// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.

// SPDX-License-Identifier: Apache-2.0

package logging

import (

"io"

"sync"

)

// TailLogWriter writes tail/debug log to provided io.Writer

type TailLogWriter struct {

out io.Writer

enabled bool

mutex sync.Mutex

}

// Enable enables log writer.

func (lw *TailLogWriter) Enable() {

lw.mutex.Lock()

defer lw.mutex.Unlock()

lw.enabled = true

}

// Disable disables log writer.

func (lw *TailLogWriter) Disable() {

lw.mutex.Lock()

defer lw.mutex.Unlock()

lw.enabled = false

}

// Writer wraps the basic io.Write method

func (lw *TailLogWriter) Write(p []byte) (n int, err error) {

lw.mutex.Lock()

defer lw.mutex.Unlock()

if lw.enabled {

return lw.out.Write(p)

}

// Else returns a successful write so that MultiWriter won't stop

return len(p), nil

}

// NewTailLogWriter returns a new invoke tail log writer, default output is discarded until output is configured.

func NewTailLogWriter(w io.Writer) *TailLogWriter {

return &TailLogWriter{

out: w,

enabled: false,

}

}