Reorganize code

5 files changed, 1414 insertions, 0 deletions

diff --git a/src/rpc/membership.rs b/src/rpc/membership.rs
new file mode 100644
index 00000000..e0509536
--- /dev/null
+++ b/src/rpc/membership.rs
@@ -0,0 +1,692 @@
+use std::collections::HashMap;
+use std::hash::Hash as StdHash;
+use std::hash::Hasher;
+use std::io::{Read, Write};
+use std::net::{IpAddr, SocketAddr};
+use std::path::PathBuf;
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::sync::Arc;
+use std::time::Duration;
+
+use futures::future::join_all;
+use futures::select;
+use futures_util::future::*;
+use serde::{Deserialize, Serialize};
+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::rpc::rpc_client::*;
+use crate::rpc::rpc_server::*;
+
+const PING_INTERVAL: Duration = Duration::from_secs(10);
+const PING_TIMEOUT: Duration = Duration::from_secs(2);
+const MAX_FAILURES_BEFORE_CONSIDERED_DOWN: usize = 5;
+
+pub const MEMBERSHIP_RPC_PATH: &str = "_membership";
+
+#[derive(Debug, Serialize, Deserialize)]
+pub enum Message {
+	Ok,
+	Ping(PingMessage),
+	PullStatus,
+	PullConfig,
+	AdvertiseNodesUp(Vec<AdvertisedNode>),
+	AdvertiseConfig(NetworkConfig),
+}
+
+impl RpcMessage for Message {}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct PingMessage {
+	pub id: UUID,
+	pub rpc_port: u16,
+
+	pub status_hash: Hash,
+	pub config_version: u64,
+
+	pub state_info: StateInfo,
+}
+
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct AdvertisedNode {
+	pub id: UUID,
+	pub addr: SocketAddr,
+
+	pub is_up: bool,
+	pub last_seen: u64,
+
+	pub state_info: StateInfo,
+}
+
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct NetworkConfig {
+	pub members: HashMap<UUID, NetworkConfigEntry>,
+	pub version: u64,
+}
+
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct NetworkConfigEntry {
+	pub datacenter: String,
+	pub n_tokens: u32,
+	pub tag: String,
+}
+
+pub struct System {
+	pub id: UUID,
+	pub data_dir: PathBuf,
+	pub rpc_local_port: u16,
+
+	pub state_info: StateInfo,
+
+	pub rpc_http_client: Arc<RpcHttpClient>,
+	rpc_client: Arc<RpcClient<Message>>,
+
+	pub status: watch::Receiver<Arc<Status>>,
+	pub ring: watch::Receiver<Arc<Ring>>,
+
+	update_lock: Mutex<(watch::Sender<Arc<Status>>, watch::Sender<Arc<Ring>>)>,
+
+	pub background: Arc<BackgroundRunner>,
+}
+
+#[derive(Debug, Clone)]
+pub struct Status {
+	pub nodes: HashMap<UUID, Arc<StatusEntry>>,
+	pub hash: Hash,
+}
+
+#[derive(Debug)]
+pub struct StatusEntry {
+	pub addr: SocketAddr,
+	pub last_seen: u64,
+	pub num_failures: AtomicUsize,
+	pub state_info: StateInfo,
+}
+
+impl StatusEntry {
+	pub fn is_up(&self) -> bool {
+		self.num_failures.load(Ordering::SeqCst) < MAX_FAILURES_BEFORE_CONSIDERED_DOWN
+	}
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct StateInfo {
+	pub hostname: String,
+}
+
+#[derive(Clone)]
+pub struct Ring {
+	pub config: NetworkConfig,
+	pub ring: Vec<RingEntry>,
+	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,
+			Arc::new(StatusEntry {
+				addr,
+				last_seen: now_msec(),
+				num_failures: AtomicUsize::from(0),
+				state_info: info.state_info.clone(),
+			}),
+		);
+		match old_status {
+			None => {
+				info!("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::<Vec<_>>();
+		nodes.sort_unstable_by_key(|(id, _status)| *id);
+
+		let mut hasher = Sha256::new();
+		debug!("Current set of pingable nodes: --");
+		for (id, status) in nodes {
+			debug!("{} {}", hex::encode(&id), status.addr);
+			hasher.input(format!("{} {}\n", hex::encode(&id), status.addr));
+		}
+		debug!("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,
+					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<UUID> {
+		if n >= self.config.members.len() {
+			return self.config.members.keys().cloned().collect::<Vec<_>>();
+		}
+
+		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)
+	}
+
+	fn walk_ring_from_pos(&self, start: usize, n: usize) -> Vec<UUID> {
+		if n >= self.config.members.len() {
+			return self.config.members.keys().cloned().collect::<Vec<_>>();
+		}
+
+		let mut ret = vec![];
+		let mut datacenters = vec![];
+
+		let mut delta = 0;
+		while ret.len() < n {
+			let i = (start + delta) % self.ring.len();
+			delta += 1;
+
+			if !datacenters.contains(&self.ring[i].datacenter) {
+				ret.push(self.ring[i].node);
+				datacenters.push(self.ring[i].datacenter);
+			} else if datacenters.len() == self.n_datacenters && !ret.contains(&self.ring[i].node) {
+				ret.push(self.ring[i].node);
+			}
+		}
+
+		ret
+	}
+}
+
+fn gen_node_id(metadata_dir: &PathBuf) -> Result<UUID, Error> {
+	let mut id_file = metadata_dir.clone();
+	id_file.push("node_id");
+	if id_file.as_path().exists() {
+		let mut f = std::fs::File::open(id_file.as_path())?;
+		let mut d = vec![];
+		f.read_to_end(&mut d)?;
+		if d.len() != 32 {
+			return Err(Error::Message(format!("Corrupt node_id file")));
+		}
+
+		let mut id = [0u8; 32];
+		id.copy_from_slice(&d[..]);
+		Ok(id.into())
+	} else {
+		let id = gen_uuid();
+
+		let mut f = std::fs::File::create(id_file.as_path())?;
+		f.write_all(id.as_slice())?;
+		Ok(id)
+	}
+}
+
+fn read_network_config(metadata_dir: &PathBuf) -> Result<NetworkConfig, Error> {
+	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[..])
