Merge remote-tracking branch 'upstream/master'

.travis.yml

@@ -1,9 +1,7 @@
 language: go
 go:
-  - 1.8.x
   - 1.9.x
   - 1.10.x
-  - tip
 env:
   - GOMAXPROCS=4 GORACE=halt_on_error=1
 install:

entry.go

@@ -83,14 +83,28 @@ func (entry *Entry) WithFields(fields Fields) *Entry {
 	for k, v := range fields {
 		data[k] = v
 	}
-	return &Entry{Logger: entry.Logger, Data: data}
+	return &Entry{Logger: entry.Logger, Data: data, Time: entry.Time}
+}
+
+// Overrides the time of the Entry.
+func (entry *Entry) WithTime(t time.Time) *Entry {
+	return &Entry{Logger: entry.Logger, Data: entry.Data, Time: t}
 }
 
 // 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
+
+	// Default to now, but allow users to override if they want.
+	//
+	// We don't have to worry about polluting future calls to Entry#log()
+	// with this assignment because this function is declared with a
+	// non-pointer receiver.
+	if entry.Time.IsZero() {
 		entry.Time = time.Now()
+	}
+
 	entry.Level = level
 	entry.Message = msg
 
@@ -113,21 +127,19 @@ func (entry Entry) log(level Level, msg string) {
 	}
 }
 
-// This function is not declared with a pointer value because otherwise
-// race conditions will occur when using multiple goroutines
-func (entry Entry) fireHooks() {
+func (entry *Entry) fireHooks() {
 	entry.Logger.mu.Lock()
 	defer entry.Logger.mu.Unlock()
-	err := entry.Logger.Hooks.Fire(entry.Level, &entry)
+	err := entry.Logger.Hooks.Fire(entry.Level, entry)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "Failed to fire hook: %v\n", err)
 	}
 }
 
 func (entry *Entry) write() {
-	serialized, err := entry.Logger.Formatter.Format(entry)
 	entry.Logger.mu.Lock()
 	defer entry.Logger.mu.Unlock()
+	serialized, err := entry.Logger.Formatter.Format(entry)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "Failed to obtain reader, %v\n", err)
 	} else {

exported.go

@@ -2,6 +2,7 @@ package logrus
 
 import (
 	"io"
+	"time"
 )
 
 var (
@@ -15,30 +16,22 @@ func StandardLogger() *Logger {
 
 // SetOutput sets the standard logger output.
 func SetOutput(out io.Writer) {
-	std.mu.Lock()
-	defer std.mu.Unlock()
-	std.Out = out
+	std.SetOutput(out)
 }
 
 // SetFormatter sets the standard logger formatter.
 func SetFormatter(formatter Formatter) {
-	std.mu.Lock()
-	defer std.mu.Unlock()
-	std.Formatter = formatter
+	std.SetFormatter(formatter)
 }
 
 // SetLevel sets the standard logger level.
 func SetLevel(level Level) {
-	std.mu.Lock()
-	defer std.mu.Unlock()
 	std.SetLevel(level)
 }
 
 // GetLevel returns the standard logger level.
 func GetLevel() Level {
-	std.mu.Lock()
-	defer std.mu.Unlock()
-	return std.level()
+	return std.GetLevel()
 }
 
 func IsDebugEnabled() bool {
@@ -67,9 +60,7 @@ func IsPanicEnabled() bool {
 
 // AddHook adds a hook to the standard logger hooks.
 func AddHook(hook Hook) {
-	std.mu.Lock()
-	defer std.mu.Unlock()
-	std.Hooks.Add(hook)
+	std.AddHook(hook)
 }
 
 // WithError creates an entry from the standard logger and adds an error to it, using the value defined in ErrorKey as key.
@@ -96,6 +87,15 @@ func WithFields(fields Fields) *Entry {
 	return std.WithFields(fields)
 }
 
+// WithTime creats an entry from the standard logger and overrides the time of
+// logs generated with it.
+//
+// Note that it doesn't log until you call Debug, Print, Info, Warn, Fatal
+// or Panic on the Entry it returns.
+func WithTime(t time.Time) *Entry {
+	return std.WithTime(t)
+}
+
 // Debug logs a message at level Debug on the standard logger.
 func Debug(args ...interface{}) {
 	std.Debug(args...)
@@ -131,7 +131,7 @@ func Panic(args ...interface{}) {
 	std.Panic(args...)
 }
 
