Milestone 1: workspace skeleton, wire protocol, socket round-trip

Three-crate workspace per SPECS.md. varde-proto defines the full JSON
Lines protocol (requests, envelopes, structured errors, events) with
string-typed hashes so the crate carries no iroh dependency. The daemon
binds its unix socket, loads config with flags > env > file > defaults
precedence, and answers status/list; everything else returns a
structured "unimplemented" error. varde-ctl maps subcommands 1:1 onto
requests and round-trips status against a real daemon in the tests.

Dependencies: serde/serde_json (wire format), tokio (async runtime and
unix sockets), tracing/tracing-subscriber (structured logging), toml
(config file), anyhow (binary-edge errors), thiserror (reserved for
library errors), clap (ctl flag parsing, per spec), tempfile (dev-only,
ephemeral test dirs).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
2026-07-14 20:10:29 +02:00
commit 4e1a95613b
19 changed files with 2466 additions and 0 deletions
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[package]
name = "varde-daemon"
description = "varde: content-addressed blob mirror daemon on iroh"
version.workspace = true
edition.workspace = true
license.workspace = true
repository.workspace = true
rust-version.workspace = true
[[bin]]
name = "varde-daemon"
path = "src/main.rs"
[dependencies]
varde-proto = { workspace = true }
anyhow = { workspace = true }
serde = { workspace = true }
serde_json = { workspace = true }
thiserror = { workspace = true }
tokio = { workspace = true }
toml = { workspace = true }
tracing = { workspace = true }
tracing-subscriber = { workspace = true }
[dev-dependencies]
tempfile = "3"
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//! Daemon configuration.
//!
//! Precedence: CLI flags > environment > config file > defaults.
//! The daemon must run with an empty (or absent) config file.
use std::path::{Path, PathBuf};
use anyhow::{Context, Result};
use serde::Deserialize;
/// Fully resolved runtime configuration.
#[derive(Debug, Clone)]
pub struct Config {
/// Directory holding the blob store, metadata and secret key.
pub store_dir: PathBuf,
/// Path of the unix socket to serve the API on.
pub socket_path: PathBuf,
/// Upload rate cap in bytes/sec. 0 disables serving entirely.
pub max_upload_bytes_per_sec: u64,
/// Download rate cap in bytes/sec. 0 means unlimited.
pub max_download_bytes_per_sec: u64,
/// Whether LAN discovery (mDNS-style) is enabled.
pub discovery: bool,
/// Whether any WAN (non-link-local) upload is permitted. Default off:
/// LAN-only posture with zero WAN upload.
pub wan_upload: bool,
}
/// Serde image of the TOML config file. Everything optional so an empty
/// file (or none at all) is valid.
#[derive(Debug, Default, Deserialize)]
#[serde(deny_unknown_fields)]
struct FileConfig {
store_dir: Option<PathBuf>,
socket_path: Option<PathBuf>,
max_upload_bytes_per_sec: Option<u64>,
max_download_bytes_per_sec: Option<u64>,
discovery: Option<bool>,
wan_upload: Option<bool>,
}
/// Values collected from CLI flags; `None` means "not given".
#[derive(Debug, Default)]
pub struct Overrides {
pub config_path: Option<PathBuf>,
pub store_dir: Option<PathBuf>,
pub socket_path: Option<PathBuf>,
}
/// Whether the daemon runs as a system service or a per-user service.
/// Decides default paths only; everything can be overridden.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Mode {
System,
User,
}
impl Mode {
/// System mode when running as root, user mode otherwise.
pub fn detect() -> Mode {
// SAFETY: geteuid has no preconditions and cannot fail.
if unsafe { libc_geteuid() } == 0 {
Mode::System
} else {
Mode::User
}
}
fn default_store_dir(self) -> PathBuf {
match self {
Mode::System => PathBuf::from("/var/lib/varde"),
Mode::User => xdg_dir("XDG_DATA_HOME", ".local/share").join("varde"),
}
}
fn default_socket_path(self) -> PathBuf {
match self {
Mode::System => PathBuf::from("/run/varde/varde.sock"),
Mode::User => match std::env::var_os("XDG_RUNTIME_DIR") {
Some(dir) => PathBuf::from(dir).join("varde.sock"),
// No XDG_RUNTIME_DIR (rare outside a session): fall back
// next to the store so the daemon still starts.
