linkerd2/pkg/shell/shell.go

99 lines
2.3 KiB
Go

package shell
import (
"bufio"
"fmt"
"io"
"os"
"os/exec"
"runtime"
"time"
)
type Shell interface {
CombinedOutput(name string, arg ...string) (string, error)
AsyncStdout(potentialErrorFromAsyncProcess chan error, name string, arg ...string) (*bufio.Reader, error)
WaitForCharacter(charToWaitFor byte, output *bufio.Reader, timeout time.Duration) (string, error)
HomeDir() string
Path() string
}
type unixShell struct{}
func (sh *unixShell) CombinedOutput(name string, arg ...string) (string, error) {
command := exec.Command(name, arg...)
bytes, err := command.CombinedOutput()
if err != nil {
return string(bytes), err
}
return string(bytes), nil
}
func (sh *unixShell) AsyncStdout(potentialErrorFromAsyncProcess chan error, name string, arg ...string) (*bufio.Reader, error) {
command := exec.Command(name, arg...)
stdout, err := command.StdoutPipe()
if err != nil {
return nil, fmt.Errorf("error executing command in an async way: %v", err)
}
reader := bufio.NewReader(stdout)
go func(e chan error) { e <- command.Run() }(potentialErrorFromAsyncProcess)
return reader, nil
}
func (sh *unixShell) WaitForCharacter(charToWaitFor byte, outputReader *bufio.Reader, timeout time.Duration) (string, error) {
output := make(chan string, 1)
potentialError := make(chan error, 1)
go func(output chan string, e chan error) {
outputString, err := outputReader.ReadString(charToWaitFor)
if err != nil {
if err == io.EOF {
e <- fmt.Errorf("reached end of stream while waiting for character [%c] in output [%s] of command: %v", charToWaitFor, outputString, err)
} else {
e <- fmt.Errorf("error while reading output from command: %v", err)
}
}
output <- outputString
}(output, potentialError)
select {
case <-time.After(timeout):
return "", fmt.Errorf("timed-out expoecting token [%c] in reader", charToWaitFor)
case e := <-potentialError:
return "", e
case o := <-output:
return o, nil
}
}
func (sh *unixShell) HomeDir() string {
var homeEnvVar string
if runtime.GOOS == "windows" {
homeEnvVar = "USERPROFILE"
} else {
homeEnvVar = "HOME"
}
return os.Getenv(homeEnvVar)
}
func (sh *unixShell) Path() string {
var pathEnvVar string
if runtime.GOOS == "windows" {
pathEnvVar = "Path"
} else {
pathEnvVar = "PATH"
}
return os.Getenv(pathEnvVar)
}
func NewUnixShell() Shell {
return &unixShell{}
}