use std::collections::HashMap; use std::hash::Hash as StdHash; use std::hash::Hasher; use std::io::Read; use std::net::{IpAddr, SocketAddr}; use std::path::PathBuf; use std::sync::Arc; use std::time::Duration; use futures::future::join_all; use futures::select; use futures_util::future::*; use sha2::{Digest, Sha256}; use tokio::prelude::*; use tokio::sync::watch; use tokio::sync::Mutex; use crate::background::BackgroundRunner; use crate::data::*; use crate::error::Error; use crate::proto::*; use crate::rpc_client::*; use crate::server::Config; const PING_INTERVAL: Duration = Duration::from_secs(10); const PING_TIMEOUT: Duration = Duration::from_secs(2); const MAX_FAILED_PINGS: usize = 3; pub struct System { pub config: Config, pub id: UUID, pub rpc_client: RpcClient, pub status: watch::Receiver>, pub ring: watch::Receiver>, update_lock: Mutex<(watch::Sender>, watch::Sender>)>, pub background: Arc, } #[derive(Debug, Clone)] pub struct Status { pub nodes: HashMap, pub hash: Hash, } #[derive(Debug, Clone)] pub struct NodeStatus { pub addr: SocketAddr, pub remaining_ping_attempts: usize, } #[derive(Clone)] pub struct Ring { pub config: NetworkConfig, pub ring: Vec, pub n_datacenters: usize, } #[derive(Clone, Debug)] pub struct RingEntry { pub location: Hash, pub node: UUID, pub datacenter: u64, } impl Status { fn handle_ping(&mut self, ip: IpAddr, info: &PingMessage) -> bool { let addr = SocketAddr::new(ip, info.rpc_port); let old_status = self.nodes.insert( info.id.clone(), NodeStatus { addr: addr.clone(), remaining_ping_attempts: MAX_FAILED_PINGS, }, ); match old_status { None => { eprintln!("Newly pingable node: {}", hex::encode(&info.id)); true } Some(x) => x.addr != addr, } } fn recalculate_hash(&mut self) { let mut nodes = self.nodes.iter().collect::>(); nodes.sort_unstable_by_key(|(id, _status)| *id); let mut hasher = Sha256::new(); eprintln!("Current set of pingable nodes: --"); for (id, status) in nodes { eprintln!("{} {}", hex::encode(&id), status.addr); hasher.input(format!("{} {}\n", hex::encode(&id), status.addr)); } eprintln!("END --"); self.hash .as_slice_mut() .copy_from_slice(&hasher.result()[..]); } } impl Ring { fn rebuild_ring(&mut self) { let mut new_ring = vec![]; let mut datacenters = vec![]; for (id, config) in self.config.members.iter() { let mut dc_hasher = std::collections::hash_map::DefaultHasher::new(); config.datacenter.hash(&mut dc_hasher); let datacenter = dc_hasher.finish(); if !datacenters.contains(&datacenter) { datacenters.push(datacenter); } for i in 0..config.n_tokens { let location = hash(format!("{} {}", hex::encode(&id), i).as_bytes()); new_ring.push(RingEntry { location: location.into(), node: id.clone(), datacenter, }) } } new_ring.sort_unstable_by(|x, y| x.location.cmp(&y.location)); self.ring = new_ring; self.n_datacenters = datacenters.len(); // eprintln!("RING: --"); // for e in self.ring.iter() { // eprintln!("{:?}", e); // } // eprintln!("END --"); } pub fn walk_ring(&self, from: &Hash, n: usize) -> Vec { if n >= self.config.members.len() { return self.config.members.keys().cloned().collect::>(); } let start = match self.ring.binary_search_by(|x| x.location.cmp(from)) { Ok(i) => i, Err(i) => { if i == 0 { self.ring.len() - 1 } else { i - 1 } } }; self.walk_ring_from_pos(start, n) } pub fn walk_ring_from_pos(&self, start: usize, n: usize) -> Vec { let mut ret = vec![]; let mut datacenters = vec![]; for delta in 0..self.ring.len() { if ret.len() == n { break; } let i = (start + delta) % self.ring.len(); if datacenters.len() == self.n_datacenters && !ret.contains(&self.ring[i].node) { ret.push(self.ring[i].node.clone()); } else if !datacenters.contains(&self.ring[i].datacenter) { ret.push(self.ring[i].node.clone()); datacenters.push(self.ring[i].datacenter); } } ret } } fn read_network_config(metadata_dir: &PathBuf) -> Result { let mut path = metadata_dir.clone(); path.push("network_config"); let mut file = std::fs::OpenOptions::new() .read(true) .open(path.as_path())?; let mut net_config_bytes = vec![]; file.read_to_end(&mut net_config_bytes)?; let net_config = rmp_serde::decode::from_read_ref(&net_config_bytes[..])