status-go/vendor/github.com/spacemonkeygo/spacelog/capture.go

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2019-06-09 07:24:20 +00:00
// Copyright (C) 2014 Space Monkey, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package spacelog
import (
"fmt"
"os"
"os/exec"
)
// CaptureOutputToFile opens a filehandle using the given path, then calls
// CaptureOutputToFd on the associated filehandle.
func CaptureOutputToFile(path string) error {
fh, err := os.OpenFile(path, os.O_RDWR|os.O_CREATE, 0644)
if err != nil {
return err
}
defer fh.Close()
return CaptureOutputToFd(int(fh.Fd()))
}
// CaptureOutputToProcess starts a process and using CaptureOutputToFd,
// redirects stdout and stderr to the subprocess' stdin.
// CaptureOutputToProcess expects the subcommand to last the lifetime of the
// process, and if the subprocess dies, will panic.
func CaptureOutputToProcess(command string, args ...string) error {
cmd := exec.Command(command, args...)
out, err := cmd.StdinPipe()
if err != nil {
return err
}
defer out.Close()
type fder interface {
Fd() uintptr
}
out_fder, ok := out.(fder)
if !ok {
return fmt.Errorf("unable to get underlying pipe")
}
err = CaptureOutputToFd(int(out_fder.Fd()))
if err != nil {
return err
}
err = cmd.Start()
if err != nil {
return err
}
go func() {
err := cmd.Wait()
if err != nil {
panic(fmt.Errorf("captured output process died! %s", err))
}
}()
return nil
}