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package logrus
import (
"bytes"
"fmt"
"sort"
"strings"
"sync"
"time"
)
const (
nocolor = 0
red = 31
green = 32
yellow = 33
blue = 36
gray = 37
)
var (
baseTimestamp time.Time
emptyFieldMap FieldMap
)
func init() {
baseTimestamp = time.Now()
}
// TextFormatter formats logs into text
type TextFormatter struct {
// Set to true to bypass checking for a TTY before outputting colors.
ForceColors bool
// Force disabling colors.
DisableColors bool
// Disable timestamp logging. useful when output is redirected to logging
// system that already adds timestamps.
DisableTimestamp bool
// Enable logging the full timestamp when a TTY is attached instead of just
// the time passed since beginning of execution.
FullTimestamp bool
// TimestampFormat to use for display when a full timestamp is printed
TimestampFormat string
// The fields are sorted by default for a consistent output. For applications
// that log extremely frequently and don't use the JSON formatter this may not
// be desired.
DisableSorting bool
// Disables the truncation of the level text to 4 characters.
DisableLevelTruncation bool
// QuoteEmptyFields will wrap empty fields in quotes if true
QuoteEmptyFields bool
// 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
}
func (f *TextFormatter) init(entry *Entry) {
if entry.Logger != nil {
f.isTerminal = checkIfTerminal(entry.Logger.Out)
}
}
// Format renders a single log entry
func (f *TextFormatter) Format(entry *Entry) ([]byte, error) {
prefixFieldClashes(entry.Data, f.FieldMap)
keys := make([]string, 0, len(entry.Data))
for k := range entry.Data {
keys = append(keys, k)
}
if !f.DisableSorting {
sort.Strings(keys)
}
var b *bytes.Buffer
if entry.Buffer != nil {
b = entry.Buffer
} else {
b = &bytes.Buffer{}
}
f.Do(func() { f.init(entry) })
isColored := (f.ForceColors || f.isTerminal) && !f.DisableColors
timestampFormat := f.TimestampFormat
if timestampFormat == "" {
timestampFormat = defaultTimestampFormat
}
if isColored {
f.printColored(b, entry, keys, timestampFormat)
} else {
if !f.DisableTimestamp {
f.appendKeyValue(b, f.FieldMap.resolve(FieldKeyTime), entry.Time.Format(timestampFormat))
}
f.appendKeyValue(b, f.FieldMap.resolve(FieldKeyLevel), entry.Level.String())
if entry.Message != "" {
f.appendKeyValue(b, f.FieldMap.resolve(FieldKeyMsg), entry.Message)
}
for _, key := range keys {
f.appendKeyValue(b, key, entry.Data[key])
}
}
b.WriteByte('\n')
return b.Bytes(), nil
}
func (f *TextFormatter) printColored(b *bytes.Buffer, entry *Entry, keys []string, timestampFormat string) {
var levelColor int
switch entry.Level {
case DebugLevel:
levelColor = gray
case WarnLevel:
levelColor = yellow
case ErrorLevel, FatalLevel, PanicLevel:
levelColor = red
default:
levelColor = blue
}
levelText := strings.ToUpper(entry.Level.String())
if !f.DisableLevelTruncation {
levelText = levelText[0:4]
}
if f.DisableTimestamp {
fmt.Fprintf(b, "\x1b[%dm%s\x1b[0m %-44s ", levelColor, levelText, entry.Message)
} else if !f.FullTimestamp {
fmt.Fprintf(b, "\x1b[%dm%s\x1b[0m[%04d] %-44s ", levelColor, levelText, int(entry.Time.Sub(baseTimestamp)/time.Second), entry.Message)
} else {
fmt.Fprintf(b, "\x1b[%dm%s\x1b[0m[%s] %-44s ", levelColor, levelText, entry.Time.Format(timestampFormat), entry.Message)
}
for _, k := range keys {
v := entry.Data[k]
fmt.Fprintf(b, " \x1b[%dm%s\x1b[0m=", levelColor, k)
f.appendValue(b, v)
}
}
func (f *TextFormatter) needsQuoting(text string) bool {
if f.QuoteEmptyFields && len(text) == 0 {
return true
}
for _, ch := range text {
if !((ch >= 'a' && ch <= 'z') ||
(ch >= 'A' && ch <= 'Z') ||
(ch >= '0' && ch <= '9') ||
ch == '-' || ch == '.' || ch == '_' || ch == '/' || ch == '@' || ch == '^' || ch == '+') {
return true
}
}
return false
}
func (f *TextFormatter) appendKeyValue(b *bytes.Buffer, key string, value interface{}) {
if b.Len() > 0 {
b.WriteByte(' ')
}
b.WriteString(key)
b.WriteByte('=')
f.appendValue(b, value)
}
func (f *TextFormatter) appendValue(b *bytes.Buffer, value interface{}) {
stringVal, ok := value.(string)
if !ok {
stringVal = fmt.Sprint(value)
}
if !f.needsQuoting(stringVal) {
b.WriteString(stringVal)
} else {
b.WriteString(fmt.Sprintf("%q", stringVal))
}
}