?; Ok(net_config) } impl System { pub fn new(config: Config, id: UUID, background: Arc) -> Self { let net_config = match read_network_config(&config.metadata_dir) { Ok(x) => x, Err(e) => { println!( "No valid previous network configuration stored ({}), starting fresh.", e ); NetworkConfig { members: HashMap::new(), version: 0, } } }; let mut status = Status { nodes: HashMap::new(), hash: Hash::default(), }; status.recalculate_hash(); let (update_status, status) = watch::channel(Arc::new(status)); let mut ring = Ring { config: net_config, ring: Vec::new(), n_datacenters: 0, }; ring.rebuild_ring(); let (update_ring, ring) = watch::channel(Arc::new(ring)); let rpc_client = RpcClient::new(&config.rpc_tls).expect("Could not create RPC client"); System { config, id, rpc_client, status, ring, update_lock: Mutex::new((update_status, update_ring)), background, } } async fn save_network_config(self: Arc) -> Result<(), Error> { let mut path = self.config.metadata_dir.clone(); path.push("network_config"); let ring = self.ring.borrow().clone(); let data = rmp_to_vec_all_named(&ring.config)?; let mut f = tokio::fs::File::create(path.as_path()).await?; f.write_all(&data[..]).await?; Ok(()) } pub fn make_ping(&self) -> Message { let status = self.status.borrow().clone(); let ring = self.ring.borrow().clone(); Message::Ping(PingMessage { id: self.id.clone(), rpc_port: self.config.rpc_port, status_hash: status.hash.clone(), config_version: ring.config.version, }) } pub async fn broadcast(self: Arc, msg: Message, timeout: Duration) { let status = self.status.borrow().clone(); let to = status .nodes .keys() .filter(|x| **x != self.id) .cloned() .collect::>(); rpc_call_many(self.clone(), &to[..], msg, timeout).await; } pub async fn bootstrap(self: Arc) { let bootstrap_peers = self .config .bootstrap_peers .iter() .map(|ip| (ip.clone(), None)) .collect::>(); self.clone().ping_nodes(bootstrap_peers).await; self.clone() .background .spawn_worker(|stop_signal| self.ping_loop(stop_signal).map(Ok)) .await; } async fn ping_nodes(self: Arc, peers: Vec<(SocketAddr, Option)>) { let ping_msg = self.make_ping(); let ping_resps = join_all(peers.iter().map(|(addr, id_option)| { let sys = self.clone(); let ping_msg_ref = &ping_msg; async move { ( id_option, addr.clone(), sys.rpc_client.call(&addr, ping_msg_ref, PING_TIMEOUT).await, ) } })) .await; let update_locked = self.update_lock.lock().await; let mut status: Status = self.status.borrow().as_ref().clone(); let ring = self.ring.borrow().clone(); let mut has_changes = false; let mut to_advertise = vec![]; for (id_option, addr, ping_resp) in ping_resps { if let Ok(Message::Ping(info)) = ping_resp { let is_new = status.handle_ping(addr.ip(), &info); if is_new { has_changes = true; to_advertise.push(AdvertisedNode { id: info.id.clone(), addr: addr.clone(), }); } if is_new || status.hash != info.status_hash { self.background .spawn_cancellable(self.clone().pull_status(info.id.clone()).map(Ok)); } if is_new || ring.config.version < info.config_version { self.background .spawn_cancellable(self.clone().pull_config(info.id.clone()).map(Ok)); } } else if let Some(id) = id_option { let remaining_attempts = status .nodes .get(id) .map(|x| x.remaining_ping_attempts) .unwrap_or(0); if remaining_attempts == 0 { eprintln!( "Removing node {} after too many failed pings", hex::encode(&id) ); status.nodes.remove(&id); has_changes = true; } else { if let Some(st) = status.nodes.get_mut(id) { st.remaining_ping_attempts = remaining_attempts - 1; } } } } if has_changes { status.recalculate_hash(); } if let Err(e) = update_locked.0.broadcast(Arc::new(status)) { eprintln!