Monorepo for Tangled
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Rust
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pub async fn run(host_cid: u32, port: u32) -> Result<()> { let mut conn = VsockStream::connect(VsockAddr::new(host_cid, port)) .await .with_context(|| format!("dial host vsock cid={host_cid} port={port}"))?;
send_hello(&mut conn).await?;
let (reader_conn, writer_conn) = tokio::io::split(conn); let (out_tx, out_rx) = mpsc::channel::<Message>(256); let writer = tokio::spawn(async move { writer_loop(writer_conn, out_rx).await }); let mut reader = BufReader::new(reader_conn);
let init = match protocol::read_message(&mut reader).await? { Some(Message { init: Some(init), .. }) => init, Some(other) => bail!("expected init, got {}", protocol::kind(&other)), None => bail!("read init: EOF"), }; info!(job_id = %init.job_id, "received init");
let read_proxy = ReadCacheProxy::start(host_cid, init.cache_read_proxy_port) .await .context("start read cache proxy")?; let write_proxy = WriteCacheProxy::start(host_cid, init.cache_upload_proxy_port) .await .context("start write cache proxy")?; let _dns_proxy = DnsProxy::start(host_cid, init.dns_proxy_port) .await .context("start dns proxy")?; let _cache_cfg = nix_config::configure( &init, read_proxy.as_ref().map(ReadCacheProxy::url).unwrap_or(""), ) .await .context("configure nix cache")?; let uploader = CacheUploadManager::start( write_proxy.as_ref().map(WriteCacheProxy::url).unwrap_or(""), out_tx.clone(), ) .await .context("start cache upload manager")?;
let mut tasks = JoinSet::new(); let read_result: Result<()> = loop { tokio::select! { read = protocol::read_message(&mut reader) => match read { Ok(Some(msg)) => spawn_message_task(&mut tasks, host_cid, msg, &out_tx, uploader.clone()), Ok(None) => break Ok(()), Err(error) => break Err(error).context("read message"), }, Some(result) = tasks.join_next(), if !tasks.is_empty() => { log_task_result(result, false); } } };
tasks.abort_all(); while let Some(result) = tasks.join_next().await { log_task_result(result, true); }
drop(out_tx); let _ = writer.await; read_result?; Ok(())}
fn spawn_message_task( tasks: &mut JoinSet<()>, host_cid: u32, msg: Message, out_tx: &Sender<Message>, uploader: Option<CacheUploadManager>,) { let kind = protocol::kind(&msg); let handle = on_payload!(msg, { activate_config => tasks.spawn(activation::run(msg.id, activate_config, out_tx.clone())), exec_start => tasks.spawn(exec::run(msg.id, exec_start, out_tx.clone())), cache_drain => tasks.spawn(run_cache_drain(msg.id, cache_drain, out_tx.clone(), uploader)), poweroff => tasks.spawn(run_poweroff(msg.id, poweroff, out_tx.clone())), open_debug_shell => tasks.spawn(pty::run(host_cid, open_debug_shell)), }); if handle.is_none() { warn!(kind, "ignoring unsupported message"); }}
fn log_task_result(result: Result<(), JoinError>, shutting_down: bool) { match result { Ok(()) => {} Err(error) if shutting_down && error.is_cancelled() => {} Err(error) => warn!(%error, "session handler task failed"), }}
async fn writer_loop<W>(mut conn: W, mut rx: mpsc::Receiver<Message>)where W: AsyncWrite + Unpin,{ while let Some(msg) = rx.recv().await { if let Err(error) = protocol::write_message(&mut conn, &msg).await { warn!(%error, "failed to write protocol message"); break; } }}
async fn send_hello(conn: &mut VsockStream) -> Result<()> { let boot_id = tokio::fs::read_to_string("/proc/sys/kernel/random/boot_id") .await .unwrap_or_default() .trim() .to_owned(); let nix_version = nix_config::nix_version().await;
let hello_payload = v1::Hello { protocol_version: protocol::PROTOCOL_VERSION, agent_version: env!("CARGO_PKG_VERSION").to_string(), boot_id: boot_id.clone(), nix_version: nix_version.clone(), }; info!( protocol = hello_payload.protocol_version, version = %hello_payload.agent_version, boot = %hello_payload.boot_id, nix = %hello_payload.nix_version, "sent hello" ); let hello = Message { id: "hello".to_owned(), hello: Some(hello_payload), ..Default::default() };
protocol::write_message(conn, &hello) .await .context("send hello")?; Ok(())}
async fn run_cache_drain( id: String, req: v1::CacheDrain, out: Sender<Message>, uploader: Option<CacheUploadManager>,) { let timeout = (req.timeout_seconds > 0).then(|| Duration::from_secs(u64::from(req.timeout_seconds))); let stats = match uploader.as_ref() { Some(uploader) => uploader.drain(timeout).await, None => Default::default(), };
if let Some(error) = &stats.last_error { warn!( %id, pending = stats.pending, active = stats.active, uploaded = stats.uploaded, failed = stats.failed, %error, "cache drain completed with error" ); } else { info!( %id, uploaded = stats.uploaded, failed = stats.failed, "cache drain completed" ); }
let result = Message { id, cache_drain_result: Some(v1::CacheDrainResult { error: protocol::error_or_empty(stats.last_error), cache_queued: stats.pending, cache_active: stats.active, cache_uploaded: stats.uploaded, cache_failed: stats.failed, }), ..Default::default() }; let _ = out.send(result).await;}
async fn run_poweroff(id: String, _req: v1::Poweroff, out: Sender<Message>) { let result = Message { id, poweroff_result: Some(v1::PoweroffResult { error: String::new(), }), ..Default::default() }; let _ = out.send(result).await;
tokio::spawn(async move { tokio::time::sleep(Duration::from_millis(100)).await;
// prefer a clean shutdown through the init system when one is around // (systemd on NixOS, busybox/openrc elsewhere), then fall back to the // raw reboot(2) syscall on minimal guests for poweroff in [SYSTEMCTL_EXECUTABLE, "/sbin/poweroff", "/usr/sbin/poweroff"] { if !std::path::Path::new(poweroff).exists() { continue; } let mut spec = Spec::new(poweroff).timeout(Duration::from_secs(5)); if poweroff == SYSTEMCTL_EXECUTABLE { spec = spec.args(["poweroff"]); } match command::run_capture(spec).await { Ok(output) if output.success() => return, Ok(output) => warn!( %poweroff, exit_code = output.exit.exit_code, error = ?output.exit.error, output = %output.combined_lossy(), "poweroff command failed" ), Err(error) => warn!(%poweroff, %error, "poweroff command failed"), } }
// only ever returns on failure let error = nix::sys::reboot::reboot(nix::sys::reboot::RebootMode::RB_POWER_OFF).unwrap_err(); warn!(%error, "reboot(RB_POWER_OFF) syscall failed"); });}