+		.expect("Unable to parse network configuration file (has version format changed?).");
+
+	Ok(net_config)
+}
+
+impl System {
+	pub fn new(
+		data_dir: PathBuf,
+		rpc_http_client: Arc<RpcHttpClient>,
+		background: Arc<BackgroundRunner>,
+		rpc_server: &mut RpcServer,
+	) -> Arc<Self> {
+		let id = gen_node_id(&data_dir).expect("Unable to read or generate node ID");
+		info!("Node ID: {}", hex::encode(&id));
+
+		let net_config = match read_network_config(&data_dir) {
+			Ok(x) => x,
+			Err(e) => {
+				info!(
+					"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 state_info = StateInfo {
+			hostname: gethostname::gethostname()
+				.into_string()
+				.unwrap_or("<invalid utf-8>".to_string()),
+		};
+
+		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_path = MEMBERSHIP_RPC_PATH.to_string();
+		let rpc_client = RpcClient::new(
+			RpcAddrClient::<Message>::new(rpc_http_client.clone(), rpc_path.clone()),
+			background.clone(),
+			status.clone(),
+		);
+
+		let sys = Arc::new(System {
+			id,
+			data_dir,
+			rpc_local_port: rpc_server.bind_addr.port(),
+			state_info,
+			rpc_http_client,
+			rpc_client,
+			status,
+			ring,
+			update_lock: Mutex::new((update_status, update_ring)),
+			background,
+		});
+		sys.clone().register_handler(rpc_server, rpc_path);
+		sys
+	}
+
+	fn register_handler(self: Arc<Self>, rpc_server: &mut RpcServer, path: String) {
+		rpc_server.add_handler::<Message, _, _>(path, move |msg, addr| {
+			let self2 = self.clone();
+			async move {
+				match msg {
+					Message::Ping(ping) => self2.handle_ping(&addr, &ping).await,
+
+					Message::PullStatus => self2.handle_pull_status(),
+					Message::PullConfig => self2.handle_pull_config(),
+					Message::AdvertiseNodesUp(adv) => self2.handle_advertise_nodes_up(&adv).await,
+					Message::AdvertiseConfig(adv) => self2.handle_advertise_config(&adv).await,
+
+					_ => Err(Error::BadRequest(format!("Unexpected RPC message"))),
+				}
+			}
+		});
+	}
+
+	pub fn rpc_client<M: RpcMessage + 'static>(self: &Arc<Self>, path: &str) -> Arc<RpcClient<M>> {
+		RpcClient::new(
+			RpcAddrClient::new(self.rpc_http_client.clone(), path.to_string()),
+			self.background.clone(),
+			self.status.clone(),
+		)
+	}
+
+	async fn save_network_config(self: Arc<Self>) -> Result<(), Error> {
+		let mut path = self.data_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,
+			rpc_port: self.rpc_local_port,
+			status_hash: status.hash,
+			config_version: ring.config.version,
+			state_info: self.state_info.clone(),
+		})
+	}
+
+	pub async fn broadcast(self: Arc<Self>, msg: Message, timeout: Duration) {
+		let status = self.status.borrow().clone();
+		let to = status
+			.nodes
+			.keys()
+			.filter(|x| **x != self.id)
+			.cloned()
+			.collect::<Vec<_>>();
+		self.rpc_client.call_many(&to[..], msg, timeout).await;
+	}
+
+	pub async fn bootstrap(self: Arc<Self>, peers: &[SocketAddr]) {
+		let bootstrap_peers = peers.iter().map(|ip| (*ip, None)).collect::<Vec<_>>();
+		self.clone().ping_nodes(bootstrap_peers).await;
+
+		self.clone()
+			.background
+			.spawn_worker(format!("ping loop"), |stop_signal| {
+				self.ping_loop(stop_signal).map(Ok)
+			})
+			.await;
+	}
+
+	async fn ping_nodes(self: Arc<Self>, peers: Vec<(SocketAddr, Option<UUID>)>) {
+		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,
+					sys.rpc_client
+						.by_addr()
+						.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(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,
+						addr: *addr,
+						is_up: true,
+						last_seen: now_msec(),
+						state_info: info.state_info.clone(),
+					});
+				}
+				if is_new || status.hash != info.status_hash {
+					self.background
+						.spawn_cancellable(self.clone().pull_status(info.id).map(Ok));
+				}
+				if is_new || ring.config.version < info.config_version {
+					self.background
+						.spawn_cancellable(self.clone().pull_config(info.id).map(Ok));
+				}
+			} else if let Some(id) = id_option {
+				if let Some(st) = status.nodes.get_mut(id) {
+					st.num_failures.fetch_add(1, Ordering::SeqCst);
+					if !st.is_up() {
+						warn!("Node {:?} seems to be down.", id);
+						if !ring.config.members.contains_key(id) {
+							info!("Removing node {:?} from status (not in config and not responding to pings anymore)", id);
