dotcloud/docker

package streamformatter // import "github.com/docker/docker/pkg/streamformatter"

import (
    "encoding/json"
    "io"

    "github.com/docker/docker/pkg/jsonmessage"
)

type streamWriter struct {
    io.Writer
    lineFormat func([]byte) string
}

func (sw *streamWriter) Write(buf []byte) (int, error) {
    formattedBuf := sw.format(buf)
    n, err := sw.Writer.Write(formattedBuf)
    if n != len(formattedBuf) {
        return n, io.ErrShortWrite
    }
    return len(buf), err
}

func (sw *streamWriter) format(buf []byte) []byte {
    msg := &jsonmessage.JSONMessage{Stream: sw.lineFormat(buf)}
    b, err := json.Marshal(msg)
    if err != nil {
        return FormatError(err)
    }
    return appendNewline(b)
}

// NewStdoutWriter returns a writer which formats the output as json message
// representing stdout lines
func NewStdoutWriter(out io.Writer) io.Writer {
    return &streamWriter{Writer: out, lineFormat: func(buf []byte) string {
        return string(buf)
    }}
}

// NewStderrWriter returns a writer which formats the output as json message
// representing stderr lines
func NewStderrWriter(out io.Writer) io.Writer {
    return &streamWriter{Writer: out, lineFormat: func(buf []byte) string {
        return "\033[91m" + string(buf) + "\033[0m"
    }}
}