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remove ApprovalCheckingVotingRule
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@ordian
ordian committed Jul 20, 2021
1 parent b7bc78d commit c3d51b8
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Showing 2 changed files with 1 addition and 191 deletions.
175 changes: 1 addition & 174 deletions node/service/src/grandpa_support.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -23,156 +23,7 @@ use sp_runtime::generic::BlockId;
use sp_runtime::traits::Header as _;

#[cfg(feature = "full-node")]
use {
polkadot_primitives::v1::{Hash, Block as PolkadotBlock, Header as PolkadotHeader},
polkadot_subsystem::messages::ApprovalVotingMessage,
polkadot_overseer::Handle,
futures::channel::oneshot,
};

/// A custom GRANDPA voting rule that acts as a diagnostic for the approval
/// voting subsystem's desired votes.
///
/// The practical effect of this voting rule is to implement a fixed delay of
/// blocks.
#[cfg(feature = "full-node")]
#[derive(Clone)]
pub(crate) struct ApprovalCheckingVotingRule {
overseer: Handle,
}

#[cfg(feature = "full-node")]
impl ApprovalCheckingVotingRule {
/// Create a new approval checking diagnostic voting rule.
pub fn new(overseer: Handle) -> Self {
Self {
overseer,
}
}
}

#[cfg(feature = "full-node")]
#[derive(Debug, PartialEq)]
/// Vote explicitly on the given hash.
enum ParachainVotingRuleTarget<H, N> {
Explicit((H, N)),
/// Vote on the current target.
Current,
/// Vote on the base target - the minimal possible vote.
Base,
}

#[cfg(feature = "full-node")]
fn approval_checking_vote_to_grandpa_vote<H, N: PartialOrd>(
approval_checking_vote: Option<(H, N)>,
current_number: N,
) -> ParachainVotingRuleTarget<H, N> {
match approval_checking_vote {
Some((hash, number)) => if number > current_number {
// respect other voting rule.
ParachainVotingRuleTarget::Current
} else {
ParachainVotingRuleTarget::Explicit((hash, number))
},
// If approval-voting chooses 'None', that means we should vote on the base (last round estimate).
None => ParachainVotingRuleTarget::Base,
}
}

/// The maximum amount of unfinalized blocks we are willing to allow due to approval checking lag.
/// This is a safety net that should be removed at some point in the future.
#[cfg(feature = "full-node")]
const MAX_APPROVAL_CHECKING_FINALITY_LAG: polkadot_primitives::v1::BlockNumber = 50;

#[cfg(feature = "full-node")]
impl<B> grandpa::VotingRule<PolkadotBlock, B> for ApprovalCheckingVotingRule
where B: sp_blockchain::HeaderBackend<PolkadotBlock> + 'static
{
fn restrict_vote(
&self,
backend: Arc<B>,
base: &PolkadotHeader,
best_target: &PolkadotHeader,
current_target: &PolkadotHeader,
) -> grandpa::VotingRuleResult<PolkadotBlock> {
// Query approval checking and issue metrics.
let mut overseer = self.overseer.clone();

let best_hash = best_target.hash();
let best_number = best_target.number.clone();
let best_header = best_target.clone();

let current_hash = current_target.hash();
let current_number = current_target.number.clone();

let base_hash = base.hash();
let base_number = base.number;

Box::pin(async move {
let (tx, rx) = oneshot::channel();
let approval_checking_subsystem_vote = {
overseer.send_msg(
ApprovalVotingMessage::ApprovedAncestor(
best_hash,
base_number,
tx,
),
std::any::type_name::<Self>(),
).await;

rx.await.ok().and_then(|v| v)
};

let approval_checking_subsystem_lag = approval_checking_subsystem_vote.map_or(
best_number - base_number,
|(_h, n)| best_number - n,
);

let min_vote = {
let diff = best_number.saturating_sub(base_number);
if diff >= MAX_APPROVAL_CHECKING_FINALITY_LAG {
// Catch up to the best, with some extra lag.
let target_number = best_number - MAX_APPROVAL_CHECKING_FINALITY_LAG;
if target_number >= current_number {
Some((current_hash, current_number))
} else {
walk_backwards_to_target_block(&*backend, target_number, &best_header).ok()
}
} else {
Some((base_hash, base_number))
}
};

let vote = match approval_checking_vote_to_grandpa_vote(
approval_checking_subsystem_vote,
current_number,
) {
ParachainVotingRuleTarget::Explicit(vote) => {
if min_vote.as_ref().map_or(false, |min| min.1 > vote.1) {
min_vote
} else {
Some(vote)
}
}
ParachainVotingRuleTarget::Current => Some((current_hash, current_number)),
ParachainVotingRuleTarget::Base => min_vote.or(Some((base_hash, base_number))),
};

tracing::trace!(
target: "parachain::approval-voting",
?vote,
?approval_checking_subsystem_vote,
approval_checking_subsystem_lag,
current_number,
best_number,
base_number,
"GRANDPA: voting based on approved ancestor.",
);

vote
})
}
}
use polkadot_primitives::v1::Hash;

/// Returns the block hash of the block at the given `target_number` by walking
/// backwards from the given `current_header`.
Expand Down Expand Up @@ -410,7 +261,6 @@ mod tests {
use sp_runtime::{generic::BlockId, traits::Header};
use consensus_common::BlockOrigin;
use std::sync::Arc;
use super::{approval_checking_vote_to_grandpa_vote, ParachainVotingRuleTarget};

#[test]
fn grandpa_pause_voting_rule_works() {
Expand Down Expand Up @@ -522,27 +372,4 @@ mod tests {
None,
);
}

#[test]
fn approval_checking_to_grandpa_rules() {
assert_eq!(
approval_checking_vote_to_grandpa_vote::<(), _>(None, 5),
ParachainVotingRuleTarget::Base,
);

assert_eq!(
approval_checking_vote_to_grandpa_vote(Some(("2", 2)), 3),
ParachainVotingRuleTarget::Explicit(("2", 2)),
);

assert_eq!(
approval_checking_vote_to_grandpa_vote(Some(("2", 2)), 2),
ParachainVotingRuleTarget::Explicit(("2", 2)),
);

assert_eq!(
approval_checking_vote_to_grandpa_vote(Some(("2", 2)), 1),
ParachainVotingRuleTarget::Current,
);
}
}
17 changes: 0 additions & 17 deletions node/service/src/lib.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -907,23 +907,6 @@ pub fn new_full<RuntimeApi, Executor, OverseerGenerator>(
// after the given pause block is finalized and restarting after the
// given delay.
let builder = grandpa::VotingRulesBuilder::default();
// we should enable approval checking voting rule before we deploy parachains on polkadot
let enable_approval_checking_voting_rule = chain_spec.is_kusama()
|| chain_spec.is_westend()
|| chain_spec.is_rococo()
|| chain_spec.is_wococo();

let builder = if let Some(ref overseer) = overseer_handler {
if enable_approval_checking_voting_rule {
builder.add(grandpa_support::ApprovalCheckingVotingRule::new(
overseer.clone(),
))
} else {
builder
}
} else {
builder
};

let voting_rule = match grandpa_pause {
Some((block, delay)) => {
Expand Down

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