add 'restart' option to all external commands

README.md

@@ -109,6 +109,7 @@ Edit `rtsp-simple-server.yml` and replace everything inside section `paths` with
 paths:
   cam:
     runOnInit: ffmpeg -f v4l2 -i /dev/video0 -f rtsp rtsp://localhost:8554/$RTSP_SERVER_PATH
+    runOnInitRestart: yes
 ```
 
 After starting the server, the webcam is available on `rtsp://localhost:8554/cam`. The ffmpeg command works only on Linux; for Windows and Mac equivalents, read the [ffmpeg wiki](https://trac.ffmpeg.org/wiki/Capture/Webcam).
@@ -128,6 +129,7 @@ Then edit `rtsp-simple-server.yml` and replace everything inside section `paths`
 paths:
   cam:
     runOnInit: gst-launch-1.0 rpicamsrc preview=false bitrate=2000000 keyframe-interval=50 ! video/x-h264,width=1920,height=1080,framerate=25/1 ! rtspclientsink location=rtsp://localhost:8554/$RTSP_SERVER_PATH
+    runOnInitRestart: yes
 ```
 
 After starting the server, the webcam is available on `rtsp://localhost:8554/cam`.
@@ -139,6 +141,7 @@ Edit `rtsp-simple-server.yml` and replace everything inside section `paths` with
 paths:
   ondemand:
     runOnDemand: ffmpeg -re -stream_loop -1 -i file.ts -c copy -f rtsp rtsp://localhost:8554/$RTSP_SERVER_PATH
+    runOnDemandRestart: yes
 ```
 
 The command inserted into `runOnDemand` will start only when a client requests the path `ondemand`, therefore the file will start streaming only when requested.
@@ -151,6 +154,7 @@ paths:
   all:
   original:
     runOnPublish: ffmpeg -i rtsp://localhost:8554/$RTSP_SERVER_PATH -b:a 64k -c:v libx264 -preset ultrafast -b:v 500k -max_muxing_queue_size 1024 -f rtsp rtsp://localhost:8554/compressed
+    runOnPublishRestart: yes
 ```
 
 ### Authentication

client/client.go

@@ -103,6 +103,7 @@ type Client struct {
 	serverUdpRtcp       *serverudp.Server
 	readTimeout         time.Duration
 	runOnConnect        string
+	runOnConnectRestart bool
 	protocols           map[gortsplib.StreamProtocol]struct{}
 	conn                *gortsplib.ConnServer
 	parent              Parent
@@ -134,6 +135,7 @@ func New(
 	readTimeout time.Duration,
 	writeTimeout time.Duration,
 	runOnConnect string,
+	runOnConnectRestart bool,
 	protocols map[gortsplib.StreamProtocol]struct{},
 	nconn net.Conn,
 	parent Parent) *Client {
@@ -145,6 +147,7 @@ func New(
 		serverUdpRtcp:       serverUdpRtcp,
 		readTimeout:         readTimeout,
 		runOnConnect:        runOnConnect,
+		runOnConnectRestart: runOnConnectRestart,
 		protocols:           protocols,
 		conn: gortsplib.NewConnServer(gortsplib.ConnServerConf{
 			Conn:            nconn,
@@ -198,11 +201,7 @@ func (c *Client) run() {
 
 	var onConnectCmd *externalcmd.ExternalCmd
 	if c.runOnConnect != "" {
-		var err error
-		onConnectCmd, err = externalcmd.New(c.runOnConnect, "")
-		if err != nil {
-			c.log("ERR: %s", err)
-		}
+		onConnectCmd = externalcmd.New(c.runOnConnect, c.runOnConnectRestart, "")
 	}
 
 	for {
@@ -939,11 +938,8 @@ func (c *Client) runPlay() bool {
 
 	var onReadCmd *externalcmd.ExternalCmd
 	if c.path.Conf().RunOnRead != "" {
-		var err error
-		onReadCmd, err = externalcmd.New(c.path.Conf().RunOnRead, c.path.Name())
-		if err != nil {
-			c.log("ERR: %s", err)
-		}
+		onReadCmd = externalcmd.New(c.path.Conf().RunOnRead,
+			c.path.Conf().RunOnReadRestart, c.path.Name())
 	}
 
