Allow setting custom name

Change-type: patch
Signed-off-by: Roman Mazur <roman@balena.io>

README.md

@@ -32,6 +32,16 @@ To run this project is as simple as deploying it to a balenaCloud application; n
 * Flash the downloaded OS to your SD card with [balenaEtcher](https://balena.io/etcher)
 * Power up the Pi and check it's online in the dashboard
 
+### Customize device name
+
+By default, your device will be displayed as `balenaSound xxxx` when you search for Bluetooth devices.
+You can change this using `BLUETOOTH_DEVICE_NAME` environment variable that can be set in balena dashboard
+(navigate to dashboard -> app -> device -> device variables).
+![Setting the device name](docs/device-name.png)
+
+If you modify the Bluetooth device name after deploying the application, you should restart `bluetooth-audio` service
+to apply the changes.
+
 ### Deploy this application
 
 * Install the [balena CLI tools](https://github.com/balena-io/balena-cli/blob/master/INSTALL.md)
@@ -42,7 +52,7 @@ To run this project is as simple as deploying it to a balenaCloud application; n
 
 * After the application has pushed and the device has downloaded the latest changes you're ready to go!
 * Connect the audio output of your Pi to the AUX input on your Hi-Fi or speakers
-* Search for the `balenaSound xxxx` device on your phone or laptop and pair. `xxxx` will be the first 4 characters of the device ID in the balenaCloud dashboard.
+* Search for your device (`balenaSound xxxx` name is used by default) on your phone or laptop and pair. `xxxx` will be the first 4 characters of the device ID in the balenaCloud dashboard.
 * Let the music play!
 
 This project is in active development so if you have any feature requests or issues please submit them here on GitHub. PRs are welcome, too.

bluetooth-audio/start.sh

@@ -1,6 +1,8 @@
 #!/usr/bin/env bash
 
-BSHOSTNAME=$(printf "balenaSound %s" $(hostname | cut -c -4))
+if [[ -z "$BLUETOOTH_DEVICE_NAME" ]]; then
+  BLUETOOTH_DEVICE_NAME=$(printf "balenaSound %s" $(hostname | cut -c -4))
+fi
 
 # set the discoverable timeout here
 dbus-send --system --dest=org.bluez --print-reply /org/bluez/hci0 org.freedesktop.DBus.Properties.Set string:'org.bluez.Adapter1' string:'DiscoverableTimeout' variant:uint32:0
@@ -19,7 +21,7 @@ rm -rf /var/run/bluealsa/
 /usr/bin/bluealsa -i hci0 -p a2dp-sink &
 
 hciconfig hci0 up
-hciconfig hci0 name "$BSHOSTNAME"
+hciconfig hci0 name "$BLUETOOTH_DEVICE_NAME"
 
 sleep 2
 /usr/bin/bluealsa-aplay --pcm-buffer-time=1000000 00:00:00:00:00:00