From 1e628d0aaaa9137efa52d05351083abf05f97106 Mon Sep 17 00:00:00 2001
From: Sebastien Douheret <sebastien.douheret@iot.bzh>
Date: Mon, 26 Jun 2017 17:58:36 +0200
Subject: Initial commit to add golib

Signed-off-by: Sebastien Douheret <sebastien.douheret@iot.bzh>
---
 golib/execPipeWs.go | 151 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 151 insertions(+)
 create mode 100644 golib/execPipeWs.go

(limited to 'golib/execPipeWs.go')

diff --git a/golib/execPipeWs.go b/golib/execPipeWs.go
new file mode 100644
index 0000000..9bb4517
--- /dev/null
+++ b/golib/execPipeWs.go
@@ -0,0 +1,151 @@
+package common
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+	"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, data *map[string]interface{})
+
+// EmitExitCB is the function callback used to emit exit proc code
+type EmitExitCB func(sid string, cmdID int, code int, err error, data *map[string]interface{})
+
+// 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, env []string, so *socketio.Socket, sid string, cmdID int,
+	cmdExecTimeout int, log *logrus.Logger, eoCB EmitOutputCB, eeCB EmitExitCB, data *map[string]interface{}) 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", strings.Join(cmd, " ")}
+	proc, err := os.StartProcess("/bin/bash", bashArgs, &os.ProcAttr{
+		Files: []*os.File{inr, outw, outw},
+		Env:   append(os.Environ(), env...),
+	})
+	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, data)
+
+		// Blocking function that poll input or wait for end of process
+		cmdPumpStdin(so, inw, proc, sid, cmdID, cmdExecTimeout, log, eeCB, data)
+
+		// 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,
+	data *map[string]interface{}) {
+	/* 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, data)
+	case <-time.After(time.Duration(tmo) * time.Second):
+		exitFuncCB(sid, cmdID, -99,
+			fmt.Errorf("Exit Timeout for command ID %v", cmdID), data)
+	}
+}
+
+func cmdPumpStdout(so *socketio.Socket, r io.Reader, done chan struct{},
+	sid string, cmdID int, log *logrus.Logger, emitFuncCB EmitOutputCB, data *map[string]interface{}) {
+	defer func() {
+	}()
+
+	sc := bufio.NewScanner(r)
+	for sc.Scan() {
+		emitFuncCB(sid, cmdID, string(sc.Bytes()), "", data)
+	}
+	if sc.Err() != nil {
+		log.Errorln("scan:", sc.Err())
+	}
+	close(done)
+}
-- 
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