("In ping_nodes: could not save status update ({})", e); } drop(update_locked); if to_advertise.len() > 0 { self.broadcast(Message::AdvertiseNodesUp(to_advertise), PING_TIMEOUT) .await; } } pub async fn handle_ping( self: Arc, from: &SocketAddr, ping: &PingMessage, ) -> Result { let update_locked = self.update_lock.lock().await; let mut status: Status = self.status.borrow().as_ref().clone(); let is_new = status.handle_ping(from.ip(), ping); if is_new { status.recalculate_hash(); } let status_hash = status.hash.clone(); let config_version = self.ring.borrow().config.version; update_locked.0.broadcast(Arc::new(status))?; drop(update_locked); if is_new || status_hash != ping.status_hash { self.background .spawn_cancellable(self.clone().pull_status(ping.id.clone()).map(Ok)); } if is_new || config_version < ping.config_version { self.background .spawn_cancellable(self.clone().pull_config(ping.id.clone()).map(Ok)); } Ok(self.make_ping()) } pub fn handle_pull_status(&self) -> Result { let status = self.status.borrow().clone(); let mut mem = vec![]; for (node, status) in status.nodes.iter() { mem.push(AdvertisedNode { id: node.clone(), addr: status.addr.clone(), }); } Ok(Message::AdvertiseNodesUp(mem)) } pub fn handle_pull_config(&self) -> Result { let ring = self.ring.borrow().clone(); Ok(Message::AdvertiseConfig(ring.config.clone())) } pub async fn handle_advertise_nodes_up( self: Arc, adv: &[AdvertisedNode], ) -> Result { let mut to_ping = vec![]; let update_lock = self.update_lock.lock().await; let mut status: Status = self.status.borrow().as_ref().clone(); let mut has_changed = false; for node in adv.iter() { if node.id == self.id { // learn our own ip address let self_addr = SocketAddr::new(node.addr.ip(), self.config.rpc_port); let old_self = status.nodes.insert( node.id.clone(), NodeStatus { addr: self_addr, remaining_ping_attempts: MAX_FAILED_PINGS, }, ); has_changed = match old_self { None => true, Some(x) => x.addr != self_addr, }; } else if !status.nodes.contains_key(&node.id) { to_ping.push((node.addr.clone(), Some(node.id.clone()))); } } if has_changed { status.recalculate_hash(); } update_lock.0.broadcast(Arc::new(status))?; drop(update_lock); if to_ping.len() > 0 { self.background .spawn_cancellable(self.clone().ping_nodes(to_ping).map(Ok)); } Ok(Message::Ok) } pub async fn handle_advertise_config( self: Arc, adv: &NetworkConfig, ) -> Result { let mut ring: Ring = self.ring.borrow().as_ref().clone(); let update_lock = self.update_lock.lock().await; if adv.version > ring.config.version { ring.config = adv.clone(); ring.rebuild_ring(); update_lock.1.broadcast(Arc::new(ring))?; drop(update_lock); self.background.spawn_cancellable( self.clone() .broadcast(Message::AdvertiseConfig(adv.clone()), PING_TIMEOUT) .map(Ok), ); self.background.spawn(self.clone().save_network_config()); } Ok(Message::Ok) } pub async fn ping_loop(self: Arc, mut stop_signal: watch::Receiver) { loop { let restart_at = tokio::time::delay_for(PING_INTERVAL); let status = self.status.borrow().clone(); let ping_addrs = status .nodes .iter() .filter(|(id, _)| **id != self.id) .map(|(id, status)| (status.addr.clone(), Some(id.clone()))) .collect::>(); self.clone().ping_nodes(ping_addrs).await; select! { _ = restart_at.fuse() => (), must_exit = stop_signal.recv().fuse() => { match must_exit { None | Some(true) => return, _ => (), } } } } } pub fn pull_status( self: Arc, peer: UUID, ) -> impl futures::future::Future + Send + 'static { async move { let resp = rpc_call(self.clone(), &peer, &Message::PullStatus, PING_TIMEOUT).await; if let Ok(Message::AdvertiseNodesUp(nodes)) = resp { let _: Result<_, _> = self.handle_advertise_nodes_up(&nodes).await; } } } pub async fn pull_config(self: Arc, peer: UUID) { let resp = rpc_call(self.clone(), &peer, &Message::PullConfig, PING_TIMEOUT).await; if let Ok(Message::AdvertiseConfig(config)) = resp { let _: Result<_, _> = self.handle_advertise_config(&config).await; } } }