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|
package gexec
import (
"io"
"sync"
)
/*
PrefixedWriter wraps an io.Writer, emiting the passed in prefix at the beginning of each new line.
This can be useful when running multiple gexec.Sessions concurrently - you can prefix the log output of each
session by passing in a PrefixedWriter:
gexec.Start(cmd, NewPrefixedWriter("[my-cmd] ", GinkgoWriter), NewPrefixedWriter("[my-cmd] ", GinkgoWriter))
*/
type PrefixedWriter struct {
prefix []byte
writer io.Writer
lock *sync.Mutex
atStartOfLine bool
}
func NewPrefixedWriter(prefix string, writer io.Writer) *PrefixedWriter {
return &PrefixedWriter{
prefix: []byte(prefix),
writer: writer,
lock: &sync.Mutex{},
atStartOfLine: true,
}
}
func (w *PrefixedWriter) Write(b []byte) (int, error) {
w.lock.Lock()
defer w.lock.Unlock()
toWrite := []byte{}
for _, c := range b {
if w.atStartOfLine {
toWrite = append(toWrite, w.prefix...)
}
toWrite = append(toWrite, c)
w.atStartOfLine = c == '\n'
}
_, err := w.writer.Write(toWrite)
if err != nil {
return 0, err
}
return len(b), nil
}
|
