/
appender.go
108 lines (88 loc) · 2.33 KB
/
appender.go
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// Copyright 2013 MongoDB, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package slogger
import (
"bytes"
"fmt"
"os"
)
type Appender interface {
Append(log *Log) error
}
func FormatLog(log *Log) string {
year, month, day := log.Timestamp.Date()
hour, min, sec := log.Timestamp.Clock()
return fmt.Sprintf("[%.4d/%.2d/%.2d %.2d:%.2d:%.2d] [%v.%v] [%v:%d] %v\n",
year, month, day,
hour, min, sec,
log.Prefix, log.Level.Type(),
log.Filename, log.Line,
log.Message())
}
type WriteStringer interface {
WriteString(str string) (int, error)
}
// WriteStringer is implemented by *os.File.
type FileAppender struct {
WriteStringer
}
func (self FileAppender) Append(log *Log) error {
_, err := self.WriteString(FormatLog(log))
return err
}
func StdOutAppender() *FileAppender {
return &FileAppender{os.Stdout}
}
func StdErrAppender() *FileAppender {
return &FileAppender{os.Stderr}
}
func DevNullAppender() (*FileAppender, error) {
devNull, err := os.Open(os.DevNull)
if err != nil {
return nil, err
}
return &FileAppender{devNull}, nil
}
type StringAppender struct {
*bytes.Buffer
}
func NewStringAppender(buffer *bytes.Buffer) *StringAppender {
return &StringAppender{buffer}
}
func (self StringAppender) Append(log *Log) error {
_, err := self.WriteString(FormatLog(log) + "\n")
return err
}
// Return true if the log should be passed to the underlying
// `Appender`
type Filter func(log *Log) bool
type FilterAppender struct {
Appender Appender
Filter Filter
}
func (self *FilterAppender) Append(log *Log) error {
if self.Filter(log) == false {
return nil
}
return self.Appender.Append(log)
}
func LevelFilter(threshold Level, appender Appender) *FilterAppender {
filterFunc := func(log *Log) bool {
return log.Level >= threshold
}
return &FilterAppender{
Appender: appender,
Filter: filterFunc,
}
}