support assigning paths to different configurations without closing stream (#4576)

Co-authored-by: aler9 <46489434+aler9@users.noreply.github.com>

internal/core/path_manager.go

@@ -19,6 +19,9 @@ import (
 func pathConfCanBeUpdated(oldPathConf *conf.Path, newPathConf *conf.Path) bool {
 	clone := oldPathConf.Clone()
 
+	clone.Name = newPathConf.Name
+	clone.Regexp = newPathConf.Regexp
+
 	clone.Record = newPathConf.Record
 
 	clone.RPICameraBrightness = newPathConf.RPICameraBrightness
@@ -51,8 +54,9 @@ type pathSetHLSServerReq struct {
 }
 
 type pathData struct {
-	path  *path
-	ready bool
+	path     *path
+	ready    bool
+	confName string
 }
 
 type pathManagerParent interface {
@@ -209,34 +213,37 @@ func (pm *pathManager) doReloadConf(newPaths map[string]*conf.Path) {
 	// process existing paths
 	for pathName, pathData := range pm.paths {
 		path := pathData.path
-		pathConf, _, err := conf.FindPathConf(newPaths, pathName)
+		newPathConf, _, err := conf.FindPathConf(newPaths, pathName)
 		// path does not have a config anymore: delete it
 		if err != nil {
-			pm.removePath(path)
-			path.close()
-			path.wait() // avoid conflicts between sources
+			pm.removeAndClosePath(path)
 			continue
 		}
 
-		// path now belongs to a different config: delete it
-		if pathConf.Name != path.conf.Name {
-			pm.removePath(path)
-			path.close()
-			path.wait() // avoid conflicts between sources
+		// path now belongs to a different config
+		if newPathConf.Name != pathData.confName {
+			// path config can be hot reloaded
+			oldPathConf := pm.pathConfs[pathData.confName]
+			if pathConfCanBeUpdated(oldPathConf, newPathConf) {
+				pm.paths[path.name].confName = newPathConf.Name
+				go path.reloadConf(newPathConf)
+				continue
+			}
+
+			// Configuration cannot be hot reloaded: delete the path
+			pm.removeAndClosePath(path)
 			continue
 		}
 
 		// path configuration has changed and cannot be hot reloaded: delete path
-		if _, ok := confsToRecreate[pathConf.Name]; ok {
-			pm.removePath(path)
-			path.close()
-			path.wait() // avoid conflicts between sources
+		if _, ok := confsToRecreate[newPathConf.Name]; ok {
+			pm.removeAndClosePath(path)
 			continue
 		}
 
 		// path configuration has changed but can be hot reloaded: reload it
-		if _, ok := confsToReload[pathConf.Name]; ok {
-			go path.reloadConf(pathConf)
+		if _, ok := confsToReload[newPathConf.Name]; ok {
+			go path.reloadConf(newPathConf)
 		}
 	}
 
@@ -252,6 +259,12 @@ func (pm *pathManager) doReloadConf(newPaths map[string]*conf.Path) {
 	}
 }
 
+func (pm *pathManager) removeAndClosePath(path *path) {
+	pm.removePath(path)
+	path.close()
+	path.wait() // avoid conflicts between sources
+}
+
 func (pm *pathManager) doSetHLSServer(m *hls.Server) []defs.Path {
 	pm.hlsServer = m
 
@@ -425,7 +438,10 @@ func (pm *pathManager) createPath(
 	}
 	pa.initialize()
 
-	pm.paths[name] = &pathData{path: pa}
+	pm.paths[name] = &pathData{
+		path:     pa,
+		confName: pathConf.Name,
+	}
 }
 
 func (pm *pathManager) removePath(pa *path) {

internal/core/path_manager_test.go

@@ -3,11 +3,18 @@ package core
 import (
 	"bufio"
 	"net"
+	"net/http"
 	"testing"
+	"time"
 
