host.rs 28.8 KB
Newer Older
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
// Copyright 2021 Parity Technologies (UK) Ltd.
// This file is part of Polkadot.

// Polkadot is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Polkadot is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.

//! Validation host - is the primary interface for this crate. It allows the clients to enqueue
//! jobs for PVF execution or preparation.
//!
//! The validation host is represented by a future/task that runs an event-loop and by a handle,
//! [`ValidationHost`], that allows communication with that event-loop.

use crate::{
24
	artifacts::{ArtifactId, ArtifactPathId, ArtifactState, Artifacts},
25
26
27
	execute,
	metrics::Metrics,
	prepare, Priority, Pvf, ValidationError, LOG_TARGET,
28
29
};
use always_assert::never;
Shawn Tabrizi's avatar
Shawn Tabrizi committed
30
use async_std::path::{Path, PathBuf};
31
32
use futures::{
	channel::{mpsc, oneshot},
Shawn Tabrizi's avatar
Shawn Tabrizi committed
33
34
35
36
37
38
	Future, FutureExt, SinkExt, StreamExt,
};
use polkadot_parachain::primitives::ValidationResult;
use std::{
	collections::HashMap,
	time::{Duration, SystemTime},
39
40
41
42
43
44
45
46
47
48
49
50
};

/// An alias to not spell the type for the oneshot sender for the PVF execution result.
pub(crate) type ResultSender = oneshot::Sender<Result<ValidationResult, ValidationError>>;

/// A handle to the async process serving the validation host requests.
#[derive(Clone)]
pub struct ValidationHost {
	to_host_tx: mpsc::Sender<ToHost>,
}

impl ValidationHost {
51
52
	/// Execute PVF with the given code, execution timeout, parameters and priority.
	/// The result of execution will be sent to the provided result sender.
53
	///
Bernhard Schuster's avatar
Bernhard Schuster committed
54
55
	/// This is async to accommodate the fact a possibility of back-pressure. In the vast majority of
	/// situations this function should return immediately.
56
57
58
59
60
	///
	/// Returns an error if the request cannot be sent to the validation host, i.e. if it shut down.
	pub async fn execute_pvf(
		&mut self,
		pvf: Pvf,
61
		execution_timeout: Duration,
62
63
64
65
66
		params: Vec<u8>,
		priority: Priority,
		result_tx: ResultSender,
	) -> Result<(), String> {
		self.to_host_tx
67
			.send(ToHost::ExecutePvf { pvf, execution_timeout, params, priority, result_tx })
68
69
70
71
72
73
			.await
			.map_err(|_| "the inner loop hung up".to_string())
	}

	/// Sends a signal to the validation host requesting to prepare a list of the given PVFs.
	///
Bernhard Schuster's avatar
Bernhard Schuster committed
74
75
	/// This is async to accommodate the fact a possibility of back-pressure. In the vast majority of
	/// situations this function should return immediately.
76
77
78
79
80
81
82
83
84
85
86
	///
	/// Returns an error if the request cannot be sent to the validation host, i.e. if it shut down.
	pub async fn heads_up(&mut self, active_pvfs: Vec<Pvf>) -> Result<(), String> {
		self.to_host_tx
			.send(ToHost::HeadsUp { active_pvfs })
			.await
			.map_err(|_| "the inner loop hung up".to_string())
	}
}

enum ToHost {
87
88
89
90
91
92
93
94
95
96
	ExecutePvf {
		pvf: Pvf,
		execution_timeout: Duration,
		params: Vec<u8>,
		priority: Priority,
		result_tx: ResultSender,
	},
	HeadsUp {
		active_pvfs: Vec<Pvf>,
	},
97
98
99
100
101
102
103
104
}

/// Configuration for the validation host.
pub struct Config {
	/// The root directory where the prepared artifacts can be stored.
	pub cache_path: PathBuf,
	/// The path to the program that can be used to spawn the prepare workers.
	pub prepare_worker_program_path: PathBuf,
Denis_P's avatar
Denis_P committed
105
	/// The time allotted for a prepare worker to spawn and report to the host.
106
107
108
109
110
111
112
113
	pub prepare_worker_spawn_timeout: Duration,
	/// The maximum number of workers that can be spawned in the prepare pool for tasks with the
	/// priority below critical.
	pub prepare_workers_soft_max_num: usize,
	/// The absolute number of workers that can be spawned in the prepare pool.
	pub prepare_workers_hard_max_num: usize,
	/// The path to the program that can be used to spawn the execute workers.
	pub execute_worker_program_path: PathBuf,
Denis_P's avatar
Denis_P committed
114
	/// The time allotted for an execute worker to spawn and report to the host.
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
	pub execute_worker_spawn_timeout: Duration,
	/// The maximum number of execute workers that can run at the same time.
	pub execute_workers_max_num: usize,
}

impl Config {
	/// Create a new instance of the configuration.
	pub fn new(cache_path: std::path::PathBuf, program_path: std::path::PathBuf) -> Self {
		// Do not contaminate the other parts of the codebase with the types from async_std.
		let cache_path = PathBuf::from(cache_path);
		let program_path = PathBuf::from(program_path);