 	if c.streamProtocol == gortsplib.StreamProtocolUDP {
@@ -1121,11 +1117,8 @@ func (c *Client) runRecord() bool {
 
 	var onPublishCmd *externalcmd.ExternalCmd
 	if c.path.Conf().RunOnPublish != "" {
-		var err error
-		onPublishCmd, err = externalcmd.New(c.path.Conf().RunOnPublish, c.path.Name())
-		if err != nil {
-			c.log("ERR: %s", err)
-		}
+		onPublishCmd = externalcmd.New(c.path.Conf().RunOnPublish,
+			c.path.Conf().RunOnPublishRestart, c.path.Name())
 	}
 
 	if c.streamProtocol == gortsplib.StreamProtocolUDP {

clientman/clientman.go

@@ -23,6 +23,7 @@ type ClientManager struct {
 	readTimeout         time.Duration
 	writeTimeout        time.Duration
 	runOnConnect        string
+	runOnConnectRestart bool
 	protocols           map[headers.StreamProtocol]struct{}
 	stats               *stats.Stats
 	serverUdpRtp        *serverudp.Server
@@ -46,6 +47,7 @@ func New(
 	readTimeout time.Duration,
 	writeTimeout time.Duration,
 	runOnConnect string,
+	runOnConnectRestart bool,
 	protocols map[headers.StreamProtocol]struct{},
 	stats *stats.Stats,
 	serverUdpRtp *serverudp.Server,
@@ -58,6 +60,7 @@ func New(
 		readTimeout:         readTimeout,
 		writeTimeout:        writeTimeout,
 		runOnConnect:        runOnConnect,
+		runOnConnectRestart: runOnConnectRestart,
 		protocols:           protocols,
 		stats:               stats,
 		serverUdpRtp:        serverUdpRtp,
@@ -98,6 +101,7 @@ outer:
 				cm.readTimeout,
 				cm.writeTimeout,
 				cm.runOnConnect,
+				cm.runOnConnectRestart,
 				cm.protocols,
 				conn,
 				cm)

conf/conf.go

@@ -20,6 +20,7 @@ type Conf struct {
 	RtpPort               int                                   `yaml:"rtpPort"`
 	RtcpPort              int                                   `yaml:"rtcpPort"`
 	RunOnConnect          string                                `yaml:"runOnConnect"`
+	RunOnConnectRestart   bool                                  `yaml:"runOnConnectRestart"`
 	ReadTimeout           time.Duration                         `yaml:"readTimeout"`
 	WriteTimeout          time.Duration                         `yaml:"writeTimeout"`
 	AuthMethods           []string                              `yaml:"authMethods"`

conf/pathconf.go

@@ -22,9 +22,13 @@ type PathConf struct {
 	SourceOnDemand       bool                     `yaml:"sourceOnDemand"`
 	SourceRedirect       string                   `yaml:"sourceRedirect"`
 	RunOnInit            string                   `yaml:"runOnInit"`
+	RunOnInitRestart     bool                     `yaml:"runOnInitRestart"`
 	RunOnDemand          string                   `yaml:"runOnDemand"`
+	RunOnDemandRestart   bool                     `yaml:"runOnDemandRestart"`
 	RunOnPublish         string                   `yaml:"runOnPublish"`
+	RunOnPublishRestart  bool                     `yaml:"runOnPublishRestart"`
 	RunOnRead            string                   `yaml:"runOnRead"`
+	RunOnReadRestart     bool                     `yaml:"runOnReadRestart"`
 	PublishUser          string                   `yaml:"publishUser"`
 	PublishPass          string                   `yaml:"publishPass"`
 	PublishIps           []string                 `yaml:"publishIps"`

externalcmd/externalcmd.go

@@ -5,29 +5,91 @@ import (
 	"os/exec"
 	"runtime"
 	"strings"
+	"time"
+)
+
+const (
+	restartPause = 2 * time.Second
 )
 
