garage/src/membership.rs

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use std::sync::Arc;
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use std::hash::Hash as StdHash;
use std::hash::Hasher;
use std::path::PathBuf;
use std::io::{Read};
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use std::collections::HashMap;
use std::time::Duration;
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use std::net::{IpAddr, SocketAddr};
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use sha2::{Sha256, Digest};
use tokio::prelude::*;
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use futures::future::join_all;
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use tokio::sync::RwLock;
use crate::server::Config;
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use crate::error::Error;
use crate::data::*;
use crate::proto::*;
use crate::rpc_client::*;
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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,
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pub members: RwLock<Members>,
}
pub struct Members {
pub status: HashMap<UUID, NodeStatus>,
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pub status_hash: Hash,
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pub config: NetworkConfig,
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pub ring: Vec<RingEntry>,
pub n_datacenters: usize,
}
pub struct NodeStatus {
pub addr: SocketAddr,
pub remaining_ping_attempts: usize,
}
pub struct RingEntry {
pub location: Hash,
pub node: UUID,
pub datacenter: u64,
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}
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impl Members {
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fn handle_ping(&mut self, ip: IpAddr, info: &PingMessage) -> bool {
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let addr = SocketAddr::new(ip, info.rpc_port);
let old_status = self.status.insert(info.id.clone(),
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NodeStatus{
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addr: addr.clone(),
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remaining_ping_attempts: MAX_FAILED_PINGS,
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});
match old_status {
None => {
eprintln!("Newly pingable node: {}", hex::encode(&info.id));
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true
}
Some(x) => x.addr != addr,
}
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}
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fn recalculate_status_hash(&mut self) {
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let mut nodes = self.status.iter().collect::<Vec<_>>();
nodes.sort_unstable_by_key(|(id, _status)| *id);
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let mut hasher = Sha256::new();
eprintln!("Current set of pingable nodes: --");
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for (id, status) in nodes {
eprintln!("{} {}", hex::encode(&id), status.addr);
hasher.input(format!("{} {}\n", hex::encode(&id), status.addr));
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}
eprintln!("END --");
self.status_hash.as_slice_mut().copy_from_slice(&hasher.result()[..]);
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}
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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());
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new_ring.push(RingEntry{
location: location.into(),
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node: id.clone(),
datacenter,
})
}
}
new_ring.sort_unstable_by(|x, y| x.location.cmp(&y.location));
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self.ring = new_ring;
self.n_datacenters = datacenters.len();
}
pub fn walk_ring(&self, from: &Hash, n: usize) -> Vec<UUID> {
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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)) {
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Ok(i) => i,
Err(i) => if i == 0 {
self.ring.len() - 1
} else {
i - 1
}
};
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
}
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}
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)
.expect("Failure when reading network_config");
let net_config = rmp_serde::decode::from_read_ref(&net_config_bytes[..])
.expect("Invalid or corrupt network_config file");
Ok(net_config)
}
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impl System {
pub fn new(config: Config, id: UUID) -> Self {
let net_config = match read_network_config(&config.metadata_dir) {
Ok(x) => x,
Err(_) => NetworkConfig{
members: HashMap::new(),
version: 0,
},
};
let mut members = Members{
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status: HashMap::new(),
status_hash: Hash::default(),
config: net_config,
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ring: Vec::new(),
n_datacenters: 0,
};
members.recalculate_status_hash();
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members.rebuild_ring();
System{
config,
id,
rpc_client: RpcClient::new(),
members: RwLock::new(members),
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}
}
async fn save_network_config(self: Arc<Self>) {
let mut path = self.config.metadata_dir.clone();
path.push("network_config");
let members = self.members.read().await;
let data = rmp_serde::encode::to_vec_named(&members.config)
.expect("Error while encoding network config");
drop(members);
let mut f = tokio::fs::File::create(path.as_path()).await
.expect("Could not create network_config");
f.write_all(&data[..]).await
.expect("Could not write network_config");
}
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pub async fn make_ping(&self) -> Message {
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let members = self.members.read().await;
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Message::Ping(PingMessage{
id: self.id.clone(),
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rpc_port: self.config.rpc_port,
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status_hash: members.status_hash.clone(),
config_version: members.config.version,
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})
}
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pub async fn broadcast(self: Arc<Self>, msg: Message, timeout: Duration) {
let members = self.members.read().await;
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let to = members.status.keys().filter(|x| **x != self.id).cloned().collect::<Vec<_>>();
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drop(members);
rpc_call_many(self.clone(), &to[..], &msg, timeout).await;
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}