+							drop(st);
+							status.nodes.remove(&id);
+							has_changes = true;
+						}
+					}
+				}
+			}
+		}
+		if has_changes {
+			status.recalculate_hash();
+		}
+		if let Err(e) = update_locked.0.broadcast(Arc::new(status)) {
+			error!("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<Self>,
+		from: &SocketAddr,
+		ping: &PingMessage,
+	) -> Result<Message, Error> {
+		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;
+		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).map(Ok));
+		}
+		if is_new || config_version < ping.config_version {
+			self.background
+				.spawn_cancellable(self.clone().pull_config(ping.id).map(Ok));
+		}
+
+		Ok(self.make_ping())
+	}
+
+	pub fn handle_pull_status(&self) -> Result<Message, Error> {
+		let status = self.status.borrow().clone();
+		let mut mem = vec![];
+		for (node, status) in status.nodes.iter() {
+			let state_info = if *node == self.id {
+				self.state_info.clone()
+			} else {
+				status.state_info.clone()
+			};
+			mem.push(AdvertisedNode {
+				id: *node,
+				addr: status.addr,
+				is_up: status.is_up(),
+				last_seen: status.last_seen,
+				state_info,
+			});
+		}
+		Ok(Message::AdvertiseNodesUp(mem))
+	}
+
+	pub fn handle_pull_config(&self) -> Result<Message, Error> {
+		let ring = self.ring.borrow().clone();
+		Ok(Message::AdvertiseConfig(ring.config.clone()))
+	}
+
+	pub async fn handle_advertise_nodes_up(
+		self: Arc<Self>,
+		adv: &[AdvertisedNode],
+	) -> Result<Message, Error> {
+		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.rpc_local_port);
+				let old_self = status.nodes.insert(
+					node.id,
+					Arc::new(StatusEntry {
+						addr: self_addr,
+						last_seen: now_msec(),
+						num_failures: AtomicUsize::from(0),
+						state_info: self.state_info.clone(),
+					}),
+				);
+				has_changed = match old_self {
+					None => true,
+					Some(x) => x.addr != self_addr,
+				};
+			} else {
+				let ping_them = match status.nodes.get(&node.id) {
+					// Case 1: new node
+					None => true,
+					// Case 2: the node might have changed address
+					Some(our_node) => node.is_up && !our_node.is_up() && our_node.addr != node.addr,
+				};
+				if ping_them {
+					to_ping.push((node.addr, Some(node.id)));
+				}
+			}
+		}
+		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<Self>,
+		adv: &NetworkConfig,
+	) -> Result<Message, Error> {
+		let update_lock = self.update_lock.lock().await;
+		let mut ring: Ring = self.ring.borrow().as_ref().clone();
+
+		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<Self>, mut stop_signal: watch::Receiver<bool>) {
+		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, Some(*id)))
+				.collect::<Vec<_>>();
+
+			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<Self>,
+		peer: UUID,
+	) -> impl futures::future::Future<Output = ()> + Send + 'static {
+		async move {
+			let resp = self
+				.rpc_client
+				.call(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<Self>, peer: UUID) {
+		let resp = self
+			.rpc_client
+			.call(peer, Message::PullConfig, PING_TIMEOUT)
+			.await;
+		if let Ok(Message::AdvertiseConfig(config)) = resp {
+			let _: Result<_, _> = self.handle_advertise_config(&config).await;
+		}
+	}
+}
diff --git a/src/rpc/mod.rs b/src/rpc/mod.rs
new file mode 100644
index 00000000..83fd0aac
--- /dev/null
+++ b/src/rpc/mod.rs
@@ -0,0 +1,4 @@
+pub mod membership;
+pub mod rpc_client;
+pub mod rpc_server;
+pub mod tls_util;
diff --git a/src/rpc/rpc_client.rs b/src/rpc/rpc_client.rs
new file mode 100644
index 00000000..027a3cde
--- /dev/null
+++ b/src/rpc/rpc_client.rs
@@ -0,0 +1,360 @@
+use std::borrow::Borrow;
+use std::marker::PhantomData;
+use std::net::SocketAddr;
+use std::pin::Pin;
+use std::sync::atomic::Ordering;
+use std::sync::Arc;
+use std::time::Duration;
+
+use arc_swap::ArcSwapOption;
+use bytes::IntoBuf;
+use err_derive::Error;
+use futures::future::Future;
+use futures::stream::futures_unordered::FuturesUnordered;
+use futures::stream::StreamExt;
+use futures_util::future::FutureExt;
+use hyper::client::{Client, HttpConnector};
+use hyper::{Body, Method, Request};
+use tokio::sync::{watch, Semaphore};
+
+use crate::background::BackgroundRunner;
+use crate::data::*;
+use crate::error::Error;
+