		Self {
			cache_path,
			prepare_worker_program_path: program_path.clone(),
			prepare_worker_spawn_timeout: Duration::from_secs(3),
131
132
			prepare_workers_soft_max_num: 1,
			prepare_workers_hard_max_num: 1,
133
134
			execute_worker_program_path: program_path,
			execute_worker_spawn_timeout: Duration::from_secs(3),
135
			execute_workers_max_num: 2,
136
137
138
139
140
141
142
143
144
145
		}
	}
}

/// Start the validation host.
///
/// Returns a [handle][`ValidationHost`] to the started validation host and the future. The future
/// must be polled in order for validation host to function.
///
/// The future should not return normally but if it does then that indicates an unrecoverable error.
Denis_P's avatar
Denis_P committed
146
/// In that case all pending requests will be canceled, dropping the result senders and new ones
147
/// will be rejected.
148
pub fn start(config: Config, metrics: Metrics) -> (ValidationHost, impl Future<Output = ()>) {
149
150
151
152
153
	let (to_host_tx, to_host_rx) = mpsc::channel(10);

	let validation_host = ValidationHost { to_host_tx };

	let (to_prepare_pool, from_prepare_pool, run_prepare_pool) = prepare::start_pool(
154
		metrics.clone(),
155
156
		config.prepare_worker_program_path.clone(),
		config.cache_path.clone(),
157
158
159
160
		config.prepare_worker_spawn_timeout,
	);

	let (to_prepare_queue_tx, from_prepare_queue_rx, run_prepare_queue) = prepare::start_queue(
161
		metrics.clone(),
162
163
164
165
166
167
168
169
		config.prepare_workers_soft_max_num,
		config.prepare_workers_hard_max_num,
		config.cache_path.clone(),
		to_prepare_pool,
		from_prepare_pool,
	);

	let (to_execute_queue_tx, run_execute_queue) = execute::start(
170
		metrics.clone(),
171
172
173
174
175
176
177
178
179
180
181
		config.execute_worker_program_path.to_owned(),
		config.execute_workers_max_num,
		config.execute_worker_spawn_timeout,
	);

	let (to_sweeper_tx, to_sweeper_rx) = mpsc::channel(100);
	let run_sweeper = sweeper_task(to_sweeper_rx);

	let run = async move {
		let artifacts = Artifacts::new(&config.cache_path).await;

Shawn Tabrizi's avatar
Shawn Tabrizi committed
182
		futures::pin_mut!(run_prepare_queue, run_prepare_pool, run_execute_queue, run_sweeper);
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

		run(
			Inner {
				cache_path: config.cache_path,
				cleanup_pulse_interval: Duration::from_secs(3600),
				artifact_ttl: Duration::from_secs(3600 * 24),
				artifacts,
				to_host_rx,
				to_prepare_queue_tx,
				from_prepare_queue_rx,
				to_execute_queue_tx,
				to_sweeper_tx,
				awaiting_prepare: AwaitingPrepare::default(),
			},
			run_prepare_pool,
			run_prepare_queue,
			run_execute_queue,
			run_sweeper,
		)
		.await
	};

	(validation_host, run)
}

/// An execution request that should execute the PVF (known in the context) and send the results
/// to the given result sender.
#[derive(Debug)]
struct PendingExecutionRequest {
212
	execution_timeout: Duration,
213
214
215
216
	params: Vec<u8>,
	result_tx: ResultSender,
}

Bernhard Schuster's avatar
Bernhard Schuster committed
217
/// A mapping from an artifact ID which is in preparation state to the list of pending execution
Denis_P's avatar
Denis_P committed
218
/// requests that should be executed once the artifact's preparation is finished.
219
220
221
222
#[derive(Default)]
struct AwaitingPrepare(HashMap<ArtifactId, Vec<PendingExecutionRequest>>);

impl AwaitingPrepare {
223
224
225
226
227
228
229
230
231
232
233
234
	fn add(
		&mut self,
		artifact_id: ArtifactId,
		execution_timeout: Duration,
		params: Vec<u8>,
		result_tx: ResultSender,
	) {
		self.0.entry(artifact_id).or_default().push(PendingExecutionRequest {
			execution_timeout,
			params,
			result_tx,
		});
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
	}

	fn take(&mut self, artifact_id: &ArtifactId) -> Vec<PendingExecutionRequest> {
		self.0.remove(artifact_id).unwrap_or_default()
	}
}

struct Inner {
	cache_path: PathBuf,
	cleanup_pulse_interval: Duration,
	artifact_ttl: Duration,
	artifacts: Artifacts,

	to_host_rx: mpsc::Receiver<ToHost>,

	to_prepare_queue_tx: mpsc::Sender<prepare::ToQueue>,
	from_prepare_queue_rx: mpsc::UnboundedReceiver<prepare::FromQueue>,