-// Fatal logs a message at level Fatal on the standard logger.
+// Fatal logs a message at level Fatal on the standard logger then the process will exit with status set to 1.
 func Fatal(args ...interface{}) {
 	std.Fatal(args...)
 }
@@ -171,7 +171,7 @@ func Panicf(format string, args ...interface{}) {
 	std.Panicf(format, args...)
 }
 
-// Fatalf logs a message at level Fatal on the standard logger.
+// Fatalf logs a message at level Fatal on the standard logger then the process will exit with status set to 1.
 func Fatalf(format string, args ...interface{}) {
 	std.Fatalf(format, args...)
 }
@@ -211,7 +211,7 @@ func Panicln(args ...interface{}) {
 	std.Panicln(args...)
 }
 
-// Fatalln logs a message at level Fatal on the standard logger.
+// Fatalln logs a message at level Fatal on the standard logger then the process will exit with status set to 1.
 func Fatalln(args ...interface{}) {
 	std.Fatalln(args...)
 }

formatter.go

@@ -34,15 +34,18 @@ func prefixFieldClashes(data Fields, fieldMap FieldMap) {
 	timeKey := fieldMap.resolve(FieldKeyTime)
 	if t, ok := data[timeKey]; ok {
 		data["fields."+timeKey] = t
+		delete(data, timeKey)
 	}
 
 	msgKey := fieldMap.resolve(FieldKeyMsg)
 	if m, ok := data[msgKey]; ok {
 		data["fields."+msgKey] = m
+		delete(data, msgKey)
 	}
 
 	levelKey := fieldMap.resolve(FieldKeyLevel)
 	if l, ok := data[levelKey]; ok {
 		data["fields."+levelKey] = l
+		delete(data, levelKey)
 	}
 }

hook_test.go

@@ -1,10 +1,13 @@
 package logrus
 
 import (
+	"bytes"
+	"encoding/json"
 	"sync"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 type TestHook struct {
@@ -85,6 +88,46 @@ func TestCanFireMultipleHooks(t *testing.T) {
 	})
 }
 
+type SingleLevelModifyHook struct {
+	ModifyHook
+}
+
+func (h *SingleLevelModifyHook) Levels() []Level {
+	return []Level{InfoLevel}
+}
+
+func TestHookEntryIsPristine(t *testing.T) {
+	l := New()
+	b := &bytes.Buffer{}
+	l.Formatter = &JSONFormatter{}
+	l.Out = b
+	l.AddHook(&SingleLevelModifyHook{})
+
+	l.Error("error message")
+	data := map[string]string{}
+	err := json.Unmarshal(b.Bytes(), &data)
+	require.NoError(t, err)
+	_, ok := data["wow"]
+	require.False(t, ok)
+	b.Reset()
+
+	l.Info("error message")
+	data = map[string]string{}
+	err = json.Unmarshal(b.Bytes(), &data)
+	require.NoError(t, err)
+	_, ok = data["wow"]
+	require.True(t, ok)
+	b.Reset()
+
+	l.Error("error message")
+	data = map[string]string{}
+	err = json.Unmarshal(b.Bytes(), &data)
+	require.NoError(t, err)
+	_, ok = data["wow"]
+	require.False(t, ok)
+	b.Reset()
+}
+
 type ErrorHook struct {
 	Fired bool
 }

hooks/test/test.go

@@ -15,7 +15,7 @@ type Hook struct {
 	// Entries is an array of all entries that have been received by this hook.
 	// For safe access, use the AllEntries() method, rather than reading this
 	// value directly.
-	Entries []*logrus.Entry
+	Entries []logrus.Entry
 	mu      sync.RWMutex
 }
 
@@ -52,7 +52,7 @@ func NewNullLogger() (*logrus.Logger, *Hook) {
 func (t *Hook) Fire(e *logrus.Entry) error {
 	t.mu.Lock()
 	defer t.mu.Unlock()
-	t.Entries = append(t.Entries, e)
+	t.Entries = append(t.Entries, *e)
 	return nil
 }
 
@@ -68,9 +68,7 @@ func (t *Hook) LastEntry() *logrus.Entry {
 	if i < 0 {
 		return nil
 	}
-	// Make a copy, for safety
-	e := *t.Entries[i]
-	return &e
+	return &t.Entries[i]
 }
 
