print error that caused an external command to exit (#1869)

internal/core/path.go

@@ -333,8 +333,8 @@ func (pa *path) run() {
 			pa.conf.RunOnInit,
 			pa.conf.RunOnInitRestart,
 			pa.externalCmdEnv(),
-			func(co int) {
-				pa.Log(logger.Info, "runOnInit command exited with code %d", co)
+			func(err error) {
+				pa.Log(logger.Info, "runOnInit command exited: %v", err)
 			})
 	}
 
@@ -588,8 +588,8 @@ func (pa *path) onDemandPublisherStart() {
 		pa.conf.RunOnDemand,
 		pa.conf.RunOnDemandRestart,
 		pa.externalCmdEnv(),
-		func(co int) {
-			pa.Log(logger.Info, "runOnDemand command exited with code %d", co)
+		func(err error) {
+			pa.Log(logger.Info, "runOnDemand command exited: %v", err)
 		})
 
 	pa.onDemandPublisherReadyTimer.Stop()
@@ -647,8 +647,8 @@ func (pa *path) sourceSetReady(medias media.Medias, allocateEncoder bool) error
 			pa.conf.RunOnReady,
 			pa.conf.RunOnReadyRestart,
 			pa.externalCmdEnv(),
-			func(co int) {
-				pa.Log(logger.Info, "runOnReady command exited with code %d", co)
+			func(err error) {
+				pa.Log(logger.Info, "runOnReady command exited: %v", err)
 			})
 	}
 

internal/core/rtmp_conn.go

@@ -299,8 +299,8 @@ func (c *rtmpConn) run() {
 				"RTSP_PATH": "",
 				"RTSP_PORT": port,
 			},
-			func(co int) {
-				c.Log(logger.Info, "runOnConnect command exited with code %d", co)
+			func(err error) {
+				c.Log(logger.Info, "runOnConnect command exited: %v", err)
 			})
 
 		defer func() {
@@ -424,8 +424,8 @@ func (c *rtmpConn) runRead(ctx context.Context, u *url.URL) error {
 			pathConf.RunOnRead,
 			pathConf.RunOnReadRestart,
 			res.path.externalCmdEnv(),
-			func(co int) {
-				c.Log(logger.Info, "runOnRead command exited with code %d", co)
+			func(err error) {
+				c.Log(logger.Info, "runOnRead command exited: %v", err)
 			})
 		defer func() {
 			onReadCmd.Close()

internal/core/rtsp_conn.go

@@ -80,8 +80,8 @@ func newRTSPConn(
 				"RTSP_PATH": "",
 				"RTSP_PORT": port,
 			},
-			func(co int) {
-				c.Log(logger.Info, "runOnInit command exited with code %d", co)
+			func(err error) {
+				c.Log(logger.Info, "runOnInit command exited: %v", err)
 			})
 	}
 

internal/core/rtsp_session.go

@@ -276,8 +276,8 @@ func (s *rtspSession) onPlay(ctx *gortsplib.ServerHandlerOnPlayCtx) (*base.Respo
 				pathConf.RunOnRead,
 				pathConf.RunOnReadRestart,
 				s.path.externalCmdEnv(),
-				func(co int) {
-					s.Log(logger.Info, "runOnRead command exited with code %d", co)
+				func(err error) {
+					s.Log(logger.Info, "runOnRead command exited: %v", err)
 				})
 		}
 

internal/externalcmd/cmd.go

@@ -2,6 +2,7 @@
 package externalcmd
 
 import (
+	"errors"
 	"strings"
 	"time"
 )
@@ -10,6 +11,8 @@ const (
 	restartPause = 5 * time.Second
 )
 
+var errTerminated = errors.New("terminated")
+
 // Environment is a Cmd environment.
 type Environment map[string]string
 
@@ -19,7 +22,7 @@ type Cmd struct {
 	cmdstr  string
 	restart bool
 	env     Environment
-	onExit  func(int)
+	onExit  func(error)
 
