garage/src/table.rs

501 lines
13 KiB
Rust

use std::collections::{BTreeMap, HashMap};
use std::sync::Arc;
use std::time::Duration;
use arc_swap::ArcSwapOption;
use async_trait::async_trait;
use futures::stream::*;
use serde::{Deserialize, Serialize};
use serde_bytes::ByteBuf;
use crate::data::*;
use crate::error::Error;
use crate::membership::{Ring, System};
use crate::rpc_client::*;
use crate::rpc_server::*;
use crate::table_sync::*;
const TABLE_RPC_TIMEOUT: Duration = Duration::from_secs(10);
pub struct Table<F: TableSchema, R: TableReplication> {
pub instance: F,
pub replication: R,
pub name: String,
pub rpc_client: Arc<RpcClient<TableRPC<F>>>,
pub system: Arc<System>,
pub store: sled::Tree,
pub syncer: ArcSwapOption<TableSyncer<F, R>>,
}
#[derive(Serialize, Deserialize)]
pub enum TableRPC<F: TableSchema> {
Ok,
ReadEntry(F::P, F::S),
ReadEntryResponse(Option<ByteBuf>),
ReadRange(F::P, F::S, Option<F::Filter>, usize),
Update(Vec<Arc<ByteBuf>>),
SyncRPC(SyncRPC),
}
impl<F: TableSchema> RpcMessage for TableRPC<F> {}
pub trait PartitionKey {
fn hash(&self) -> Hash;
}
pub trait SortKey {
fn sort_key(&self) -> &[u8];
}
pub trait Entry<P: PartitionKey, S: SortKey>:
PartialEq + Clone + Serialize + for<'de> Deserialize<'de> + Send + Sync
{
fn partition_key(&self) -> &P;
fn sort_key(&self) -> &S;
fn merge(&mut self, other: &Self);
}
#[derive(Clone, Serialize, Deserialize)]
pub struct EmptySortKey;
impl SortKey for EmptySortKey {
fn sort_key(&self) -> &[u8] {
&[]
}
}
impl<T: AsRef<str>> PartitionKey for T {
fn hash(&self) -> Hash {
hash(self.as_ref().as_bytes())
}
}
impl<T: AsRef<str>> SortKey for T {
fn sort_key(&self) -> &[u8] {
self.as_ref().as_bytes()
}
}
impl PartitionKey for Hash {
fn hash(&self) -> Hash {
self.clone()
}
}
impl SortKey for Hash {
fn sort_key(&self) -> &[u8] {
self.as_slice()
}
}
#[async_trait]
pub trait TableSchema: Send + Sync {
type P: PartitionKey + Clone + PartialEq + Serialize + for<'de> Deserialize<'de> + Send + Sync;
type S: SortKey + Clone + Serialize + for<'de> Deserialize<'de> + Send + Sync;
type E: Entry<Self::P, Self::S>;
type Filter: Clone + Serialize + for<'de> Deserialize<'de> + Send + Sync;
async fn updated(&self, old: Option<Self::E>, new: Option<Self::E>);
fn matches_filter(_entry: &Self::E, _filter: &Self::Filter) -> bool {
true
}
}
pub trait TableReplication: Send + Sync {
// See examples in table_sharded.rs and table_fullcopy.rs
// To understand various replication methods
// Which nodes to send reads from
fn read_nodes(&self, hash: &Hash, system: &System) -> Vec<UUID>;
fn read_quorum(&self) -> usize;
// Which nodes to send writes to
fn write_nodes(&self, hash: &Hash, system: &System) -> Vec<UUID>;
fn write_quorum(&self) -> usize;
fn max_write_errors(&self) -> usize;
fn epidemic_writes(&self) -> bool;
// Which are the nodes that do actually replicate the data
fn replication_nodes(&self, hash: &Hash, ring: &Ring) -> Vec<UUID>;
fn split_points(&self, ring: &Ring) -> Vec<Hash>;
}
impl<F, R> Table<F, R>
where
F: TableSchema + 'static,
R: TableReplication + 'static,
{
// =============== PUBLIC INTERFACE FUNCTIONS (new, insert, get, etc) ===============
pub async fn new(
instance: F,
replication: R,
system: Arc<System>,
db: &sled::Db,
name: String,
rpc_server: &mut RpcServer,
) -> Arc<Self> {
let store = db.open_tree(&name).expect("Unable to open DB tree");
let rpc_path = format!("table_{}", name);
let rpc_client = system.rpc_client::<TableRPC<F>>(&rpc_path);
let table = Arc::new(Self {
instance,
replication,
name,
rpc_client,
system,
store,
syncer: ArcSwapOption::from(None),
});
table.clone().register_handler(rpc_server, rpc_path);
let syncer = TableSyncer::launch(table.clone()).await;
table.syncer.swap(Some(syncer));
table
}
pub async fn insert(&self, e: &F::E) -> Result<(), Error> {
let hash = e.partition_key().hash();
let who = self.replication.write_nodes(&hash, &self.system);
//eprintln!("insert who: {:?}", who);
let e_enc = Arc::new(ByteBuf::from(rmp_to_vec_all_named(e)?));