 // AllEntries returns all entries that were logged.
@@ -79,10 +77,9 @@ func (t *Hook) AllEntries() []*logrus.Entry {
 	defer t.mu.RUnlock()
 	// Make a copy so the returned value won't race with future log requests
 	entries := make([]*logrus.Entry, len(t.Entries))
-	for i, entry := range t.Entries {
+	for i := 0; i < len(t.Entries); i++ {
 		// Make a copy, for safety
-		e := *entry
-		entries[i] = &e
+		entries[i] = &t.Entries[i]
 	}
 	return entries
 }
@@ -91,5 +88,5 @@ func (t *Hook) AllEntries() []*logrus.Entry {
 func (t *Hook) Reset() {
 	t.mu.Lock()
 	defer t.mu.Unlock()
-	t.Entries = make([]*logrus.Entry, 0)
+	t.Entries = make([]logrus.Entry, 0)
 }

hooks/test/test_test.go

@@ -1,8 +1,10 @@
 package test
 
 import (
+	"math/rand"
 	"sync"
 	"testing"
+	"time"
 
 	"github.com/sirupsen/logrus"
 	"github.com/stretchr/testify/assert"
@@ -38,24 +40,34 @@ func TestAllHooks(t *testing.T) {
 }
 
 func TestLoggingWithHooksRace(t *testing.T) {
+
+	rand.Seed(time.Now().Unix())
+	unlocker := rand.Int() % 100
+
 	assert := assert.New(t)
 	logger, hook := NewNullLogger()
 
-	var wg sync.WaitGroup
-	wg.Add(100)
+	var wgOne, wgAll sync.WaitGroup
+	wgOne.Add(1)
+	wgAll.Add(100)
 
 	for i := 0; i < 100; i++ {
-		go func() {
+		go func(i int) {
 			logger.Info("info")
-			wg.Done()
-		}()
+			wgAll.Done()
+			if i == unlocker {
+				wgOne.Done()
+			}
+		}(i)
 	}
 
-	wg.Wait()
+	wgOne.Wait()
 
 	assert.Equal(logrus.InfoLevel, hook.LastEntry().Level)
 	assert.Equal("info", hook.LastEntry().Message)
 
+	wgAll.Wait()
+
 	entries := hook.AllEntries()
 	assert.Equal(100, len(entries))
 }

json_formatter.go

@@ -1,6 +1,7 @@
 package logrus
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 )
@@ -33,6 +34,9 @@ type JSONFormatter struct {
 	// DisableTimestamp allows disabling automatic timestamps in output
 	DisableTimestamp bool
 
+	// DataKey allows users to put all the log entry parameters into a nested dictionary at a given key.
+	DataKey string
+
 	// FieldMap allows users to customize the names of keys for default fields.
 	// As an example:
 	// formatter := &JSONFormatter{
@@ -58,6 +62,13 @@ func (f *JSONFormatter) Format(entry *Entry) ([]byte, error) {
 			data[k] = v
 		}
 	}
+
+	if f.DataKey != "" {
+		newData := make(Fields, 4)
+		newData[f.DataKey] = data
+		data = newData
+	}
+
 	prefixFieldClashes(data, f.FieldMap)
 
 	timestampFormat := f.TimestampFormat
@@ -71,9 +82,15 @@ func (f *JSONFormatter) Format(entry *Entry) ([]byte, error) {
 	data[f.FieldMap.resolve(FieldKeyMsg)] = entry.Message
 	data[f.FieldMap.resolve(FieldKeyLevel)] = entry.Level.String()
 
-	serialized, err := json.Marshal(data)
+	var b *bytes.Buffer
+	if entry.Buffer != nil {
+		b = entry.Buffer
+	} else {
+		b = &bytes.Buffer{}
+	}
+	err := json.NewEncoder(b).Encode(data)
 	if err != nil {
 		return nil, fmt.Errorf("Failed to marshal fields to JSON, %v", err)
 	}
-	return append(serialized, '\n'), nil
+	return b.Bytes(), nil
 }

json_formatter_test.go

@@ -161,6 +161,48 @@ func TestFieldClashWithRemappedFields(t *testing.T) {
 	}
 }
 
+func TestFieldsInNestedDictionary(t *testing.T) {
+	formatter := &JSONFormatter{
+		DataKey: "args",
+	}
+
+	logEntry := WithFields(Fields{
+		"level":      "level",
+		"test":		  "test",
+	})
+	logEntry.Level = InfoLevel
+
+	b, err := formatter.Format(logEntry)
+	if err != nil {
+		t.Fatal("Unable to format entry: ", err)
+	}
+
+	entry := make(map[string]interface{})
+	err = json.Unmarshal(b, &entry)
+	if err != nil {
+		t.Fatal("Unable to unmarshal formatted entry: ", err)
+	}
+
+	args := entry["args"].(map[string]interface{})
+
+	for _, field := range []string{"test", "level"} {
+		if value, present := args[field]; !present || value != field {
+			t.Errorf("Expected field %v to be present under 'args'; untouched", field)
+		}
+	}
+
+	for _, field := range []string{"test", "fields.level"} {
+		if _, present := entry[field]; present {
+			t.Errorf("Expected field %v not to be present at top level", field)
+		}
+	}
+
+	// with nested object, "level" shouldn't clash
+	if entry["level"] != "info" {
+		t.Errorf("Expected 'level' field to contain 'info'")
+	}
+}
+
 func TestJSONEntryEndsWithNewline(t *testing.T) {
 	formatter := &JSONFormatter{}
 

