lighthouse/beacon_node/http_api/tests/fork_tests.rs
Paul Hauner be4e261e74 Use async code when interacting with EL (#3244)
## Overview

This rather extensive PR achieves two primary goals:

1. Uses the finalized/justified checkpoints of fork choice (FC), rather than that of the head state.
2. Refactors fork choice, block production and block processing to `async` functions.

Additionally, it achieves:

- Concurrent forkchoice updates to the EL and cache pruning after a new head is selected.
- Concurrent "block packing" (attestations, etc) and execution payload retrieval during block production.
- Concurrent per-block-processing and execution payload verification during block processing.
- The `Arc`-ification of `SignedBeaconBlock` during block processing (it's never mutated, so why not?):
    - I had to do this to deal with sending blocks into spawned tasks.
    - Previously we were cloning the beacon block at least 2 times during each block processing, these clones are either removed or turned into cheaper `Arc` clones.
    - We were also `Box`-ing and un-`Box`-ing beacon blocks as they moved throughout the networking crate. This is not a big deal, but it's nice to avoid shifting things between the stack and heap.
    - Avoids cloning *all the blocks* in *every chain segment* during sync.
    - It also has the potential to clean up our code where we need to pass an *owned* block around so we can send it back in the case of an error (I didn't do much of this, my PR is already big enough 😅)
- The `BeaconChain::HeadSafetyStatus` struct was removed. It was an old relic from prior merge specs.

For motivation for this change, see https://github.com/sigp/lighthouse/pull/3244#issuecomment-1160963273

## Changes to `canonical_head` and `fork_choice`

Previously, the `BeaconChain` had two separate fields:

```
canonical_head: RwLock<Snapshot>,
fork_choice: RwLock<BeaconForkChoice>
```

Now, we have grouped these values under a single struct:

```
canonical_head: CanonicalHead {
  cached_head: RwLock<Arc<Snapshot>>,
  fork_choice: RwLock<BeaconForkChoice>
} 
```

Apart from ergonomics, the only *actual* change here is wrapping the canonical head snapshot in an `Arc`. This means that we no longer need to hold the `cached_head` (`canonical_head`, in old terms) lock when we want to pull some values from it. This was done to avoid deadlock risks by preventing functions from acquiring (and holding) the `cached_head` and `fork_choice` locks simultaneously.

## Breaking Changes

### The `state` (root) field in the `finalized_checkpoint` SSE event

Consider the scenario where epoch `n` is just finalized, but `start_slot(n)` is skipped. There are two state roots we might in the `finalized_checkpoint` SSE event:

1. The state root of the finalized block, which is `get_block(finalized_checkpoint.root).state_root`.
4. The state root at slot of `start_slot(n)`, which would be the state from (1), but "skipped forward" through any skip slots.

Previously, Lighthouse would choose (2). However, we can see that when [Teku generates that event](de2b2801c8/data/beaconrestapi/src/main/java/tech/pegasys/teku/beaconrestapi/handlers/v1/events/EventSubscriptionManager.java (L171-L182)) it uses [`getStateRootFromBlockRoot`](de2b2801c8/data/provider/src/main/java/tech/pegasys/teku/api/ChainDataProvider.java (L336-L341)) which uses (1).

I have switched Lighthouse from (2) to (1). I think it's a somewhat arbitrary choice between the two, where (1) is easier to compute and is consistent with Teku.

## Notes for Reviewers

I've renamed `BeaconChain::fork_choice` to `BeaconChain::recompute_head`. Doing this helped ensure I broke all previous uses of fork choice and I also find it more descriptive. It describes an action and can't be confused with trying to get a reference to the `ForkChoice` struct.

I've changed the ordering of SSE events when a block is received. It used to be `[block, finalized, head]` and now it's `[block, head, finalized]`. It was easier this way and I don't think we were making any promises about SSE event ordering so it's not "breaking".

I've made it so fork choice will run when it's first constructed. I did this because I wanted to have a cached version of the last call to `get_head`. Ensuring `get_head` has been run *at least once* means that the cached values doesn't need to wrapped in an `Option`. This was fairly simple, it just involved passing a `slot` to the constructor so it knows *when* it's being run. When loading a fork choice from the store and a slot clock isn't handy I've just used the `slot` that was saved in the `fork_choice_store`. That seems like it would be a faithful representation of the slot when we saved it.

I added the `genesis_time: u64` to the `BeaconChain`. It's small, constant and nice to have around.

Since we're using FC for the fin/just checkpoints, we no longer get the `0x00..00` roots at genesis. You can see I had to remove a work-around in `ef-tests` here: b56be3bc2. I can't find any reason why this would be an issue, if anything I think it'll be better since the genesis-alias has caught us out a few times (0x00..00 isn't actually a real root). Edit: I did find a case where the `network` expected the 0x00..00 alias and patched it here: 3f26ac3e2.