None => Mode::User.default_store_dir().join("varde.sock"),
},
}
}
fn default_config_path(self) -> PathBuf {
match self {
Mode::System => PathBuf::from("/etc/varde/config.toml"),
Mode::User => xdg_dir("XDG_CONFIG_HOME", ".config").join("varde/config.toml"),
}
}
}
fn xdg_dir(var: &str, home_rel: &str) -> PathBuf {
if let Some(dir) = std::env::var_os(var) {
return PathBuf::from(dir);
}
let home = std::env::var_os("HOME").unwrap_or_else(|| "/".into());
PathBuf::from(home).join(home_rel)
}
// Minimal FFI shim instead of pulling in the libc crate for one call.
extern "C" {
#[link_name = "geteuid"]
fn libc_geteuid() -> u32;
}
impl Config {
/// Resolve configuration with full precedence:
/// `overrides` (flags) > environment > config file > mode defaults.
pub fn load(mode: Mode, overrides: &Overrides) -> Result<Config> {
let config_path = overrides
.config_path
.clone()
.or_else(|| std::env::var_os("VARDE_CONFIG").map(PathBuf::from))
.unwrap_or_else(|| mode.default_config_path());
// An explicitly named config file must exist; the default one is
// allowed to be absent.
let explicit =
overrides.config_path.is_some() || std::env::var_os("VARDE_CONFIG").is_some();
let file = Self::read_file(&config_path, explicit)?;
let env_path = |var: &str| std::env::var_os(var).map(PathBuf::from);
let env_u64 = |var: &str| -> Result<Option<u64>> {
match std::env::var(var) {
Ok(v) => {
Ok(Some(v.parse().with_context(|| {
format!("{var} must be an integer, got {v:?}")
})?))
}
Err(_) => Ok(None),
}
};
let env_bool = |var: &str| -> Result<Option<bool>> {
match std::env::var(var) {
Ok(v) => {
Ok(Some(v.parse().with_context(|| {
format!("{var} must be true/false, got {v:?}")
})?))
}
Err(_) => Ok(None),
}
};
Ok(Config {
store_dir: overrides
.store_dir
.clone()
.or_else(|| env_path("VARDE_STORE"))
.or(file.store_dir)
.unwrap_or_else(|| mode.default_store_dir()),
socket_path: overrides
.socket_path
.clone()
.or_else(|| env_path("VARDE_SOCKET"))
.or(file.socket_path)
.unwrap_or_else(|| mode.default_socket_path()),
max_upload_bytes_per_sec: env_u64("VARDE_MAX_UPLOAD")?
.or(file.max_upload_bytes_per_sec)
// Conservative default: 10 MB/s on LAN.
.unwrap_or(10 * 1024 * 1024),
max_download_bytes_per_sec: env_u64("VARDE_MAX_DOWNLOAD")?
.or(file.max_download_bytes_per_sec)
.unwrap_or(0),
discovery: env_bool("VARDE_DISCOVERY")?
.or(file.discovery)
.unwrap_or(true),
wan_upload: env_bool("VARDE_WAN_UPLOAD")?
.or(file.wan_upload)
.unwrap_or(false),
})
}
fn read_file(path: &Path, must_exist: bool) -> Result<FileConfig> {
match std::fs::read_to_string(path) {
Ok(text) => toml::from_str(&text)
.with_context(|| format!("parsing config file {}", path.display())),
Err(e) if e.kind() == std::io::ErrorKind::NotFound && !must_exist => {
Ok(FileConfig::default())
}
Err(e) => Err(e).with_context(|| format!("reading config file {}", path.display())),
}
}
}
#[cfg(test)]
mod tests {
use super::*;
// Env-var manipulation is process-global, so these tests only use
// overrides and files, never set_var.
