// Copyright (C) 2010, Kyle Lemons <kyle@kylelemons.net>. All rights reserved.
package log4go
import (
"bytes"
"fmt"
"io"
"strings"
)
const (
FORMAT_DEFAULT = "[%D %T] [%L] (%S) %M"
FORMAT_SHORT = "[%t %d] [%L] %M"
FORMAT_ABBREV = "[%L] %M"
)
type formatCacheType struct {
LastUpdateSeconds int64
shortTime, shortDate string
longTime, longDate string
}
var formatCache = &formatCacheType{}
// Known format codes:
// %T - Time (15:04:05 MST)
// %t - Time (15:04)
// %D - Date (2006/01/02)
// %d - Date (01/02/06)
// %L - Level (FNST, FINE, DEBG, TRAC, WARN, EROR, CRIT)
// %S - Source
// %M - Message
// Ignores unknown formats
// Recommended: "[%D %T] [%L] (%S) %M"
func FormatLogRecord(format string, rec *LogRecord) string {
if rec == nil {
return "<nil>"
}
if len(format) == 0 {
return ""
}
out := bytes.NewBuffer(make([]byte, 0, 64))
secs := rec.Created.UnixNano() / 1e9
cache := *formatCache
if cache.LastUpdateSeconds != secs {
month, day, year := rec.Created.Month(), rec.Created.Day(), rec.Created.Year()
hour, minute, second := rec.Created.Hour(), rec.Created.Minute(), rec.Created.Second()
zone, _ := rec.Created.Zone()
updated := &formatCacheType{
LastUpdateSeconds: secs,
shortTime: fmt.Sprintf("%02d:%02d", hour, minute),
shortDate: fmt.Sprintf("%02d/%02d/%02d", day, month, year%100),
longTime: fmt.Sprintf("%02d:%02d:%02d %s", hour, minute, second, zone),
longDate: fmt.Sprintf("%04d/%02d/%02d", year, month, day),
}
cache = *updated
formatCache = updated
}
// Split the string into pieces by % signs
pieces := bytes.Split([]byte(format), []byte{'%'})
// Iterate over the pieces, replacing known formats
for i, piece := range pieces {
if i > 0 && len(piece) > 0 {
switch piece[0] {
case 'T':
out.WriteString(cache.longTime)
case 't':
out.WriteString(cache.shortTime)
case 'D':
out.WriteString(cache.longDate)
case 'd':
out.WriteString(cache.shortDate)
case 'L':
out.WriteString(levelStrings[rec.Level])
case 'S':
out.WriteString(rec.Source)
case 's':
slice := strings.Split(rec.Source, "/")
out.WriteString(slice[len(slice)-1])
case 'M':
out.WriteString(rec.Message)
}
if len(piece) > 1 {
out.Write(piece[1:])
}
} else if len(piece) > 0 {
out.Write(piece)
}
}
out.WriteByte('\n')
return out.String()
}
// This is the standard writer that prints to standard output.
type FormatLogWriter chan *LogRecord
// This creates a new FormatLogWriter
func NewFormatLogWriter(out io.Writer, format string) FormatLogWriter {
records := make(FormatLogWriter, LogBufferLength)
go records.run(out, format)
return records
}
func (w FormatLogWriter) run(out io.Writer, format string) {
for rec := range w {
fmt.Fprint(out, FormatLogRecord(format, rec))
}
}
// This is the FormatLogWriter's output method. This will block if the output
// buffer is full.
func (w FormatLogWriter) LogWrite(rec *LogRecord) {
w <- rec
}
// Close stops the logger from sending messages to standard output. Attempts to
// send log messages to this logger after a Close have undefined behavior.
func (w FormatLogWriter) Close() {
close(w)
}