+use crate::rpc::membership::Status;
+use crate::rpc::rpc_server::RpcMessage;
+use crate::rpc::tls_util;
+
+use crate::config::TlsConfig;
+
+const DEFAULT_TIMEOUT: Duration = Duration::from_secs(10);
+
+#[derive(Debug, Error)]
+pub enum RPCError {
+	#[error(display = "Node is down: {:?}.", _0)]
+	NodeDown(UUID),
+	#[error(display = "Timeout: {}", _0)]
+	Timeout(#[error(source)] tokio::time::Elapsed),
+	#[error(display = "HTTP error: {}", _0)]
+	HTTP(#[error(source)] http::Error),
+	#[error(display = "Hyper error: {}", _0)]
+	Hyper(#[error(source)] hyper::Error),
+	#[error(display = "Messagepack encode error: {}", _0)]
+	RMPEncode(#[error(source)] rmp_serde::encode::Error),
+	#[error(display = "Messagepack decode error: {}", _0)]
+	RMPDecode(#[error(source)] rmp_serde::decode::Error),
+	#[error(display = "Too many errors: {:?}", _0)]
+	TooManyErrors(Vec<String>),
+}
+
+#[derive(Copy, Clone)]
+pub struct RequestStrategy {
+	pub rs_timeout: Duration,
+	pub rs_quorum: usize,
+	pub rs_interrupt_after_quorum: bool,
+}
+
+impl RequestStrategy {
+	pub fn with_quorum(quorum: usize) -> Self {
+		RequestStrategy {
+			rs_timeout: DEFAULT_TIMEOUT,
+			rs_quorum: quorum,
+			rs_interrupt_after_quorum: false,
+		}
+	}
+	pub fn with_timeout(mut self, timeout: Duration) -> Self {
+		self.rs_timeout = timeout;
+		self
+	}
+	pub fn interrupt_after_quorum(mut self, interrupt: bool) -> Self {
+		self.rs_interrupt_after_quorum = interrupt;
+		self
+	}
+}
+
+pub type LocalHandlerFn<M> =
+	Box<dyn Fn(Arc<M>) -> Pin<Box<dyn Future<Output = Result<M, Error>> + Send>> + Send + Sync>;
+
+pub struct RpcClient<M: RpcMessage> {
+	status: watch::Receiver<Arc<Status>>,
+	background: Arc<BackgroundRunner>,
+
+	local_handler: ArcSwapOption<(UUID, LocalHandlerFn<M>)>,
+
+	pub rpc_addr_client: RpcAddrClient<M>,
+}
+
+impl<M: RpcMessage + 'static> RpcClient<M> {
+	pub fn new(
+		rac: RpcAddrClient<M>,
+		background: Arc<BackgroundRunner>,
+		status: watch::Receiver<Arc<Status>>,
+	) -> Arc<Self> {
+		Arc::new(Self {
+			rpc_addr_client: rac,
+			background,
+			status,
+			local_handler: ArcSwapOption::new(None),
+		})
+	}
+
+	pub fn set_local_handler<F, Fut>(&self, my_id: UUID, handler: F)
+	where
+		F: Fn(Arc<M>) -> Fut + Send + Sync + 'static,
+		Fut: Future<Output = Result<M, Error>> + Send + 'static,
+	{
+		let handler_arc = Arc::new(handler);
+		let handler: LocalHandlerFn<M> = Box::new(move |msg| {
+			let handler_arc2 = handler_arc.clone();
+			Box::pin(async move { handler_arc2(msg).await })
+		});
+		self.local_handler.swap(Some(Arc::new((my_id, handler))));
+	}
+
+	pub fn by_addr(&self) -> &RpcAddrClient<M> {
+		&self.rpc_addr_client
+	}
+
+	pub async fn call(&self, to: UUID, msg: M, timeout: Duration) -> Result<M, Error> {
+		self.call_arc(to, Arc::new(msg), timeout).await
+	}
+
+	pub async fn call_arc(&self, to: UUID, msg: Arc<M>, timeout: Duration) -> Result<M, Error> {
+		if let Some(lh) = self.local_handler.load_full() {
+			let (my_id, local_handler) = lh.as_ref();
+			if to.borrow() == my_id {
+				return local_handler(msg).await;
+			}
+		}
+		let status = self.status.borrow().clone();
+		let node_status = match status.nodes.get(&to) {
+			Some(node_status) => {
+				if node_status.is_up() {
+					node_status
+				} else {
+					return Err(Error::from(RPCError::NodeDown(to)));
+				}
+			}
+			None => {
+				return Err(Error::Message(format!(
+					"Peer ID not found: {:?}",
+					to.borrow()
+				)))
+			}
+		};
+		match self
+			.rpc_addr_client
+			.call(&node_status.addr, msg, timeout)
+			.await
+		{
+			Err(rpc_error) => {
+				node_status.num_failures.fetch_add(1, Ordering::SeqCst);
+				// TODO: Save failure info somewhere
+				Err(Error::from(rpc_error))
+			}
+			Ok(x) => x,
+		}
+	}
+
+	pub async fn call_many(&self, to: &[UUID], msg: M, timeout: Duration) -> Vec<Result<M, Error>> {
+		let msg = Arc::new(msg);
+		let mut resp_stream = to
+			.iter()
+			.map(|to| self.call_arc(*to, msg.clone(), timeout))
+			.collect::<FuturesUnordered<_>>();
+
+		let mut results = vec![];
+		while let Some(resp) = resp_stream.next().await {
+			results.push(resp);
+		}
+		results
+	}
+
+	pub async fn try_call_many(
+		self: &Arc<Self>,
+		to: &[UUID],
+		msg: M,
+		strategy: RequestStrategy,
+	) -> Result<Vec<M>, Error> {
