Bump protocols. Added proto status

src/federation/capabilities.rs

@@ -0,0 +1,190 @@
+//! Informational publication and observation of protocol versions.
+
+use std::collections::BTreeMap;
+use std::sync::{Arc, Mutex, MutexGuard};
+use std::time::Duration;
+
+use anyhow::{Context, Result};
+pub use music_dht::capabilities::CAPABILITIES_ALPN;
+use music_dht::capabilities::{
+    CAPABILITIES_PROTOCOL_VERSION, CapabilityManifest, CapabilityMessage, read_message,
+    write_message,
+};
+use music_dht::{ByteStream, EndpointId, MusicDhtService, StreamAcceptor};
+
+const PROBE_INTERVAL: Duration = Duration::from_secs(30);
+
+#[derive(Debug, Clone, Default, PartialEq, Eq)]
+pub struct ProtocolVersions {
+    pub local: BTreeMap<String, u16>,
+    pub observed: BTreeMap<String, u16>,
+    pub observed_peers: usize,
+    pub newer: Vec<NewerProtocol>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct NewerProtocol {
+    pub id: String,
+    pub local: u16,
+    pub observed: u16,
+}
+
+impl ProtocolVersions {
+    pub fn snapshot(observed: &ObservedVersions) -> Self {
+        let local = local_manifest().protocols;
+        let observed_versions = lock(&observed.versions).clone();
+        let newer = observed_versions
+            .iter()
+            .filter_map(|(id, remote)| {
+                let local_version = local.get(id)?;
+                (*remote > *local_version).then(|| NewerProtocol {
+                    id: id.clone(),
+                    local: *local_version,
+                    observed: *remote,
+                })
+            })
+            .collect();
+        Self {
+            local,
+            observed: observed_versions,
+            observed_peers: lock(&observed.peers).len(),
+            newer,
+        }
+    }
+}
+
+#[derive(Default)]
+pub struct ObservedVersions {
+    versions: Mutex<BTreeMap<String, u16>>,
+    peers: Mutex<BTreeMap<String, String>>,
+}
+
+fn local_manifest() -> CapabilityManifest {
+    CapabilityManifest::frid("furumi", env!("CARGO_PKG_VERSION"))
+        .with_protocol("audio", super::audio::AUDIO_PROTOCOL_VERSION)
+}
+
+pub async fn serve(mut acceptor: StreamAcceptor) {
+    while let Some(stream) = acceptor.accept().await {
+        tokio::spawn(async move {
+            if let Err(error) = serve_one(stream).await {
+                tracing::debug!("capability stream failed: {error:#}");
+            }
+        });
+    }
+}
+
+async fn serve_one(mut stream: ByteStream) -> Result<()> {
+    let response = match read_message(&mut stream).await? {
+        CapabilityMessage::Get {
+            version: CAPABILITIES_PROTOCOL_VERSION,
+        } => CapabilityMessage::Manifest {
+            manifest: local_manifest(),
+        },
+        CapabilityMessage::Get { version } => CapabilityMessage::Error {
+            message: format!("unsupported capability protocol {version}"),
+        },
+        _ => CapabilityMessage::Error {
+            message: "expected capability request".to_string(),
+        },
+    };
+    write_message(&mut stream, &response).await?;
+    stream.send.finish()?;
+    let _ = tokio::time::timeout(Duration::from_secs(2), stream.send.stopped()).await;
+    Ok(())
+}
+
+pub async fn probe_loop(service: Arc<MusicDhtService>, observed: Arc<ObservedVersions>) {
+    let mut interval = tokio::time::interval(PROBE_INTERVAL);
+    loop {
+        interval.tick().await;
+        let peers = service
+            .connected_peers()
+            .into_iter()
+            .chain(
+                service
+                    .known_peers()
+                    .into_iter()
+                    .map(|contact| contact.peer_id),
+            )
+            .collect::<std::collections::BTreeSet<_>>();
+        for peer in peers {
+            if let Err(error) = probe_peer(&service, peer, &observed).await {
+                tracing::trace!(%peer, "peer capability probe unavailable: {error:#}");
+            }
+        }
+    }
+}
+
+async fn probe_peer(
+    service: &MusicDhtService,
+    peer: EndpointId,
+    observed: &ObservedVersions,
+) -> Result<()> {
+    let mut stream = service.open_stream(peer, CAPABILITIES_ALPN).await?;
+    write_message(
+        &mut stream,
+        &CapabilityMessage::Get {
+            version: CAPABILITIES_PROTOCOL_VERSION,
+        },
+    )
+    .await?;
+    stream.send.finish()?;
+    let response = tokio::time::timeout(Duration::from_secs(5), read_message(&mut stream))
+        .await
+        .context("capability request timed out")??;
+    let CapabilityMessage::Manifest { manifest } = response else {
+        anyhow::bail!("peer did not return a capability manifest");
+    };
+    manifest.validate()?;
+    {
+        let mut versions = lock(&observed.versions);
+        for (id, version) in manifest.protocols {
+            versions
+                .entry(id)
+                .and_modify(|current| *current = (*current).max(version))
+                .or_insert(version);
+        }
+    }
+    lock(&observed.peers).insert(peer.to_string(), manifest.application_version);
+    Ok(())
+}
+
+fn lock<T>(mutex: &Mutex<T>) -> MutexGuard<'_, T> {
+    mutex
+        .lock()
+        .unwrap_or_else(std::sync::PoisonError::into_inner)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn local_manifest_lists_every_player_protocol() {
+        let manifest = local_manifest();
+        for id in [
+            "federation_net",
+            "ticket",
+            "rendezvous",
+            "music_dht",
+            "catalog",
+            "audio",
+            "device_sync",
+            "jam",
+        ] {
+            assert!(manifest.protocols.contains_key(id), "missing {id}");
+        }
+        manifest.validate().unwrap();
+    }
+
+    #[test]
+    fn snapshot_reports_only_strictly_newer_versions() {
+        let observed = ObservedVersions::default();
+        lock(&observed.versions).insert("music_dht".to_string(), 99);
+        lock(&observed.versions).insert("jam".to_string(), crate::jam::PROTOCOL_VERSION);
+        let snapshot = ProtocolVersions::snapshot(&observed);
+        assert_eq!(snapshot.newer.len(), 1);
+        assert_eq!(snapshot.newer[0].id, "music_dht");
+    }
+}