let rpc = TableRPC::<F>::Update(vec![e_enc]);
self.rpc_client
.try_call_many(
&who[..],
rpc,
self.replication.write_quorum(),
TABLE_RPC_TIMEOUT,
)
.await?;
Ok(())
}
pub async fn insert_many(&self, entries: &[F::E]) -> Result<(), Error> {
let mut call_list = HashMap::new();
for entry in entries.iter() {
let hash = entry.partition_key().hash();
let who = self.replication.write_nodes(&hash, &self.system);
let e_enc = Arc::new(ByteBuf::from(rmp_to_vec_all_named(entry)?));
for node in who {
if !call_list.contains_key(&node) {
call_list.insert(node.clone(), vec![]);
}
call_list.get_mut(&node).unwrap().push(e_enc.clone());
}
}
let call_futures = call_list.drain().map(|(node, entries)| async move {
let rpc = TableRPC::<F>::Update(entries);
let resp = self.rpc_client.call(&node, rpc, TABLE_RPC_TIMEOUT).await?;
Ok::<_, Error>((node, resp))
});
let mut resps = call_futures.collect::<FuturesUnordered<_>>();
let mut errors = vec![];
while let Some(resp) = resps.next().await {
if let Err(e) = resp {
errors.push(e);
}
}
if errors.len() > self.replication.max_write_errors() {
Err(Error::Message("Too many errors".into()))
} else {
Ok(())
}
}
pub async fn get(
self: &Arc<Self>,
partition_key: &F::P,
sort_key: &F::S,
) -> Result<Option<F::E>, Error> {
let hash = partition_key.hash();
let who = self.replication.read_nodes(&hash, &self.system);
//eprintln!("get who: {:?}", who);
let rpc = TableRPC::<F>::ReadEntry(partition_key.clone(), sort_key.clone());
let resps = self
.rpc_client
.try_call_many(
&who[..],
rpc,
self.replication.read_quorum(),
TABLE_RPC_TIMEOUT,
)
.await?;
let mut ret = None;
let mut not_all_same = false;
for resp in resps {
if let TableRPC::ReadEntryResponse(value) = resp {
if let Some(v_bytes) = value {
let v = rmp_serde::decode::from_read_ref::<_, F::E>(v_bytes.as_slice())?;
ret = match ret {
None => Some(v),
Some(mut x) => {
if x != v {
not_all_same = true;
x.merge(&v);
}
Some(x)
}
}
}
} else {
return Err(Error::Message(format!("Invalid return value to read")));
}
}
if let Some(ret_entry) = &ret {
if not_all_same {
let self2 = self.clone();
let ent2 = ret_entry.clone();
self.system
.background
.spawn(async move { self2.repair_on_read(&who[..], ent2).await });
}
}
Ok(ret)
}
pub async fn get_range(
self: &Arc<Self>,
partition_key: &F::P,
begin_sort_key: &F::S,
filter: Option<F::Filter>,
limit: usize,
) -> Result<Vec<F::E>, Error> {
let hash = partition_key.hash();
let who = self.replication.read_nodes(&hash, &self.system);
let rpc =
TableRPC::<F>::ReadRange(partition_key.clone(), begin_sort_key.clone(), filter, limit);
let resps = self
.rpc_client
.try_call_many(
&who[..],
rpc,
self.replication.read_quorum(),
TABLE_RPC_TIMEOUT,
)
.await?;
let mut ret = BTreeMap::new();
let mut to_repair = BTreeMap::new();
for resp in resps {
if let TableRPC::Update(entries) = resp {
for entry_bytes in entries.iter() {
let entry =
rmp_serde::decode::from_read_ref::<_, F::E>(entry_bytes.as_slice())?;
let entry_key = self.tree_key(entry.partition_key(), entry.sort_key());
match ret.remove(&entry_key) {
None => {
ret.insert(entry_key, Some(entry));
}
Some(Some(mut prev)) => {
let must_repair = prev != entry;
prev.merge(&entry);
if must_repair {
to_repair.insert(entry_key.clone(), Some(prev.clone()));
}
ret.insert(entry_key, Some(prev));
}
Some(None) => unreachable!(),
}
}
}
}
if !to_repair.is_empty() {
let self2 = self.clone();
self.system.background.spawn(async move {
for (_, v) in to_repair.iter_mut() {
self2.repair_on_read(&who[..], v.take().unwrap()).await?;
}
Ok(())
});
}
let ret_vec = ret
.iter_mut()
.take(limit)
.map(|(_k, v)| v.take().unwrap())
.collect::<Vec<_>>();
Ok(ret_vec)
}
// =============== UTILITY FUNCTION FOR CLIENT OPERATIONS ===============
async fn repair_on_read(&self, who: &[UUID], what: F::E) -> Result<(), Error> {
let what_enc = Arc::new(ByteBuf::from(rmp_to_vec_all_named(&what)?));
self.rpc_client
.try_call_many(
&who[..],
TableRPC::<F>::Update(vec![what_enc]),
who.len(),
TABLE_RPC_TIMEOUT,
)
.await?;
