Pipewire as system service with PA tunnel needs clear documentation

PipeWire version (pipewire --version):

pipewire 
Compiled with libpipewire 0.3.48
Linked with libpipewire 0.3.48

Distribution and distribution version (PRETTY_NAME from /etc/os-release): Ubuntu Jammy Jellyfish (development branch)
Desktop Environment: kodi
Kernel version (uname -r): 5.15.0-18-generic

Description of Problem:

I have not been able to successfully configure Pipewire in a system mode similar to that of Pulseaudio. There are hints that this should be possible, but nothing I have tried succeeds.

I am happy to update the documentation and wiki with support received here and otherwise.

What I am trying to achieve

I have a server running Kodi, a Bluetooth receiver, and I wish to stream audio from laptops on the local network using the Pulseaudio Tunnel. Ideally I would like to do this in a Pipewire native manner so I can use the patchbays etc so I can add delays and eq.

How Reproducible:

I have had no success playing audio using Pipewire from fresh install.

Steps to Reproduce:

Install Ubuntu Jammy with minimal packages
Ensure Pipewire is installed sudo apt install pipewire pipewire-pulse wireplumber
Add the pipewire group and user:

sudo addgroup --gid 901 pipewire 
sudo adduser --system  --uid 091 --gid 901 pipewire

Create pipewire directory in /etc:

sudo mkdir /etc/pipewire

Copy the system wide profiles from into /etc/systemd/system and

# clone pipewire somewhere
sudo cp -a ~/src/pipewire/src/daemon/systemd/system/pipewire.service.in /etc/systemd/system/pipewire.service
sudo cp -a ~/src/pipewire/src/daemon/systemd/system/pipewire.socket /etc/systemd/system/

Edit to be:

[Unit]
Description=PipeWire Multimedia Service

# We require pipewire.socket to be active before starting the daemon, because
# while it is possible to use the service without the socket, it is not clear
# why it would be desirable.
#
# Installing pipewire and doing `systemctl start pipewire` will not get the
# socket started, which might be confusing and problematic if the server is to
# be restarted later on, as the client autospawn feature might kick in. Also, a
# start of the socket unit will fail, adding to the confusion.
#
# After=pipewire.socket is not needed, as it is already implicit in the
# socket-service relationship, see systemd.socket(5).
Requires=pipewire.socket

[Service]
LockPersonality=yes
MemoryDenyWriteExecute=yes
NoNewPrivileges=yes
RestrictNamespaces=yes
SystemCallArchitectures=native
SystemCallFilter=@system-service
Type=simple
AmbientCapabilities=CAP_SYS_NICE
#ExecStart=@PW_BINARY@
ExecStart=/usr/bin/pipewire
Restart=on-failure
RuntimeDirectory=pipewire
RuntimeDirectoryPreserve=yes
User=pipewire
Environment=PIPEWIRE_RUNTIME_DIR=%t/pipewire
# Added for debugging
Environment=PIPEWIRE_DEBUG=4

[Install]
Also=pipewire.socket
WantedBy=default.target

Disable user services and enable system services:

sudo systemctl daemon-reload
systemctl --user disable --now pipewire-pulse.socket pipewire-pulse.service pipewire.service wireplumber.service
sudo systemctl enable pipewire.socket pipewire.service # wireplumber?
sudo systemctl start pipewire.socket pipewire.service
sudo systemctl status pipewire.socket
● pipewire.socket - PipeWire Multimedia System Socket
     Loaded: loaded (/etc/systemd/system/pipewire.socket; disabled; vendor preset: enabled)
     Active: active (running) since Tue 2022-03-08 19:52:13 NZDT; 2min 11s ago
   Triggers: ● pipewire.service
     Listen: /run/pipewire/pipewire-0 (Stream)
      Tasks: 0 (limit: 9350)
     Memory: 0B
        CPU: 1ms
     CGroup: /system.slice/pipewire.socket

Mar 08 19:52:13 nuliayuk systemd[1]: Starting PipeWire Multimedia System Socket...
Mar 08 19:52:13 nuliayuk systemd[1]: Listening on PipeWire Multimedia System Socket.
systemctl status pipewire.service 
● pipewire.service - PipeWire Multimedia Service
     Loaded: loaded (/etc/systemd/system/pipewire.service; disabled; vendor preset: enabled)
     Active: active (running) since Tue 2022-03-08 19:54:58 NZDT; 19s ago
TriggeredBy: ● pipewire.socket
   Main PID: 2928 (pipewire)
      Tasks: 2 (limit: 9350)
     Memory: 1.1M
        CPU: 13ms
     CGroup: /system.slice/pipewire.service
             └─2928 /usr/bin/pipewire