logger.go

@@ -5,12 +5,13 @@ import (
 	"os"
 	"sync"
 	"sync/atomic"
+	"time"
 )
 
 type Logger struct {
 	// The logs are `io.Copy`'d to this in a mutex. It's common to set this to a
 	// file, or leave it default which is `os.Stderr`. You can also set this to
-	// something more adventorous, such as logging to Kafka.
+	// something more adventurous, such as logging to Kafka.
 	Out io.Writer
 	// Hooks for the logger instance. These allow firing events based on logging
 	// levels and log entries. For example, to send errors to an error tracking
@@ -84,11 +85,12 @@ func (logger *Logger) newEntry() *Entry {
 }
 
 func (logger *Logger) releaseEntry(entry *Entry) {
+	entry.Data = map[string]interface{}{}
 	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.
+// Debug, Print, Info, Warn, Error, 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 {
 	entry := logger.newEntry()
@@ -112,6 +114,13 @@ func (logger *Logger) WithError(err error) *Entry {
 	return entry.WithError(err)
 }
 
+// Overrides the time of the log entry.
+func (logger *Logger) WithTime(t time.Time) *Entry {
+	entry := logger.newEntry()
+	defer logger.releaseEntry(entry)
+	return entry.WithTime(t)
+}
+
 func (logger *Logger) Debugf(format string, args ...interface{}) {
 	if logger.IsDebugEnabled() {
 		entry := logger.newEntry()
@@ -312,10 +321,17 @@ func (logger *Logger) level() Level {
 	return Level(atomic.LoadUint32((*uint32)(&logger.Level)))
 }
 
+// SetLevel sets the logger level.
 func (logger *Logger) SetLevel(level Level) {
 	atomic.StoreUint32((*uint32)(&logger.Level), uint32(level))
 }
 
+// GetLevel returns the logger level.
+func (logger *Logger) GetLevel() Level {
+	return logger.level()
+}
+
+// AddHook adds a hook to the logger hooks.
 func (logger *Logger) AddHook(hook Hook) {
 	logger.mu.Lock()
 	defer logger.mu.Unlock()
@@ -344,4 +360,25 @@ func (logger *Logger) IsFatalEnabled() bool {
 
 func (logger *Logger) IsPanicEnabled() bool {
 	return logger.level() >= PanicLevel
+// SetFormatter sets the logger formatter.
+func (logger *Logger) SetFormatter(formatter Formatter) {
+	logger.mu.Lock()
+	defer logger.mu.Unlock()
+	logger.Formatter = formatter
+}
+
+// SetOutput sets the logger output.
+func (logger *Logger) SetOutput(output io.Writer) {
+	logger.mu.Lock()
+	defer logger.mu.Unlock()
+	logger.Out = output
+}
+
+// ReplaceHooks replaces the logger hooks and returns the old ones
+func (logger *Logger) ReplaceHooks(hooks LevelHooks) LevelHooks {
+	logger.mu.Lock()
+	oldHooks := logger.Hooks
+	logger.Hooks = hooks
+	logger.mu.Unlock()
+	return oldHooks
 }

logger_bench_test.go

@@ -1,6 +1,7 @@
 package logrus
 
 import (
+	"io/ioutil"
 	"os"
 	"testing"
 )
@@ -59,3 +60,26 @@ func doLoggerBenchmarkNoLock(b *testing.B, out *os.File, formatter Formatter, fi
 		}
 	})
 }
+
+func BenchmarkLoggerJSONFormatter(b *testing.B) {
+	doLoggerBenchmarkWithFormatter(b, &JSONFormatter{})
+}
+
+func BenchmarkLoggerTextFormatter(b *testing.B) {
+	doLoggerBenchmarkWithFormatter(b, &TextFormatter{})
+}
+
+func doLoggerBenchmarkWithFormatter(b *testing.B, f Formatter) {
+	b.SetParallelism(100)
+	log := New()
+	log.Formatter = f
+	log.Out = ioutil.Discard
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			log.
+				WithField("foo1", "bar1").
+				WithField("foo2", "bar2").
+				Info("this is a dummy log")
+		}
+	})
+}

logrus_test.go

@@ -3,10 +3,12 @@ package logrus
 import (
 	"bytes"
 	"encoding/json"
+	"io/ioutil"
 	"strconv"
 	"strings"
 	"sync"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -209,6 +211,65 @@ func TestDefaultFieldsAreNotPrefixed(t *testing.T) {
 	})
 }
 
