io_writer_to_logger/iowrlog.go

package io_writer_to_logger

import (
	"bufio"
	"io"
)

type LogEmitFunc func(msg string)

type WriterLogWrapper struct {
	emitFunc   LogEmitFunc
	pipeWriter *io.PipeWriter
	pipeReader *io.PipeReader
	scanner    *bufio.Scanner
}

func (w *WriterLogWrapper) Close() error {
	err1 := w.pipeWriter.Close()
	err2 := w.pipeReader.Close()
	if err1 != nil {
		return err1
	}
	if err2 != nil {
		return err2
	}
	return nil
}

func NewWriterLogWrapper(emitFunc LogEmitFunc) *WriterLogWrapper {
	pr, pw := io.Pipe()
	return &WriterLogWrapper{
		emitFunc:   emitFunc,
		pipeWriter: pw,
		pipeReader: pr,
		scanner:    bufio.NewScanner(pr),
	}
}

func (w WriterLogWrapper) Write(p []byte) (n int, err error) {
	return w.pipeWriter.Write(p)
}

func (w WriterLogWrapper) Run() {
	for w.scanner.Scan() {
		t := w.scanner.Text()
		w.emitFunc(t)
	}
}

var _ io.WriteCloser = (*WriterLogWrapper)(nil)