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authorSebastien Douheret <sebastien.douheret@iot.bzh>2017-05-11 19:42:00 +0200
committerSebastien Douheret <sebastien.douheret@iot.bzh>2017-05-11 19:42:22 +0200
commitec7051e1da665206f594c7616ad381bfeaea333a (patch)
treeecc01ee358794c9d8c5fbb87d2f5b6ce3f60f431 /lib/common/execPipeWs.go
parentca3e1762832b27dc25cf90125b376c56e24e2db2 (diff)
Initial main commit.
Signed-off-by: Sebastien Douheret <sebastien.douheret@iot.bzh>
Diffstat (limited to 'lib/common/execPipeWs.go')
-rw-r--r--lib/common/execPipeWs.go148
1 files changed, 148 insertions, 0 deletions
diff --git a/lib/common/execPipeWs.go b/lib/common/execPipeWs.go
new file mode 100644
index 0000000..3b63cdc
--- /dev/null
+++ b/lib/common/execPipeWs.go
@@ -0,0 +1,148 @@
+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)
+}