multiroom: update snapcast to v0.22 and various improvements

- Update snapcast to v0.22.0-r0
- Replace FIFO stream source with ALSA which significantly reduces CPU and I/O usage (fixes #294)
- Reduce multiroom-server image with multi stage builds for a slimmer image
- Reduce verbose level for both multiroom services

Connects-to: #294
Change-type: minor
Signed-off-by: Tomás Migone <tomas@balena.io>

core/audio/balena-sound.pa

@@ -3,7 +3,7 @@
 # Create balena-sound sinks
 load-module module-null-sink sink_name=balena-sound.input
 load-module module-null-sink sink_name=balena-sound.output
-load-module module-pipe-sink file=/var/cache/snapcast/snapfifo sink_name=snapcast format=s16le rate=44100
+load-module module-null-sink sink_name=snapcast
 
 # Route audio internally, loopback sinks depend on configuration. See start.sh for details:
 # balena-sound.input: For multiroom it's routed to snapcast sink, for standalone directly wired to balena-sound.output

core/multiroom/client/Dockerfile.template

@@ -1,13 +1,15 @@
-FROM balenalib/%%BALENA_MACHINE_NAME%%-alpine:3.12
+# Minimum snapcast version for ALSA stream source is v0.21
+# Currently Alpine 3.12 is pinned to snapcast v0.19 so we need to use Alpine edge
+FROM balenalib/%%BALENA_MACHINE_NAME%%-alpine:edge
+WORKDIR /usr/src
 
 RUN install_packages snapcast-client
 
 # Audio block setup
-RUN curl --silent https://raw.githubusercontent.com/balenablocks/audio/master/scripts/alsa-bridge/alpine-setup.sh | sh
 ENV PULSE_SERVER=tcp:audio:4317
 ENV PULSE_SINK=balena-sound.output
+RUN curl --silent https://raw.githubusercontent.com/balenablocks/audio/master/scripts/alsa-bridge/alpine-setup.sh | sh
 
-WORKDIR /usr/src
 COPY start.sh .
 
 CMD [ "/bin/bash", "/usr/src/start.sh" ]

core/multiroom/client/start.sh

@@ -21,10 +21,7 @@ echo "Target snapcast server: $SNAPSERVER"
 
 # Start snapclient
 if [[ "$MODE" == "MULTI_ROOM" || "$MODE" == "MULTI_ROOM_CLIENT" ]]; then
-  # Start snapclient and filter out those pesky chunk logs
-  # grep filter can be removed when we get snapcast v0.20
-  # see: https://github.com/badaix/snapcast/issues/559#issuecomment-615874719
-  /usr/bin/snapclient --host $SNAPSERVER $LATENCY | grep -v "\[Info\] (Stream) Chunk"
+  /usr/bin/snapclient --host $SNAPSERVER $LATENCY --logfilter *:notice
 else
   echo "Multi-room client disabled. Exiting..."
   exit 0

core/multiroom/server/Dockerfile.template

@@ -1,12 +1,30 @@
-FROM balenalib/%%BALENA_MACHINE_NAME%%-alpine:3.12
+# Build snapweb separately
+FROM balenalib/%%BALENA_MACHINE_NAME%%-alpine-node:latest as web-builder
+WORKDIR /usr/src
+
+RUN install_packages git make npm
+
+RUN git clone https://github.com/badaix/snapweb.git snapweb
+RUN npm install --global --no-save typescript
+RUN cd snapweb && make
 
+# Minimum snapcast version for ALSA stream source is v0.21
+# Currently Alpine 3.12 is pinned to snapcast v0.19 so we need to use Alpine edge
+FROM balenalib/%%BALENA_MACHINE_NAME%%-alpine:edge
 WORKDIR /usr/src
 
-RUN install_packages snapcast-server git make npm
+# Install snapweb
+RUN mkdir -p /var/www
+COPY --from=web-builder /usr/src/snapweb/dist/* /var/www/
+
+# Install snapcast
+RUN install_packages snapcast-server
 COPY snapserver.conf /etc/snapserver.conf
 COPY start.sh .
-RUN git clone https://github.com/badaix/snapweb.git snapweb
-RUN npm install --global --no-save typescript
-RUN cd snapweb && make && mkdir -p /var/www && mv dist/* /var/www
+
+# Audio block setup
+ENV PULSE_SERVER=tcp:audio:4317
+ENV PULSE_SOURCE=snapcast.monitor
+RUN curl --silent https://raw.githubusercontent.com/balenablocks/audio/master/scripts/alsa-bridge/alpine-setup.sh| sh
 
 CMD [ "/bin/bash", "/usr/src/start.sh" ]

core/multiroom/server/snapserver.conf

@@ -8,6 +8,8 @@ port = 1780
 doc_root = /var/www/
 
 [stream]
-stream = pipe:///var/cache/snapcast/snapfifo?name=balenaSound
+stream = alsa://?name=balenaSoundAlsa&device=pulse
 sampleformat = 44100:16:2
 
+[logging]
+filter = *:notice