)
 }
 
 func (logger *Logger) Panicf(format string, args ...interface{}) {
 	if logger.Level >= PanicLevel {
-		NewEntry(logger).Panicf(format, args...)
+		entry := logger.newEntry()
+		entry.Panicf(format, args...)
+		logger.releaseEntry(entry)
 	}
 }
 
 func (logger *Logger) Debug(args ...interface{}) {
 	if logger.Level >= DebugLevel {
-		NewEntry(logger).Debug(args...)
+		entry := logger.newEntry()
+		entry.Debug(args...)
+		logger.releaseEntry(entry)
 	}
 }
 
 func (logger *Logger) Info(args ...interface{}) {
 	if logger.Level >= InfoLevel {
-		NewEntry(logger).Info(args...)
+		entry := logger.newEntry()
+		entry.Info(args...)
+		logger.releaseEntry(entry)
 	}
 }
 
 func (logger *Logger) Print(args ...interface{}) {
-	NewEntry(logger).Info(args...)
+	entry := logger.newEntry()
+	entry.Info(args...)
+	logger.releaseEntry(entry)
 }
 
 func (logger *Logger) Warn(args ...interface{}) {
 	if logger.Level >= WarnLevel {
-		NewEntry(logger).Warn(args...)
+		entry := logger.newEntry()
+		entry.Warn(args...)
+		logger.releaseEntry(entry)
 	}
 }
 
 func (logger *Logger) Warning(args ...interface{}) {
 	if logger.Level >= WarnLevel {
-		NewEntry(logger).Warn(args...)
+		entry := logger.newEntry()
+		entry.Warn(args...)
+		logger.releaseEntry(entry)
 	}
 }
 
 func (logger *Logger) Error(args ...interface{}) {
 	if logger.Level >= ErrorLevel {
-		NewEntry(logger).Error(args...)
+		entry := logger.newEntry()
+		entry.Error(args...)
+		logger.releaseEntry(entry)
 	}
 }
 
 func (logger *Logger) Fatal(args ...interface{}) {
 	if logger.Level >= FatalLevel {
-		NewEntry(logger).Fatal(args...)
+		entry := logger.newEntry()
+		entry.Fatal(args...)
+		logger.releaseEntry(entry)
 	}
-	os.Exit(1)
+	Exit(1)
 }
 
 func (logger *Logger) Panic(args ...interface{}) {
 	if logger.Level >= PanicLevel {
-		NewEntry(logger).Panic(args...)
+		entry := logger.newEntry()
+		entry.Panic(args...)
+		logger.releaseEntry(entry)
 	}
 }
 
 func (logger *Logger) Debugln(args ...interface{}) {
 	if logger.Level >= DebugLevel {
-		NewEntry(logger).Debugln(args...)
+		entry := logger.newEntry()
+		entry.Debugln(args...)
+		logger.releaseEntry(entry)
 	}
 }
 
 func (logger *Logger) Infoln(args ...interface{}) {
 	if logger.Level >= InfoLevel {
-		NewEntry(logger).Infoln(args...)
+		entry := logger.newEntry()
+		entry.Infoln(args...)
+		logger.releaseEntry(entry)
 	}
 }
 
 func (logger *Logger) Println(args ...interface{}) {
-	NewEntry(logger).Println(args...)
+	entry := logger.newEntry()
+	entry.Println(args...)
+	logger.releaseEntry(entry)
 }
 
 func (logger *Logger) Warnln(args ...interface{}) {
 	if logger.Level >= WarnLevel {
-		NewEntry(logger).Warnln(args...)
+		entry := logger.newEntry()
+		entry.Warnln(args...)
+		logger.releaseEntry(entry)
 	}
 }
 
 func (logger *Logger) Warningln(args ...interface{}) {
 	if logger.Level >= WarnLevel {
-		NewEntry(logger).Warnln(args...)
+		entry := logger.newEntry()
+		entry.Warnln(args...)
+		logger.releaseEntry(entry)
 	}
 }
 
 func (logger *Logger) Errorln(args ...interface{}) {
 	if logger.Level >= ErrorLevel {
-		NewEntry(logger).Errorln(args...)
+		entry := logger.newEntry()
+		entry.Errorln(args...)
+		logger.releaseEntry(entry)
 	}
 }
 
 func (logger *Logger) Fatalln(args ...interface{}) {
 	if logger.Level >= FatalLevel {
-		NewEntry(logger).Fatalln(args...)
+		entry := logger.newEntry()
+		entry.Fatalln(args...)
+		logger.releaseEntry(entry)
 	}
-	os.Exit(1)
+	Exit(1)
 }
 
 func (logger *Logger) Panicln(args ...interface{}) {
 	if logger.Level >= PanicLevel {
-		NewEntry(logger).Panicln(args...)
+		entry := logger.newEntry()
+		entry.Panicln(args...)
+		logger.releaseEntry(entry)
 	}
 }
+
+//When file is opened with appending mode, it's safe to
+//write concurrently to a file (within 4k message on Linux).
+//In these cases user can choose to disable the lock.
+func (logger *Logger) SetNoLock() {
+	logger.mu.Disable()
+}

vendor/src/github.com/Sirupsen/logrus/terminal_appengine.go

@@ -0,0 +1,8 @@
+// +build appengine
+
+package logrus
+
+// IsTerminal returns true if stderr's file descriptor is a terminal.
+func IsTerminal() bool {
+	return true
+}

vendor/src/github.com/Sirupsen/logrus/terminal_bsd.go

@@ -1,4 +1,5 @@
 // +build darwin freebsd openbsd netbsd dragonfly
+// +build !appengine
 
 package logrus
 

vendor/src/github.com/Sirupsen/logrus/terminal_linux.go

@@ -3,6 +3,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build !appengine
+
 package logrus
 
 import "syscall"

vendor/src/github.com/Sirupsen/logrus/terminal_notwindows.go

@@ -4,6 +4,7 @@
 // license that can be found in the LICENSE file.
 
