install go2rtc on bob

installs_on_host/go2rtc/internal/ngrok/README.md

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+# ngrok
+
+With the ngrok integration, you can get external access to your streams when your Internet connection is behind a private IP address.
+
+- you may need external access for two different things:
+    - WebRTC streams (tunnel the WebRTC TCP port, e.g. 8555)
+    - go2rtc web interface (tunnel the API HTTP port, e.g. 1984)
+- ngrok supports authorization for your web interface
+- ngrok automatically adds HTTPS to your web interface
+
+The ngrok free subscription has the following limitations:
+
+- You can reserve a free domain for serving the web interface, but the TCP address you get will always be random and will change with each restart of the ngrok agent (not a problem for WebRTC streams)
+- You can forward multiple ports from a single agent, but you can only run one ngrok agent on the free plan
+
+go2rtc will automatically get your external TCP address (if you enable it in the ngrok config) and use it for WebRTC connections (if you enable it in the WebRTC config).
+
+You need to manually download the [ngrok agent](https://ngrok.com/download) for your OS and register with the [ngrok service](https://ngrok.com/signup).
+
+**Tunnel for only WebRTC Stream**
+
+You need to add your [ngrok authtoken](https://dashboard.ngrok.com/get-started/your-authtoken) and WebRTC TCP port to YAML:
+
+```yaml
+ngrok:
+  command: ngrok tcp 8555 --authtoken eW91IHNoYWxsIG5vdCBwYXNzCnlvdSBzaGFsbCBub3QgcGFzcw
+```
+
+**Tunnel for WebRTC and Web interface**
+
+You need to create `ngrok.yaml` config file and add it to the go2rtc config:
+
+```yaml
+ngrok:
+  command: ngrok start --all --config ngrok.yaml
+```
+
+ngrok config example:
+
+```yaml
+version: "2"
+authtoken: eW91IHNoYWxsIG5vdCBwYXNzCnlvdSBzaGFsbCBub3QgcGFzcw
+tunnels:
+  api:
+    addr: 1984  # use the same port as in the go2rtc config
+    proto: http
+    basic_auth:
+      - admin:password  # you can set login/pass for your web interface
+  webrtc:
+    addr: 8555  # use the same port as in the go2rtc config
+    proto: tcp
+```
+
+See the [ngrok agent documentation](https://ngrok.com/docs/agent/config/) for more details on the ngrok configuration file.

installs_on_host/go2rtc/internal/ngrok/ngrok.go

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+package ngrok
+
+import (
+	"fmt"
+	"net"
+	"strings"
+
+	"github.com/AlexxIT/go2rtc/internal/app"
+	"github.com/AlexxIT/go2rtc/internal/webrtc"
+	"github.com/AlexxIT/go2rtc/pkg/ngrok"
+	"github.com/rs/zerolog"
+)
+
+func Init() {
+	var cfg struct {
+		Mod struct {
+			Cmd string `yaml:"command"`
+		} `yaml:"ngrok"`
+	}
+
+	app.LoadConfig(&cfg)
+
+	if cfg.Mod.Cmd == "" {
+		return
+	}
+
+	log = app.GetLogger("ngrok")
+
+	ngr, err := ngrok.NewNgrok(cfg.Mod.Cmd)
+	if err != nil {
+		log.Error().Err(err).Msg("[ngrok] start")
+	}
+
+	ngr.Listen(func(msg any) {
+		if msg := msg.(*ngrok.Message); msg != nil {
+			if strings.HasPrefix(msg.Line, "ERROR:") {
+				log.Warn().Msg("[ngrok] " + msg.Line)
+			} else {
+				log.Debug().Msg("[ngrok] " + msg.Line)
+			}
+
+			// Addr: "//localhost:8555", URL: "tcp://1.tcp.eu.ngrok.io:12345"
+			if strings.HasPrefix(msg.Addr, "//localhost:") && strings.HasPrefix(msg.URL, "tcp://") {
+				// don't know if really necessary use IP
+				address, err := ConvertHostToIP(msg.URL[6:])
+				if err != nil {
+					log.Warn().Err(err).Msg("[ngrok] add candidate")
+					return
+				}
+
+				log.Info().Str("addr", address).Msg("[ngrok] add external candidate for WebRTC")
+
+				webrtc.AddCandidate("tcp", address)
+			}
+		}
+	})
+
+	go func() {
+		if err = ngr.Serve(); err != nil {
+			log.Error().Err(err).Msg("[ngrok] run")
+		}
+	}()
+
+}
+
+var log zerolog.Logger
+
+func ConvertHostToIP(address string) (string, error) {
+	host, port, err := net.SplitHostPort(address)
+	if err != nil {
+		return "", err
+	}
+
+	ip, err := net.LookupIP(host)
+	if err != nil {
+		return "", err
+	}
+
+	if len(ip) == 0 {
+		return "", fmt.Errorf("can't resolve: %s", host)
+	}
+
+	return ip[0].String() + ":" + port, nil
+}