#[test]
fn empty_config_file_is_valid() {
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("config.toml");
std::fs::write(&path, "").unwrap();
let overrides = Overrides {
config_path: Some(path),
..Default::default()
};
let cfg = Config::load(Mode::User, &overrides).unwrap();
assert!(!cfg.wan_upload, "WAN upload must default off");
assert!(cfg.discovery, "discovery defaults on");
assert_eq!(cfg.max_upload_bytes_per_sec, 10 * 1024 * 1024);
}
#[test]
fn missing_default_config_is_fine() {
let cfg = Config::load(Mode::User, &Overrides::default()).unwrap();
assert!(cfg.socket_path.to_string_lossy().ends_with("varde.sock"));
}
#[test]
fn missing_explicit_config_errors() {
let overrides = Overrides {
config_path: Some(PathBuf::from("/nonexistent/varde.toml")),
..Default::default()
};
assert!(Config::load(Mode::User, &overrides).is_err());
}
#[test]
fn flags_beat_file() {
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("config.toml");
std::fs::write(&path, "store_dir = \"/from/file\"\n").unwrap();
let overrides = Overrides {
config_path: Some(path),
store_dir: Some(PathBuf::from("/from/flag")),
..Default::default()
};
let cfg = Config::load(Mode::User, &overrides).unwrap();
assert_eq!(cfg.store_dir, PathBuf::from("/from/flag"));
}
#[test]
fn unknown_keys_rejected() {
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("config.toml");
std::fs::write(&path, "no_such_key = 1\n").unwrap();
let overrides = Overrides {
config_path: Some(path),
..Default::default()
};
assert!(Config::load(Mode::User, &overrides).is_err());
}
}
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//! Request dispatch and daemon state.
use tokio::sync::broadcast;
use varde_proto::{Envelope, ErrorCode, Event, GlobalStatus, Request, ResponseData};
use crate::config::Config;
/// Shared daemon state. Handlers grow with the milestones; anything not
/// yet wired returns [`ErrorCode::Unimplemented`] rather than pretending.
pub struct Daemon {
config: Config,
events: broadcast::Sender<Event>,
}
impl Daemon {
pub fn new(config: Config) -> Self {
// Capacity bounds memory if a subscriber stalls; laggards get a
// Lagged error, not unbounded buffering.
let (events, _) = broadcast::channel(1024);
Daemon { config, events }
}
pub fn config(&self) -> &Config {
&self.config
}
/// New receiver for the daemon event stream.
pub fn subscribe_events(&self) -> broadcast::Receiver<Event> {
self.events.subscribe()
}
/// Handle one API request. Infallible at this level: all failures are
/// mapped to structured error envelopes.
pub async fn handle(&self, request: Request) -> Envelope {
match request {
Request::Status { hash: None } => Envelope::ok(ResponseData::Status(GlobalStatus {
version: env!("CARGO_PKG_VERSION").to_string(),
protocol: varde_proto::PROTOCOL_VERSION,
node_id: None,
store_path: self.config.store_dir.display().to_string(),
pins: 0,
connected_peers: 0,
})),
Request::List {} => Envelope::ok(ResponseData::Pins { pins: Vec::new() }),
Request::Subscribe {} => Envelope::ok(ResponseData::Done {}),
other => Envelope::err(
ErrorCode::Unimplemented,
format!("not implemented yet: {other:?}"),
),
}
}
}
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//! varde-daemon library surface.
//!
//! The daemon is a binary, but its internals are exposed as a library so
//! integration tests can run real daemons in-process on ephemeral sockets.
pub mod config;
pub mod daemon;
pub mod server;
use std::sync::Arc;
use anyhow::{Context, Result};
/// Run a daemon with the given config until the future is dropped or the
/// listener fails. Binds the socket before returning control to the
/// runtime so callers can rely on it existing once this future is polled.
pub async fn run(config: config::Config) -> Result<()> {
std::fs::create_dir_all(&config.store_dir)
.with_context(|| format!("creating store directory {}", config.store_dir.display()))?;
let listener = server::bind_socket(&config.socket_path)?;
let daemon = Arc::new(daemon::Daemon::new(config));
server::serve(listener, daemon).await
}
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//! varde-daemon: content-addressed blob mirror daemon.
