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|
use std::collections::HashMap;
use serde::{Deserialize, Serialize};
use garage_util::data::*;
#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct NetworkConfig {
pub members: HashMap<UUID, NetworkConfigEntry>,
pub version: u64,
}
impl NetworkConfig {
pub(crate) fn new() -> Self {
Self{
members: HashMap::new(),
version: 0,
}
}
}
#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct NetworkConfigEntry {
pub datacenter: String,
pub n_tokens: u32,
pub tag: 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,
datacenter: usize,
}
impl Ring {
pub(crate) fn rebuild_ring(&mut self) {
let mut new_ring = vec![];
let mut datacenters = vec![];
for (id, config) in self.config.members.iter() {
let datacenter = &config.datacenter;
if !datacenters.contains(datacenter) {
datacenters.push(datacenter.to_string());
}
let datacenter_idx = datacenters.iter().enumerate().find(|(_, dc)| *dc == datacenter).unwrap().0;
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: datacenter_idx,
})
}
}
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
}
}
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