	to_execute_queue_tx: mpsc::Sender<execute::ToQueue>,
	to_sweeper_tx: mpsc::Sender<PathBuf>,

	awaiting_prepare: AwaitingPrepare,
}

#[derive(Debug)]
struct Fatal;

async fn run(
	Inner {
		cache_path,
		cleanup_pulse_interval,
		artifact_ttl,
		mut artifacts,
		to_host_rx,
		from_prepare_queue_rx,
		mut to_prepare_queue_tx,
		mut to_execute_queue_tx,
		mut to_sweeper_tx,
		mut awaiting_prepare,
	}: Inner,
	prepare_pool: impl Future<Output = ()> + Unpin,
	prepare_queue: impl Future<Output = ()> + Unpin,
	execute_queue: impl Future<Output = ()> + Unpin,
	sweeper: impl Future<Output = ()> + Unpin,
) {
	macro_rules! break_if_fatal {
		($expr:expr) => {
			match $expr {
				Err(Fatal) => break,
				Ok(v) => v,
			}
		};
	}

	let cleanup_pulse = pulse_every(cleanup_pulse_interval).fuse();
	futures::pin_mut!(cleanup_pulse);

	let mut to_host_rx = to_host_rx.fuse();
	let mut from_prepare_queue_rx = from_prepare_queue_rx.fuse();

	// Make sure that the task-futures are fused.
	let mut prepare_queue = prepare_queue.fuse();
	let mut prepare_pool = prepare_pool.fuse();
	let mut execute_queue = execute_queue.fuse();
	let mut sweeper = sweeper.fuse();

	loop {
		// biased to make it behave deterministically for tests.
		futures::select_biased! {
			_ = prepare_queue => {
				never!("prepare_pool: long-running task never concludes; qed");
				break;
			},
			_ = prepare_pool => {
				never!("prepare_pool: long-running task never concludes; qed");
				break;
			},
			_ = execute_queue => {
				never!("execute_queue: long-running task never concludes; qed");
				break;
			},
			_ = sweeper => {
				never!("sweeper: long-running task never concludes; qed");
				break;
			},
			() = cleanup_pulse.select_next_some() => {
				// `select_next_some` because we don't expect this to fail, but if it does, we
				// still don't fail. The tradeoff is that the compiled cache will start growing
				// in size. That is, however, rather a slow process and hopefully the operator
				// will notice it.

				break_if_fatal!(handle_cleanup_pulse(
					&cache_path,
					&mut to_sweeper_tx,
					&mut artifacts,
					artifact_ttl,
				).await);
			},
			to_host = to_host_rx.next() => {
				let to_host = break_if_fatal!(to_host.ok_or(Fatal));

				break_if_fatal!(handle_to_host(
					&cache_path,
					&mut artifacts,
					&mut to_prepare_queue_tx,
					&mut to_execute_queue_tx,
					&mut awaiting_prepare,
					to_host,
				)
				.await);
			},
			from_prepare_queue = from_prepare_queue_rx.next() => {
347
				let from_queue = break_if_fatal!(from_prepare_queue.ok_or(Fatal));
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362

				// Note that preparation always succeeds.
				//
				// That's because the error conditions are written into the artifact and will be
				// reported at the time of the  execution. It potentially, but not necessarily,
				// can be scheduled as a result of this function call, in case there are pending
				// executions.
				//
				// We could be eager in terms of reporting and plumb the result from the prepartion
				// worker but we don't for the sake of simplicity.
				break_if_fatal!(handle_prepare_done(
					&cache_path,
					&mut artifacts,
					&mut to_execute_queue_tx,
					&mut awaiting_prepare,
363
					from_queue,
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
				).await);
			},
		}
	}
}

async fn handle_to_host(
	cache_path: &Path,
	artifacts: &mut Artifacts,
	prepare_queue: &mut mpsc::Sender<prepare::ToQueue>,
	execute_queue: &mut mpsc::Sender<execute::ToQueue>,
	awaiting_prepare: &mut AwaitingPrepare,
	to_host: ToHost,
) -> Result<(), Fatal> {
	match to_host {
379
		ToHost::ExecutePvf { pvf, execution_timeout, params, priority, result_tx } => {
380
381
382
383
384
385
386
			handle_execute_pvf(
				cache_path,
				artifacts,
				prepare_queue,
				execute_queue,
				awaiting_prepare,
				pvf,
387
				execution_timeout,
388
389
390
391
392
				params,
				priority,
				result_tx,
			)
			.await?;
Shawn Tabrizi's avatar
Shawn Tabrizi committed
393
		},
394
395
		ToHost::HeadsUp { active_pvfs } => {
			handle_heads_up(artifacts, prepare_queue, active_pvfs).await?;
Shawn Tabrizi's avatar
Shawn Tabrizi committed
396
		},
397
398
399
400
401
402
403
404
405
406
407
408
	}