+	"github.com/bluenviron/gortsplib/v4"
 	"github.com/bluenviron/gortsplib/v4/pkg/base"
+	"github.com/bluenviron/gortsplib/v4/pkg/description"
 	"github.com/bluenviron/gortsplib/v4/pkg/headers"
+	"github.com/pion/rtp"
 	"github.com/stretchr/testify/require"
+
+	"github.com/bluenviron/mediamtx/internal/test"
 )
 
 func TestPathAutoDeletion(t *testing.T) {
@@ -82,3 +89,97 @@ func TestPathAutoDeletion(t *testing.T) {
 		})
 	}
 }
+
+func TestPathConfigurationHotReload(t *testing.T) {
+	// Start MediaMTX with basic configuration
+	p, ok := newInstance("api: yes\n" +
+		"paths:\n" +
+		"  all:\n" +
+		"    record: no\n")
+	require.Equal(t, true, ok)
+	defer p.Close()
+
+	// Set up HTTP client for API calls
+	tr := &http.Transport{}
+	defer tr.CloseIdleConnections()
+	hc := &http.Client{Transport: tr}
+
+	// Create a publisher that will use the "all" configuration
+	media0 := test.UniqueMediaH264()
+	source := gortsplib.Client{}
+	err := source.StartRecording(
+		"rtsp://localhost:8554/undefined_stream",
+		&description.Session{Medias: []*description.Media{media0}})
+	require.NoError(t, err)
+	defer source.Close()
+
+	// Send some data to establish the stream
+	err = source.WritePacketRTP(media0, &rtp.Packet{
+		Header: rtp.Header{
+			Version:     2,
+			PayloadType: 96,
+		},
+		Payload: []byte{5, 1, 2, 3, 4},
+	})
+	require.NoError(t, err)
+
+	time.Sleep(100 * time.Millisecond)
+
+	// Verify the path exists and is using the "all" configuration
+	pathData, err := p.pathManager.APIPathsGet("undefined_stream")
+	require.NoError(t, err)
+	require.Equal(t, "undefined_stream", pathData.Name)
+	require.Equal(t, "all", pathData.ConfName)
+
+	// Check the current configuration via API
+	var allConfig map[string]interface{}
+	httpRequest(t, hc, http.MethodGet, "http://localhost:9997/v3/config/paths/get/all", nil, &allConfig)
+	require.Equal(t, false, allConfig["record"]) // Should be false from "all" config
+
+	// Add a new specific configuration for "undefined_stream" with record enabled
+	httpRequest(t, hc, http.MethodPost, "http://localhost:9997/v3/config/paths/add/undefined_stream",
+		map[string]interface{}{
+			"record": true,
+		}, nil)
+
+	// Give the system time to process the configuration change
+	time.Sleep(200 * time.Millisecond)
+
+	// Verify the path now uses the new specific configuration
+	pathData, err = p.pathManager.APIPathsGet("undefined_stream")
+	require.NoError(t, err)
+	require.Equal(t, "undefined_stream", pathData.Name)
+	require.Equal(t, "undefined_stream", pathData.ConfName) // Should now use the specific config
+
+	// Check the new configuration via API
+	var newConfig map[string]interface{}
+	httpRequest(t, hc, http.MethodGet, "http://localhost:9997/v3/config/paths/get/undefined_stream", nil, &newConfig)
+	require.Equal(t, true, newConfig["record"]) // Should be true from new config
+
+	// Verify the stream is still active and working
+	err = source.WritePacketRTP(media0, &rtp.Packet{
+		Header: rtp.Header{
+			Version:        2,
+			PayloadType:    96,
+			SequenceNumber: 2,
+		},
+		Payload: []byte{5, 1, 2, 3, 4},
+	})
+	require.NoError(t, err)
+
+	// Verify the path is still ready and functional
+	require.Equal(t, true, pathData.Ready)
+
+	// revert configuration
+	httpRequest(t, hc, http.MethodDelete, "http://localhost:9997/v3/config/paths/delete/undefined_stream",
+		nil, nil)
+
+	// Give the system time to process the configuration change
+	time.Sleep(200 * time.Millisecond)
+
+	// Verify the path now uses the old configuration
+	pathData, err = p.pathManager.APIPathsGet("undefined_stream")
+	require.NoError(t, err)
+	require.Equal(t, "undefined_stream", pathData.Name)
+	require.Equal(t, "all", pathData.ConfName)
+}