+func TestWithTimeShouldOverrideTime(t *testing.T) {
+	now := time.Now().Add(24 * time.Hour)
+
+	LogAndAssertJSON(t, func(log *Logger) {
+		log.WithTime(now).Info("foobar")
+	}, func(fields Fields) {
+		assert.Equal(t, fields["time"], now.Format(defaultTimestampFormat))
+	})
+}
+
+func TestWithTimeShouldNotOverrideFields(t *testing.T) {
+	now := time.Now().Add(24 * time.Hour)
+
+	LogAndAssertJSON(t, func(log *Logger) {
+		log.WithField("herp", "derp").WithTime(now).Info("blah")
+	}, func(fields Fields) {
+		assert.Equal(t, fields["time"], now.Format(defaultTimestampFormat))
+		assert.Equal(t, fields["herp"], "derp")
+	})
+}
+
+func TestWithFieldShouldNotOverrideTime(t *testing.T) {
+	now := time.Now().Add(24 * time.Hour)
+
+	LogAndAssertJSON(t, func(log *Logger) {
+		log.WithTime(now).WithField("herp", "derp").Info("blah")
+	}, func(fields Fields) {
+		assert.Equal(t, fields["time"], now.Format(defaultTimestampFormat))
+		assert.Equal(t, fields["herp"], "derp")
+	})
+}
+
+func TestTimeOverrideMultipleLogs(t *testing.T) {
+	var buffer bytes.Buffer
+	var firstFields, secondFields Fields
+
+	logger := New()
+	logger.Out = &buffer
+	formatter := new(JSONFormatter)
+	formatter.TimestampFormat = time.StampMilli
+	logger.Formatter = formatter
+
+	llog := logger.WithField("herp", "derp")
+	llog.Info("foo")
+
+	err := json.Unmarshal(buffer.Bytes(), &firstFields)
+	assert.NoError(t, err, "should have decoded first message")
+
+	buffer.Reset()
+
+	time.Sleep(10 * time.Millisecond)
+	llog.Info("bar")
+
+	err = json.Unmarshal(buffer.Bytes(), &secondFields)
+	assert.NoError(t, err, "should have decoded second message")
+
+	assert.NotEqual(t, firstFields["time"], secondFields["time"], "timestamps should not be equal")
+}
+
 func TestDoubleLoggingDoesntPrefixPreviousFields(t *testing.T) {
 
 	var buffer bytes.Buffer
@@ -343,6 +404,45 @@ func TestLoggingRace(t *testing.T) {
 	wg.Wait()
 }
 
+func TestLoggingRaceWithHooksOnEntry(t *testing.T) {
+	logger := New()
+	hook := new(ModifyHook)
+	logger.AddHook(hook)
+	entry := logger.WithField("context", "clue")
+
+	var wg sync.WaitGroup
+	wg.Add(100)
+
+	for i := 0; i < 100; i++ {
+		go func() {
+			entry.Info("info")
+			wg.Done()
+		}()
+	}
+	wg.Wait()
+}
+
+func TestReplaceHooks(t *testing.T) {
+	old, cur := &TestHook{}, &TestHook{}
+
+	logger := New()
+	logger.SetOutput(ioutil.Discard)
+	logger.AddHook(old)
+
+	hooks := make(LevelHooks)
+	hooks.Add(cur)
+	replaced := logger.ReplaceHooks(hooks)
+
+	logger.Info("test")
+
+	assert.Equal(t, old.Fired, false)
+	assert.Equal(t, cur.Fired, true)
+
+	logger.ReplaceHooks(replaced)
+	logger.Info("test")
+	assert.Equal(t, old.Fired, true)
+}
+
 // Compile test
 func TestLogrusInterface(t *testing.T) {
 	var buffer bytes.Buffer

terminal_bsd.go

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

terminal_check_appengine.go

@@ -1,4 +1,4 @@
-// +build appengine gopherjs
+// +build appengine
 
 package logrus
 

terminal_check_js.go

@@ -0,0 +1,11 @@
+// +build js
+
+package logrus
+
+import (
+	"io"
+)
+
+func checkIfTerminal(w io.Writer) bool {
+	return false
+}

terminal_check_notappengine.go

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

terminal_linux.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 !appengine,!gopherjs
+// +build !appengine,!js
 
 package logrus
 

text_formatter.go

@@ -3,6 +3,7 @@ package logrus
 import (
 	"bytes"
 	"fmt"
+	"os"
 	"sort"
 	"strings"
 	"sync"
@@ -35,6 +36,9 @@ type TextFormatter struct {
 	// Force disabling colors.
 	DisableColors bool
 