	Ok(())
}

async fn handle_execute_pvf(
	cache_path: &Path,
	artifacts: &mut Artifacts,
	prepare_queue: &mut mpsc::Sender<prepare::ToQueue>,
	execute_queue: &mut mpsc::Sender<execute::ToQueue>,
	awaiting_prepare: &mut AwaitingPrepare,
	pvf: Pvf,
409
	execution_timeout: Duration,
410
411
412
413
414
415
416
417
	params: Vec<u8>,
	priority: Priority,
	result_tx: ResultSender,
) -> Result<(), Fatal> {
	let artifact_id = pvf.as_artifact_id();

	if let Some(state) = artifacts.artifact_state_mut(&artifact_id) {
		match state {
Shawn Tabrizi's avatar
Shawn Tabrizi committed
418
			ArtifactState::Prepared { ref mut last_time_needed } => {
419
420
421
422
423
				*last_time_needed = SystemTime::now();

				send_execute(
					execute_queue,
					execute::ToQueue::Enqueue {
424
						artifact: ArtifactPathId::new(artifact_id, cache_path),
425
						execution_timeout,
426
427
428
429
430
						params,
						result_tx,
					},
				)
				.await?;
Shawn Tabrizi's avatar
Shawn Tabrizi committed
431
			},
432
433
434
			ArtifactState::Preparing => {
				send_prepare(
					prepare_queue,
Shawn Tabrizi's avatar
Shawn Tabrizi committed
435
					prepare::ToQueue::Amend { priority, artifact_id: artifact_id.clone() },
436
437
438
				)
				.await?;

439
				awaiting_prepare.add(artifact_id, execution_timeout, params, result_tx);
Shawn Tabrizi's avatar
Shawn Tabrizi committed
440
			},
441
442
443
			ArtifactState::FailedToProcess(error) => {
				let _ = result_tx.send(Err(ValidationError::from(error.clone())));
			},
444
445
446
447
448
449
450
		}
	} else {
		// Artifact is unknown: register it and enqueue a job with the corresponding priority and
		//
		artifacts.insert_preparing(artifact_id.clone());
		send_prepare(prepare_queue, prepare::ToQueue::Enqueue { priority, pvf }).await?;

451
		awaiting_prepare.add(artifact_id, execution_timeout, params, result_tx);
452
453
	}

Shawn Tabrizi's avatar
Shawn Tabrizi committed
454
	return Ok(())
455
456
457
458
459
460
461
462
463
464
465
466
467
}

async fn handle_heads_up(
	artifacts: &mut Artifacts,
	prepare_queue: &mut mpsc::Sender<prepare::ToQueue>,
	active_pvfs: Vec<Pvf>,
) -> Result<(), Fatal> {
	let now = SystemTime::now();

	for active_pvf in active_pvfs {
		let artifact_id = active_pvf.as_artifact_id();
		if let Some(state) = artifacts.artifact_state_mut(&artifact_id) {
			match state {
Shawn Tabrizi's avatar
Shawn Tabrizi committed
468
				ArtifactState::Prepared { last_time_needed, .. } => {
469
					*last_time_needed = now;
Shawn Tabrizi's avatar
Shawn Tabrizi committed
470
				},
471
472
473
				ArtifactState::Preparing => {
					// Already preparing. We don't need to send a priority amend either because
					// it can't get any lower than the background.
Shawn Tabrizi's avatar
Shawn Tabrizi committed
474
				},
475
				ArtifactState::FailedToProcess(_) => {},
476
477
478
479
480
481
482
			}
		} else {
			// The artifact is unknown: register it and put a background job into the prepare queue.
			artifacts.insert_preparing(artifact_id.clone());

			send_prepare(
				prepare_queue,
Shawn Tabrizi's avatar
Shawn Tabrizi committed
483
				prepare::ToQueue::Enqueue { priority: Priority::Background, pvf: active_pvf },
484
485
486
487
488
489
490
491
492
493
494
495
496
			)
			.await?;
		}
	}

	Ok(())
}

async fn handle_prepare_done(
	cache_path: &Path,
	artifacts: &mut Artifacts,
	execute_queue: &mut mpsc::Sender<execute::ToQueue>,
	awaiting_prepare: &mut AwaitingPrepare,
497
	from_queue: prepare::FromQueue,
498
) -> Result<(), Fatal> {
499
500
	let prepare::FromQueue { artifact_id, result } = from_queue;

