feat(chrome): Improve mdns discovery for docker

* Switch to lower-level mdns library for more control during debugging
* Use avahi-browse with host avahi-daemon to circumvent musl (alpline) issues with mdns resolution https://johnsiu.com/blog/alpine-linux/

Dockerfile

@@ -6,6 +6,8 @@ RUN \
   echo "**** install build packages ****" && \
   apk add --no-cache \
     alpine-base \
+    avahi \
+    avahi-tools \
     git \
     nodejs \
     npm \

docsite/docs/configuration/configuration.md

@@ -701,7 +701,29 @@ If your media device can be **Cast** to using this button ![Chromecast Icon](htt
 
 **Note:** This source relies on common, **basic** music data provided by the cast device which will always be less exhaustive than data parsed from full source integrations. If there is an existing [Source](#source-configurations) it is recommended to configure for it and blacklist the app on Google Cast, rather than relying solely on Google Cast for scrobbling.
 
-The machine and/or container running multi-scrobbler must be configured to allow [mDNS traffic on port 5353/UDP](https://book.hacktricks.xyz/network-services-pentesting/5353-udp-multicast-dns-mdns).
+#### Networking Requirements
+
+The host machine running multi-scrobbler must be configured to allow [mDNS traffic on port 5353/UDP](https://book.hacktricks.xyz/network-services-pentesting/5353-udp-multicast-dns-mdns).
+
+##### Linux
+
+**Docker**
+
+The host machine must have [avahi-daemon](https://avahi.org/) running to circumvent limitations with DNS resolution due to musl in Alpine. All major linux distributions package avahi and many have it built-in. Once avahi is running you must pass D-Bus and the avahi daemon socket to your container like so:
+
+```
+docker run ... -v /var/run/dbus:/var/run/dbus -v  	/var/run/avahi-daemon/socket:/var/run/avahi-daemon/socket ... foxxmd/multi-scrobbler
+```
+
+**Flatpak**
+
+No additional steps are required.
+
+##### Windows
+
+**Docker**
+
+Unsupported at this time.
 
 #### Cast Troubleshooting
 

package.json

@@ -47,6 +47,7 @@
   "private": true,
   "homepage": ".",
   "dependencies": {
+    "@astronautlabs/mdns": "^1.0.7",
     "@awaitjs/express": "^0.6.3",
     "@fortawesome/fontawesome-svg-core": "^6.4.2",
     "@fortawesome/free-solid-svg-icons": "^6.4.2",
@@ -59,9 +60,9 @@
     "@supercharge/promise-pool": "^3.0.0",
     "address": "^1.2.2",
     "ajv": "^7.2.4",
+    "avahi-browse": "^1.1.4",
     "better-sse": "^0.8.0",
     "body-parser": "^1.19.0",
-    "bonjour-service": "^1.2.1",
     "castv2": "^0.1.10",
     "chromecast-client": "github:foxxmd/chromecast-client#dist",
     "clsx": "^2.0.0",

src/backend/common/infrastructure/Atomic.ts

@@ -226,3 +226,9 @@ export interface Authenticatable {
     authFailure?: boolean
     testAuth: () => Promise<any>
 }
+
+export interface MdnsDeviceInfo {
+    name: string
+    type: string
+    addresses: string[]
+}

src/backend/common/infrastructure/config/source/chromecast.ts

@@ -32,6 +32,15 @@ export interface ChromecastData extends CommonSourceData {
      * @examples [["spotify","pandora"]]
      * */
     whitelistApps?: string | string[]
+
+    /**
+     * Try to use Avahi and avahi-browse to resolve mDNS devices instead of native mDNS querying
+     *
+     * Useful for docker (alpine) container where mDNS resolution is not yet supported. Avahi socket must be exposed to the container and avahi-tools must be installed.
+     *
+     * @default false
+     * */
+    useAvahi?: boolean
 }
 
 export interface ChromecastSourceConfig extends CommonSourceConfig {

src/backend/common/vendor/chromecast/ChromecastClientUtils.ts

@@ -1,4 +1,4 @@
-import {REPORTED_PLAYER_STATUSES, ReportedPlayerStatus} from "../../infrastructure/Atomic";
+import {MdnsDeviceInfo, REPORTED_PLAYER_STATUSES, ReportedPlayerStatus} from "../../infrastructure/Atomic";
 import {PlatformApplication, PlatformType} from "./interfaces";
 import {connect, createPlatform, Media, MediaController, PersistentClient, Result} from "chromecast-client";
 import {ErrorWithCause} from "pony-cause";
@@ -43,13 +43,13 @@ export const getCurrentPlatformApplications = async (platform: PlatformType): Pr
     }
 }
 
-export const initializeClientPlatform = async (service: Service): Promise<[CastClient, PersistentClient, PlatformType]> => {
+export const initializeClientPlatform = async (device: MdnsDeviceInfo): Promise<[CastClient, PersistentClient, PlatformType]> => {
     let client: PersistentClient;
     let castClient = new CastClient;
     try {
-        client = await connect({host: service.addresses?.[0]});
+        client = await connect({host: device.addresses?.[0]});
     } catch (e) {
-        throw new ErrorWithCause(`Could not connect to ${service.name}`, {cause: e});
+        throw new ErrorWithCause(`Could not connect to ${device.name}`, {cause: e});
     }
 
     const platform = createPlatform(client);