 type ExternalCmd struct {
-	cmd *exec.Cmd
+	cmdstr   string
+	restart  bool
+	pathName string
+
+	// in
+	terminate chan struct{}
+
+	// out
+	done chan struct{}
+}
+
+func New(cmdstr string, restart bool, pathName string) *ExternalCmd {
+	e := &ExternalCmd{
+		cmdstr:    cmdstr,
+		restart:   restart,
+		pathName:  pathName,
+		terminate: make(chan struct{}),
+		done:      make(chan struct{}),
+	}
+
+	go e.run()
+	return e
+}
+
+func (e *ExternalCmd) Close() {
+	close(e.terminate)
+	<-e.done
+}
+
+func (e *ExternalCmd) run() {
+	defer close(e.done)
+
+	for {
+		if !e.runInner() {
+			break
 		}
+	}
+}
+
+func (e *ExternalCmd) runInner() bool {
+	ok := e.runInnerInner()
+	if !ok {
+		return false
+	}
+
+	if !e.restart {
+		<-e.terminate
+		return false
+	}
+
+	t := time.NewTimer(restartPause)
+	defer t.Stop()
 
-func New(cmdstr string, pathName string) (*ExternalCmd, error) {
+	select {
+	case <-t.C:
+		return true
+	case <-e.terminate:
+		return false
+	}
+}
+
+func (e *ExternalCmd) runInnerInner() bool {
 	var cmd *exec.Cmd
 	if runtime.GOOS == "windows" {
 		// on Windows the shell is not used and command is started directly
-		// variables are replaced manually in order to allow
-		// compatibility with linux commands
-		cmdstr = strings.ReplaceAll(cmdstr, "$RTSP_SERVER_PATH", pathName)
-		args := strings.Fields(cmdstr)
+		// variables are replaced manually in order to guarantee compatibility
+		// with Linux commands
+		args := strings.Fields(strings.ReplaceAll(e.cmdstr, "$RTSP_SERVER_PATH", e.pathName))
 		cmd = exec.Command(args[0], args[1:]...)
 
 	} else {
-		cmd = exec.Command("/bin/sh", "-c", "exec "+cmdstr)
+		cmd = exec.Command("/bin/sh", "-c", "exec "+e.cmdstr)
 	}
 
-	// variables are available through environment variables
+	// variables are inserted into the environment
 	cmd.Env = append(os.Environ(),
-		"RTSP_SERVER_PATH="+pathName,
+		"RTSP_SERVER_PATH="+e.pathName,
 	)
 
 	cmd.Stdout = os.Stdout
@@ -35,21 +97,28 @@ func New(cmdstr string, pathName string) (*ExternalCmd, error) {
 
 	err := cmd.Start()
 	if err != nil {
-		return nil, err
+		return true
 	}
 
-	return &ExternalCmd{
-		cmd: cmd,
-	}, nil
-}
+	cmdDone := make(chan struct{})
+	go func() {
+		defer close(cmdDone)
+		cmd.Wait()
+	}()
 
-func (e *ExternalCmd) Close() {
+	select {
+	case <-e.terminate:
 		// on Windows it's not possible to send os.Interrupt to a process
 		// Kill() is the only supported way
 		if runtime.GOOS == "windows" {
-		e.cmd.Process.Kill()
+			cmd.Process.Kill()
 		} else {
-		e.cmd.Process.Signal(os.Interrupt)
+			cmd.Process.Signal(os.Interrupt)
+		}
+		<-cmdDone
+		return false
+
+	case <-cmdDone:
+		return true
 	}
-	e.cmd.Wait()
 }

main.go

@@ -181,8 +181,9 @@ func (p *program) createResources(initial bool) error {
 
 	if p.clientMan == nil {
 		p.clientMan = clientman.New(p.conf.ReadTimeout, p.conf.WriteTimeout,
-			p.conf.RunOnConnect, p.conf.ProtocolsParsed, p.stats,
-			p.serverUdpRtp, p.serverUdpRtcp, p.pathMan, p.serverTcp, p)
+			p.conf.RunOnConnect, p.conf.RunOnConnectRestart,
+			p.conf.ProtocolsParsed, p.stats, p.serverUdpRtp, p.serverUdpRtcp,
+			p.pathMan, p.serverTcp, p)
 	}
 
 	if p.confWatcher == nil {
@@ -295,6 +296,7 @@ func (p *program) reloadConf() error {
 		conf.ReadTimeout != p.conf.ReadTimeout ||
 		conf.WriteTimeout != p.conf.WriteTimeout ||
 		conf.RunOnConnect != p.conf.RunOnConnect ||
+		conf.RunOnConnectRestart != p.conf.RunOnConnectRestart ||
 		!reflect.DeepEqual(conf.ProtocolsParsed, p.conf.ProtocolsParsed) {
 		closeClientMan = true
 	}