+	// Override coloring based on CLICOLOR and CLICOLOR_FORCE. - https://bixense.com/clicolors/
+	EnvironmentOverrideColors bool
+
 	// Disable timestamp logging. useful when output is redirected to logging
 	// system that already adds timestamps.
 	DisableTimestamp bool
@@ -51,7 +55,6 @@ type TextFormatter struct {
 	// be desired.
 	DisableSorting bool
 
-
 	// Disables the truncation of the level text to 4 characters.
 	DisableLevelTruncation bool
 
@@ -61,6 +64,15 @@ type TextFormatter struct {
 	// Whether the logger's out is to a terminal
 	isTerminal bool
 
+	// FieldMap allows users to customize the names of keys for default fields.
+	// As an example:
+	// formatter := &TextFormatter{
+	//     FieldMap: FieldMap{
+	//         FieldKeyTime:  "@timestamp",
+	//         FieldKeyLevel: "@level",
+	//         FieldKeyMsg:   "@message"}}
+	FieldMap FieldMap
+
 	sync.Once
 }
 
@@ -70,9 +82,26 @@ func (f *TextFormatter) init(entry *Entry) {
 	}
 }
 
+func (f *TextFormatter) isColored() bool {
+	isColored := f.ForceColors || f.isTerminal
+
+	if f.EnvironmentOverrideColors {
+		if force, ok := os.LookupEnv("CLICOLOR_FORCE"); ok && force != "0" {
+			isColored = true
+		} else if ok && force == "0" {
+			isColored = false
+		} else if os.Getenv("CLICOLOR") == "0" {
+			isColored = false
+		}
+	}
+
+	return isColored && !f.DisableColors
+}
+
 // Format renders a single log entry
 func (f *TextFormatter) Format(entry *Entry) ([]byte, error) {
-	var b *bytes.Buffer
+	prefixFieldClashes(entry.Data, f.FieldMap)
+
 	keys := make([]string, 0, len(entry.Data))
 	for k := range entry.Data {
 		keys = append(keys, k)
@@ -81,31 +110,29 @@ func (f *TextFormatter) Format(entry *Entry) ([]byte, error) {
 	if !f.DisableSorting {
 		sort.Strings(keys)
 	}
+
+	var b *bytes.Buffer
 	if entry.Buffer != nil {
 		b = entry.Buffer
 	} else {
 		b = &bytes.Buffer{}
 	}
 
-	prefixFieldClashes(entry.Data, emptyFieldMap)
-
 	f.Do(func() { f.init(entry) })
 
-	isColored := (f.ForceColors || f.isTerminal) && !f.DisableColors
-
 	timestampFormat := f.TimestampFormat
 	if timestampFormat == "" {
 		timestampFormat = defaultTimestampFormat
 	}
-	if isColored {
+	if f.isColored() {
 		f.printColored(b, entry, keys, timestampFormat)
 	} else {
 		if !f.DisableTimestamp {
-			f.appendKeyValue(b, "time", entry.Time.Format(timestampFormat))
+			f.appendKeyValue(b, f.FieldMap.resolve(FieldKeyTime), entry.Time.Format(timestampFormat))
 		}
-		f.appendKeyValue(b, "level", entry.Level.String())
+		f.appendKeyValue(b, f.FieldMap.resolve(FieldKeyLevel), entry.Level.String())
 		if entry.Message != "" {
-			f.appendKeyValue(b, "msg", entry.Message)
+			f.appendKeyValue(b, f.FieldMap.resolve(FieldKeyMsg), entry.Message)
 		}
 		for _, key := range keys {
 			f.appendKeyValue(b, key, entry.Data[key])
@@ -134,6 +161,10 @@ func (f *TextFormatter) printColored(b *bytes.Buffer, entry *Entry, keys []strin
 		levelText = levelText[0:4]
 	}
 