use std::path::PathBuf;
use std::sync::Arc;
use anyhow::{bail, Context, Result};
use tracing::info;
use varde_daemon::config::{Config, Mode, Overrides};
use varde_daemon::{daemon, server};
const USAGE: &str = "\
varde-daemon — content-addressed blob mirror daemon
USAGE:
varde-daemon [OPTIONS]
OPTIONS:
--config <PATH> Config file (default: /etc/varde/config.toml or
$XDG_CONFIG_HOME/varde/config.toml)
--store <PATH> Store directory override
--socket <PATH> API socket path override
--system Force system-mode default paths
--user Force user-mode default paths
--version Print version and exit
--help Print this help and exit
";
// The spec reserves clap for varde-ctl; the daemon takes five flags, which
// a hand parse covers without the dependency.
fn parse_args() -> Result<(Mode, Overrides)> {
let mut overrides = Overrides::default();
let mut mode = Mode::detect();
let mut args = std::env::args().skip(1);
while let Some(arg) = args.next() {
let mut value = |name: &str| -> Result<PathBuf> {
args.next()
.map(PathBuf::from)
.with_context(|| format!("{name} requires a value"))
};
match arg.as_str() {
"--config" => overrides.config_path = Some(value("--config")?),
"--store" => overrides.store_dir = Some(value("--store")?),
"--socket" => overrides.socket_path = Some(value("--socket")?),
"--system" => mode = Mode::System,
"--user" => mode = Mode::User,
"--version" => {
println!("varde-daemon {}", env!("CARGO_PKG_VERSION"));
std::process::exit(0);
}
"--help" | "-h" => {
print!("{USAGE}");
std::process::exit(0);
}
other => bail!("unknown argument {other:?}\n\n{USAGE}"),
}
}
Ok((mode, overrides))
}
fn main() -> Result<()> {
tracing_subscriber::fmt()
.with_env_filter(
tracing_subscriber::EnvFilter::try_from_default_env()
.unwrap_or_else(|_| "varde_daemon=info".into()),
)
.init();
let (mode, overrides) = parse_args()?;
let config = Config::load(mode, &overrides)?;
info!(store = %config.store_dir.display(), socket = %config.socket_path.display(), "starting");
std::fs::create_dir_all(&config.store_dir)
.with_context(|| format!("creating store directory {}", config.store_dir.display()))?;
tokio::runtime::Builder::new_multi_thread()
.enable_all()
.build()
.context("building tokio runtime")?
.block_on(run(config))
}
async fn run(config: Config) -> Result<()> {
let socket_path = config.socket_path.clone();
let listener = server::bind_socket(&socket_path)?;
let daemon = Arc::new(daemon::Daemon::new(config));
let result = tokio::select! {
r = server::serve(listener, daemon) => r,
r = shutdown_signal() => r.map(|signal| info!(signal, "shutting down")),
};
// Best-effort cleanup so the next start doesn't find a stale socket.
let _ = std::fs::remove_file(&socket_path);
result
}
async fn shutdown_signal() -> Result<&'static str> {
use tokio::signal::unix::{signal, SignalKind};
let mut term = signal(SignalKind::terminate()).context("installing SIGTERM handler")?;
let mut int = signal(SignalKind::interrupt()).context("installing SIGINT handler")?;
tokio::select! {
_ = term.recv() => Ok("SIGTERM"),
_ = int.recv() => Ok("SIGINT"),
}
}
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//! Unix socket server: JSON Lines request/response plus event streaming.
use std::path::Path;
use std::sync::Arc;
use anyhow::{Context, Result};
use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
use tokio::net::{UnixListener, UnixStream};
use tracing::{debug, info, warn};
use varde_proto::{Envelope, ErrorCode, Request};
use crate::daemon::Daemon;
/// Bind the API socket, replacing a stale socket file if the previous
/// daemon did not shut down cleanly.