path/path.go

@@ -223,11 +223,8 @@ func (pa *Path) run() {
 
 	if pa.conf.RunOnInit != "" {
 		pa.Log("starting on init command")
-		var err error
-		pa.onInitCmd, err = externalcmd.New(pa.conf.RunOnInit, pa.name)
-		if err != nil {
-			pa.Log("ERR: %s", err)
-		}
+		pa.onInitCmd = externalcmd.New(pa.conf.RunOnInit,
+			pa.conf.RunOnInitRestart, pa.name)
 	}
 
 	tickerCheck := time.NewTicker(pathCheckPeriod)
@@ -516,11 +513,8 @@ func (pa *Path) onClientDescribe(c *client.Client) {
 			if pa.onDemandCmd == nil { // start if needed
 				pa.Log("starting on demand command")
 				pa.lastDescribeActivation = time.Now()
-				var err error
-				pa.onDemandCmd, err = externalcmd.New(pa.conf.RunOnDemand, pa.name)
-				if err != nil {
-					pa.Log("ERR: %s", err)
-				}
+				pa.onDemandCmd = externalcmd.New(pa.conf.RunOnDemand,
+					pa.conf.RunOnDemandRestart, pa.name)
 			}
 
 			pa.clients[c] = clientStateWaitingDescribe

rtsp-simple-server.yml

@@ -17,10 +17,6 @@ writeTimeout: 5s
 # to enforce security).
 authMethods: [basic, digest]
 
-# command to run when a client connects.
-# this is terminated with SIGINT when a client disconnects.
-runOnConnect:
-
 # enable Prometheus-compatible metrics on port 9998.
 metrics: no
 # enable pprof on port 9999 to monitor performances.
@@ -31,6 +27,11 @@ logDestinations: [stdout]
 # if "file" is in logDestinations, this is the file that will receive the logs.
 logFile: rtsp-simple-server.log
 
+# command to run when a client connects to the server.
+# this is terminated with SIGINT when a client disconnects from the server.
+runOnConnect:
+runOnConnectRestart: no
+
 # these settings are path-dependent.
 # it's possible to use regular expressions by using a tilde as prefix.
 # for example, "~^(test1|test2)$" will match both "test1" and "test2".
@@ -57,38 +58,42 @@ paths:
     # redirected to.
     sourceRedirect:
 
+    # username required to publish.
+    publishUser:
+    # password required to publish.
+    publishPass:
+    # ips or networks (x.x.x.x/24) allowed to publish.
+    publishIps: []
+
+    # username required to read.
+    readUser:
+    # password required to read.
+    readPass:
+    # ips or networks (x.x.x.x/24) allowed to read.
+    readIps: []
+
     # command to run when this path is loaded by the program.
     # this can be used, for example, to publish a stream and keep it always opened.
     # this is terminated with SIGINT when the program closes.
     # the path name is available in the RTSP_SERVER_PATH variable.
     runOnInit:
+    runOnInitRestart: no
 
     # command to run when this path is requested.
     # this can be used, for example, to publish a stream on demand.
     # this is terminated with SIGINT when the path is not requested anymore.
     # the path name is available in the RTSP_SERVER_PATH variable.
     runOnDemand:
+    runOnDemandRestart: no
 
     # command to run when a client starts publishing.
     # this is terminated with SIGINT when a client stops publishing.
     # the path name is available in the RTSP_SERVER_PATH variable.
     runOnPublish:
+    runOnPublishRestart: no
 
     # command to run when a clients starts reading.
     # this is terminated with SIGINT when a client stops reading.
     # the path name is available in the RTSP_SERVER_PATH variable.
     runOnRead:
-
-    # username required to publish.
-    publishUser:
-    # password required to publish.
-    publishPass:
-    # ips or networks (x.x.x.x/24) allowed to publish.
-    publishIps: []
-
-    # username required to read.
-    readUser:
-    # password required to read.
-    readPass:
-    # ips or networks (x.x.x.x/24) allowed to read.
-    readIps: []
+    runOnReadRestart: no