+	// Remove a single newline if it already exists in the message to keep
+	// the behavior of logrus text_formatter the same as the stdlib log package
+	entry.Message = strings.TrimSuffix(entry.Message, "\n")
+
 	if f.DisableTimestamp {
 		fmt.Fprintf(b, "\x1b[%dm%s\x1b[0m %-44s ", levelColor, levelText, entry.Message)
 	} else if !f.FullTimestamp {

text_formatter_test.go

@@ -4,9 +4,12 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
+	"os"
 	"strings"
 	"testing"
 	"time"
+
+	"github.com/stretchr/testify/assert"
 )
 
 func TestFormatting(t *testing.T) {
@@ -175,5 +178,273 @@ func TestDisableTimestampWithColoredOutput(t *testing.T) {
 	}
 }
 
+func TestNewlineBehavior(t *testing.T) {
+	tf := &TextFormatter{ForceColors: true}
+
+	// Ensure a single new line is removed as per stdlib log
+	e := NewEntry(StandardLogger())
+	e.Message = "test message\n"
+	b, _ := tf.Format(e)
+	if bytes.Contains(b, []byte("test message\n")) {
+		t.Error("first newline at end of Entry.Message resulted in unexpected 2 newlines in output. Expected newline to be removed.")
+	}
+
+	// Ensure a double new line is reduced to a single new line
+	e = NewEntry(StandardLogger())
+	e.Message = "test message\n\n"
+	b, _ = tf.Format(e)
+	if bytes.Contains(b, []byte("test message\n\n")) {
+		t.Error("Double newline at end of Entry.Message resulted in unexpected 2 newlines in output. Expected single newline")
+	}
+	if !bytes.Contains(b, []byte("test message\n")) {
+		t.Error("Double newline at end of Entry.Message did not result in a single newline after formatting")
+	}
+}
+
+func TestTextFormatterFieldMap(t *testing.T) {
+	formatter := &TextFormatter{
+		DisableColors: true,
+		FieldMap: FieldMap{
+			FieldKeyMsg:   "message",
+			FieldKeyLevel: "somelevel",
+			FieldKeyTime:  "timeywimey",
+		},
+	}
+
+	entry := &Entry{
+		Message: "oh hi",
+		Level:   WarnLevel,
+		Time:    time.Date(1981, time.February, 24, 4, 28, 3, 100, time.UTC),
+		Data: Fields{
+			"field1":     "f1",
+			"message":    "messagefield",
+			"somelevel":  "levelfield",
+			"timeywimey": "timeywimeyfield",
+		},
+	}
+
+	b, err := formatter.Format(entry)
+	if err != nil {
+		t.Fatal("Unable to format entry: ", err)
+	}
+
+	assert.Equal(t,
+		`timeywimey="1981-02-24T04:28:03Z" `+
+			`somelevel=warning `+
+			`message="oh hi" `+
+			`field1=f1 `+
+			`fields.message=messagefield `+
+			`fields.somelevel=levelfield `+
+			`fields.timeywimey=timeywimeyfield`+"\n",
+		string(b),
+		"Formatted output doesn't respect FieldMap")
+}
+
+func TestTextFormatterIsColored(t *testing.T) {
+	params := []struct {
+		name               string
+		expectedResult     bool
+		isTerminal         bool
+		disableColor       bool
+		forceColor         bool
+		envColor           bool
+		clicolorIsSet      bool
+		clicolorForceIsSet bool
+		clicolorVal        string
+		clicolorForceVal   string
+	}{
+		// Default values
+		{
+			name:               "testcase1",
+			expectedResult:     false,
+			isTerminal:         false,
+			disableColor:       false,
+			forceColor:         false,
+			envColor:           false,
+			clicolorIsSet:      false,
+			clicolorForceIsSet: false,
+		},
+		// Output on terminal
+		{
+			name:               "testcase2",
+			expectedResult:     true,
+			isTerminal:         true,
+			disableColor:       false,
+			forceColor:         false,
+			envColor:           false,
+			clicolorIsSet:      false,
+			clicolorForceIsSet: false,
+		},
+		// Output on terminal with color disabled
+		{
+			name:               "testcase3",
+			expectedResult:     false,
+			isTerminal:         true,
+			disableColor:       true,
+			forceColor:         false,
+			envColor:           false,
+			clicolorIsSet:      false,
+			clicolorForceIsSet: false,
+		},
+		// Output not on terminal with color disabled
+		{
+			name:               "testcase4",
+			expectedResult:     false,
+			isTerminal:         false,
+			disableColor:       true,
+			forceColor:         false,
+			envColor:           false,
+			clicolorIsSet:      false,
+			clicolorForceIsSet: false,
+		},
+		// Output not on terminal with color forced
+		{
+			name:               "testcase5",