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pub async fn bootstrap(self: Arc<Self>) {
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let bootstrap_peers = self.config.bootstrap_peers
.iter()
.map(|ip| (ip.clone(), None))
.collect::<Vec<_>>();
self.clone().ping_nodes(bootstrap_peers).await;
tokio::spawn(self.ping_loop());
}
pub async fn ping_nodes(self: Arc<Self>, peers: Vec<(SocketAddr, Option<UUID>)>) {
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let ping_msg = self.make_ping().await;
let ping_resps = join_all(
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peers.iter()
.map(|(addr, id_option)| {
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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)
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}
})).await;
let mut members = self.members.write().await;
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let mut has_changes = false;
let mut to_advertise = vec![];
for (id_option, addr, ping_resp) in ping_resps {
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if let Ok(Message::Ping(info)) = ping_resp {
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let is_new = members.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 || members.status_hash != info.status_hash {
tokio::spawn(self.clone().pull_status(info.id.clone()));
}
if is_new || members.config.version < info.config_version {
tokio::spawn(self.clone().pull_config(info.id.clone()));
}
} else if let Some(id) = id_option {
let remaining_attempts = members.status.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));
members.status.remove(&id);
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has_changes = true;
} else {
if let Some(st) = members.status.get_mut(id) {
st.remaining_ping_attempts = remaining_attempts - 1;
}
}
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}
}
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if has_changes {
members.recalculate_status_hash();
}
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drop(members);
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if to_advertise.len() > 0 {
self.broadcast(Message::AdvertiseNodesUp(to_advertise), PING_TIMEOUT).await;
}
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}
pub async fn handle_ping(self: Arc<Self>,
from: &SocketAddr,
ping: &PingMessage)
-> Result<Message, Error>
{
let mut members = self.members.write().await;
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let is_new = members.handle_ping(from.ip(), ping);
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if is_new {
members.recalculate_status_hash();
}
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let status_hash = members.status_hash.clone();
let config_version = members.config.version;
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drop(members);
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if is_new || status_hash != ping.status_hash {
tokio::spawn(self.clone().pull_status(ping.id.clone()));
}
if is_new || config_version < ping.config_version {
tokio::spawn(self.clone().pull_config(ping.id.clone()));
}
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Ok(self.make_ping().await)
}
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pub async fn handle_pull_status(&self) -> Result<Message, Error> {
let members = self.members.read().await;
let mut mem = vec![];
for (node, status) in members.status.iter() {
mem.push(AdvertisedNode{
id: node.clone(),
addr: status.addr.clone(),
});
}
Ok(Message::AdvertiseNodesUp(mem))
}
pub async fn handle_pull_config(&self) -> Result<Message, Error> {
let members = self.members.read().await;
Ok(Message::AdvertiseConfig(members.config.clone()))
}
pub async fn handle_advertise_nodes_up(self: Arc<Self>,
adv: &[AdvertisedNode])
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-> Result<Message, Error>
{
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let mut to_ping = vec![];
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let mut members = self.members.write().await;
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let mut has_changed = false;
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for node in adv.iter() {
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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 = members.status.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 !members.status.contains_key(&node.id) {
to_ping.push((node.addr.clone(), Some(node.id.clone())));
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}
}
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if has_changed {
members.recalculate_status_hash();
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}
drop(members);
if to_ping.len() > 0 {
tokio::spawn(self.clone().ping_nodes(to_ping));
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}
Ok(Message::Ok)
}
pub async fn handle_advertise_config(self: Arc<Self>,
adv: &NetworkConfig)
-> Result<Message, Error>
{
let mut members = self.members.write().await;
if adv.version > members.config.version {
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members.config = adv.clone();
members.rebuild_ring();
tokio::spawn(self.clone().broadcast(Message::AdvertiseConfig(adv.clone()), PING_TIMEOUT));
tokio::spawn(self.clone().save_network_config());
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}
Ok(Message::Ok)
}
pub async fn ping_loop(self: Arc<Self>) {
loop {
let restart_at = tokio::time::delay_for(PING_INTERVAL);
let members = self.members.read().await;
let ping_addrs = members.status.iter()
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.filter(|(id, _)| **id != self.id)
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.map(|(id, status)| (status.addr.clone(), Some(id.clone())))
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.collect::<Vec<_>>();
drop(members);
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self.clone().ping_nodes(ping_addrs).await;
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restart_at.await
}
}
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pub fn pull_status(self: Arc<Self>, peer: UUID) -> impl futures::future::Future<Output=()> + 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;
}
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}
}
pub async fn pull_config(self: Arc<Self>, peer: UUID) {
let resp = rpc_call(self.clone(),
&peer,
&Message::PullConfig,
PING_TIMEOUT).await;
if let Ok(Message::AdvertiseConfig(config)) = resp {
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let _: Result<_, _> = self.handle_advertise_config(&config).await;
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}
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}
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}