add PipeWire audio backend and mixer

.github/workflows/rust.yml

@@ -0,0 +1,22 @@
+name: Rust
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Build
+      run: cargo build --verbose
+    - name: Run tests
+      run: cargo test --verbose

Cargo.toml

@@ -41,6 +41,10 @@ thiserror = "2.0"
 time = { version = "0.3.47", default-features = false, features = ["formatting"] }
 clap = { version = "4.5.23", features = ["derive"] }
 serde_ignored = "0.1.10"
+# Pinned: 0.9 renamed MainLoop/Context/Core to *Rc variants, which
+# pipewire_backend.rs/pipewire_mixer.rs don't use yet.
+pipewire = { version = "=0.8.0", optional = true }
+ringbuf = { version = "0.4", optional = true }
 
 [target.'cfg(unix)'.dependencies]
 daemonize = "0.5"
@@ -62,6 +66,7 @@ env_logger = "0.11"
 alsa_backend = ["librespot-playback/alsa-backend", "dep:alsa"]
 dbus_mpris = ["dep:dbus", "dep:dbus-tokio", "dep:dbus-crossroads"]
 default = ["alsa_backend", "pulseaudio_backend", "dbus_mpris"]
+pipewire_backend = ["dep:pipewire", "dep:ringbuf"]
 portaudio_backend = ["librespot-playback/portaudio-backend"]
 pulseaudio_backend = ["librespot-playback/pulseaudio-backend"]
 rodio_backend = ["librespot-playback/rodio-backend"]

docs/src/configuration/audio.md

@@ -16,6 +16,7 @@ Instead of using the default device, which can sometimes be different to what yo
 
 - For ALSA, you can use `aplay -L` to get a list of possible devices.
 - For PulseAudio, run `pactl list short sinks` to get a list of possible names.
+- For PipeWire, run `wpctl status` to get a list of sink names, or leave unset to use the current default sink.
 
 ## Bitrate
 
@@ -29,7 +30,7 @@ To reduce bandwidth usage or increase quality, you can play with the bitrate.
 
 In most cases, leaving this at the default (`softvol`) should be fine.
 
-If you want your `spotifyd` volume to be synchronized with an output device's hardware volume, you can set this to `alsa` or `alsa_linear`. In both cases, you might also want to set the `mixer` device to set which device's volume should be changed.
+If you want your `spotifyd` volume to be synchronized with an output device's hardware volume, you can set this to `alsa` or `alsa_linear` (with the `mixer`/`control` settings), or, when using the PipeWire backend, `pipewire` or `pipewire_linear` (with the `pipewire_mixer_mode`/`pipewire_mixer_device` settings).
 
 If you want to prevent the user to be able to adjust the volume, set this instead to `none`.
 

src/config.rs

@@ -39,6 +39,10 @@ pub enum VolumeController {
     Alsa,
     #[cfg(feature = "alsa_backend")]
     AlsaLinear,
+    #[cfg(feature = "pipewire_backend")]
+    Pipewire,
+    #[cfg(feature = "pipewire_backend")]
+    PipewireLinear,
     #[serde(rename = "softvol")]
     SoftVolume,
     None,
@@ -168,7 +172,12 @@ impl From<AudioFormat> for LSAudioFormat {
 }
 
 fn possible_backends() -> Vec<&'static str> {
-    audio_backend::BACKENDS.iter().map(|b| b.0).collect()
+    let mut backends: Vec<&'static str> = audio_backend::BACKENDS.iter().map(|b| b.0).collect();
+    // Not in librespot's backend table; add explicitly or CLI/config
+    // validation rejects "pipewire".
+    #[cfg(feature = "pipewire_backend")]
+    backends.push("pipewire");
+    backends
 }
 
 fn deserialize_backend<'de, D>(de: D) -> Result<Option<String>, D::Error>
@@ -363,6 +372,11 @@ pub struct SharedConfigValues {
     #[serde(flatten)]
     alsa_config: AlsaConfig,
 
