Feat: Run in userspace with systemd and mpd over pipewire

[Anagastes]

Firstly, I am happy that there are still active mpd clients who keep themselves modern.

Now that qt6 is out, I guess I will have to slowly bury cantata.

And there are almost no local clients that are that good. I only found mympd.

But I can't get it to run on a modern local environment.

It requires root privileges and on modern pipewire systems, mpd runs in userspace otherwise it can't get pipewire connect.

Likewise, mpd then usually runs via a socket in the userspace. mympd can then no longer access all of this.

I have only been able to start it by switching to pulse. But that is not an alternative for me :)

[jcorporation]

myMPD does not require root privileges, it runs perfectly with standard user permissions.

You must simply create an appropriated systemd user unit.

[Anagastes]

I have now changed the port.

Mympd now starts via CLI. And I was also able to access my locally running socket connection.

But how do I get the SystemD service to do this? Somehow it does not take the config file.

And the stickerdb is still causing me problems in userspace. :)

mympd -w ~/.config/mympd -a ~/.cache/mympd
16:23:31 NOTICE   mympd     Cache dir: "/home/XXX/.cache/mympd"
16:23:31 NOTICE   mympd     Work dir: "/home/XXX/.config/mympd"
16:23:31 NOTICE   mympd     Config dir: "/home/XXX/.config/mympd/config"
16:23:31 NOTICE   mympd     Setting loglevel to NOTICE
16:23:31 NOTICE   mympd     Starting myMPD 14.1.0
16:23:31 NOTICE   mympd     Listening on http://[::]:5500
16:23:31 NOTICE   mympd     Listening on https://[::]:5550
16:23:31 NOTICE   mympd     Serving files from "/var/lib/mympd/empty"
16:23:31 NOTICE   mympd     SSL cert dir: "/home/XXX/.config/mympd/ssl"
16:23:31 NOTICE   mympd     CA certificate and private key found
16:23:31 NOTICE   mympd     Server certificate and private key found
16:23:31 NOTICE   mympd     Empty dir: "/home/XXX/.config/mympd/empty" created
16:23:31 NOTICE   mympd     Pics dir: "/home/XXX/.config/mympd/pics" created
16:23:31 NOTICE   mympd     Backgrounds dir: "/home/XXX/.config/mympd/pics/backgrounds" created
16:23:31 NOTICE   mympd     Thumbnails dir: "/home/XXX/.config/mympd/pics/thumbs" created
16:23:31 NOTICE   mympd     Scripts dir: "/home/XXX/.config/mympd/scripts" created
16:23:31 NOTICE   mympd     Smartpls dir: "/home/XXX/.config/mympd/smartpls" created
16:23:31 NOTICE   mympd     State dir: "/home/XXX/.config/mympd/state" created
16:23:31 NOTICE   mympd     Default partition dir: "/home/XXX/.config/mympd/state/default" created
16:23:31 NOTICE   mympd     Tags cache dir: "/home/XXX/.config/mympd/tags" created
16:23:31 NOTICE   mympd     Webradio dir: "/home/XXX/.config/mympd/webradios" created
16:23:31 NOTICE   mympd     Covercache dir: "/home/XXX/.cache/mympd/covercache" created
16:23:31 NOTICE   mympd     Webradiodb cache dir: "/home/XXX/.cache/mympd/webradiodb" created
16:23:31 NOTICE   mympd     Starting mympd api thread
16:23:31 NOTICE   mympd     Starting webserver thread
16:23:31 NOTICE   mympd     myMPD is ready
16:23:31 NOTICE   mympdapi  Starting myMPD autoconfiguration
16:23:31 NOTICE   mympdapi  Reading environment
16:23:31 WARN     mympdapi  MPD autoconfiguration failed
16:23:31 NOTICE   mympdapi  Setting mpd host to "localhost"
16:23:31 NOTICE   mympdapi  Setting mpd port to "6600"
16:23:31 NOTICE   mympdapi  Reading global states
16:23:31 NOTICE   mympdapi  "default": Reading partition states from directory "/home/XXX/.config/mympd/state/default"
16:23:31 NOTICE   mympdapi  "stickerdb": Connecting to "localhost:6600"
16:23:31 ERROR    mympdapi  "stickerdb": Connection: Connection refused
16:23:31 NOTICE   mympdapi  "default": Connecting to "localhost:6600"

[Anagastes]

Sorry that I'm a bit annoying xD
I'm working hard on it...