You'll notice a lot of changes in tests. Generally, tests should be functionally equivalent. Here are the things creating the most diff-noise in tests:
- Changing tests to be `tokio::async` tests.
- Adding `.await` to fork choice, block processing and block production functions.
- Refactor of the `canonical_head` "API" provided by the `BeaconChain`. E.g., `chain.canonical_head.cached_head()` instead of `chain.canonical_head.read()`.
- Wrapping `SignedBeaconBlock` in an `Arc`.
- In the `beacon_chain/tests/block_verification`, we can't use the `lazy_static` `CHAIN_SEGMENT` variable anymore since it's generated with an async function. We just generate it in each test, not so efficient but hopefully insignificant.

I had to disable `rayon` concurrent tests in the `fork_choice` tests. This is because the use of `rayon` and `block_on` was causing a panic.

Co-authored-by: Mac L <mjladson@pm.me>
2022-07-03 05:36:50 +00:00

310 lines
9.8 KiB
Rust

//! Tests for API behaviour across fork boundaries.
use crate::common::*;
use beacon_chain::{test_utils::RelativeSyncCommittee, StateSkipConfig};
use eth2::types::{StateId, SyncSubcommittee};
use types::{ChainSpec, Epoch, EthSpec, MinimalEthSpec, Slot};
type E = MinimalEthSpec;
fn altair_spec(altair_fork_epoch: Epoch) -> ChainSpec {
let mut spec = E::default_spec();
spec.altair_fork_epoch = Some(altair_fork_epoch);
spec
}
#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn sync_committee_duties_across_fork() {
let validator_count = E::sync_committee_size();
let fork_epoch = Epoch::new(8);
let spec = altair_spec(fork_epoch);
let tester = InteractiveTester::<E>::new(Some(spec.clone()), validator_count).await;
let harness = &tester.harness;
let client = &tester.client;
let all_validators = harness.get_all_validators();
let all_validators_u64 = all_validators.iter().map(|x| *x as u64).collect::<Vec<_>>();
assert_eq!(harness.get_current_slot(), 0);
// Prior to the fork the endpoint should return an empty vec.
let early_duties = client
.post_validator_duties_sync(fork_epoch - 1, &all_validators_u64)
.await
.unwrap()
.data;
assert!(early_duties.is_empty());
// If there's a skip slot at the fork slot, the endpoint should return duties, even
// though the head state hasn't transitioned yet.
let fork_slot = fork_epoch.start_slot(E::slots_per_epoch());
let (genesis_state, genesis_state_root) = harness.get_current_state_and_root();
let (_, state) = harness
.add_attested_block_at_slot(
fork_slot - 1,
genesis_state,
genesis_state_root,
&all_validators,
)
.await
.unwrap();
harness.advance_slot();
assert_eq!(harness.get_current_slot(), fork_slot);
let sync_duties = client
.post_validator_duties_sync(fork_epoch, &all_validators_u64)
.await
.unwrap()
.data;
assert_eq!(sync_duties.len(), E::sync_committee_size());
// After applying a block at the fork slot the duties should remain unchanged.
let state_root = state.canonical_root();
harness
.add_attested_block_at_slot(fork_slot, state, state_root, &all_validators)
.await
.unwrap();
assert_eq!(
client
.post_validator_duties_sync(fork_epoch, &all_validators_u64)
.await
.unwrap()
.data,
sync_duties
);
// Sync duties should also be available for the next period.
let current_period = fork_epoch.sync_committee_period(&spec).unwrap();
let next_period_epoch = spec.epochs_per_sync_committee_period * (current_period + 1);
let next_period_duties = client
.post_validator_duties_sync(next_period_epoch, &all_validators_u64)
.await
.unwrap()
.data;
assert_eq!(next_period_duties.len(), E::sync_committee_size());
// Sync duties should *not* be available for the period after the next period.
// We expect a 400 (bad request) response.
let next_next_period_epoch = spec.epochs_per_sync_committee_period * (current_period + 2);
assert_eq!(
client
.post_validator_duties_sync(next_next_period_epoch, &all_validators_u64)
.await
.unwrap_err()
.status()
.unwrap(),
400
);
}
#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn attestations_across_fork_with_skip_slots() {
let validator_count = E::sync_committee_size();
let fork_epoch = Epoch::new(8);
let spec = altair_spec(fork_epoch);
let tester = InteractiveTester::<E>::new(Some(spec.clone()), validator_count).await;
let harness = &tester.harness;
let client = &tester.client;
let all_validators = harness.get_all_validators();
let fork_slot = fork_epoch.start_slot(E::slots_per_epoch());
let fork_state = harness
.chain
.state_at_slot(fork_slot, StateSkipConfig::WithStateRoots)
.unwrap();
harness.set_current_slot(fork_slot);
let attestations = harness.make_attestations(
&all_validators,
&fork_state,