501
502
503
504
505
506
507
508
509
	// Make some sanity checks and extract the current state.
	let state = match artifacts.artifact_state_mut(&artifact_id) {
		None => {
			// before sending request to prepare, the artifact is inserted with `preparing` state;
			// the requests are deduplicated for the same artifact id;
			// there is only one possible state change: prepare is done;
			// thus the artifact cannot be unknown, only preparing;
			// qed.
			never!("an unknown artifact was prepared: {:?}", artifact_id);
Shawn Tabrizi's avatar
Shawn Tabrizi committed
510
511
			return Ok(())
		},
512
513
514
515
516
517
518
		Some(ArtifactState::Prepared { .. }) => {
			// before sending request to prepare, the artifact is inserted with `preparing` state;
			// the requests are deduplicated for the same artifact id;
			// there is only one possible state change: prepare is done;
			// thus the artifact cannot be prepared, only preparing;
			// qed.
			never!("the artifact is already prepared: {:?}", artifact_id);
Shawn Tabrizi's avatar
Shawn Tabrizi committed
519
520
			return Ok(())
		},
521
522
523
524
525
526
		Some(ArtifactState::FailedToProcess(_)) => {
			// The reasoning is similar to the above, the artifact cannot be
			// processed at this point.
			never!("the artifact is already processed unsuccessfully: {:?}", artifact_id);
			return Ok(())
		},
527
528
529
530
531
532
		Some(state @ ArtifactState::Preparing) => state,
	};

	// It's finally time to dispatch all the execution requests that were waiting for this artifact
	// to be prepared.
	let pending_requests = awaiting_prepare.take(&artifact_id);
533
	for PendingExecutionRequest { execution_timeout, params, result_tx } in pending_requests {
534
535
536
		if result_tx.is_canceled() {
			// Preparation could've taken quite a bit of time and the requester may be not interested
			// in execution anymore, in which case we just skip the request.
Shawn Tabrizi's avatar
Shawn Tabrizi committed
537
			continue
538
539
		}

540
541
542
543
544
545
		// Don't send failed artifacts to the execution's queue.
		if let Err(ref error) = result {
			let _ = result_tx.send(Err(ValidationError::from(error.clone())));
			continue
		}

546
547
		send_execute(
			execute_queue,
548
549
			execute::ToQueue::Enqueue {
				artifact: ArtifactPathId::new(artifact_id.clone(), cache_path),
550
				execution_timeout,
551
552
553
				params,
				result_tx,
			},
554
555
556
557
		)
		.await?;
	}

558
559
560
561
	*state = match result {
		Ok(()) => ArtifactState::Prepared { last_time_needed: SystemTime::now() },
		Err(error) => ArtifactState::FailedToProcess(error.clone()),
	};
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586

	Ok(())
}

async fn send_prepare(
	prepare_queue: &mut mpsc::Sender<prepare::ToQueue>,
	to_queue: prepare::ToQueue,
) -> Result<(), Fatal> {
	prepare_queue.send(to_queue).await.map_err(|_| Fatal)
}

async fn send_execute(
	execute_queue: &mut mpsc::Sender<execute::ToQueue>,
	to_queue: execute::ToQueue,
) -> Result<(), Fatal> {
	execute_queue.send(to_queue).await.map_err(|_| Fatal)
}

async fn handle_cleanup_pulse(
	cache_path: &Path,
	sweeper_tx: &mut mpsc::Sender<PathBuf>,
	artifacts: &mut Artifacts,
	artifact_ttl: Duration,
) -> Result<(), Fatal> {
	let to_remove = artifacts.prune(artifact_ttl);
587
588
589
590
591
	tracing::info!(
		target: LOG_TARGET,
		"PVF pruning: {} artifacts reached their end of life",
		to_remove.len(),
	);
592
	for artifact_id in to_remove {
593
594
595
596
597
		tracing::debug!(
			target: LOG_TARGET,
			validation_code_hash = ?artifact_id.code_hash,
			"pruning artifact",
		);
598
599
600
601
602
603
604
605
606
607
608
609
610
		let artifact_path = artifact_id.path(cache_path);
		sweeper_tx.send(artifact_path).await.map_err(|_| Fatal)?;
	}

	Ok(())
}

/// A simple task which sole purpose is to delete files thrown at it.
async fn sweeper_task(mut sweeper_rx: mpsc::Receiver<PathBuf>) {
	loop {
		match sweeper_rx.next().await {
			None => break,
			Some(condemned) => {
611
612
613
614
615
616
617
				let result = async_std::fs::remove_file(&condemned).await;
				tracing::trace!(
					target: LOG_TARGET,
					?result,
					"Sweeping the artifact file {}",
					condemned.display(),
				);
Shawn Tabrizi's avatar
Shawn Tabrizi committed
618
			},
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
		}
	}
}

/// A stream that yields a pulse continuously at a given interval.
fn pulse_every(interval: std::time::Duration) -> impl futures::Stream<Item = ()> {
	futures::stream::unfold(interval, {
		|interval| async move {
			futures_timer::Delay::new(interval).await;
			Some(((), interval))
		}
	})
	.map(|_| ())
}

#[cfg(test)]
mod tests {
	use super::*;
	use assert_matches::assert_matches;
Shawn Tabrizi's avatar
Shawn Tabrizi committed
638
	use futures::future::BoxFuture;
639

640
641
	const TEST_EXECUTION_TIMEOUT: Duration = Duration::from_secs(3);