+		let timeout = strategy.rs_timeout;
+
+		let msg = Arc::new(msg);
+		let mut resp_stream = to
+			.to_vec()
+			.into_iter()
+			.map(|to| {
+				let self2 = self.clone();
+				let msg = msg.clone();
+				async move { self2.call_arc(to, msg, timeout).await }
+			})
+			.collect::<FuturesUnordered<_>>();
+
+		let mut results = vec![];
+		let mut errors = vec![];
+
+		while let Some(resp) = resp_stream.next().await {
+			match resp {
+				Ok(msg) => {
+					results.push(msg);
+					if results.len() >= strategy.rs_quorum {
+						break;
+					}
+				}
+				Err(e) => {
+					errors.push(e);
+				}
+			}
+		}
+
+		if results.len() >= strategy.rs_quorum {
+			// Continue requests in background.
+			// Continue the remaining requests immediately using tokio::spawn
+			// but enqueue a task in the background runner
+			// to ensure that the process won't exit until the requests are done
+			// (if we had just enqueued the resp_stream.collect directly in the background runner,
+			// the requests might have been put on hold in the background runner's queue,
+			// in which case they might timeout or otherwise fail)
+			if !strategy.rs_interrupt_after_quorum {
+				let wait_finished_fut = tokio::spawn(async move {
+					resp_stream.collect::<Vec<_>>().await;
+					Ok(())
+				});
+				self.background.spawn(wait_finished_fut.map(|x| {
+					x.unwrap_or_else(|e| Err(Error::Message(format!("Await failed: {}", e))))
+				}));
+			}
+
+			Ok(results)
+		} else {
+			let errors = errors.iter().map(|e| format!("{}", e)).collect::<Vec<_>>();
+			Err(Error::from(RPCError::TooManyErrors(errors)))
+		}
+	}
+}
+
+pub struct RpcAddrClient<M: RpcMessage> {
+	phantom: PhantomData<M>,
+
+	pub http_client: Arc<RpcHttpClient>,
+	pub path: String,
+}
+
+impl<M: RpcMessage> RpcAddrClient<M> {
+	pub fn new(http_client: Arc<RpcHttpClient>, path: String) -> Self {
+		Self {
+			phantom: PhantomData::default(),
+			http_client: http_client,
+			path,
+		}
+	}
+
+	pub async fn call<MB>(
+		&self,
+		to_addr: &SocketAddr,
+		msg: MB,
+		timeout: Duration,
+	) -> Result<Result<M, Error>, RPCError>
+	where
+		MB: Borrow<M>,
+	{
+		self.http_client
+			.call(&self.path, to_addr, msg, timeout)
+			.await
+	}
+}
+
+pub struct RpcHttpClient {
+	request_limiter: Semaphore,
+	method: ClientMethod,
+}
+
+enum ClientMethod {
+	HTTP(Client<HttpConnector, hyper::Body>),
+	HTTPS(Client<tls_util::HttpsConnectorFixedDnsname<HttpConnector>, hyper::Body>),
+}
+
+impl RpcHttpClient {
+	pub fn new(
+		max_concurrent_requests: usize,
+		tls_config: &Option<TlsConfig>,
+	) -> Result<Self, Error> {
+		let method = if let Some(cf) = tls_config {
+			let ca_certs = tls_util::load_certs(&cf.ca_cert)?;
+			let node_certs = tls_util::load_certs(&cf.node_cert)?;
+			let node_key = tls_util::load_private_key(&cf.node_key)?;
+
+			let mut config = rustls::ClientConfig::new();
+
+			for crt in ca_certs.iter() {
+				config.root_store.add(crt)?;
+			}
+
+			config.set_single_client_cert([&node_certs[..], &ca_certs[..]].concat(), node_key)?;
+
+			let connector =
+				tls_util::HttpsConnectorFixedDnsname::<HttpConnector>::new(config, "garage");
+
+			ClientMethod::HTTPS(Client::builder().build(connector))
+		} else {
+			ClientMethod::HTTP(Client::new())
+		};
+		Ok(RpcHttpClient {
+			method,
+			request_limiter: Semaphore::new(max_concurrent_requests),
+		})
+	}
+
+	async fn call<M, MB>(
+		&self,
+		path: &str,
+		to_addr: &SocketAddr,
+		msg: MB,
+		timeout: Duration,
+	) -> Result<Result<M, Error>, RPCError>
+	where
+		MB: Borrow<M>,
+		M: RpcMessage,
+	{
+		let uri = match self.method {
+			ClientMethod::HTTP(_) => format!("http://{}/{}", to_addr, path),
+			ClientMethod::HTTPS(_) => format!("https://{}/{}", to_addr, path),
+		};
+
+		let req = Request::builder()
+			.method(Method::POST)
+			.uri(uri)
+			.body(Body::from(rmp_to_vec_all_named(msg.borrow())?))?;
+
+		let resp_fut = match &self.method {
+			ClientMethod::HTTP(client) => client.request(req).fuse(),
+			ClientMethod::HTTPS(client) => client.request(req).fuse(),
+		};
+
+		let slot = self.request_limiter.acquire().await;
+		let resp = tokio::time::timeout(timeout, resp_fut)
+			.await
+			.map_err(|e| {
+				debug!(
+					"RPC timeout to {}: {}",
+					to_addr,
+					debug_serialize(msg.borrow())
+				);
+				e
+			})?