 	// in
 	terminate chan struct{}
@@ -31,7 +34,7 @@ func NewCmd(
 	cmdstr string,
 	restart bool,
 	env Environment,
-	onExit func(int),
+	onExit func(error),
 ) *Cmd {
 	// replace variables in both Linux and Windows, in order to allow using the
 	// same commands on both of them.
@@ -64,30 +67,22 @@ func (e *Cmd) run() {
 	defer e.pool.wg.Done()
 
 	for {
-		ok := e.runInner()
-		if !ok {
-			break
+		err := e.runOSSpecific()
+		if err == errTerminated {
+			return
+		}
+
+		e.onExit(err)
+
+		if !e.restart {
+			<-e.terminate
+			return
+		}
+
+		select {
+		case <-time.After(restartPause):
+		case <-e.terminate:
+			return
 		}
 	}
 }
-
-func (e *Cmd) runInner() bool {
-	c, ok := e.runOSSpecific()
-	if !ok {
-		return false
-	}
-
-	e.onExit(c)
-
-	if !e.restart {
-		<-e.terminate
-		return false
-	}
-
-	select {
-	case <-time.After(restartPause):
-		return true
-	case <-e.terminate:
-		return false
-	}
-}

internal/externalcmd/cmd_unix.go

@@ -4,6 +4,7 @@
 package externalcmd
 
 import (
+	"fmt"
 	"os"
 	"os/exec"
 	"syscall"
@@ -11,10 +12,10 @@ import (
 	"github.com/kballard/go-shellquote"
 )
 
-func (e *Cmd) runOSSpecific() (int, bool) {
+func (e *Cmd) runOSSpecific() error {
 	cmdParts, err := shellquote.Split(e.cmdstr)
 	if err != nil {
-		return 0, true
+		return err
 	}
 
 	cmd := exec.Command(cmdParts[0], cmdParts[1:]...)
@@ -29,7 +30,7 @@ func (e *Cmd) runOSSpecific() (int, bool) {
 
 	err = cmd.Start()
 	if err != nil {
-		return 0, true
+		return err
 	}
 
 	cmdDone := make(chan int)
@@ -51,9 +52,9 @@ func (e *Cmd) runOSSpecific() (int, bool) {
 	case <-e.terminate:
 		syscall.Kill(cmd.Process.Pid, syscall.SIGINT)
 		<-cmdDone
-		return 0, false
+		return errTerminated
 
 	case c := <-cmdDone:
-		return c, true
+		return fmt.Errorf("command returned code %d", c)
 	}
 }

internal/externalcmd/cmd_win.go

@@ -4,6 +4,7 @@
 package externalcmd
 
 import (
+	"fmt"
 	"os"
 	"os/exec"
 	"strings"
@@ -12,7 +13,7 @@ import (
 	"github.com/kballard/go-shellquote"
 )
 
-func (e *Cmd) runOSSpecific() (int, bool) {
+func (e *Cmd) runOSSpecific() error {
 	var cmd *exec.Cmd
 
 	// from Golang documentation:
@@ -32,7 +33,7 @@ func (e *Cmd) runOSSpecific() (int, bool) {
 	} else {
 		cmdParts, err := shellquote.Split(e.cmdstr)
 		if err != nil {
-			return 0, true
+			return err
 		}
 
 		cmd = exec.Command(cmdParts[0], cmdParts[1:]...)
@@ -48,7 +49,7 @@ func (e *Cmd) runOSSpecific() (int, bool) {
 
 	err := cmd.Start()
 	if err != nil {
-		return 0, true
+		return err
 	}
 
 	cmdDone := make(chan int)
@@ -72,9 +73,9 @@ func (e *Cmd) runOSSpecific() (int, bool) {
 		// Kill() is the only supported way.
 		cmd.Process.Kill()
 		<-cmdDone
-		return 0, false
+		return errTerminated
 
 	case c := <-cmdDone:
-		return c, true
+		return fmt.Errorf("command returned code %d", c)
 	}
 }