aboutsummaryrefslogtreecommitdiff
path: root/src/table.rs
blob: 40114aec138257083160bdf93da08bb6444dc7d7 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
use std::collections::{HashMap, BTreeMap};
use std::sync::Arc;
use std::time::Duration;

use async_trait::async_trait;
use futures::stream::*;
use serde::{Deserialize, Serialize};
use serde_bytes::ByteBuf;
use tokio::sync::RwLock;

use crate::data::*;
use crate::error::Error;
use crate::membership::System;
use crate::proto::*;
use crate::rpc_client::*;
use crate::table_sync::*;

pub struct Table<F: TableSchema> {
	pub instance: F,

	pub name: String,

	pub system: Arc<System>,
	pub store: sled::Tree,
	pub syncer: RwLock<Option<Arc<TableSyncer<F>>>>,

	pub param: TableReplicationParams,
}

#[derive(Clone)]
pub struct TableReplicationParams {
	pub replication_factor: usize,
	pub read_quorum: usize,
	pub write_quorum: usize,
	pub timeout: Duration,
}

#[async_trait]
pub trait TableRpcHandler {
	async fn handle(&self, rpc: &[u8]) -> Result<Vec<u8>, Error>;
}

struct TableRpcHandlerAdapter<F: TableSchema> {
	table: Arc<Table<F>>,
}

#[async_trait]
impl<F: TableSchema + 'static> TableRpcHandler for TableRpcHandlerAdapter<F> {
	async fn handle(&self, rpc: &[u8]) -> Result<Vec<u8>, Error> {
		let msg = rmp_serde::decode::from_read_ref::<_, TableRPC<F>>(rpc)?;
		let rep = self.table.handle(msg).await?;
		Ok(rmp_to_vec_all_named(&rep)?)
	}
}

#[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),
}

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 }
}

impl<F: TableSchema + 'static> Table<F> {
	// =============== PUBLIC INTERFACE FUNCTIONS (new, insert, get, etc) ===============

	pub async fn new(
		instance: F,
		system: Arc<System>,
		db: &sled::Db,
		name: String,
		param: TableReplicationParams,
	) -> Arc<Self> {
		let store = db.open_tree(&name).expect("Unable to open DB tree");
		let table = Arc::new(Self {
			instance,
			name,
			system,
			store,
			param,
			syncer: RwLock::new(None),
		});
		let syncer = TableSyncer::launch(table.clone()).await;
		*table.syncer.write().await = Some(syncer);
		table
	}

	pub async fn insert(&self, e: &F::E) -> Result<(), Error> {
		let hash = e.partition_key().hash();
		let ring = self.system.ring.borrow().clone();
		let who = ring.walk_ring(&hash, self.param.replication_factor);
		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_try_call_many(&who[..], &rpc, self.param.write_quorum)
			.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 ring = self.system.ring.borrow().clone();
			let who = ring.walk_ring(&hash, self.param.replication_factor);
			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 rpc_bytes = rmp_to_vec_all_named(&rpc)?;
			let message = Message::TableRPC(self.name.to_string(), rpc_bytes);

			let resp = rpc_call(self.system.clone(), &node, &message, self.param.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.param.replication_factor - self.param.write_quorum {
			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 ring = self.system.ring.borrow().clone();
		let who = ring.walk_ring(&hash, self.param.replication_factor);
		eprintln!("get who: {:?}", who);

		let rpc = &TableRPC::<F>::ReadEntry(partition_key.clone(), sort_key.clone());
		let resps = self
			.rpc_try_call_many(&who[..], &rpc, self.param.read_quorum)
			.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 ring = self.system.ring.borrow().clone();
		let who = ring.walk_ring(&hash, self.param.replication_factor);

		let rpc = &TableRPC::<F>::ReadRange(partition_key.clone(), begin_sort_key.clone(), filter, limit);
		let resps = self
			.rpc_try_call_many(&who[..], &rpc, self.param.read_quorum)
			.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_try_call_many(&who[..], &TableRPC::<F>::Update(vec![what_enc]), who.len())
			.await?;
		Ok(())
	}

	async fn rpc_try_call_many(
		&self,
		who: &[UUID],
		rpc: &TableRPC<F>,
		quorum: usize,
	) -> Result<Vec<TableRPC<F>>, Error> {
		eprintln!("Table RPC to {:?}: {}", who, serde_json::to_string(&rpc)?);

		let rpc_bytes = rmp_to_vec_all_named(rpc)?;
		let rpc_msg = Message::TableRPC(self.name.to_string(), rpc_bytes);

		let resps = rpc_try_call_many(
			self.system.clone(),
			who,
			rpc_msg,
			quorum,
			self.param.timeout,
		)
		.await?;

		let mut resps_vals = vec![];
		for resp in resps {
			if let Message::TableRPC(tbl, rep_by) = &resp {
				if *tbl == self.name {
					resps_vals.push(rmp_serde::decode::from_read_ref(&rep_by)?);
					continue;
				}
			}
			return Err(Error::Message(format!(
				"Invalid reply to TableRPC: {:?}",
				resp
			)));
		}
		eprintln!(
			"Table RPC responses: {}",
			serde_json::to_string(&resps_vals)?
		);
		Ok(resps_vals)
	}

	pub async fn rpc_call(&self, who: &UUID, rpc: &TableRPC<F>) -> Result<TableRPC<F>, Error> {
		let rpc_bytes = rmp_to_vec_all_named(rpc)?;
		let rpc_msg = Message::TableRPC(self.name.to_string(), rpc_bytes);

		let resp = rpc_call(self.system.clone(), who, &rpc_msg, self.param.timeout).await?;
		if let Message::TableRPC(tbl, rep_by) = &resp {
			if *tbl == self.name {
				return Ok(rmp_serde::decode::from_read_ref(&rep_by)?);
			}
		}
		Err(Error::Message(format!(
			"Invalid reply to TableRPC: {:?}",
			resp
		)))
	}

	// =============== HANDLERS FOR RPC OPERATIONS (SERVER SIDE) ==============

	pub fn rpc_handler(self: Arc<Self>) -> Box<dyn TableRpcHandler + Send + Sync> {
		Box::new(TableRpcHandlerAdapter::<F> { table: self })
	}

	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::Update(pairs) => {
				self.handle_update(pairs).await?;
				Ok(TableRPC::Ok)
			}
			TableRPC::SyncRPC(rpc) => {
				let syncer = self.syncer.read().await.as_ref().unwrap().clone();
				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)
		}
	}

	async fn handle_update(self: &Arc<Self>, mut entries: Vec<Arc<ByteBuf>>) -> Result<(), Error> {
		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, Some(new_entry)))
			})?;

			if old_entry != new_entry {
				self.instance.updated(old_entry, new_entry).await;

				let syncer = self.syncer.read().await.as_ref().unwrap().clone();
				self.system.background.spawn(syncer.invalidate(tree_key));
			}
		}
		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
	}
}