allow configuring device and delay ms in config

Cargo.lock

@@ -71,6 +71,7 @@ dependencies = [
  "nix 0.26.2",
  "rand",
  "serde",
+ "serde_json",
  "socket2",
  "static_assertions",
  "structopt",
@@ -352,6 +353,12 @@ dependencies = [
  "hashbrown",
 ]
 
+[[package]]
+name = "itoa"
+version = "1.0.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "af150ab688ff2122fcef229be89cb50dd66af9e01a4ff320cc137eecc9bacc38"
+
 [[package]]
 name = "jni"
 version = "0.19.0"
@@ -793,6 +800,12 @@ dependencies = [
  "semver",
 ]
 
+[[package]]
+name = "ryu"
+version = "1.0.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ad4cc8da4ef723ed60bced201181d83791ad433213d8c24efffda1eec85d741"
+
 [[package]]
 name = "same-file"
 version = "1.0.6"
@@ -834,6 +847,17 @@ dependencies = [
  "syn 2.0.28",
 ]
 
+[[package]]
+name = "serde_json"
+version = "1.0.105"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "693151e1ac27563d6dbcec9dee9fbd5da8539b20fa14ad3752b2e6d363ace360"
+dependencies = [
+ "itoa",
+ "ryu",
+ "serde",
+]
+
 [[package]]
 name = "serde_spanned"
 version = "0.6.3"

Cargo.toml

@@ -14,6 +14,7 @@ libc = "0.2.147"
 nix = { version = "0.26.2", features = ["time", "socket", "net", "poll", "user", "hostname"], default-features = false }
 rand = "0.8.5"
 serde = { version = "1.0.183", features = ["derive"] }
+serde_json = "1.0.105"
 socket2 = "0.5.3"
 static_assertions = "1.1.0"
 structopt = "0.3.26"

src/audio.rs

@@ -0,0 +1,81 @@
+use std::process::{Command, Stdio};
+
+use serde::Deserialize;
+
+pub fn set_sink_env(device: &str) {
+    let Some(index) = find_pulse_node(Kind::Sink, device) else {
+        eprintln!("falling back to default audio sink");
+        return;
+    };
+
+    println!("using audio sink at index {}: {}", index.0, device);
+
+    std::env::set_var("PULSE_SINK", device);
+    std::env::set_var("PIPEWIRE_NODE", index.0.to_string());
+}
+
+pub fn set_source_env(device: &str) {
+    let Some(index) = find_pulse_node(Kind::Source, device) else {
+        eprintln!("falling back to default audio source");
+        return;
+    };
+
+    println!("using audio source at index {}: {}", index.0, device);
+
+    std::env::set_var("PULSE_SOURCE", device);
+    std::env::set_var("PIPEWIRE_NODE", index.0.to_string());
+}
+
+enum Kind {
+    Source,
+    Sink,
+}
+
+#[derive(Deserialize)]
+struct Node {
+    index: NodeIndex,
+    name: String,
+}
+
+#[derive(Deserialize)]
+struct NodeIndex(u64);
+
+fn find_pulse_node(kind: Kind, name: &str) -> Option<NodeIndex> {
+    let kind = match kind {
+        Kind::Source => "sources",
+        Kind::Sink => "sinks",
+    };
+
+    let result = Command::new("pactl")
+        .args(["--format=json", "list", kind])
+        .stdout(Stdio::piped())
+        .output();
+
+    let output = match result {
+        Ok(output) => output,
+        Err(e) => {
+            eprintln!("error running pactl to find audio device: {e:?}");
+            return None;
+        }
+    };
+
+    let text = match std::str::from_utf8(&output.stdout) {
+        Ok(text) => text,
+        Err(e) => {
+            eprintln!("could not parse pactl output: {e:?}");
+            return None;
+        }
+    };
+
+    let nodes = match serde_json::from_str::<Vec<Node>>(text) {
+        Ok(nodes) => nodes,
+        Err(e) => {
+            eprintln!("could not parse pactl output: {e:?}");
+            return None;
+        }
+    };
+
+    nodes.into_iter()
+        .find(|node| node.name == name)
+        .map(|node| node.index)
+}

src/config.rs

@@ -7,6 +7,21 @@ use serde::Deserialize;
 #[derive(Deserialize)]
 pub struct Config {
     multicast: Option<SocketAddr>,
+    #[serde(default)]
+    source: Source,
+    #[serde(default)]
+    receive: Receive,
+}
+
+#[derive(Deserialize, Default)]
+pub struct Source {
+    device: Option<String>,
+    delay_ms: Option<u64>,
+}
+
+#[derive(Deserialize, Default)]
+pub struct Receive {
+    device: Option<String>,
 }
 
 fn set_env_option<T: ToString>(name: &str, value: Option<T>) {
@@ -16,7 +31,10 @@ fn set_env_option<T: ToString>(name: &str, value: Option<T>) {
 }
 
 pub fn load_into_env(config: &Config) {
-    set_env_option("BARK_MULTICAST", config.multicast)
+    set_env_option("BARK_MULTICAST", config.multicast);
+    set_env_option("BARK_SOURCE_DEVICE", config.source.device.as_ref());
+    set_env_option("BARK_SOURCE_DELAY_MS", config.source.delay_ms);
+    set_env_option("BARK_RECEIVE_DEVICE", config.receive.device.as_ref());
 }
 
 fn load_file(path: &Path) -> Option<Config> {

src/main.rs

@@ -1,3 +1,4 @@
+mod audio;
 mod config;
 mod protocol;
 mod receive;

src/receive.rs

@@ -472,6 +472,8 @@ impl<T: Copy + Default + Ord> Aggregate<T> {
 pub struct ReceiveOpt {
     #[structopt(flatten)]
     pub socket: SocketOpt,
+    #[structopt(long, env = "BARK_RECEIVE_DEVICE")]
+    pub device: Option<String>,
     #[structopt(long, default_value="12")]
     pub max_seq_gap: usize,
 }
@@ -480,6 +482,10 @@ pub fn run(opt: ReceiveOpt) -> Result<(), RunError> {
     let receiver_id = ReceiverId::generate();
     let node = NodeStats::get();
 
+    if let Some(device) = &opt.device {
+        crate::audio::set_sink_env(device);
+    }
+
     let host = cpal::default_host();
 
     let device = host.default_output_device()

src/stream.rs

@@ -18,13 +18,28 @@ use crate::RunError;
 pub struct StreamOpt {
     #[structopt(flatten)]
     pub socket: SocketOpt,
-    #[structopt(long, default_value="20")]
+
+    #[structopt(
+        long,
+        env = "BARK_SOURCE_DEVICE",
+    )]
+    pub device: Option<String>,
+
+    #[structopt(
+        long,
+        env = "BARK_SOURCE_DELAY_MS",
+        default_value = "20",
+    )]
     pub delay_ms: u64,
 }
 
 pub fn run(opt: StreamOpt) -> Result<(), RunError> {
     let host = cpal::default_host();
 
+    if let Some(device) = &opt.device {
+        crate::audio::set_source_env(device);
+    }
+
     let device = host.default_input_device()
         .ok_or(RunError::NoDeviceAvailable)?;