HomeAssistant-PulseAudio-Disable

At the time of writing (and actually already since long before) there are issues caused by PulseAudio in the Home Assistant hassio_audio Docker container.

• In some cases PulseAudio causes loss of audio for users who use audio on their host devices.
• PulseAudio consumes high CPU on the host in some environments, e.g. when running Raspbian on a RPi, with a specific combination of OS version and hassio_audio release.
• Another reason to suspend PulseAudio is because the container in HA is configured to run in debug mode, continuously spamming the downstream logging systems with unnecessary messages. (See the journalctl command under "Useful Commands" to view the messages currently logged by your implementation).

This is typically the case for the following:

RPI (host) OS: Raspbian version 10 (buster), 5.10.11-v7
hassio_audio OS: Alpine Linux, 3.13.1
hassio_audio image (tag): 2021.02.1

One workaround to all this is to load the PulseAudio module-suspend-on-idle module in the hassio_audio container. As the name suggests, this module suspends the PulseAudio processing within hassio_audio when it is idle for some time.

Below are a couple of ways to do this:

1. Manually from the command line using the Docker command set. This would be useful to e.g. test first if this solution actually helps your situation. This is not a long-term solution though, as the container is started again with the default configuration (how the container was created) after each restart/reboot.
   docker exec -it hassio_audio pactl load-module module-suspend-on-idle

2. Execute the Docker command mentioned above, from within Home Assistant as a HA Shell Command, either manually (button?) or perhaps as automation e.g. when HA starts up.

3. Install the HA OPHoperHPO hassio add-on that was created by Nikita Selin.

4. Wrap the Docker command from (1) in a shell script that will load the module automatically whenever the hassio_audio container is (re)started.

   The solution discussed here is a crude way to implement this option.

The solution discussed below assumes you are running Home Assistant in Docker in a "supervised" configuration

Script Functionality

The script addresses two separate issues, namely
a) Reduces CPU consumption of the hassio_audio container by suspending PulseAudio when idle.
b) Reduces writing to logfiles by changing the PulseAudio log level from "verbose" to "error".

The Docker pactl load command is wrapped in a shell script. This script will be started on bootup, run in the background and automatically do its thing when needed, like when Home Assistant is restarted from within the UI, or when a new version of hassio_audio is released and the HA Supervisor (automatically) installs and reloads the container.

pa-suspend.sh is a simple shell script that does the following:

• When the script is started and hassio_audio is already running.
  OR
  When the script is already running, and the hassio_audio container is (re)started.
• The script will do the following (inside the PulseAudio container):
  1. Update the PulseAudio run parameters (/run/s6/services/pulseaudio/run) to change the logging from verbose ("-vvv") to error ("--log-level=0") logging.
  2. Add a parameter to display the system time in the logs ("--log-time=true").
  3. Stop PulseAudio. PulseAudio will automatically be restarted, but now using the new parameters. So it will no longer spam the logs with debug statements.
  4. Load the PulseAudio module-suspend-on-idle module.
• The script will then wait in an endless loop and listen to Docker Events related to the hassio_audio container.
• When a hassio_audio container start event is received the script will repeat the actions listed above, i.e. set the run parameters, restart PulseAudio, and load the module-suspend-on-idle module inside the PulseAudio container.
• The script will raise events to rsyslog (facility = "user") when the script is started, and also when the module is loaded.
  (see /var/log/user.log)

Configuration

The script uses two boolean variables that you can edit to change the program behavior. Both are initially true, which means the logging parameters are updated and the module is loaded to suspend PulseAudio when idle. Set the proper value based on your needs:

Variable		Description
DO_CHANGE_PARAMS		set to true to update the PulseAudio parameters, else false to skip.
DO_LOAD_MODULE		set to true to load the PulseAudio module-suspend-on-idle module, else false to skip.
DO_SET_NULL_AS_DEFAULT		set to true to load the PulseAudio module-null-sink module and set default sink and source (input) to it, else false to skip.

Note that if the docker exec command is executed immediately after receiving the container start event, the container is not accepting commands yet and a "Connection failure: Connection refused" error is raised. To prevent this error the script will wait for 5 seconds to allow the container to settle down, before executing the command. Based on your hardware and system performance you may have to tune this delay to make things work.
Search for: sleep 5 and change as needed.

