go_goutils/logging/funcs_logwriter.go

package logging

import (
	"unicode/utf8"

	"r00t2.io/goutils/multierr"
)

/*
Close calls Logger.Shutdown() on the underlying Logger.
The Logger *must not be used* after this; it will need to be re-initialized with Logger.Setup()
or a new Logger (and thuse new logWriter) must be created to replace it.

It (along with logWriter.Write()) conforms to WriteCloser().
*/
func (l *logWriter) Close() (err error) {

	if err = l.backend.Shutdown(); err != nil {
		return
	}

	return
}

/*
Write writes bytes b to the underlying Logger's priority level if the logWriter's priority level(s) match.
It conforms to io.Writer. n will *always* == len(b) on success, because otherwise n would technically be >= len(b)
(if multiple priorities are enabled), which is undefined behavior per io.Writer.

b is converted to a string to normalize to the underlying Logger.
*/
func (l *logWriter) Write(b []byte) (n int, err error) {

	var s string
	var mErr *multierr.MultiError = multierr.NewMultiError(nil)

	if b == nil {
		return
	}

	s = string(b)

	// Since this explicitly checks each priority level, there's no need for IsOneOf in case of PriorityAll.

	if l.prio.HasFlag(PriorityEmergency) {
		if err = l.backend.Emerg(s); err != nil {
			mErr.AddError(err)
			err = nil
		}
	}
	if l.prio.HasFlag(PriorityAlert) {
		if err = l.backend.Alert(s); err != nil {
			mErr.AddError(err)
			err = nil
		}
	}
	if l.prio.HasFlag(PriorityCritical) {
		if err = l.backend.Crit(s); err != nil {
			mErr.AddError(err)
			err = nil
		}
	}
	if l.prio.HasFlag(PriorityError) {
		if err = l.backend.Err(s); err != nil {
			mErr.AddError(err)
			err = nil
		}
	}
	if l.prio.HasFlag(PriorityWarning) {
		if err = l.backend.Warning(s); err != nil {
			mErr.AddError(err)
			err = nil
		}
	}
	if l.prio.HasFlag(PriorityNotice) {
		if err = l.backend.Notice(s); err != nil {
			mErr.AddError(err)
			err = nil
		}
	}
	if l.prio.HasFlag(PriorityInformational) {
		if err = l.backend.Info(s); err != nil {
			mErr.AddError(err)
			err = nil
		}
	}
	if l.prio.HasFlag(PriorityDebug) {
		if err = l.backend.Debug(s); err != nil {
			mErr.AddError(err)
			err = nil
		}
	}

	if !mErr.IsEmpty() {
		err = mErr
		return
	}

	n = len(b)

	return
}

/*
WriteByte conforms a logWriter to an io.ByteWriter. (It just wraps logWriter.Write().)
You should probably never use this; the logging overhead/prefix is going to be more data than the single byte itself.

c is converted to a string to normalize to the underlying Logger.
*/
func (l *logWriter) WriteByte(c byte) (err error) {

	if _, err = l.Write([]byte{c}); err != nil {
		return
	}

	return
}

/*
WriteRune follows the same signature of (bytes.Buffer).WriteRune() and (bufio.Writer).WriteRune(); thus if `io` ever defines an io.RuneWriter interface, here ya go.

n will *always* be equal to (unicode/utf8).RuneLen(r), unless r is an "invalid rune" -- in which case n will be 0 and err will be ErrInvalidRune..
*/
func (l *logWriter) WriteRune(r rune) (n int, err error) {

	var b []byte

	n = utf8.RuneLen(r)
	if n < 0 {
		err = ErrInvalidRune
		n = 0
		return
	}

	b = make([]byte, n)
	utf8.EncodeRune(b, r)

	if n, err = l.Write(b); err != nil {
		return
	}

	return
}

/*
WriteString writes string s to the underlying Logger's priority level if the logWriter's priority level(s) match.
It conforms to io.StringWriter. n will *always* == len(s) on success, because otherwise n would technically be >= len(s)
(if multiple priorities are enabled), which is undefined behavior per io.StringWriter.
*/
func (l *logWriter) WriteString(s string) (n int, err error) {

	var mErr *multierr.MultiError = multierr.NewMultiError(nil)

	if l.prio.HasFlag(PriorityEmergency) {
		if err = l.backend.Emerg(s); err != nil {
			mErr.AddError(err)
			err = nil
		}
	}
	if l.prio.HasFlag(PriorityAlert) {
		if err = l.backend.Alert(s); err != nil {
			mErr.AddError(err)
			err = nil
		}
	}
	if l.prio.HasFlag(PriorityCritical) {
		if err = l.backend.Crit(s); err != nil {
			mErr.AddError(err)
			err = nil
		}
	}
	if l.prio.HasFlag(PriorityError) {
		if err = l.backend.Err(s); err != nil {
			mErr.AddError(err)
			err = nil
		}
	}
	if l.prio.HasFlag(PriorityWarning) {
		if err = l.backend.Warning(s); err != nil {
			mErr.AddError(err)
			err = nil
		}
	}
	if l.prio.HasFlag(PriorityNotice) {
		if err = l.backend.Notice(s); err != nil {
			mErr.AddError(err)
			err = nil
		}
	}
	if l.prio.HasFlag(PriorityInformational) {
		if err = l.backend.Info(s); err != nil {
			mErr.AddError(err)
			err = nil
		}
	}
	if l.prio.HasFlag(PriorityDebug) {
		if err = l.backend.Debug(s); err != nil {
			mErr.AddError(err)
			err = nil
		}
	}

	if !mErr.IsEmpty() {
		err = mErr
		return
	}

	n = len(s)

	return
}