642
643
644
645
646
647
648
649
650
651
652
653
654
655
	#[async_std::test]
	async fn pulse_test() {
		let pulse = pulse_every(Duration::from_millis(100));
		futures::pin_mut!(pulse);

		for _ in 0usize..5usize {
			let start = std::time::Instant::now();
			let _ = pulse.next().await.unwrap();

			let el = start.elapsed().as_millis();
			assert!(el > 50 && el < 150, "{}", el);
		}
	}

Denis_P's avatar
Denis_P committed
656
	/// Creates a new PVF which artifact id can be uniquely identified by the given number.
657
658
659
660
661
	fn artifact_id(descriminator: u32) -> ArtifactId {
		Pvf::from_discriminator(descriminator).as_artifact_id()
	}

	fn artifact_path(descriminator: u32) -> PathBuf {
Shawn Tabrizi's avatar
Shawn Tabrizi committed
662
		artifact_id(descriminator).path(&PathBuf::from(std::env::temp_dir())).to_owned()
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
	}

	struct Builder {
		cleanup_pulse_interval: Duration,
		artifact_ttl: Duration,
		artifacts: Artifacts,
	}

	impl Builder {
		fn default() -> Self {
			Self {
				// these are selected high to not interfere in tests in which pruning is irrelevant.
				cleanup_pulse_interval: Duration::from_secs(3600),
				artifact_ttl: Duration::from_secs(3600),

				artifacts: Artifacts::empty(),
			}
		}

		fn build(self) -> Test {
			Test::new(self)
		}
	}

	struct Test {
		to_host_tx: Option<mpsc::Sender<ToHost>>,

		to_prepare_queue_rx: mpsc::Receiver<prepare::ToQueue>,
		from_prepare_queue_tx: mpsc::UnboundedSender<prepare::FromQueue>,
		to_execute_queue_rx: mpsc::Receiver<execute::ToQueue>,
		to_sweeper_rx: mpsc::Receiver<PathBuf>,

		run: BoxFuture<'static, ()>,
	}

	impl Test {
Shawn Tabrizi's avatar
Shawn Tabrizi committed
699
		fn new(Builder { cleanup_pulse_interval, artifact_ttl, artifacts }: Builder) -> Self {
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
			let cache_path = PathBuf::from(std::env::temp_dir());

			let (to_host_tx, to_host_rx) = mpsc::channel(10);
			let (to_prepare_queue_tx, to_prepare_queue_rx) = mpsc::channel(10);
			let (from_prepare_queue_tx, from_prepare_queue_rx) = mpsc::unbounded();
			let (to_execute_queue_tx, to_execute_queue_rx) = mpsc::channel(10);
			let (to_sweeper_tx, to_sweeper_rx) = mpsc::channel(10);

			let mk_dummy_loop = || std::future::pending().boxed();

			let run = run(
				Inner {
					cache_path,
					cleanup_pulse_interval,
					artifact_ttl,
					artifacts,
					to_host_rx,
					to_prepare_queue_tx,
					from_prepare_queue_rx,
					to_execute_queue_tx,
					to_sweeper_tx,
					awaiting_prepare: AwaitingPrepare::default(),
				},
				mk_dummy_loop(),
				mk_dummy_loop(),
				mk_dummy_loop(),
				mk_dummy_loop(),
			)
			.boxed();

			Self {
				to_host_tx: Some(to_host_tx),
				to_prepare_queue_rx,
				from_prepare_queue_tx,
				to_execute_queue_rx,
				to_sweeper_rx,
				run,
			}
		}

		fn host_handle(&mut self) -> ValidationHost {
			let to_host_tx = self.to_host_tx.take().unwrap();
			ValidationHost { to_host_tx }
		}

		async fn poll_and_recv_to_prepare_queue(&mut self) -> prepare::ToQueue {
			let to_prepare_queue_rx = &mut self.to_prepare_queue_rx;
Shawn Tabrizi's avatar
Shawn Tabrizi committed
747
748
			run_until(&mut self.run, async { to_prepare_queue_rx.next().await.unwrap() }.boxed())
				.await
749
750
751
752
		}

		async fn poll_and_recv_to_execute_queue(&mut self) -> execute::ToQueue {
			let to_execute_queue_rx = &mut self.to_execute_queue_rx;
Shawn Tabrizi's avatar
Shawn Tabrizi committed
753
754
			run_until(&mut self.run, async { to_execute_queue_rx.next().await.unwrap() }.boxed())
				.await
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
		}

		async fn poll_ensure_to_execute_queue_is_empty(&mut self) {
			use futures_timer::Delay;

			let to_execute_queue_rx = &mut self.to_execute_queue_rx;
			run_until(
				&mut self.run,
				async {
					futures::select! {
						_ = Delay::new(Duration::from_millis(500)).fuse() => (),
						_ = to_execute_queue_rx.next().fuse() => {
							panic!("the execute queue supposed to be empty")
						}
					}
				}
				.boxed(),
			)
			.await
		}

