summaryrefslogtreecommitdiff
path: root/go/src/lib/pipeline/pipeline.go
blob: 56a32effa016547d043f4a045a5832461b629022 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
package pipeline

import (
	"io"
	"os/exec"
)

type Pipe struct {
	Cmds []exec.Cmd
}

func (pl *Pipe) preStart() error {
	for _, cmd := range pl.Cmds[:len(pl.Cmds)-2] {
		if err := cmd.Start(); err != nil {
			return err
		}
	}
	return nil
}

func (pl *Pipe) Start() error {
	for _, cmd := range pl.Cmds {
		if err := cmd.Start(); err != nil {
			return err
		}
	}
	return nil
}

func (pl *Pipe) Wait() error {
	for _, cmd := range pl.Cmds {
		if err := cmd.Wait(); err != nil {
			return err
		}
	}
	return nil
}

func (pl *Pipe) Run() error {
	if err := pl.Start(); err != nil {
		return err
	}
	return pl.Wait()
}

func (pl *Pipe) CombinedOutput() ([]byte, error) {
	if err := pl.preStart(); err != nil {
		return nil, err
	}
	return pl.Cmds[len(pl.Cmds)-1].CombinedOutput()
}

func (pl *Pipe) Output() ([]byte, error) {
	if err := pl.preStart(); err != nil {
		return nil, err
	}
	return pl.Cmds[len(pl.Cmds)-1].Output()
}

func (pl *Pipe) StdinPipe() (io.WriteCloser, error) {
	return pl.Cmds[0].StdinPipe()
}

func (pl *Pipe) StdoutPipe() (io.ReadCloser, error) {
	return pl.Cmds[len(pl.Cmds)-1].StdoutPipe()
}

var _ = &Pipe{}

func Pipeline(cmds ...exec.Cmd) (*Pipe, error) {
	pl := &Pipe{cmds}
	for i := range pl.Cmds[:len(pl.Cmds)-2] {
		out, err := pl.Cmds[i].StdoutPipe()
		if err != nil {
			return nil, err
		}
		pl.Cmds[i+1].Stdin = out
	}
	return pl, nil
}