Implementation

The shell script can be kicked off in a number of ways. Below are instructions to set it up as a Linux daemon service that will be automatically started on bootup.
Assumptions:

• The script is called pa-suspend.sh.
• The script is located in /home/pi/Scripts.
• The service will run in the context of user pi.
  Set the proper "User=" setting for your environment in the service file.
  This ensures that $HOME is set, to prevent the Docker error: "WARNING: Error loading config file: .dockercfg: $HOME is not defined"

Instructions: (adjust to match your own implementation)

1. In the host OS (Debian?), create a shell script by copying the contents from or downloading the pa-suspend.sh script.
   sudo vi /home/pi/Scripts/pa-suspend.sh
2. Ensure the shell script is executable:
   chmod +x /home/pi/Scripts/pa-suspend.sh
3. Create the service file, and enter the content from pa-suspend.service:
   sudo vi /etc/systemd/system/pa-suspend.service
4. Create the systemd service:
   sudo systemctl enable pa-suspend
   This will also create any related symlinks.
5. Check the status and confirm there are no errors.
   sudo systemctl status pa-suspend

---

---

A. Useful Commands

Linux

• Related to the pa-suspend Service:
  - Start the service:
  sudo systemctl start pa-suspend
  - Stop the service:
  sudo systemctl stop pa-suspend
  - Disable the service. Also drops related sym links:
  sudo systemctl disable pa-suspend
  - Reload the service, e.g. after editing or making changes:
  sudo systemctl daemon-reload
  - Restart the service:
  sudo systemctl restart pa-suspend
  - Edit an existing service. No need to reload the service afterwards:
  sudo systemctl edit pa-suspend --full

• Related to pa-suspend logging:
  - Using journalctl (-f shows logs in realtime continuously):
  sudo journalctl -u pa-suspend [-f]
  - From system logs:
  tail [-f] /var/log/user.log

Docker

• List the Docker Images:
  docker images
• List all running Docker containers:
  docker ps
• Stop the specified container:
  docker stop <container>
• List the logs for the specified container (-f means continuous in realtime):
  docker logs -f <container>
• Execute a command inside a container:
  docker exec -it <container> <command>

---

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B. Example Output

Based on my implementation, below are some commands and their output, as reference to help you troubleshoot possible issues.

1. Status of the implemented service:
   sudo systemctl status pa-suspend

● pa-suspend.service - Loads PulseAudio suspend-on-idle module in hassio_audio when started
   Loaded: loaded (/etc/systemd/system/pa-suspend.service; enabled; vendor preset: enabled)
   Active: active (running) since Fri 2021-02-26 13:24:35 CET; 1h 22min ago
 Main PID: 1992 (pa-suspend.sh)
    Tasks: 11 (limit: 3858)
   CGroup: /system.slice/pa-suspend.service
           ├─1992 /bin/bash /home/pi/Scripts/pa-suspend.sh
           ├─1994 docker events --filter container=hassio_audio --format Container={{.Actor.Attributes.name}} Status={{.Status}}
           └─1995 /bin/bash /home/pi/Scripts/pa-suspend.sh

2. Check if the "pa-suspend" process is running:
   (There should be two processes, as Bash forks on the "while read" command used in the script)
   ps -ef | grep pa-suspend

root      1992     1  0 13:24 ?        00:00:00 /bin/bash /home/pi/Scripts/pa-suspend.sh
root      1995  1992  0 13:24 ?        00:00:00 /bin/bash /home/pi/Scripts/pa-suspend.sh

3. Journal logs for a (successfully) running service:
   sudo journalctl -u pa-suspend

-- Logs begin at Fri 2021-02-26 13:24:24 CET, end at Fri 2021-02-26 14:25:14 CET. --
-- No entries --

4. Files and sym links created under "/etc" after successful setup:
   sudo find /etc -name "*pa-suspend*" -print0 | xargs -0 ls -la

lrwxrwxrwx 1 root root  38 Feb 26 12:54 /etc/systemd/system/multi-user.target.wants/pa-suspend.service -> /etc/systemd/system/pa-suspend.service
-rw-r--r-- 1 root root 253 Feb 26 12:44 /etc/systemd/system/pa-suspend.service

5. Successful manual load of the PulseAudio module:
   The returned value is based on the number of modules currently loaded (but sometimes there are gaps)
   docker exec -it hassio_audio pactl load-module module-suspend-on-idle

16

6. Failed manual load of module. In this case the module was already loaded, and it can't be loaded a second time:
   docker exec -it hassio_audio pactl load-module module-suspend-on-idle

Failure: Module initialization failed

More detail on the error is logged by PulseAudio in /var/log/daemon.log:

Mar  5 01:08:27 RPiHost 8de681ad489c[676]: E: [pulseaudio] module.c: Module "module-suspend-on-idle" should be loaded once at most. Refusing to load.
Mar  5 01:08:27 RPiHost 8de681ad489c[676]: I: [pulseaudio] client.c: Freed 15 "pactl"
Mar  5 01:08:27 RPiHost 8de681ad489c[676]: I: [pulseaudio] protocol-native.c: Connection died.

