workgroups/vendor/github.com/posener/script/exec.go
Marvin Preuss f121b05b58
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repo: adds goreadme
2021-09-24 18:29:05 +02:00

86 lines
2.3 KiB
Go

package script
import (
"fmt"
"io"
"io/ioutil"
"os/exec"
"github.com/hashicorp/go-multierror"
)
// Exec executes a command and returns a stream of the stdout of the command.
func Exec(cmd string, args ...string) Stream {
return From("empty", nil).Through(exe{cmd: cmd, args: args})
}
// ExecHandleStderr executes a command, returns a stream of the stdout of the command and enable
// collecting the stderr of the command.
//
// If the stderr is nil, it will be ignored.
//
// For example, collecting the stderr to memory can be done by providing a `&bytes.Buffer` as
// `stderr`. Writing it to stderr can be done by providing `os.Stderr` as `stderr`. Logging it
// to a file can be done by providing an `os.File` as the `stderr`.
func ExecHandleStderr(stderr io.Writer, cmd string, args ...string) Stream {
return From("empty", nil).Through(exe{cmd: cmd, args: args, stderr: stderr})
}
// Exec executes a command and returns a stream of the stdout of the command.
func (s Stream) Exec(cmd string, args ...string) Stream {
return s.Through(exe{cmd: cmd, args: args})
}
// ExecHandleStderr executes a command, returns a stream of the stdout of the command and enable
// collecting the stderr of the command.
//
// If the stderr is nil, it will be ignored.
func (s Stream) ExecHandleStderr(stderr io.Writer, cmd string, args ...string) Stream {
return s.Through(exe{cmd: cmd, args: args, stderr: stderr})
}
type exe struct {
cmd string
args []string
stderr io.Writer
}
func (e exe) Name() string {
return fmt.Sprintf("exec(%v, %+v)", e.cmd, e.args)
}
func (e exe) Pipe(stdin io.Reader) (io.Reader, error) {
cmd := exec.Command(e.cmd, e.args...)
var errors *multierror.Error
// Pipe previous stdin if available.
if stdin != nil {
cmd.Stdin = stdin
}
// Pipe stdout to the current command output.
cmdOut, err := cmd.StdoutPipe()
if err != nil {
errors = multierror.Append(errors, fmt.Errorf("pipe stdout: %v", err))
}
if e.stderr == nil {
e.stderr = ioutil.Discard
}
cmd.Stderr = e.stderr
// start the process
err = cmd.Start()
if err != nil {
errors = multierror.Append(errors, fmt.Errorf("start process: %v", err))
}
return readcloser{
Reader: cmdOut,
Closer: closerFn(func() error { return cmd.Wait() }),
}, errors.ErrorOrNil()
}
type closerFn func() error
func (f closerFn) Close() error { return f() }