+    #[cfg(feature = "pipewire_backend")]
+    #[command(flatten)]
+    #[serde(flatten)]
+    pipewire_config: PipewireConfig,
+
     #[cfg(feature = "dbus_mpris")]
     #[command(flatten)]
     #[serde(flatten)]
@@ -391,15 +405,28 @@ pub struct MprisConfig {
 #[cfg(feature = "alsa_backend")]
 #[derive(Debug, Default, Clone, Deserialize, Args, PartialEq, Eq)]
 pub struct AlsaConfig {
-    /// The control device
+    /// The ALSA control device
     #[arg(long)]
     pub(crate) control: Option<String>,
 
-    /// The mixer to use
+    /// The ALSA mixer to use
     #[arg(long)]
     pub(crate) mixer: Option<String>,
 }
 
+#[cfg(feature = "pipewire_backend")]
+#[derive(Debug, Default, Clone, Deserialize, Args, PartialEq, Eq)]
+pub struct PipewireConfig {
+    /// The PipeWire mixer "stream" (default) or "sink".
+    #[arg(long)]
+    pub(crate) pipewire_mixer_mode: Option<String>,
+
+    /// For PipeWire "sink" mixer. The name of the PipeWire sink node 
+    /// Leave unset for `default.audio.sink`
+    #[arg(long)]
+    pub(crate) pipewire_mixer_device: Option<String>,
+}
+
 #[derive(Debug, Default, Deserialize)]
 pub struct FileConfig {
     global: Option<SharedConfigValues>,
@@ -421,7 +448,11 @@ impl FileConfig {
 #[derive(Copy, Clone)]
 enum KnownConfigProblem {
     #[cfg_attr(
-        all(feature = "alsa_backend", feature = "dbus_mpris"),
+        all(
+            feature = "alsa_backend",
+            feature = "pipewire_backend",
+            feature = "dbus_mpris"
+        ),
         expect(dead_code)
     )]
     MissingFeature(&'static str),
@@ -435,6 +466,11 @@ fn get_known_config_problem(path: &serde_ignored::Path<'_>) -> Option<KnownConfi
             KnownConfigProblem::MissingFeature("alsa_backend"),
             &["control", "mixer"],
         ),
+        #[cfg(not(feature = "pipewire_backend"))]
+        (
+            KnownConfigProblem::MissingFeature("pipewire_backend"),
+            &["pipewire_mixer_mode", "pipewire_mixer_device"],
+        ),
         #[cfg(not(feature = "dbus_mpris"))]
         (
             KnownConfigProblem::MissingFeature("dbus_mpris"),
@@ -594,6 +630,8 @@ impl SharedConfigValues {
         merge!(self.mpris_config; and other.mpris_config => {use_mpris, dbus_type});
         #[cfg(feature = "alsa_backend")]
         merge!(self.alsa_config; and other.alsa_config => {mixer, control});
+        #[cfg(feature = "pipewire_backend")]
+        merge!(self.pipewire_config; and other.pipewire_config => {pipewire_mixer_mode, pipewire_mixer_device});
     }
 }
 
@@ -639,6 +677,8 @@ pub(crate) struct SpotifydConfig {
     pub(crate) mpris: MprisConfig,
     #[cfg(feature = "alsa_backend")]
     pub(crate) alsa_config: AlsaConfig,
+    #[cfg(feature = "pipewire_backend")]
+    pub(crate) pipewire_config: PipewireConfig,
 }
 
 pub(crate) fn get_internal_config(config: CliConfig) -> SpotifydConfig {
@@ -764,6 +804,8 @@ pub(crate) fn get_internal_config(config: CliConfig) -> SpotifydConfig {
         mpris: config.shared_config.mpris_config,
         #[cfg(feature = "alsa_backend")]
         alsa_config: config.shared_config.alsa_config,
+        #[cfg(feature = "pipewire_backend")]
+        pipewire_config: config.shared_config.pipewire_config,
     }
 }
 

src/main.rs

@@ -24,6 +24,10 @@ mod error;
 mod main_loop;
 mod no_mixer;
 mod oauth;
+#[cfg(feature = "pipewire_backend")]
+mod pipewire_backend;
+#[cfg(feature = "pipewire_backend")]
+mod pipewire_mixer;
 mod process;
 mod setup;
 mod utils;