I have now removed ALL extras from the standard service and it now runs as a user service without any problems.

systemctl --user status mympd.service
● mympd.service - myMPD server daemon
     Loaded: loaded (/home/XXX/.config/systemd/user/mympd.service; disabled; preset: enabled)
     Active: active (running) since Thu 2024-03-28 16:57:06 CET; 13s ago
       Docs: man:mympd(1)
   Main PID: 124911 (mympd)
      Tasks: 3 (limit: 28679)
     Memory: 4.2M (peak: 5.0M)
        CPU: 22ms
     CGroup: /user.slice/user-1000.slice/user@1000.service/app.slice/mympd.service
             └─124911 /usr/bin/mympd -w /home/XXX/.config/mympd -a /home/XXX/.cache/mympd

Mär 28 16:57:08 pchome mympd[124911]: NOTICE   mpdworker Stopping mpd_worker thread
Mär 28 16:57:10 pchome mympd[124911]: ERROR    webserver HTTP 404: Embedded asset "/assets/favicon.ico" not found

Working conf

[Unit]
Description=myMPD server daemon
Documentation=man:mympd(1)
After=mpd.service

[Service]
ExecStart=/usr/bin/mympd -w %h/.config/mympd -a %h/.cache/mympd
Restart=always
WorkingDirectory=%h/.config/mympd

[Install]
WantedBy=default.target

Which of the standard variables are needed and could trigger this behaviour?

Removed variables

AmbientCapabilities=CAP_NET_BIND_SERVICE
CapabilityBoundingSet=CAP_NET_BIND_SERVICE
DynamicUser=yes
LockPersonality=yes
MemoryDenyWriteExecute=yes
PrivateDevices=yes
ProtectClock=yes
ProtectControlGroups=yes
ProtectHome=yes
ProtectHostname=yes
ProtectKernelLogs=yes
ProtectKernelModules=yes
ProtectKernelTunables=yes
ProtectProc=invisible
RestrictRealtime=yes
RestrictAddressFamilies=AF_INET AF_INET6 AF_NETLINK AF_UNIX
RestrictNamespaces=yes
SystemCallArchitectures=native
SystemCallFilter=@system-service

[jcorporation]

I think DynamicUser=yes can not work in a user unit. Is there no systemd documentation for it? I would gladly deliver a functional user unit as alternative with myMPD.

[Anagastes]

I have now started with trial and error.... :D

This is the service config now wich works in userpsace.

[Unit]
Description=myMPD server daemon
Documentation=man:mympd(1)
After=mpd.service

[Service]
ExecStart=/usr/bin/mympd -w %h/.config/mympd -a %h/.cache/mympd
Restart=always
WorkingDirectory=%h/.config/mympd
LockPersonality=yes
MemoryDenyWriteExecute=yes
PrivateDevices=yes
ProtectClock=yes
ProtectControlGroups=yes
ProtectKernelLogs=yes
ProtectKernelModules=yes
ProtectKernelTunables=yes
ProtectProc=invisible
RestrictRealtime=yes
RestrictAddressFamilies=AF_INET AF_INET6 AF_NETLINK AF_UNIX
RestrictNamespaces=yes
SystemCallArchitectures=native
SystemCallFilter=@system-service

[Install]
WantedBy=default.target

I have removed this variables

AmbientCapabilities=CAP_NET_BIND_SERVICE
CapabilityBoundingSet=CAP_NET_BIND_SERVICE
DynamicUser=yes
ProtectHome=yes

This works, but you still have to explicitly specify in the exec cmd where it finds the config etc.

If necessary, this could be made dynamic for future versions. That it finds the paths automatically as a user service. ^

[jcorporation]

I added your systemd user unit to myMPD (devel branch). Thanks for figuring out the correct configuration.