+			.map_err(|e| {
+				warn!(
+					"RPC HTTP client error when connecting to {}: {}",
+					to_addr, e
+				);
+				e
+			})?;
+		drop(slot);
+
+		let status = resp.status();
+		let body = hyper::body::to_bytes(resp.into_body()).await?;
+		match rmp_serde::decode::from_read::<_, Result<M, String>>(body.into_buf())? {
+			Err(e) => Ok(Err(Error::RemoteError(e, status))),
+			Ok(x) => Ok(Ok(x)),
+		}
+	}
+}
diff --git a/src/rpc/rpc_server.rs b/src/rpc/rpc_server.rs
new file mode 100644
index 00000000..4ee53909
--- /dev/null
+++ b/src/rpc/rpc_server.rs
@@ -0,0 +1,219 @@
+use std::collections::HashMap;
+use std::net::SocketAddr;
+use std::pin::Pin;
+use std::sync::Arc;
+use std::time::Instant;
+
+use bytes::IntoBuf;
+use futures::future::Future;
+use futures_util::future::*;
+use futures_util::stream::*;
+use hyper::server::conn::AddrStream;
+use hyper::service::{make_service_fn, service_fn};
+use hyper::{Body, Method, Request, Response, Server, StatusCode};
+use serde::{Deserialize, Serialize};
+use tokio::net::{TcpListener, TcpStream};
+use tokio_rustls::server::TlsStream;
+use tokio_rustls::TlsAcceptor;
+
+use crate::config::TlsConfig;
+use crate::data::*;
+use crate::error::Error;
+
+use crate::rpc::tls_util;
+
+pub trait RpcMessage: Serialize + for<'de> Deserialize<'de> + Send + Sync {}
+
+type ResponseFuture = Pin<Box<dyn Future<Output = Result<Response<Body>, Error>> + Send>>;
+type Handler = Box<dyn Fn(Request<Body>, SocketAddr) -> ResponseFuture + Send + Sync>;
+
+pub struct RpcServer {
+	pub bind_addr: SocketAddr,
+	pub tls_config: Option<TlsConfig>,
+
+	handlers: HashMap<String, Handler>,
+}
+
+async fn handle_func<M, F, Fut>(
+	handler: Arc<F>,
+	req: Request<Body>,
+	sockaddr: SocketAddr,
+	name: Arc<String>,
+) -> Result<Response<Body>, Error>
+where
+	M: RpcMessage + 'static,
+	F: Fn(M, SocketAddr) -> Fut + Send + Sync + 'static,
+	Fut: Future<Output = Result<M, Error>> + Send + 'static,
+{
+	let begin_time = Instant::now();
+	let whole_body = hyper::body::to_bytes(req.into_body()).await?;
+	let msg = rmp_serde::decode::from_read::<_, M>(whole_body.into_buf())?;
+	match handler(msg, sockaddr).await {
+		Ok(resp) => {
+			let resp_bytes = rmp_to_vec_all_named::<Result<M, String>>(&Ok(resp))?;
+			let rpc_duration = (Instant::now() - begin_time).as_millis();
+			if rpc_duration > 100 {
+				debug!("RPC {} ok, took long: {} ms", name, rpc_duration,);
+			}
+			Ok(Response::new(Body::from(resp_bytes)))
+		}
+		Err(e) => {
+			let err_str = format!("{}", e);
+			let rep_bytes = rmp_to_vec_all_named::<Result<M, String>>(&Err(err_str))?;
+			let mut err_response = Response::new(Body::from(rep_bytes));
+			*err_response.status_mut() = e.http_status_code();
+			warn!(
+				"RPC error ({}): {} ({} ms)",
+				name,
+				e,
+				(Instant::now() - begin_time).as_millis(),
+			);
+			Ok(err_response)
+		}
+	}
+}
+
+impl RpcServer {
+	pub fn new(bind_addr: SocketAddr, tls_config: Option<TlsConfig>) -> Self {
+		Self {
+			bind_addr,
+			tls_config,
+			handlers: HashMap::new(),
+		}
+	}
+
+	pub fn add_handler<M, F, Fut>(&mut self, name: String, handler: F)
+	where
+		M: RpcMessage + 'static,
+		F: Fn(M, SocketAddr) -> Fut + Send + Sync + 'static,
+		Fut: Future<Output = Result<M, Error>> + Send + 'static,
+	{
+		let name2 = Arc::new(name.clone());
+		let handler_arc = Arc::new(handler);
+		let handler = Box::new(move |req: Request<Body>, sockaddr: SocketAddr| {
+			let handler2 = handler_arc.clone();
+			let b: ResponseFuture = Box::pin(handle_func(handler2, req, sockaddr, name2.clone()));
+			b
+		});
+		self.handlers.insert(name, handler);
+	}
+
+	async fn handler(
+		self: Arc<Self>,
+		req: Request<Body>,
+		addr: SocketAddr,