fork_state.canonical_root(),
(*fork_state.get_block_root(fork_slot - 1).unwrap()).into(),
fork_slot,
);
let unaggregated_attestations = attestations
.iter()
.flat_map(|(atts, _)| atts.iter().map(|(att, _)| att.clone()))
.collect::<Vec<_>>();
assert!(!unaggregated_attestations.is_empty());
client
.post_beacon_pool_attestations(&unaggregated_attestations)
.await
.unwrap();
let signed_aggregates = attestations
.into_iter()
.filter_map(|(_, op_aggregate)| op_aggregate)
.collect::<Vec<_>>();
assert!(!signed_aggregates.is_empty());
client
.post_validator_aggregate_and_proof(&signed_aggregates)
.await
.unwrap();
}
#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn sync_contributions_across_fork_with_skip_slots() {
let validator_count = E::sync_committee_size();
let fork_epoch = Epoch::new(8);
let spec = altair_spec(fork_epoch);
let tester = InteractiveTester::<E>::new(Some(spec.clone()), validator_count).await;
let harness = &tester.harness;
let client = &tester.client;
let fork_slot = fork_epoch.start_slot(E::slots_per_epoch());
let fork_state = harness
.chain
.state_at_slot(fork_slot, StateSkipConfig::WithStateRoots)
.unwrap();
harness.set_current_slot(fork_slot);
let sync_messages = harness.make_sync_contributions(
&fork_state,
*fork_state.get_block_root(fork_slot - 1).unwrap(),
fork_slot,
RelativeSyncCommittee::Current,
);
let sync_committee_messages = sync_messages
.iter()
.flat_map(|(messages, _)| messages.iter().map(|(message, _subnet)| message.clone()))
.collect::<Vec<_>>();
assert!(!sync_committee_messages.is_empty());
client
.post_beacon_pool_sync_committee_signatures(&sync_committee_messages)
.await
.unwrap();
let signed_contributions = sync_messages
.into_iter()
.filter_map(|(_, op_aggregate)| op_aggregate)
.collect::<Vec<_>>();
assert!(!signed_contributions.is_empty());
client
.post_validator_contribution_and_proofs(&signed_contributions)
.await
.unwrap();
}
#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn sync_committee_indices_across_fork() {
let validator_count = E::sync_committee_size();
let fork_epoch = Epoch::new(8);
let spec = altair_spec(fork_epoch);
let tester = InteractiveTester::<E>::new(Some(spec.clone()), validator_count).await;
let harness = &tester.harness;
let client = &tester.client;
let all_validators = harness.get_all_validators();
// Flatten subcommittees into a single vec.
let flatten = |subcommittees: &[SyncSubcommittee]| -> Vec<u64> {
subcommittees
.iter()
.flat_map(|sub| sub.indices.iter().copied())
.collect()
};
// Prior to the fork the `sync_committees` endpoint should return a 400 error.
assert_eq!(
client
.get_beacon_states_sync_committees(StateId::Slot(Slot::new(0)), None)
.await
.unwrap_err()
.status()
.unwrap(),
400
);
assert_eq!(
client
.get_beacon_states_sync_committees(StateId::Head, Some(Epoch::new(0)))
.await
.unwrap_err()
.status()
.unwrap(),
400
);
// If there's a skip slot at the fork slot, the endpoint will return a 400 until a block is
// applied.
let fork_slot = fork_epoch.start_slot(E::slots_per_epoch());
let (genesis_state, genesis_state_root) = harness.get_current_state_and_root();
let (_, state) = harness
.add_attested_block_at_slot(
fork_slot - 1,
genesis_state,
genesis_state_root,
&all_validators,
)
.await
.unwrap();
harness.advance_slot();
assert_eq!(harness.get_current_slot(), fork_slot);
// Using the head state must fail.
assert_eq!(
client
.get_beacon_states_sync_committees(StateId::Head, Some(fork_epoch))
.await
.unwrap_err()
.status()
.unwrap(),
400
);
// In theory we could do a state advance and make this work, but to keep things simple I've
// avoided doing that for now.
assert_eq!(
client
.get_beacon_states_sync_committees(StateId::Slot(fork_slot), None)
.await
.unwrap_err()
.status()
.unwrap(),
400
);
// Once the head is updated it should be useable for requests, including in the next sync
// committee period.
let state_root = state.canonical_root();
harness
.add_attested_block_at_slot(fork_slot + 1, state, state_root, &all_validators)
.await
.unwrap();
let current_period = fork_epoch.sync_committee_period(&spec).unwrap();
let next_period_epoch = spec.epochs_per_sync_committee_period * (current_period + 1);
assert!(next_period_epoch > fork_epoch);
for epoch in [
None,
Some(fork_epoch),
Some(fork_epoch + 1),
Some(next_period_epoch),
Some(next_period_epoch + 1),
] {
let committee = client
.get_beacon_states_sync_committees(StateId::Head, epoch)
.await
.unwrap()
.data;
assert_eq!(committee.validators.len(), E::sync_committee_size());
assert_eq!(
committee.validators,
flatten(&committee.validator_aggregates)
);
}
}