		async fn poll_ensure_to_sweeper_is_empty(&mut self) {
			use futures_timer::Delay;

			let to_sweeper_rx = &mut self.to_sweeper_rx;
			run_until(
				&mut self.run,
				async {
					futures::select! {
						_ = Delay::new(Duration::from_millis(500)).fuse() => (),
						msg = to_sweeper_rx.next().fuse() => {
							panic!("the sweeper supposed to be empty, but received: {:?}", msg)
						}
					}
				}
				.boxed(),
			)
			.await
		}
	}

	async fn run_until<R>(
		task: &mut (impl Future<Output = ()> + Unpin),
		mut fut: (impl Future<Output = R> + Unpin),
	) -> R {
		use std::task::Poll;

		let start = std::time::Instant::now();
		let fut = &mut fut;
		loop {
			if start.elapsed() > std::time::Duration::from_secs(2) {
				// We expect that this will take only a couple of iterations and thus to take way
				// less than a second.
				panic!("timeout");
			}

			if let Poll::Ready(r) = futures::poll!(&mut *fut) {
Shawn Tabrizi's avatar
Shawn Tabrizi committed
812
				break r
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
			}

			if futures::poll!(&mut *task).is_ready() {
				panic!()
			}
		}
	}

	#[async_std::test]
	async fn shutdown_on_handle_drop() {
		let test = Builder::default().build();

		let join_handle = async_std::task::spawn(test.run);

		// Dropping the handle will lead to conclusion of the read part and thus will make the event
		// loop to stop, which in turn will resolve the join handle.
		drop(test.to_host_tx);
		join_handle.await;
	}

	#[async_std::test]
	async fn pruning() {
		let mock_now = SystemTime::now() - Duration::from_millis(1000);

		let mut builder = Builder::default();
		builder.cleanup_pulse_interval = Duration::from_millis(100);
		builder.artifact_ttl = Duration::from_millis(500);
		builder.artifacts.insert_prepared(artifact_id(1), mock_now);
		builder.artifacts.insert_prepared(artifact_id(2), mock_now);
		let mut test = builder.build();
		let mut host = test.host_handle();

Shawn Tabrizi's avatar
Shawn Tabrizi committed
845
		host.heads_up(vec![Pvf::from_discriminator(1)]).await.unwrap();
846
847
848
849
850
851
852
853
854
855
856
857
858

		let to_sweeper_rx = &mut test.to_sweeper_rx;
		run_until(
			&mut test.run,
			async {
				assert_eq!(to_sweeper_rx.next().await.unwrap(), artifact_path(2));
			}
			.boxed(),
		)
		.await;

		// Extend TTL for the first artifact and make sure we don't receive another file removal
		// request.
Shawn Tabrizi's avatar
Shawn Tabrizi committed
859
		host.heads_up(vec![Pvf::from_discriminator(1)]).await.unwrap();
860
861
862
863
864
865
866
867
		test.poll_ensure_to_sweeper_is_empty().await;
	}

	#[async_std::test]
	async fn amending_priority() {
		let mut test = Builder::default().build();
		let mut host = test.host_handle();

Shawn Tabrizi's avatar
Shawn Tabrizi committed
868
		host.heads_up(vec![Pvf::from_discriminator(1)]).await.unwrap();
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884

		// Run until we receive a prepare request.
		let prepare_q_rx = &mut test.to_prepare_queue_rx;
		run_until(
			&mut test.run,
			async {
				assert_matches!(
					prepare_q_rx.next().await.unwrap(),
					prepare::ToQueue::Enqueue { .. }
				);
			}
			.boxed(),
		)
		.await;

		let (result_tx, _result_rx) = oneshot::channel();
885
886
887
888
889
890
891
892
893
		host.execute_pvf(
			Pvf::from_discriminator(1),
			TEST_EXECUTION_TIMEOUT,
			vec![],
			Priority::Critical,
			result_tx,
		)
		.await
		.unwrap();
894
895
896
897

		run_until(
			&mut test.run,
			async {
Shawn Tabrizi's avatar
Shawn Tabrizi committed
898
				assert_matches!(prepare_q_rx.next().await.unwrap(), prepare::ToQueue::Amend { .. });
899
900
901
902
903
904
905
906
907
908
909
910
911
912
			}
			.boxed(),
		)
		.await;
	}