+			expectedResult:     true,
+			isTerminal:         false,
+			disableColor:       false,
+			forceColor:         true,
+			envColor:           false,
+			clicolorIsSet:      false,
+			clicolorForceIsSet: false,
+		},
+		// Output on terminal with clicolor set to "0"
+		{
+			name:               "testcase6",
+			expectedResult:     false,
+			isTerminal:         true,
+			disableColor:       false,
+			forceColor:         false,
+			envColor:           true,
+			clicolorIsSet:      true,
+			clicolorForceIsSet: false,
+			clicolorVal:        "0",
+		},
+		// Output on terminal with clicolor set to "1"
+		{
+			name:               "testcase7",
+			expectedResult:     true,
+			isTerminal:         true,
+			disableColor:       false,
+			forceColor:         false,
+			envColor:           true,
+			clicolorIsSet:      true,
+			clicolorForceIsSet: false,
+			clicolorVal:        "1",
+		},
+		// Output not on terminal with clicolor set to "0"
+		{
+			name:               "testcase8",
+			expectedResult:     false,
+			isTerminal:         false,
+			disableColor:       false,
+			forceColor:         false,
+			envColor:           true,
+			clicolorIsSet:      true,
+			clicolorForceIsSet: false,
+			clicolorVal:        "0",
+		},
+		// Output not on terminal with clicolor set to "1"
+		{
+			name:               "testcase9",
+			expectedResult:     false,
+			isTerminal:         false,
+			disableColor:       false,
+			forceColor:         false,
+			envColor:           true,
+			clicolorIsSet:      true,
+			clicolorForceIsSet: false,
+			clicolorVal:        "1",
+		},
+		// Output not on terminal with clicolor set to "1" and force color
+		{
+			name:               "testcase10",
+			expectedResult:     true,
+			isTerminal:         false,
+			disableColor:       false,
+			forceColor:         true,
+			envColor:           true,
+			clicolorIsSet:      true,
+			clicolorForceIsSet: false,
+			clicolorVal:        "1",
+		},
+		// Output not on terminal with clicolor set to "0" and force color
+		{
+			name:               "testcase11",
+			expectedResult:     false,
+			isTerminal:         false,
+			disableColor:       false,
+			forceColor:         true,
+			envColor:           true,
+			clicolorIsSet:      true,
+			clicolorForceIsSet: false,
+			clicolorVal:        "0",
+		},
+		// Output not on terminal with clicolor_force set to "1"
+		{
+			name:               "testcase12",
+			expectedResult:     true,
+			isTerminal:         false,
+			disableColor:       false,
+			forceColor:         false,
+			envColor:           true,
+			clicolorIsSet:      false,
+			clicolorForceIsSet: true,
+			clicolorForceVal:   "1",
+		},
+		// Output not on terminal with clicolor_force set to "0"
+		{
+			name:               "testcase13",
+			expectedResult:     false,
+			isTerminal:         false,
+			disableColor:       false,
+			forceColor:         false,
+			envColor:           true,
+			clicolorIsSet:      false,
+			clicolorForceIsSet: true,
+			clicolorForceVal:   "0",
+		},
+		// Output on terminal with clicolor_force set to "0"
+		{
+			name:               "testcase14",
+			expectedResult:     false,
+			isTerminal:         true,
+			disableColor:       false,
+			forceColor:         false,
+			envColor:           true,
+			clicolorIsSet:      false,
+			clicolorForceIsSet: true,
+			clicolorForceVal:   "0",
+		},
+	}
+
+	cleanenv := func() {
+		os.Unsetenv("CLICOLOR")
+		os.Unsetenv("CLICOLOR_FORCE")
+	}
+
+	defer cleanenv()
+
+	for _, val := range params {
+		t.Run("textformatter_"+val.name, func(subT *testing.T) {
+			tf := TextFormatter{
+				isTerminal:                val.isTerminal,
+				DisableColors:             val.disableColor,
+				ForceColors:               val.forceColor,
+				EnvironmentOverrideColors: val.envColor,
+			}
+			cleanenv()
+			if val.clicolorIsSet {
+				os.Setenv("CLICOLOR", val.clicolorVal)
+			}
+			if val.clicolorForceIsSet {
+				os.Setenv("CLICOLOR_FORCE", val.clicolorForceVal)
+			}
+			res := tf.isColored()
+			assert.Equal(subT, val.expectedResult, res)
+		})
+	}
+}
+
 // TODO add tests for sorting etc., this requires a parser for the text
 // formatter output.