Ok(())
}
// =============== HANDLERS FOR RPC OPERATIONS (SERVER SIDE) ==============
fn register_handler(self: Arc<Self>, rpc_server: &mut RpcServer, path: String) {
rpc_server.add_handler::<TableRPC<F>, _, _>(path, move |msg, _addr| {
let self2 = self.clone();
async move { self2.handle(msg).await }
})
}
async fn handle(self: &Arc<Self>, msg: TableRPC<F>) -> Result<TableRPC<F>, Error> {
match msg {
TableRPC::ReadEntry(key, sort_key) => {
let value = self.handle_read_entry(&key, &sort_key)?;
Ok(TableRPC::ReadEntryResponse(value))
}
TableRPC::ReadRange(key, begin_sort_key, filter, limit) => {
let values = self.handle_read_range(&key, &begin_sort_key, &filter, limit)?;
Ok(TableRPC::Update(values))
}
TableRPC::Update(pairs) => {
self.handle_update(pairs).await?;
Ok(TableRPC::Ok)
}
TableRPC::SyncRPC(rpc) => {
let syncer = self.syncer.load_full().unwrap();
let response = syncer
.handle_rpc(&rpc, self.system.background.stop_signal.clone())
.await?;
Ok(TableRPC::SyncRPC(response))
}
_ => Err(Error::RPCError(format!("Unexpected table RPC"))),
}
}
fn handle_read_entry(&self, p: &F::P, s: &F::S) -> Result<Option<ByteBuf>, Error> {
let tree_key = self.tree_key(p, s);
if let Some(bytes) = self.store.get(&tree_key)? {
Ok(Some(ByteBuf::from(bytes.to_vec())))
} else {
Ok(None)
}
}
fn handle_read_range(
&self,
p: &F::P,
s: &F::S,
filter: &Option<F::Filter>,
limit: usize,
) -> Result<Vec<Arc<ByteBuf>>, Error> {
let partition_hash = p.hash();
let first_key = self.tree_key(p, s);
let mut ret = vec![];
for item in self.store.range(first_key..) {
let (key, value) = item?;
if &key[..32] != partition_hash.as_slice() {
break;
}
let keep = match filter {
None => true,
Some(f) => {
let entry = rmp_serde::decode::from_read_ref::<_, F::E>(value.as_ref())?;
F::matches_filter(&entry, f)
}
};
if keep {
ret.push(Arc::new(ByteBuf::from(value.as_ref())));
}
if ret.len() >= limit {
break;
}
}
Ok(ret)
}
pub async fn handle_update(
self: &Arc<Self>,
mut entries: Vec<Arc<ByteBuf>>,
) -> Result<(), Error> {
let mut epidemic_propagate = vec![];
for update_bytes in entries.drain(..) {
let update = rmp_serde::decode::from_read_ref::<_, F::E>(update_bytes.as_slice())?;
let tree_key = self.tree_key(update.partition_key(), update.sort_key());
let (old_entry, new_entry) = self.store.transaction(|db| {
let (old_entry, new_entry) = match db.get(&tree_key)? {
Some(prev_bytes) => {
let old_entry = rmp_serde::decode::from_read_ref::<_, F::E>(&prev_bytes)
.map_err(Error::RMPDecode)
.map_err(sled::ConflictableTransactionError::Abort)?;
let mut new_entry = old_entry.clone();
new_entry.merge(&update);
(Some(old_entry), new_entry)
}
None => (None, update.clone()),
};
let new_bytes = rmp_to_vec_all_named(&new_entry)
.map_err(Error::RMPEncode)
.map_err(sled::ConflictableTransactionError::Abort)?;
db.insert(tree_key.clone(), new_bytes)?;
Ok((old_entry, new_entry))
})?;
if old_entry.as_ref() != Some(&new_entry) {
if self.replication.epidemic_writes() {
epidemic_propagate.push(new_entry.clone());
}
self.instance.updated(old_entry, Some(new_entry)).await;
let syncer = self.syncer.load_full().unwrap();
self.system.background.spawn(syncer.invalidate(tree_key));
}
}
if epidemic_propagate.len() > 0 {
let self2 = self.clone();
self.system
.background
.spawn(async move { self2.insert_many(&epidemic_propagate[..]).await });
}
Ok(())
}
pub async fn delete_range(&self, begin: &Hash, end: &Hash) -> Result<(), Error> {
eprintln!("({}) Deleting range {:?} - {:?}", self.name, begin, end);
let mut count = 0;
while let Some((key, _value)) = self.store.get_lt(end.as_slice())? {
if key.as_ref() < begin.as_slice() {
break;
}
if let Some(old_val) = self.store.remove(&key)? {
let old_entry = rmp_serde::decode::from_read_ref::<_, F::E>(&old_val)?;
self.instance.updated(Some(old_entry), None).await;
count += 1;
}
}
eprintln!("({}) {} entries deleted", self.name, count);
Ok(())
}
fn tree_key(&self, p: &F::P, s: &F::S) -> Vec<u8> {
let mut ret = p.hash().to_vec();
ret.extend(s.sort_key());
ret
}
}