pub fn bind_socket(path: &Path) -> Result<UnixListener> {
if let Some(parent) = path.parent() {
std::fs::create_dir_all(parent)
.with_context(|| format!("creating socket directory {}", parent.display()))?;
}
match std::fs::remove_file(path) {
Ok(()) => debug!(path = %path.display(), "removed stale socket"),
Err(e) if e.kind() == std::io::ErrorKind::NotFound => {}
Err(e) => {
return Err(e).with_context(|| format!("removing stale socket {}", path.display()))
}
}
UnixListener::bind(path).with_context(|| format!("binding socket {}", path.display()))
}
/// Accept connections until cancelled. Each connection is served by its
/// own task; a connection failure never takes the daemon down.
pub async fn serve(listener: UnixListener, daemon: Arc<Daemon>) -> Result<()> {
info!("listening for clients");
loop {
let (stream, _addr) = listener.accept().await.context("accepting client")?;
let daemon = daemon.clone();
tokio::spawn(async move {
if let Err(e) = handle_connection(stream, daemon).await {
debug!(error = %e, "client connection ended with error");
}
});
}
}
async fn handle_connection(stream: UnixStream, daemon: Arc<Daemon>) -> Result<()> {
let (read_half, mut write_half) = stream.into_split();
let mut lines = BufReader::new(read_half).lines();
while let Some(line) = lines.next_line().await? {
if line.trim().is_empty() {
continue;
}
let request: Request = match serde_json::from_str(&line) {
Ok(r) => r,
Err(e) => {
let reply = Envelope::err(ErrorCode::BadRequest, format!("invalid request: {e}"));
write_line(&mut write_half, &reply).await?;
continue;
}
};
debug!(?request, "request");
let subscribe = matches!(request, Request::Subscribe {});
let reply = daemon.handle(request).await;
write_line(&mut write_half, &reply).await?;
// Subscribe flips this connection into a one-way event stream;
// no further requests are read from it.
if subscribe && reply.ok {
let mut events = daemon.subscribe_events();
loop {
match events.recv().await {
Ok(event) => write_line(&mut write_half, &event).await?,
Err(tokio::sync::broadcast::error::RecvError::Lagged(n)) => {
warn!(missed = n, "event subscriber lagged, events dropped");
}
Err(tokio::sync::broadcast::error::RecvError::Closed) => return Ok(()),
}
}
}
}
Ok(())
}
async fn write_line<T: serde::Serialize>(
writer: &mut (impl AsyncWriteExt + Unpin),
value: &T,
) -> Result<()> {
let mut buf = serde_json::to_vec(value)?;
buf.push(b'\n');
writer.write_all(&buf).await?;
Ok(())
}
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//! Milestone 1: the daemon binds its socket and answers the protocol.
mod support;
use varde_proto::{ErrorCode, Request, ResponseData, PROTOCOL_VERSION};
#[test]
fn status_round_trips_on_empty_daemon() {
let daemon = support::spawn_daemon();
let mut client = support::Client::connect(&daemon.socket);
let reply = client.request(&Request::Status { hash: None });
assert!(reply.ok, "status failed: {:?}", reply.error);
match reply.data {
Some(ResponseData::Status(s)) => {
assert_eq!(s.protocol, PROTOCOL_VERSION);
assert_eq!(s.pins, 0);
assert_eq!(s.store_path, daemon.store.display().to_string());
}
other => panic!("unexpected status payload: {other:?}"),
}
}
#[test]
fn list_is_empty_on_fresh_daemon() {
let daemon = support::spawn_daemon();
let mut client = support::Client::connect(&daemon.socket);
let reply = client.request(&Request::List {});
assert!(reply.ok);
match reply.data {
Some(ResponseData::Pins { pins }) => assert!(pins.is_empty()),
other => panic!("unexpected list payload: {other:?}"),
}
}
#[test]
fn malformed_json_gets_structured_error_and_connection_survives() {
let daemon = support::spawn_daemon();
let mut client = support::Client::connect(&daemon.socket);
let reply = client.send_raw("this is not json");
assert!(!reply.ok);
assert_eq!(reply.error.expect("error body").code, ErrorCode::BadRequest);
// The same connection keeps working after a bad request.