	#[async_std::test]
	async fn execute_pvf_requests() {
		use crate::error::InvalidCandidate;

		let mut test = Builder::default().build();
		let mut host = test.host_handle();

		let (result_tx, result_rx_pvf_1_1) = oneshot::channel();
913
914
915
916
917
918
919
920
921
		host.execute_pvf(
			Pvf::from_discriminator(1),
			TEST_EXECUTION_TIMEOUT,
			b"pvf1".to_vec(),
			Priority::Normal,
			result_tx,
		)
		.await
		.unwrap();
922
923
924
925

		let (result_tx, result_rx_pvf_1_2) = oneshot::channel();
		host.execute_pvf(
			Pvf::from_discriminator(1),
926
			TEST_EXECUTION_TIMEOUT,
927
928
929
930
931
932
933
934
			b"pvf1".to_vec(),
			Priority::Critical,
			result_tx,
		)
		.await
		.unwrap();

		let (result_tx, result_rx_pvf_2) = oneshot::channel();
935
936
937
938
939
940
941
942
943
		host.execute_pvf(
			Pvf::from_discriminator(2),
			TEST_EXECUTION_TIMEOUT,
			b"pvf2".to_vec(),
			Priority::Normal,
			result_tx,
		)
		.await
		.unwrap();
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958

		assert_matches!(
			test.poll_and_recv_to_prepare_queue().await,
			prepare::ToQueue::Enqueue { .. }
		);
		assert_matches!(
			test.poll_and_recv_to_prepare_queue().await,
			prepare::ToQueue::Amend { .. }
		);
		assert_matches!(
			test.poll_and_recv_to_prepare_queue().await,
			prepare::ToQueue::Enqueue { .. }
		);

		test.from_prepare_queue_tx
959
			.send(prepare::FromQueue { artifact_id: artifact_id(1), result: Ok(()) })
960
961
962
963
964
965
966
967
968
969
970
971
			.await
			.unwrap();
		let result_tx_pvf_1_1 = assert_matches!(
			test.poll_and_recv_to_execute_queue().await,
			execute::ToQueue::Enqueue { result_tx, .. } => result_tx
		);
		let result_tx_pvf_1_2 = assert_matches!(
			test.poll_and_recv_to_execute_queue().await,
			execute::ToQueue::Enqueue { result_tx, .. } => result_tx
		);

		test.from_prepare_queue_tx
972
			.send(prepare::FromQueue { artifact_id: artifact_id(2), result: Ok(()) })
973
974
975
976
977
978
979
980
			.await
			.unwrap();
		let result_tx_pvf_2 = assert_matches!(
			test.poll_and_recv_to_execute_queue().await,
			execute::ToQueue::Enqueue { result_tx, .. } => result_tx
		);

		result_tx_pvf_1_1
Shawn Tabrizi's avatar
Shawn Tabrizi committed
981
			.send(Err(ValidationError::InvalidCandidate(InvalidCandidate::AmbigiousWorkerDeath)))
982
983
984
			.unwrap();
		assert_matches!(
			result_rx_pvf_1_1.now_or_never().unwrap().unwrap(),
Shawn Tabrizi's avatar
Shawn Tabrizi committed
985
			Err(ValidationError::InvalidCandidate(InvalidCandidate::AmbigiousWorkerDeath,))
986
987
988
		);

		result_tx_pvf_1_2
Shawn Tabrizi's avatar
Shawn Tabrizi committed
989
			.send(Err(ValidationError::InvalidCandidate(InvalidCandidate::AmbigiousWorkerDeath)))
990
991
992
			.unwrap();
		assert_matches!(
			result_rx_pvf_1_2.now_or_never().unwrap().unwrap(),
Shawn Tabrizi's avatar
Shawn Tabrizi committed
993
			Err(ValidationError::InvalidCandidate(InvalidCandidate::AmbigiousWorkerDeath,))
994
995
996
		);

		result_tx_pvf_2
Shawn Tabrizi's avatar
Shawn Tabrizi committed
997
			.send(Err(ValidationError::InvalidCandidate(InvalidCandidate::AmbigiousWorkerDeath)))
998
999
1000
			.unwrap();
		assert_matches!(
			result_rx_pvf_2.now_or_never().unwrap().unwrap(),
Shawn Tabrizi's avatar
Shawn Tabrizi committed
1001
			Err(ValidationError::InvalidCandidate(InvalidCandidate::AmbigiousWorkerDeath,))
1002
1003
1004
1005
1006
1007
1008
1009
1010
		);
	}

	#[async_std::test]
	async fn cancellation() {
		let mut test = Builder::default().build();
		let mut host = test.host_handle();

		let (result_tx, result_rx) = oneshot::channel();
1011
1012
1013
1014
1015
1016
1017
1018
1019
		host.execute_pvf(
			Pvf::from_discriminator(1),
			TEST_EXECUTION_TIMEOUT,
			b"pvf1".to_vec(),
			Priority::Normal,
			result_tx,
		)
		.await
		.unwrap();
1020
1021
1022
1023
1024
1025
1026

		assert_matches!(
			test.poll_and_recv_to_prepare_queue().await,
			prepare::ToQueue::Enqueue { .. }
		);

		test.from_prepare_queue_tx
1027
			.send(prepare::FromQueue { artifact_id: artifact_id(1), result: Ok(()) })
1028
1029
1030
1031
1032
1033
1034
1035
			.await
			.unwrap();

		drop(result_rx);

		test.poll_ensure_to_execute_queue_is_empty().await;
	}
}