return an error when rpiCamera in used in two paths (#1257)

README.md

@@ -548,7 +548,7 @@ _rtsp-simple-server_ natively support the Raspberry Pi Camera, enabling high-qua
 
 2. Make sure that the legacy camera stack is disabled. Type `sudo raspi-config`, then go to `Interfacing options`, `enable/disable legacy camera support`, choose `no`. Reboot the system.
 
-3. Make sure that the `libcamera0` package version is at least `0.0.2`, otherwise upgrade it with `sudo apt update && sudo apt upgrade`.
+3. Make sure that the `libcamera0` package version is at least `0.0.2`, otherwise upgrade it with `sudo apt update && sudo apt install libcamera0`.
 
 If you want to run the standard (non-dockerized) version of the server, just download the server executable and make sure to pick the `arm64` variant if you're using the 64-bit version of the operative system. Then edit `rtsp-simple-server.yml` and replace everything inside section `paths` with the following content:
 

internal/conf/conf.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"os"
 	"reflect"
+	"sort"
 	"strings"
 	"time"
 
@@ -422,10 +423,19 @@ func (conf *Conf) CheckAndFillMissing() error {
 		delete(conf.Paths, "all")
 	}
 
-	for name, pconf := range conf.Paths {
+	sortedNames := make([]string, len(conf.Paths))
+	i := 0
+	for name := range conf.Paths {
+		sortedNames[i] = name
+		i++
+	}
+	sort.Strings(sortedNames)
+
+	for _, name := range sortedNames {
+		pconf := conf.Paths[name]
 		if pconf == nil {
-			conf.Paths[name] = &PathConf{}
-			pconf = conf.Paths[name]
+			pconf = &PathConf{}
+			conf.Paths[name] = pconf
 		}
 
 		err := pconf.checkAndFillMissing(conf, name)

internal/conf/conf_test.go

@@ -170,24 +170,48 @@ func TestConfEncryption(t *testing.T) {
 	require.Equal(t, true, ok)
 }
 
-func TestConfErrorNonExistentParameter(t *testing.T) {
-	func() {
-		tmpf, err := writeTempFile([]byte(`invalid: param`))
-		require.NoError(t, err)
-		defer os.Remove(tmpf)
+func TestConfErrors(t *testing.T) {
+	for _, ca := range []struct {
+		name string
+		conf string
+		err  string
+	}{
+		{
+			"non existent parameter 1",
+			`invalid: param`,
+			"non-existent parameter: 'invalid'",
+		},
+		{
+			"non existent parameter 2",
+			"paths:\n" +
+				"  mypath:\n" +
+				"    invalid: parameter\n",
+			"parameter paths, key mypath: non-existent parameter: 'invalid'",
+		},
+		{
+			"invalid path name",
+			"paths:\n" +
+				"  '':\n" +
+				"    source: publisher\n",
+			"invalid path name '': cannot be empty",
+		},
+		{
+			"double raspberry pi camera",
+			"paths:\n" +
+				"  cam1:\n" +
+				"    source: rpiCamera\n" +
+				"  cam2:\n" +
+				"    source: rpiCamera\n",
+			"'rpiCamera' is used as source in two paths ('cam1' and 'cam2')",
+		},
+	} {
+		t.Run(ca.name, func(t *testing.T) {
+			tmpf, err := writeTempFile([]byte(ca.conf))
+			require.NoError(t, err)
+			defer os.Remove(tmpf)
 
-		_, _, err = Load(tmpf)
-		require.EqualError(t, err, "non-existent parameter: 'invalid'")
-	}()
-
-	func() {
-		tmpf, err := writeTempFile([]byte("paths:\n" +
-			"  mypath:\n" +
-			"    invalid: parameter\n"))
-		require.NoError(t, err)
-		defer os.Remove(tmpf)
-
-		_, _, err = Load(tmpf)
-		require.EqualError(t, err, "parameter paths, key mypath: non-existent parameter: 'invalid'")
-	}()
+			_, _, err = Load(tmpf)
+			require.EqualError(t, err, ca.err)
+		})
+	}
 }

internal/conf/path.go

@@ -96,15 +96,11 @@ type PathConf struct {
 }
 
 func (pconf *PathConf) checkAndFillMissing(conf *Conf, name string) error {
-	if name == "" {
-		return fmt.Errorf("path name can not be empty")
-	}
-
 	// normal path
-	if name[0] != '~' {
+	if name == "" || name[0] != '~' {
 		err := IsValidPathName(name)
 		if err != nil {
-			return fmt.Errorf("invalid path name: %s (%s)", err, name)
+			return fmt.Errorf("invalid path name '%s': %s", name, err)
 		}
 
 		// regular expression path
@@ -193,6 +189,12 @@ func (pconf *PathConf) checkAndFillMissing(conf *Conf, name string) error {
 				"a path with a regular expression (or path 'all') cannot have 'rpiCamera' as source. use another path")
 		}
 
+		for otherName, otherPath := range conf.Paths {
+			if otherPath != pconf && otherPath != nil && otherPath.Source == "rpiCamera" {
+				return fmt.Errorf("'rpiCamera' is used as source in two paths ('%s' and '%s')", name, otherName)
+			}
+		}
+
 		if pconf.RPICameraWidth == 0 {
 			pconf.RPICameraWidth = 1920
 		}