Mar 08 19:54:58 nuliayuk pipewire[2867]: spa.system: 0x5610450d2368: close fd:8
Mar 08 19:54:58 nuliayuk pipewire[2867]: spa.system: 0x5610450d2368: close fd:6
Mar 08 19:54:58 nuliayuk pipewire[2867]: spa.system: 0x5610450d2368: close fd:7
Mar 08 19:54:58 nuliayuk pipewire[2867]: spa.system: 0x5610450d2368: close fd:5
Mar 08 19:54:58 nuliayuk pipewire[2867]: pw.context: clear handle 'support.system'
Mar 08 19:54:58 nuliayuk systemd[1]: pipewire.service: Deactivated successfully.
Mar 08 19:54:58 nuliayuk systemd[1]: Stopped PipeWire Multimedia Service.
Mar 08 19:54:58 nuliayuk systemd[1]: Started PipeWire Multimedia Service.
Mar 08 19:54:58 nuliayuk pipewire[2928]: spa.dbus: Failed to connect to session bus: Unable to autolaunch a dbus-daemon without a $DISPLAY for X11
Mar 08 19:54:58 nuliayuk pipewire[2928]: mod.portal: Failed to connect to session bus: Input/output error

Try to add TCP tunnel etc and see if anything improves:

sudo cp -a /usr/share/pipewire/pipewire.conf /etc/pipewire/
sudo vim /etc/pipewire/pipewire.conf

add

context.modules = [
...
    { name = libpipewire-module-protocol-pulse
        args = {
            # the addresses this server listens on
            server.address = [
                "unix:native"
                #"unix:/tmp/something"              # absolute paths may be used
                "tcp:4713"                         # IPv4 and IPv6 on all addresses
                #"tcp:[::]:9999"                    # IPv6 on all addresses
                #"tcp:127.0.0.1:8888"               # IPv4 on a single address
                #
                #{ address = "tcp:4713"             # address
                #  max-clients = 64                 # maximum number of clients
                #  listen-backlog = 32              # backlog in the server listen queue
                #  client.access = "restricted"     # permissions for clients
                #}
            ]
            #pulse.min.req          = 256/48000     # 5ms
            #pulse.default.req      = 960/48000     # 20 milliseconds
            #pulse.min.frag         = 256/48000     # 5ms
            #pulse.default.frag     = 96000/48000   # 2 seconds
            #pulse.default.tlength  = 96000/48000   # 2 seconds
            #pulse.min.quantum      = 256/48000     # 5ms
            #pulse.default.format   = F32
            #pulse.default.position = [ FL FR ]
            # These overrides are only applied when running in a vm.
            vm.overrides = {
                pulse.min.quantum = 1024/48000      # 22ms
            }
        }
    }
    { name = libpipewire-module-zeroconf-discover }

restart pipewire

sudo systemctl restart pipewire.service
systemctl status pipewire.service 
● pipewire.service - PipeWire Multimedia Service
     Loaded: loaded (/etc/systemd/system/pipewire.service; disabled; vendor preset: enabled)
     Active: active (running) since Tue 2022-03-08 20:05:52 NZDT; 17s ago
TriggeredBy: ● pipewire.socket
   Main PID: 3122 (pipewire)
      Tasks: 3 (limit: 9350)
     Memory: 2.6M
        CPU: 27ms
     CGroup: /system.slice/pipewire.service
             └─3122 /usr/bin/pipewire

Mar 08 20:05:52 nuliayuk systemd[1]: Started PipeWire Multimedia Service.
Mar 08 20:05:52 nuliayuk pipewire[3122]: spa.dbus: Failed to connect to session bus: Unable to autolaunch a dbus-daemon without a $DISPLAY for X11
Mar 08 20:05:52 nuliayuk pipewire[3122]: mod.portal: Failed to connect to session bus: Input/output error
Mar 08 20:05:52 nuliayuk pipewire[3122]: mod.protocol-pulse: could not find a suitable runtime directory in$PULSE_RUNTIME_PATH and $XDG_RUNTIME_DIR
Mar 08 20:05:52 nuliayuk pipewire[3122]: mod.protocol-pulse: pulse-server 0x5570c66cf500: failed to parse address 'unix:native': No such file or directory
Mar 08 20:05:52 nuliayuk pipewire[3122]: mod.protocol-pulse: could not find a suitable runtime directory in$PULSE_RUNTIME_PATH and $XDG_RUNTIME_DIR
Mar 08 20:05:52 nuliayuk pipewire[3122]: mod.protocol-pulse: 0x5570c66cf500: can't create pid file: No such file or directory
Mar 08 20:05:52 nuliayuk pipewire[3122]: spa.dbus: Failed to connect to session bus: Unable to autolaunch a dbus-daemon without a $DISPLAY for X11
Mar 08 20:05:52 nuliayuk pipewire[3122]: mod.pulse-tunnel: failed to connect: Access denied
Mar 08 20:05:52 nuliayuk pipewire[3122]: mod.zeroconf-discover: Can't load module: Operation not permitted

Actual Results:

pactl info | grep '^Server Name'
Connection failure: Connection refused
pa_context_connect() failed: Connection refused

Expected Results:

I would expect that everything just works.

Additional Info (as attachments):

[pw-dump.log](/uploads/f33b3a424ef158e1a23bcbee45b38b93/pw-dump.log): note: that despite being disabled, the user socket and service start anyway. My bad for not understanding systemd properly 8(

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