let reply = client.request(&Request::Status { hash: None });
assert!(reply.ok);
}
#[test]
fn multiple_concurrent_clients() {
let daemon = support::spawn_daemon();
let mut a = support::Client::connect(&daemon.socket);
let mut b = support::Client::connect(&daemon.socket);
assert!(a.request(&Request::Status { hash: None }).ok);
assert!(b.request(&Request::List {}).ok);
assert!(a.request(&Request::List {}).ok);
}
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//! Shared helpers for integration tests: spawn the real daemon binary on
//! ephemeral paths and speak the JSON-lines protocol to it.
use std::io::{BufRead, BufReader, Write};
use std::os::unix::net::UnixStream;
use std::path::{Path, PathBuf};
use std::process::{Child, Command};
use std::time::{Duration, Instant};
use varde_proto::{Envelope, Request};
/// A running daemon process, killed on drop.
pub struct DaemonProc {
pub child: Child,
pub socket: PathBuf,
pub store: PathBuf,
// Kept alive so the store/socket dirs survive as long as the daemon.
_dir: Option<tempfile::TempDir>,
}
impl Drop for DaemonProc {
fn drop(&mut self) {
let _ = self.child.kill();
let _ = self.child.wait();
}
}
/// Spawn the compiled varde-daemon on a fresh tempdir.
pub fn spawn_daemon() -> DaemonProc {
let dir = tempfile::tempdir().expect("tempdir");
let mut proc = spawn_daemon_at(dir.path());
proc._dir = Some(dir);
proc
}
/// Spawn the daemon against an existing directory (for restart tests).
pub fn spawn_daemon_at(dir: &Path) -> DaemonProc {
let socket = dir.join("varde.sock");
let store = dir.join("store");
let child = Command::new(env!("CARGO_BIN_EXE_varde-daemon"))
.arg("--user")
.arg("--socket")
.arg(&socket)
.arg("--store")
.arg(&store)
// Isolate from any config file on the developer's machine.
.env("VARDE_CONFIG", dir.join("no-config.toml"))
.env("VARDE_DISCOVERY", "false")
.spawn()
.expect("spawning varde-daemon");
// An explicitly named config must exist for the daemon to start.
std::fs::write(dir.join("no-config.toml"), "").expect("writing empty config");
let proc = DaemonProc {
child,
socket,
store,
_dir: None,
};
wait_for_socket(&proc.socket);
proc
}
fn wait_for_socket(path: &Path) {
let deadline = Instant::now() + Duration::from_secs(10);
while Instant::now() < deadline {
if UnixStream::connect(path).is_ok() {
return;
}
std::thread::sleep(Duration::from_millis(20));
}
panic!("daemon socket {} never appeared", path.display());
}
/// One connected API client.
pub struct Client {
reader: BufReader<UnixStream>,
writer: UnixStream,
}
impl Client {
pub fn connect(socket: &Path) -> Client {
let stream = UnixStream::connect(socket).expect("connecting to daemon");
let reader = BufReader::new(stream.try_clone().expect("cloning stream"));
Client {
reader,
writer: stream,
}
}
/// Send a request and read the response envelope.
pub fn request(&mut self, req: &Request) -> Envelope {
let mut line = serde_json::to_string(req).expect("serializing request");
line.push('\n');
self.writer
.write_all(line.as_bytes())
.expect("writing request");
self.read_envelope()
}
/// Send a raw line (for malformed-input tests).
pub fn send_raw(&mut self, raw: &str) -> Envelope {
self.writer
.write_all(raw.as_bytes())
.expect("writing raw line");
self.writer.write_all(b"\n").expect("writing newline");
self.read_envelope()
}
fn read_envelope(&mut self) -> Envelope {
let mut reply = String::new();
self.reader.read_line(&mut reply).expect("reading reply");
assert!(
!reply.is_empty(),
"daemon closed connection without replying"
);
serde_json::from_str(&reply).expect("parsing reply envelope")
}
/// Read one line of the event stream (after Subscribe).
// Each test binary compiles its own copy of this module; not every
// binary uses every helper.
#[allow(dead_code)]
pub fn read_event_line(&mut self) -> Option<String> {
let mut line = String::new();
match self.reader.read_line(&mut line) {
Ok(0) => None,
Ok(_) => Some(line),
Err(e) => panic!("reading event line: {e}"),
}
}
}