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//! The public entry point: configure and run the thread-per-core server.
use crate::Commands;
use crate::message::{Inbound, PubSubPatternReg, PubSubReg};
use crate::shard::Shard;
use kevy_map::KevyMap;
use kevy_persist::{Aof, Fsync};
use kevy_ring::{Consumer, Producer};
use kevy_store::Store;
use kevy_sys::{Poller, Waker, tcp_listen_reuseport, waker};
use std::collections::{HashMap, VecDeque};
use std::io;
use std::path::PathBuf;
use std::sync::atomic::AtomicBool;
use std::sync::{Arc, RwLock};
/// Default slots in each per-core-pair SPSC ring. A full ring spills
/// to a local backlog (see [`Shard`]), so this only bounds the
/// lock-free fast path, not capacity. Overridable via the
/// `[advanced] ring_capacity` config field threaded through
/// [`Runtime::with_advanced`].
const DEFAULT_RING_CAPACITY: usize = 1024;
/// The public entry point: configure and run the thread-per-core server.
pub struct Runtime<C: Commands> {
ip: [u8; 4],
port: u16,
nshards: usize,
commands: C,
/// Directory for per-shard snapshot files (`dump-<id>.rdb`) and AOF logs.
data_dir: PathBuf,
/// Whether the append-only log is enabled.
enable_aof: bool,
/// fsync policy for the AOF. Default `EverySec` matches Redis.
appendfsync: Fsync,
/// auto-trigger BGREWRITEAOF when AOF grew this many % above the size
/// at the previous rewrite. `0` disables. Default `100` (matches Redis).
auto_aof_rewrite_pct: u32,
/// Floor below which auto-rewrite is skipped. Default `64 MiB`.
auto_aof_rewrite_min_size: u64,
/// Reactor SPSC ring slot count. See [`DEFAULT_RING_CAPACITY`].
ring_capacity: usize,
/// Reactor busy-poll iter limit before parking. Stored as `u32`
/// for the per-shard counter; the [`Shard`] field carries it
/// forward into the loop.
spin_limit: u32,
/// Reactor blocking-wait timeout in ms when parked.
park_timeout_ms: u32,
/// Wall-clock-read throttle for the tick check (TTL reaper / live
/// config refresh / auto-AOF-rewrite).
tick_check_every: u32,
/// `[slowlog].slower_than_micros`. Defaults match Redis (10 ms).
slowlog_slower_than_micros: i64,
/// `[slowlog].max_len`. Per-shard cap.
slowlog_max_len: u32,
}
impl<C: Commands> Runtime<C> {
pub fn new(ip: [u8; 4], port: u16, nshards: usize, commands: C) -> Self {
Runtime {
ip,
port,
nshards: nshards.max(1),
commands,
data_dir: PathBuf::from("."),
enable_aof: true,
appendfsync: Fsync::EverySec,
auto_aof_rewrite_pct: 100,
auto_aof_rewrite_min_size: 64 * 1024 * 1024,
ring_capacity: DEFAULT_RING_CAPACITY,
spin_limit: 256,
park_timeout_ms: 50,
tick_check_every: 256,
slowlog_slower_than_micros: 10_000,
slowlog_max_len: 128,
}
}
/// SLOWLOG tuning (`[slowlog]` config section). Defaults: record any
/// command slower than 10 ms (`10_000` µs), keep the most-recent 128
/// entries per shard. Pass `slower_than_micros = -1` to disable
/// (zero hot-path cost — no `Instant::now()` taken).
pub fn with_slowlog(mut self, slower_than_micros: i64, max_len: u32) -> Self {
self.slowlog_slower_than_micros = slower_than_micros;
self.slowlog_max_len = max_len;
self
}
/// Reactor tuning knobs (`[advanced]` config section). Defaults
/// match the pre-v1.4 hardcoded constants. `ring_capacity` is
/// applied at SPSC ring construction (startup only); the other
/// three are read at each iteration of the reactor loop, so
/// values applied here take effect from the next shard.run() call.
pub fn with_advanced(
mut self,
spin_limit: u32,
park_timeout_ms: u32,
tick_check_every: u32,
ring_capacity: usize,
) -> Self {
self.spin_limit = spin_limit;
self.park_timeout_ms = park_timeout_ms;
self.tick_check_every = tick_check_every;
self.ring_capacity = ring_capacity;
self
}
/// Set the directory where shards snapshot to / load from. Default: `.`.
pub fn with_data_dir(mut self, dir: impl Into<PathBuf>) -> Self {
self.data_dir = dir.into();
self
}
/// Enable/disable the append-only log. Default: enabled.
pub fn with_aof(mut self, on: bool) -> Self {
self.enable_aof = on;
self
}
/// fsync policy for the AOF. Default `EverySec` matches Redis (lose at
/// most ~1 s of writes on a crash). `Always` is zero-loss but ~50 %
/// throughput; `No` defers everything to the OS pagecache.