 // +build linux darwin freebsd openbsd netbsd dragonfly
+// +build !appengine
 
 package logrus
 

vendor/src/github.com/Sirupsen/logrus/terminal_solaris.go

@@ -1,4 +1,4 @@
-// +build solaris
+// +build solaris,!appengine
 
 package logrus
 

vendor/src/github.com/Sirupsen/logrus/terminal_windows.go

@@ -3,7 +3,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build windows
+// +build windows,!appengine
 
 package logrus
 

vendor/src/github.com/Sirupsen/logrus/text_formatter.go

@@ -57,6 +57,7 @@ type TextFormatter struct {
 }
 
 func (f *TextFormatter) Format(entry *Entry) ([]byte, error) {
+	var b *bytes.Buffer
 	var keys []string = make([]string, 0, len(entry.Data))
 	for k := range entry.Data {
 		keys = append(keys, k)
@@ -65,8 +66,11 @@ func (f *TextFormatter) Format(entry *Entry) ([]byte, error) {
 	if !f.DisableSorting {
 		sort.Strings(keys)
 	}
-
+	if entry.Buffer != nil {
-	b := &bytes.Buffer{}
+		b = entry.Buffer
+	} else {
+		b = &bytes.Buffer{}
+	}
 
 	prefixFieldClashes(entry.Data)
 
@@ -118,7 +122,8 @@ func (f *TextFormatter) printColored(b *bytes.Buffer, entry *Entry, keys []strin
 	}
 	for _, k := range keys {
 		v := entry.Data[k]
-		fmt.Fprintf(b, " \x1b[%dm%s\x1b[0m=%+v", levelColor, k, v)
+		fmt.Fprintf(b, " \x1b[%dm%s\x1b[0m=", levelColor, k)
+		f.appendValue(b, v)
 	}
 }
 
@@ -128,34 +133,36 @@ func needsQuoting(text string) bool {
 			(ch >= 'A' && ch <= 'Z') ||
 			(ch >= '0' && ch <= '9') ||
 			ch == '-' || ch == '.') {
-			return false
+			return true
 		}
 	}
-	return true
+	return false
 }
 
 func (f *TextFormatter) appendKeyValue(b *bytes.Buffer, key string, value interface{}) {
 
 	b.WriteString(key)
 	b.WriteByte('=')
+	f.appendValue(b, value)
+	b.WriteByte(' ')
+}
 
+func (f *TextFormatter) appendValue(b *bytes.Buffer, value interface{}) {
 	switch value := value.(type) {
 	case string:
-		if needsQuoting(value) {
+		if !needsQuoting(value) {
 			b.WriteString(value)
 		} else {
 			fmt.Fprintf(b, "%q", value)
 		}
 	case error:
 		errmsg := value.Error()
-		if needsQuoting(errmsg) {
+		if !needsQuoting(errmsg) {
 			b.WriteString(errmsg)
 		} else {
-			fmt.Fprintf(b, "%q", value)
+			fmt.Fprintf(b, "%q", errmsg)
 		}
 	default:
 		fmt.Fprint(b, value)
 	}
-
-	b.WriteByte(' ')
 }

vendor/src/github.com/Sirupsen/logrus/writer.go

@@ -7,18 +7,40 @@ import (
 )
 
 func (logger *Logger) Writer() *io.PipeWriter {
+	return logger.WriterLevel(InfoLevel)
+}
+
+func (logger *Logger) WriterLevel(level Level) *io.PipeWriter {
 	reader, writer := io.Pipe()
 
-	go logger.writerScanner(reader)
+	var printFunc func(args ...interface{})
+	switch level {
+	case DebugLevel:
+		printFunc = logger.Debug
+	case InfoLevel:
+		printFunc = logger.Info
+	case WarnLevel:
+		printFunc = logger.Warn
+	case ErrorLevel:
+		printFunc = logger.Error
+	case FatalLevel:
+		printFunc = logger.Fatal
+	case PanicLevel:
+		printFunc = logger.Panic
+	default:
+		printFunc = logger.Print
+	}
+
+	go logger.writerScanner(reader, printFunc)
 	runtime.SetFinalizer(writer, writerFinalizer)
 
 	return writer
 }
 
-func (logger *Logger) writerScanner(reader *io.PipeReader) {
+func (logger *Logger) writerScanner(reader *io.PipeReader, printFunc func(args ...interface{})) {
 	scanner := bufio.NewScanner(reader)
 	for scanner.Scan() {
-		logger.Print(scanner.Text())
+		printFunc(scanner.Text())
 	}
 	if err := scanner.Err(); err != nil {
 		logger.Errorf("Error while reading from Writer: %s", err)