func (logger Logger) Criticalf(message string, args ...interface{}) {
	logger.Logf(CRITICAL, message, args...)
}
Criticalf logs the printf-formatted message at critical level.
package loggo
import (
	"fmt"
	"runtime"
	"sort"
	"strings"
	"sync"
	"sync/atomic"
	"time"
)
type Level uint32
const (
	UNSPECIFIED Level = iota
	TRACE
	DEBUG
	INFO
	WARNING
	ERROR
	CRITICAL
)
type Logger struct {
	impl *module
}
type module struct {
	name   string
	level  Level
	parent *module
}
var (
	root         = &module{level: WARNING}
	modulesMutex sync.Mutex
	modules      = map[string]*module{
		"": root,
	}
)
func (level Level) String() string {
	switch level {
	case UNSPECIFIED:
		return "UNSPECIFIED"
	case TRACE:
		return "TRACE"
	case DEBUG:
		return "DEBUG"
	case INFO:
		return "INFO"
	case WARNING:
		return "WARNING"
	case ERROR:
		return "ERROR"
	case CRITICAL:
		return "CRITICAL"
	}
	return "<unknown>"
}
func (level *Level) get() Level {
	return Level(atomic.LoadUint32((*uint32)(level)))
}
func (level *Level) set(newLevel Level) {
	atomic.StoreUint32((*uint32)(level), uint32(newLevel))
}
func getLoggerInternal(name string) Logger {
	impl, found := modules[name]
	if found {
		return Logger{impl}
	}
	parentName := ""
	if i := strings.LastIndex(name, "."); i >= 0 {
		parentName = name[0:i]
	}
	parent := getLoggerInternal(parentName).impl
	impl = &module{name, UNSPECIFIED, parent}
	modules[name] = impl
	return Logger{impl}
}
func GetLogger(name string) Logger {
	name = strings.ToLower(name)
	modulesMutex.Lock()
	defer modulesMutex.Unlock()
	return getLoggerInternal(name)
}
func LoggerInfo() string {
	output := []string{}
	keys := []string{}
	modulesMutex.Lock()
	defer modulesMutex.Unlock()
	for key := range modules {
		keys = append(keys, key)
	}
	sort.Strings(keys)
	for _, name := range keys {
		mod := modules[name]
		severity := mod.level
		if severity == UNSPECIFIED {
			continue
		}
		output = append(output, fmt.Sprintf("%s=%s", mod.Name(), severity))
	}
	return strings.Join(output, ";")
}
func ParseConfigurationString(specification string) (map[string]Level, error) {
	values := strings.FieldsFunc(specification, func(r rune) bool { return r == ';' || r == ':' })
	levels := make(map[string]Level)
	for _, value := range values {
		s := strings.SplitN(value, "=", 2)
		if len(s) < 2 {
			return nil, fmt.Errorf("logger specification expected '=', found %q", value)
		}
		name := strings.TrimSpace(s[0])
		levelStr := strings.TrimSpace(s[1])
		if name == "" || levelStr == "" {
			return nil, fmt.Errorf("logger specification %q has blank name or level", value)
		}
		if name == "<root>" {
			name = ""
		}
		level, ok := ParseLevel(levelStr)
		if !ok {
			return nil, fmt.Errorf("unknown severity level %q", levelStr)
		}
		levels[name] = level
	}
	return levels, nil
}
func ConfigureLoggers(specification string) error {
	if specification == "" {
		return nil
	}
	levels, err := ParseConfigurationString(specification)
	if err != nil {
		return err
	}
	for name, level := range levels {
		GetLogger(name).SetLogLevel(level)
	}
	return nil
}
func ResetLoggers() {
	modulesMutex.Lock()
	defer modulesMutex.Unlock()
	for name, module := range modules {
		if name == "" {
			module.level.set(WARNING)
		} else {
			module.level.set(UNSPECIFIED)
		}
	}
}
func ParseLevel(level string) (Level, bool) {
	level = strings.ToUpper(level)
	switch level {
	case "UNSPECIFIED":
		return UNSPECIFIED, true
	case "TRACE":
		return TRACE, true
	case "DEBUG":
		return DEBUG, true
	case "INFO":
		return INFO, true
	case "WARN", "WARNING":
		return WARNING, true
	case "ERROR":
		return ERROR, true
	case "CRITICAL":
		return CRITICAL, true
	}
	return UNSPECIFIED, false
}
func (logger Logger) getModule() *module {
	if logger.impl == nil {
		return root
	}
	return logger.impl
}
func (logger Logger) Name() string {
	return logger.getModule().Name()
}
func (logger Logger) LogLevel() Level {
	return logger.getModule().level.get()
}
func (module *module) getEffectiveLogLevel() Level {
	for {
		if level := module.level.get(); level != UNSPECIFIED {
			return level
		}
		module = module.parent
	}
	panic("unreachable")
}
func (module *module) Name() string {
	if module.name == "" {
		return "<root>"
	}
	return module.name
}
func (logger Logger) EffectiveLogLevel() Level {
	return logger.getModule().getEffectiveLogLevel()
}
func (logger Logger) SetLogLevel(level Level) {
	module := logger.getModule()
	if module.name == "" && level == UNSPECIFIED {
		level = WARNING
	}
	module.level.set(level)
}
func (logger Logger) Logf(level Level, message string, args ...interface{}) {
	if logger.getModule().getEffectiveLogLevel() > level ||
		!WillWrite(level) ||
		level < TRACE ||
		level > CRITICAL {
		return
	}
	now := time.Now()  
	_, file, line, ok := runtime.Caller(2)
	if !ok {
		file = "???"
		line = 0
	}
	if len(message) > 0 && message[len(message)-1] == '\n' {
		message = message[0 : len(message)-1]
	}
	formattedMessage := fmt.Sprintf(message, args...)
	writeToWriters(level, logger.impl.name, file, line, now, formattedMessage)
}