pub fn with_appendfsync(mut self, fsync: Fsync) -> Self {
self.appendfsync = fsync;
self
}
/// Auto-trigger BGREWRITEAOF when the live AOF has grown by at least
/// `pct` percent above its size at the previous rewrite, AND is at
/// least `min_size` bytes. `pct=0` disables auto-rewrite (clients can
/// still run BGREWRITEAOF manually). Defaults: 100 % / 64 MiB.
pub fn with_auto_aof_rewrite(mut self, pct: u32, min_size: u64) -> Self {
self.auto_aof_rewrite_pct = pct;
self.auto_aof_rewrite_min_size = min_size;
self
}
/// Spawn one thread per shard and run until `stop` is set.
pub fn run(self, stop: Arc<AtomicBool>) -> io::Result<()> {
let n = self.nshards;
// One lock-free SPSC ring per ordered core-pair (i→j): the producer goes
// to shard i's outbox[j], the consumer to shard j's inbox[i]. There is no
// self-ring — a shard runs its own commands inline, never over a ring.
let mut outboxes: Vec<Vec<Option<Producer<Inbound>>>> =
(0..n).map(|_| (0..n).map(|_| None).collect()).collect();
let mut inboxes: Vec<Vec<Option<Consumer<Inbound>>>> =
(0..n).map(|_| (0..n).map(|_| None).collect()).collect();
for i in 0..n {
for j in 0..n {
if i == j {
continue;
}
let (p, c) = kevy_ring::ring::<Inbound>(self.ring_capacity);
outboxes[i][j] = Some(p);
inboxes[j][i] = Some(c);
}
}
let mut wakers: Vec<Arc<Waker>> = Vec::with_capacity(n);
for _ in 0..n {
wakers.push(Arc::new(waker()?));
}
let parked: Vec<Arc<AtomicBool>> =
(0..n).map(|_| Arc::new(AtomicBool::new(false))).collect();
// Shared pub/sub channel registry (one per server, read on every PUBLISH).
let pubsub: PubSubReg = Arc::new(RwLock::new(HashMap::new()));
// Shared pub/sub pattern registry. Empty in steady state — the
// channel-only PUBLISH path skips the walk when so.
let pubsub_patterns: PubSubPatternReg = Arc::new(RwLock::new(Vec::new()));
// Build every shard up front so a bind/open failure aborts before we spawn.
let mut shards = Vec::with_capacity(n);
for id in 0..n {
let listener = tcp_listen_reuseport(self.ip, self.port, 1024)?;
let aof = if self.enable_aof {
Some(Aof::open(
&self.data_dir.join(format!("aof-{id}.aof")),
self.appendfsync,
)?)
} else {
None
};
let mut store = Store::new();
self.commands.on_shard_init(&mut store);
shards.push(Shard {
id,
nshards: n,
store,
commands: self.commands.clone(),
poller: Poller::new()?,
listener,
waker: wakers[id].clone(),
inboxes: std::mem::take(&mut inboxes[id]),
outboxes: std::mem::take(&mut outboxes[id]),
backlog: (0..n).map(|_| VecDeque::new()).collect(),
wakers: wakers.clone(),
conns: KevyMap::new(),
fd_to_conn: KevyMap::new(),
next_conn_id: 1,
events: Vec::with_capacity(1024),
read_buf: vec![0u8; 64 * 1024],
pending_wakes: vec![false; n],
parked: parked.clone(),
data_dir: self.data_dir.clone(),
aof,
auto_aof_rewrite_pct: self.auto_aof_rewrite_pct,
auto_aof_rewrite_min_size: self.auto_aof_rewrite_min_size,
dirty: Vec::new(),
pubsub: pubsub.clone(),
pubsub_patterns: pubsub_patterns.clone(),
psub_local: HashMap::new(),
publish_batch: (0..n).map(|_| Vec::new()).collect(),
request_batch: (0..n).map(|_| Vec::new()).collect(),
notify_flags: crate::NotificationFlags::default(),
spin_limit: self.spin_limit,
// `Poller::wait` takes the timeout as `i32` (POSIX
// poll/epoll convention). The config knob is `u32` —
// we clamp to i32::MAX, far above any sane park-timeout.
park_timeout_ms: self.park_timeout_ms.min(i32::MAX as u32) as i32,
tick_check_every: self.tick_check_every,
slowlog: crate::exec_slowlog::SlowlogState::new(
self.slowlog_slower_than_micros,
self.slowlog_max_len,
),
blocked: crate::blocked::BlockedClients::new(),
});
}
// Opt into the Linux io_uring (completion) reactor with KEVY_IO_URING=1;
// otherwise use the readiness reactor (epoll/kqueue), the default + macOS.
#[cfg(target_os = "linux")]
let use_uring = std::env::var_os("KEVY_IO_URING").is_some();
let mut handles = Vec::with_capacity(n);
for shard in shards {
let stop = stop.clone();
let id = shard.id;
handles.push(std::thread::spawn(move || {
#[cfg(target_os = "linux")]
let res = if use_uring { shard.run_uring(stop) } else { shard.run(stop) };
#[cfg(not(target_os = "linux"))]
let res = shard.run(stop);
if let Err(e) = res {
eprintln!("kevy: shard {id} exited with error: {e}");
}
}));
}
for h in handles {
let _ = h.join();
}
Ok(())
}
}