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// Copyright (C) 2014 Jakob Borg. All rights reserved. Use of this source code
// is governed by an MIT-style license that can be found in the LICENSE file.
//go:generate -command counterfeiter go run github.com/maxbrunsfeld/counterfeiter/v6
//go:generate counterfeiter -o mocks/logger.go --fake-name Recorder . Recorder
// Package logger implements a standardized logger with callback functionality
package logger
import (
"fmt"
"io"
"log"
"os"
"strings"
"sync"
"time"
)
// This package uses stdlib sync as it may be used to debug syncthing/lib/sync
// and that would cause an implosion of the universe.
type LogLevel int
const (
LevelDebug LogLevel = iota
LevelVerbose
LevelInfo
LevelWarn
NumLevels
)
const (
DefaultFlags = log.Ltime | log.Ldate
DebugFlags = log.Ltime | log.Ldate | log.Lmicroseconds | log.Lshortfile
)
// A MessageHandler is called with the log level and message text.
type MessageHandler func(l LogLevel, msg string)
type Logger interface {
AddHandler(level LogLevel, h MessageHandler)
SetFlags(flag int)
SetPrefix(prefix string)
Debugln(vals ...interface{})
Debugf(format string, vals ...interface{})
Verboseln(vals ...interface{})
Verbosef(format string, vals ...interface{})
Infoln(vals ...interface{})
Infof(format string, vals ...interface{})
Warnln(vals ...interface{})
Warnf(format string, vals ...interface{})
ShouldDebug(facility string) bool
SetDebug(facility string, enabled bool)
IsTraced(facility string) bool
Facilities() map[string]string
FacilityDebugging() []string
NewFacility(facility, description string) Logger
}
type logger struct {
logger *log.Logger
handlers [NumLevels][]MessageHandler
facilities map[string]string // facility name => description
debug map[string]struct{} // only facility names with debugging enabled
traces string
mut sync.Mutex
}
// DefaultLogger logs to standard output with a time prefix.
var DefaultLogger = New()
func New() Logger {
if os.Getenv("LOGGER_DISCARD") != "" {
// Hack to completely disable logging, for example when running
// benchmarks.
return newLogger(io.Discard)
}
return newLogger(controlStripper{os.Stdout})
}
func newLogger(w io.Writer) Logger {
return &logger{
logger: log.New(w, "", DefaultFlags),
traces: os.Getenv("STTRACE"),
facilities: make(map[string]string),
debug: make(map[string]struct{}),
}
}
// AddHandler registers a new MessageHandler to receive messages with the
// specified log level or above.
func (l *logger) AddHandler(level LogLevel, h MessageHandler) {
l.mut.Lock()
defer l.mut.Unlock()
l.handlers[level] = append(l.handlers[level], h)
}
// See log.SetFlags
func (l *logger) SetFlags(flag int) {
l.logger.SetFlags(flag)
}
// See log.SetPrefix
func (l *logger) SetPrefix(prefix string) {
l.logger.SetPrefix(prefix)
}
func (l *logger) callHandlers(level LogLevel, s string) {
for ll := LevelDebug; ll <= level; ll++ {
for _, h := range l.handlers[ll] {
h(level, strings.TrimSpace(s))
}
}
}
// Debugln logs a line with a DEBUG prefix.
func (l *logger) Debugln(vals ...interface{}) {
l.debugln(3, vals...)
}
func (l *logger) debugln(level int, vals ...interface{}) {
s := fmt.Sprintln(vals...)
l.mut.Lock()
defer l.mut.Unlock()
l.logger.Output(level, "DEBUG: "+s)
l.callHandlers(LevelDebug, s)
}
// Debugf logs a formatted line with a DEBUG prefix.
func (l *logger) Debugf(format string, vals ...interface{}) {
l.debugf(3, format, vals...)
}
func (l *logger) debugf(level int, format string, vals ...interface{}) {
s := fmt.Sprintf(format, vals...)
l.mut.Lock()
defer l.mut.Unlock()
l.logger.Output(level, "DEBUG: "+s)
l.callHandlers(LevelDebug, s)
}
// Infoln logs a line with a VERBOSE prefix.
func (l *logger) Verboseln(vals ...interface{}) {
s := fmt.Sprintln(vals...)
l.mut.Lock()
defer l.mut.Unlock()
l.logger.Output(2, "VERBOSE: "+s)
l.callHandlers(LevelVerbose, s)
}
// Infof logs a formatted line with a VERBOSE prefix.
func (l *logger) Verbosef(format string, vals ...interface{}) {
s := fmt.Sprintf(format, vals...)
l.mut.Lock()
defer l.mut.Unlock()
l.logger.Output(2, "VERBOSE: "+s)
l.callHandlers(LevelVerbose, s)
}
// Infoln logs a line with an INFO prefix.
func (l *logger) Infoln(vals ...interface{}) {
s := fmt.Sprintln(vals...)
l.mut.Lock()
defer l.mut.Unlock()
l.logger.Output(2, "INFO: "+s)
l.callHandlers(LevelInfo, s)
}
// Infof logs a formatted line with an INFO prefix.
func (l *logger) Infof(format string, vals ...interface{}) {
s := fmt.Sprintf(format, vals...)
l.mut.Lock()
defer l.mut.Unlock()
l.logger.Output(2, "INFO: "+s)
l.callHandlers(LevelInfo, s)
}
// Warnln logs a formatted line with a WARNING prefix.
func (l *logger) Warnln(vals ...interface{}) {
s := fmt.Sprintln(vals...)
l.mut.Lock()
defer l.mut.Unlock()
l.logger.Output(2, "WARNING: "+s)
l.callHandlers(LevelWarn, s)
}
// Warnf logs a formatted line with a WARNING prefix.
func (l *logger) Warnf(format string, vals ...interface{}) {
s := fmt.Sprintf(format, vals...)
l.mut.Lock()
defer l.mut.Unlock()
l.logger.Output(2, "WARNING: "+s)
l.callHandlers(LevelWarn, s)
}
// ShouldDebug returns true if the given facility has debugging enabled.
func (l *logger) ShouldDebug(facility string) bool {
l.mut.Lock()
_, res := l.debug[facility]
l.mut.Unlock()
return res
}
// SetDebug enabled or disables debugging for the given facility name.
func (l *logger) SetDebug(facility string, enabled bool) {
l.
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