goutils/tee/tee.go

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2017-09-12 10:25:12 +00:00
package tee
import (
"fmt"
"os"
)
// Tee emulates the Unix tee(1) command.
type Tee struct {
f *os.File
}
func (t *Tee) Write(p []byte) (int64, error) {
n, err := os.Stdout.Write(p)
if err != nil {
return n, err
}
return file.Write(p)
}
func (t *Tee) Close() error {
return t.f.Close()
}
// NewOut writes to standard output only. The file is created, not
// appended to.
func NewOut(logFile string) (*Tee, error) {
if logFile == "" {
return &Tee{}, nil
}
f, err := os.Create(logFile)
if err !=nil {
return nil, err
}
return &Tee{f: f}, nil
}
// Printf formats according to a format specifier and writes to the
// tee instance.
func (t *Tee) Printf(format string, args ...interface{}) (int64, error) {
s := fmt.Sprintf(format, args...)
n, err := os.Stdout.Write(s)
if err != nil {
return n, err
}
if t.f == nil {
return n, err
}
return t.f.WriteString(s)
}
var globalTee = &Tee{}
// Open will attempt to open the logFile for the global tee instance.
func Open(logFile string) error {
f, err := os.Create(logFile)
if err !=nil {
return err
}
globalTee.f = f
}
// Printf formats according to a format specifier and writes to the
// global tee.
func Printf(format string, args ...interface{}) (int64, error) {
return globalTee.Printf(format, args...)
}