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package common
import (
"bufio"
"fmt"
"io"
"os"
"time"
"syscall"
"github.com/Sirupsen/logrus"
"github.com/googollee/go-socket.io"
)
// EmitOutputCB is the function callback used to emit data
type EmitOutputCB func(sid string, cmdID int, stdout, stderr string)
// EmitExitCB is the function callback used to emit exit proc code
type EmitExitCB func(sid string, cmdID int, code int, err error)
// Inspired by :
// https://github.com/gorilla/websocket/blob/master/examples/command/main.go
// ExecPipeWs executes a command and redirect stdout/stderr into a WebSocket
func ExecPipeWs(cmd string, so *socketio.Socket, sid string, cmdID int,
cmdExecTimeout int, log *logrus.Logger, eoCB EmitOutputCB, eeCB EmitExitCB) error {
outr, outw, err := os.Pipe()
if err != nil {
return fmt.Errorf("Pipe stdout error: " + err.Error())
}
// XXX - do we need to pipe stdin one day ?
inr, inw, err := os.Pipe()
if err != nil {
outr.Close()
outw.Close()
return fmt.Errorf("Pipe stdin error: " + err.Error())
}
bashArgs := []string{"/bin/bash", "-c", cmd}
proc, err := os.StartProcess("/bin/bash", bashArgs, &os.ProcAttr{
Files: []*os.File{inr, outw, outw},
})
if err != nil {
outr.Close()
outw.Close()
inr.Close()
inw.Close()
return fmt.Errorf("Process start error: " + err.Error())
}
go func() {
defer outr.Close()
defer outw.Close()
defer inr.Close()
defer inw.Close()
stdoutDone := make(chan struct{})
go cmdPumpStdout(so, outr, stdoutDone, sid, cmdID, log, eoCB)
// Blocking function that poll input or wait for end of process
cmdPumpStdin(so, inw, proc, sid, cmdID, cmdExecTimeout, log, eeCB)
// Some commands will exit when stdin is closed.
inw.Close()
defer outr.Close()
if status, err := proc.Wait(); err == nil {
// Other commands need a bonk on the head.
if !status.Exited() {
if err := proc.Signal(os.Interrupt); err != nil {
log.Errorln("Proc interrupt:", err)
}
select {
case <-stdoutDone:
case <-time.After(time.Second):
// A bigger bonk on the head.
if err := proc.Signal(os.Kill); err != nil {
log.Errorln("Proc term:", err)
}
<-stdoutDone
}
}
}
}()
return nil
}
func cmdPumpStdin(so *socketio.Socket, w io.Writer, proc *os.Process,
sid string, cmdID int, tmo int, log *logrus.Logger, exitFuncCB EmitExitCB) {
/* XXX - code to add to support stdin through WS
for {
_, message, err := so. ?? ReadMessage()
if err != nil {
break
}
message = append(message, '\n')
if _, err := w.Write(message); err != nil {
break
}
}
*/
// Monitor process exit
type DoneChan struct {
status int
err error
}
done := make(chan DoneChan, 1)
go func() {
status := 0
sts, err := proc.Wait()
if !sts.Success() {
s := sts.Sys().(syscall.WaitStatus)
status = s.ExitStatus()
}
done <- DoneChan{status, err}
}()
// Wait cmd complete
select {
case dC := <-done:
exitFuncCB(sid, cmdID, dC.status, dC.err)
case <-time.After(time.Duration(tmo) * time.Second):
exitFuncCB(sid, cmdID, -99,
fmt.Errorf("Exit Timeout for command ID %v", cmdID))
}
}
func cmdPumpStdout(so *socketio.Socket, r io.Reader, done chan struct{},
sid string, cmdID int, log *logrus.Logger, emitFuncCB EmitOutputCB) {
defer func() {
}()
sc := bufio.NewScanner(r)
for sc.Scan() {
emitFuncCB(sid, cmdID, string(sc.Bytes()), "")
}
if sc.Err() != nil {
log.Errorln("scan:", sc.Err())
}
close(done)
}
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