forked from kubernetes/kubernetes
-
Notifications
You must be signed in to change notification settings - Fork 3
/
go-runner.go
122 lines (102 loc) · 3.21 KB
/
go-runner.go
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
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
/*
Copyright 2020 The Kubernetes Authors.
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 main
import (
"flag"
"fmt"
"io"
"log"
"os"
"os/exec"
"os/signal"
"strings"
"syscall"
"github.com/pkg/errors"
)
var (
logFilePath = flag.String("log-file", "", "If non-empty, save stdout to this file")
alsoToStdOut = flag.Bool("also-stdout", false, "useful with log-file, log to standard output as well as the log file")
redirectStderr = flag.Bool("redirect-stderr", true, "treat stderr same as stdout")
)
func main() {
flag.Parse()
if err := configureAndRun(); err != nil {
log.Fatal(err)
}
}
func configureAndRun() error {
var (
outputStream io.Writer = os.Stdout
errStream io.Writer = os.Stderr
)
args := flag.Args()
if len(args) == 0 {
return errors.Errorf("not enough arguments to run")
}
if logFilePath != nil && *logFilePath != "" {
logFile, err := os.OpenFile(*logFilePath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
if err != nil {
return errors.Wrapf(err, "failed to create log file %v", *logFilePath)
}
if *alsoToStdOut {
outputStream = io.MultiWriter(os.Stdout, logFile)
} else {
outputStream = logFile
}
}
if *redirectStderr {
errStream = outputStream
}
exe := args[0]
var exeArgs []string
if len(args) > 1 {
exeArgs = args[1:]
}
cmd := exec.Command(exe, exeArgs...)
cmd.Stdout = outputStream
cmd.Stderr = errStream
log.Printf("Running command:\n%v", cmdInfo(cmd))
err := cmd.Start()
if err != nil {
return errors.Wrap(err, "starting command")
}
// Handle signals and shutdown process gracefully.
go setupSigHandler(cmd.Process)
return errors.Wrap(cmd.Wait(), "running command")
}
// cmdInfo generates a useful look at what the command is for printing/debug.
func cmdInfo(cmd *exec.Cmd) string {
return fmt.Sprintf(
`Command env: (log-file=%v, also-stdout=%v, redirect-stderr=%v)
Run from directory: %v
Executable path: %v
Args (comma-delimited): %v`, *logFilePath, *alsoToStdOut, *redirectStderr,
cmd.Dir, cmd.Path, strings.Join(cmd.Args, ","),
)
}
// setupSigHandler will forward any termination signals to the process
func setupSigHandler(process *os.Process) {
// terminationSignals are signals that cause the program to exit in the
// supported platforms (linux, darwin, windows).
terminationSignals := []os.Signal{syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT}
c := make(chan os.Signal, 1)
signal.Notify(c, terminationSignals...)
// Block until a signal is received.
log.Println("Now listening for interrupts")
s := <-c
log.Printf("Got signal: %v. Sending down to process (PID: %v)", s, process.Pid)
if err := process.Signal(s); err != nil {
log.Fatalf("Failed to signal process: %v", err)
}
log.Printf("Signalled process %v successfully.", process.Pid)
}