+	) -> Result<Response<Body>, Error> {
+		if req.method() != &Method::POST {
+			let mut bad_request = Response::default();
+			*bad_request.status_mut() = StatusCode::BAD_REQUEST;
+			return Ok(bad_request);
+		}
+
+		let path = &req.uri().path()[1..];
+		let handler = match self.handlers.get(path) {
+			Some(h) => h,
+			None => {
+				let mut not_found = Response::default();
+				*not_found.status_mut() = StatusCode::NOT_FOUND;
+				return Ok(not_found);
+			}
+		};
+
+		let resp_waiter = tokio::spawn(handler(req, addr));
+		match resp_waiter.await {
+			Err(err) => {
+				warn!("Handler await error: {}", err);
+				let mut ise = Response::default();
+				*ise.status_mut() = StatusCode::INTERNAL_SERVER_ERROR;
+				Ok(ise)
+			}
+			Ok(Err(err)) => {
+				let mut bad_request = Response::new(Body::from(format!("{}", err)));
+				*bad_request.status_mut() = StatusCode::BAD_REQUEST;
+				Ok(bad_request)
+			}
+			Ok(Ok(resp)) => Ok(resp),
+		}
+	}
+
+	pub async fn run(
+		self: Arc<Self>,
+		shutdown_signal: impl Future<Output = ()>,
+	) -> Result<(), Error> {
+		if let Some(tls_config) = self.tls_config.as_ref() {
+			let ca_certs = tls_util::load_certs(&tls_config.ca_cert)?;
+			let node_certs = tls_util::load_certs(&tls_config.node_cert)?;
+			let node_key = tls_util::load_private_key(&tls_config.node_key)?;
+
+			let mut ca_store = rustls::RootCertStore::empty();
+			for crt in ca_certs.iter() {
+				ca_store.add(crt)?;
+			}
+
+			let mut config =
+				rustls::ServerConfig::new(rustls::AllowAnyAuthenticatedClient::new(ca_store));
+			config.set_single_cert([&node_certs[..], &ca_certs[..]].concat(), node_key)?;
+			let tls_acceptor = Arc::new(TlsAcceptor::from(Arc::new(config)));
+
+			let mut listener = TcpListener::bind(&self.bind_addr).await?;
+			let incoming = listener.incoming().filter_map(|socket| async {
+				match socket {
+					Ok(stream) => match tls_acceptor.clone().accept(stream).await {
+						Ok(x) => Some(Ok::<_, hyper::Error>(x)),
+						Err(_e) => None,
+					},
+					Err(_) => None,
+				}
+			});
+			let incoming = hyper::server::accept::from_stream(incoming);
+
+			let self_arc = self.clone();
+			let service = make_service_fn(|conn: &TlsStream<TcpStream>| {
+				let client_addr = conn
+					.get_ref()
+					.0
+					.peer_addr()
+					.unwrap_or(([0, 0, 0, 0], 0).into());
+				let self_arc = self_arc.clone();
+				async move {
+					Ok::<_, Error>(service_fn(move |req: Request<Body>| {
+						self_arc.clone().handler(req, client_addr).map_err(|e| {
+							warn!("RPC handler error: {}", e);
+							e
+						})
+					}))
+				}
+			});
+
+			let server = Server::builder(incoming).serve(service);
+
+			let graceful = server.with_graceful_shutdown(shutdown_signal);
+			info!("RPC server listening on http://{}", self.bind_addr);
+
+			graceful.await?;
+		} else {
+			let self_arc = self.clone();
+			let service = make_service_fn(move |conn: &AddrStream| {
+				let client_addr = conn.remote_addr();
+				let self_arc = self_arc.clone();
+				async move {
+					Ok::<_, Error>(service_fn(move |req: Request<Body>| {
+						self_arc.clone().handler(req, client_addr).map_err(|e| {
+							warn!("RPC handler error: {}", e);
+							e
+						})
+					}))
+				}
+			});
+
+			let server = Server::bind(&self.bind_addr).serve(service);
+
+			let graceful = server.with_graceful_shutdown(shutdown_signal);
+			info!("RPC server listening on http://{}", self.bind_addr);
+
+			graceful.await?;
+		}
+
+		Ok(())
+	}
+}
diff --git a/src/rpc/tls_util.rs b/src/rpc/tls_util.rs
new file mode 100644
index 00000000..52c52110
--- /dev/null
+++ b/src/rpc/tls_util.rs
@@ -0,0 +1,139 @@
+use core::future::Future;