7. Entries in system logs when the pa-suspend script is started.
   On startup it will try to load the PulseAudio module, but in this case the module was already loaded, and an error was raised because it can't be loaded a second time:
   tail -f /var/log/user.log

Mar  5 01:11:38 RPiHost pi: pa-suspend.sh started
Mar  5 01:11:39 RPiHost pi: pa-suspend.sh (Script Start): PulseAudio module-suspend-on-idle failed to load! (Failure: Module initialization failed)

8. Docker "hassio_audio" logs at the time when the module-suspend-on-idle module is loaded:
   docker logs -f hassio_audio

...
I: [pulseaudio] module.c: Loaded "module-suspend-on-idle" (index: #16; argument: "").
I: [pulseaudio] client.c: Freed 0 "pactl"
I: [pulseaudio] protocol-native.c: Connection died.
I: [pulseaudio] module-suspend-on-idle.c: Sink auto_null idle for too long, suspending ...
D: [pulseaudio] sink.c: auto_null: suspend_cause: (none) -> IDLE
D: [pulseaudio] sink.c: auto_null: state: IDLE -> SUSPENDED
D: [pulseaudio] source.c: auto_null.monitor: suspend_cause: (none) -> IDLE
D: [pulseaudio] source.c: auto_null.monitor: state: IDLE -> SUSPENDED
D: [pulseaudio] core.c: Hmm, no streams around, trying to vacuum.
...

9. Listing of loaded PulseAudio modules (here the module-suspend-on-idle module is already loaded, see nr 16)
   docker exec -it hassio_audio pactl list modules

Module #0
	Name: module-device-restore
	Argument: 
	Usage counter: n/a
	Properties:
		module.author = "Lennart Poettering"
		module.description = "Automatically restore the volume/mute state of devices"
		module.version = "14.2"

Module #1
	Name: module-stream-restore
	Argument: 
	Usage counter: n/a
	Properties:
		module.author = "Lennart Poettering"
		module.description = "Automatically restore the volume/mute/device state of streams"
		module.version = "14.2"

Module #2
	Name: module-card-restore
	Argument: 
	Usage counter: n/a
	Properties:
		module.author = "Lennart Poettering"
		module.description = "Automatically restore profile of cards"
		module.version = "14.2"

Module #3
	Name: module-switch-on-port-available
	Argument: 
	Usage counter: n/a
	Properties:
		module.author = "David Henningsson"
		module.description = "Switches ports and profiles when devices are plugged/unplugged"
		module.version = "14.2"

Module #4
	Name: module-switch-on-connect
	Argument: 
	Usage counter: n/a
	Properties:
		module.author = "Michael Terry"
		module.description = "When a sink/source is added, switch to it or conditionally switch to it"
		module.version = "14.2"

Module #5
	Name: module-udev-detect
	Argument: tsched=0
	Usage counter: n/a
	Properties:
		module.author = "Lennart Poettering"
		module.description = "Detect available audio hardware and load matching drivers"
		module.version = "14.2"

Module #8
	Name: module-bluetooth-discover
	Argument: 
	Usage counter: n/a
	Properties:
		module.author = "João Paulo Rechi Vita"
		module.description = "Detect available Bluetooth daemon and load the corresponding discovery module"
		module.version = "14.2"

Module #9
	Name: module-bluez5-discover
	Argument: 
	Usage counter: n/a
	Properties:
		module.author = "João Paulo Rechi Vita"
		module.description = "Detect available BlueZ 5 Bluetooth audio devices and load BlueZ 5 Bluetooth audio drivers"
		module.version = "14.2"

Module #10
	Name: module-native-protocol-unix
	Argument: auth-anonymous=1 auth-cookie-enabled=0 socket=/data/external/pulse.sock
	Usage counter: n/a
	Properties:
		module.author = "Lennart Poettering"
		module.description = "Native protocol (UNIX sockets)"
		module.version = "14.2"

Module #11
	Name: module-default-device-restore
	Argument: 
	Usage counter: n/a
	Properties:
		module.author = "Lennart Poettering"
		module.description = "Automatically restore the default sink and source"
		module.version = "14.2"

Module #13
	Name: module-always-sink
	Argument: 
	Usage counter: n/a
	Properties:
		module.author = "Colin Guthrie"
		module.description = "Always keeps at least one sink loaded even if it's a null one"
		module.version = "14.2"

Module #14
	Name: module-null-sink
	Argument: sink_name=auto_null sink_properties='device.description="Dummy Output"'
	Usage counter: 0
	Properties:
		module.author = "Lennart Poettering"
		module.description = "Clocked NULL sink"
		module.version = "14.2"

Module #15
	Name: module-position-event-sounds
	Argument: 
	Usage counter: n/a
	Properties:
		module.author = "Lennart Poettering"
		module.description = "Position event sounds between L and R depending on the position on screen of the widget triggering them."
		module.version = "14.2"

Module #16
	Name: module-suspend-on-idle
	Argument: 
	Usage counter: n/a
	Properties:
		module.author = "Lennart Poettering"
		module.description = "When a sink/source is idle for too long, suspend it"
		module.version = "14.2"