+use core::task::{Context, Poll};
+use std::pin::Pin;
+use std::sync::Arc;
+use std::{fs, io};
+
+use futures_util::future::*;
+use hyper::client::connect::Connection;
+use hyper::client::HttpConnector;
+use hyper::service::Service;
+use hyper::Uri;
+use hyper_rustls::MaybeHttpsStream;
+use rustls::internal::pemfile;
+use tokio::io::{AsyncRead, AsyncWrite};
+use tokio_rustls::TlsConnector;
+use webpki::DNSNameRef;
+
+use crate::error::Error;
+
+pub fn load_certs(filename: &str) -> Result<Vec<rustls::Certificate>, Error> {
+	let certfile = fs::File::open(&filename)?;
+	let mut reader = io::BufReader::new(certfile);
+
+	let certs = pemfile::certs(&mut reader).map_err(|_| {
+		Error::Message(format!(
+			"Could not deecode certificates from file: {}",
+			filename
+		))
+	})?;
+
+	if certs.is_empty() {
+		return Err(Error::Message(format!(
+			"Invalid certificate file: {}",
+			filename
+		)));
+	}
+	Ok(certs)
+}
+
+pub fn load_private_key(filename: &str) -> Result<rustls::PrivateKey, Error> {
+	let keyfile = fs::File::open(&filename)?;
+	let mut reader = io::BufReader::new(keyfile);
+
+	let keys = pemfile::rsa_private_keys(&mut reader).map_err(|_| {
+		Error::Message(format!(
+			"Could not decode private key from file: {}",
+			filename
+		))
+	})?;
+
+	if keys.len() != 1 {
+		return Err(Error::Message(format!(
+			"Invalid private key file: {} ({} private keys)",
+			filename,
+			keys.len()
+		)));
+	}
+	Ok(keys[0].clone())
+}
+
+// ---- AWFUL COPYPASTA FROM HYPER-RUSTLS connector.rs
+// ---- ALWAYS USE `garage` AS HOSTNAME FOR TLS VERIFICATION
+
+#[derive(Clone)]
+pub struct HttpsConnectorFixedDnsname<T> {
+	http: T,
+	tls_config: Arc<rustls::ClientConfig>,
+	fixed_dnsname: &'static str,
+}
+
+type BoxError = Box<dyn std::error::Error + Send + Sync>;
+
+impl HttpsConnectorFixedDnsname<HttpConnector> {
+	pub fn new(mut tls_config: rustls::ClientConfig, fixed_dnsname: &'static str) -> Self {
+		let mut http = HttpConnector::new();
+		http.enforce_http(false);
+		tls_config.alpn_protocols = vec![b"h2".to_vec(), b"http/1.1".to_vec()];
+		Self {
+			http,
+			tls_config: Arc::new(tls_config),
+			fixed_dnsname,
+		}
+	}
+}
+
+impl<T> Service<Uri> for HttpsConnectorFixedDnsname<T>
+where
+	T: Service<Uri>,
+	T::Response: Connection + AsyncRead + AsyncWrite + Send + Unpin + 'static,
+	T::Future: Send + 'static,
+	T::Error: Into<BoxError>,
+{
+	type Response = MaybeHttpsStream<T::Response>;
+	type Error = BoxError;
+
+	#[allow(clippy::type_complexity)]
+	type Future =
+		Pin<Box<dyn Future<Output = Result<MaybeHttpsStream<T::Response>, BoxError>> + Send>>;
+
+	fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+		match self.http.poll_ready(cx) {
+			Poll::Ready(Ok(())) => Poll::Ready(Ok(())),
+			Poll::Ready(Err(e)) => Poll::Ready(Err(e.into())),
+			Poll::Pending => Poll::Pending,
+		}
+	}
+
+	fn call(&mut self, dst: Uri) -> Self::Future {
+		let is_https = dst.scheme_str() == Some("https");
+
+		if !is_https {
+			let connecting_future = self.http.call(dst);
+
+			let f = async move {
+				let tcp = connecting_future.await.map_err(Into::into)?;
+
+				Ok(MaybeHttpsStream::Http(tcp))
+			};
+			f.boxed()
+		} else {
+			let cfg = self.tls_config.clone();
+			let connecting_future = self.http.call(dst);
+
+			let dnsname =
+				DNSNameRef::try_from_ascii_str(self.fixed_dnsname).expect("Invalid fixed dnsname");
+
+			let f = async move {
+				let tcp = connecting_future.await.map_err(Into::into)?;
+				let connector = TlsConnector::from(cfg);
+				let tls = connector
+					.connect(dnsname, tcp)
+					.await
+					.map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
+				Ok(MaybeHttpsStream::Https(tls))
+			};
+			f.boxed()
+		}
+	}
+}