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grandpa: Use storage proofs for Grandpa authorities (paritytech#3734)
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* grandpa: Write Grandpa authorities to well known key.

Instead of requiring execution proofs for Grandpa authorities, this
enables much simpler storage proofs.

* grandpa: Introduce named AuthorityList type.

* grandpa: Storage migration for srml-grandpa module.

* Remove no-longer-used GrandpaApi runtime API.

* grandpa: Write AuthorityList to storage with encoding version.

We expect the AuthorityList type may change (eg. key changes). To make
upgrades smoother, include a version in the stored value.

* Bump node runtime spec version.

* Update srml/grandpa/src/lib.rs

Co-Authored-By: André Silva <andre.beat@gmail.com>
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jimpo and andresilva authored Oct 31, 2019
1 parent a746d38 commit c3b1a98
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Showing 18 changed files with 263 additions and 195 deletions.
1 change: 0 additions & 1 deletion Cargo.lock

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2 changes: 0 additions & 2 deletions core/finality-grandpa/primitives/Cargo.toml
Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,6 @@ authors = ["Parity Technologies <admin@parity.io>"]
edition = "2018"

[dependencies]
client = { package = "substrate-client", path = "../../client", default-features = false }
app-crypto = { package = "substrate-application-crypto", path = "../../application-crypto", default-features = false }
codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false, features = ["derive"] }
sr-primitives = { path = "../../sr-primitives", default-features = false }
Expand All @@ -15,7 +14,6 @@ serde = { version = "1.0.101", optional = true, features = ["derive"] }
[features]
default = ["std"]
std = [
"client/std",
"codec/std",
"sr-primitives/std",
"rstd/std",
Expand Down
78 changes: 56 additions & 22 deletions core/finality-grandpa/primitives/src/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -23,9 +23,9 @@ extern crate alloc;

#[cfg(feature = "std")]
use serde::Serialize;
use codec::{Encode, Decode, Codec};
use codec::{Encode, Decode, Input, Codec};
use sr_primitives::{ConsensusEngineId, RuntimeDebug};
use client::decl_runtime_apis;
use rstd::borrow::Cow;
use rstd::vec::Vec;

mod app {
Expand All @@ -46,6 +46,10 @@ pub type AuthoritySignature = app::Signature;
/// The `ConsensusEngineId` of GRANDPA.
pub const GRANDPA_ENGINE_ID: ConsensusEngineId = *b"FRNK";

/// The storage key for the current set of weighted Grandpa authorities.
/// The value stored is an encoded VersionedAuthorityList.
pub const GRANDPA_AUTHORITIES_KEY: &'static [u8] = b":grandpa_authorities";

/// The weight of an authority.
pub type AuthorityWeight = u64;

Expand All @@ -58,12 +62,15 @@ pub type SetId = u64;
/// The round indicator.
pub type RoundNumber = u64;

/// A list of Grandpa authorities with associated weights.
pub type AuthorityList = Vec<(AuthorityId, AuthorityWeight)>;

/// A scheduled change of authority set.
#[cfg_attr(feature = "std", derive(Serialize))]
#[derive(Clone, Eq, PartialEq, Encode, Decode, RuntimeDebug)]
pub struct ScheduledChange<N> {
/// The new authorities after the change, along with their respective weights.
pub next_authorities: Vec<(AuthorityId, AuthorityWeight)>,
pub next_authorities: AuthorityList,
/// The number of blocks to delay.
pub delay: N,
}
Expand Down Expand Up @@ -154,24 +161,51 @@ pub const PENDING_CHANGE_CALL: &str = "grandpa_pending_change";
/// WASM function call to get current GRANDPA authorities.
pub const AUTHORITIES_CALL: &str = "grandpa_authorities";

decl_runtime_apis! {
/// APIs for integrating the GRANDPA finality gadget into runtimes.
/// This should be implemented on the runtime side.
///
/// This is primarily used for negotiating authority-set changes for the
/// gadget. GRANDPA uses a signaling model of changing authority sets:
/// changes should be signaled with a delay of N blocks, and then automatically
/// applied in the runtime after those N blocks have passed.
///
/// The consensus protocol will coordinate the handoff externally.
#[api_version(2)]
pub trait GrandpaApi {
/// Get the current GRANDPA authorities and weights. This should not change except
/// for when changes are scheduled and the corresponding delay has passed.
///
/// When called at block B, it will return the set of authorities that should be
/// used to finalize descendants of this block (B+1, B+2, ...). The block B itself
/// is finalized by the authorities from block B-1.
fn grandpa_authorities() -> Vec<(AuthorityId, AuthorityWeight)>;
/// The current version of the stored AuthorityList type. The encoding version MUST be updated any
/// time the AuthorityList type changes.
const AUTHORITIES_VERISON: u8 = 1;

/// An AuthorityList that is encoded with a version specifier. The encoding version is updated any
/// time the AuthorityList type changes. This ensures that encodings of different versions of an
/// AuthorityList are differentiable. Attempting to decode an authority list with an unknown
/// version will fail.
#[derive(Default)]
pub struct VersionedAuthorityList<'a>(Cow<'a, AuthorityList>);

impl<'a> From<AuthorityList> for VersionedAuthorityList<'a> {
fn from(authorities: AuthorityList) -> Self {
VersionedAuthorityList(Cow::Owned(authorities))
}
}

impl<'a> From<&'a AuthorityList> for VersionedAuthorityList<'a> {
fn from(authorities: &'a AuthorityList) -> Self {
VersionedAuthorityList(Cow::Borrowed(authorities))
}
}

impl<'a> Into<AuthorityList> for VersionedAuthorityList<'a> {
fn into(self) -> AuthorityList {
self.0.into_owned()
}
}

impl<'a> Encode for VersionedAuthorityList<'a> {
fn size_hint(&self) -> usize {
(AUTHORITIES_VERISON, self.0.as_ref()).size_hint()
}

fn using_encoded<R, F: FnOnce(&[u8]) -> R>(&self, f: F) -> R {
(AUTHORITIES_VERISON, self.0.as_ref()).using_encoded(f)
}
}

impl<'a> Decode for VersionedAuthorityList<'a> {
fn decode<I: Input>(value: &mut I) -> Result<Self, codec::Error> {
let (version, authorities): (u8, AuthorityList) = Decode::decode(value)?;
if version != AUTHORITIES_VERISON {
return Err("unknown Grandpa authorities version".into());
}
Ok(authorities.into())
}
}
8 changes: 4 additions & 4 deletions core/finality-grandpa/src/authorities.rs
Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,7 @@ use grandpa::voter_set::VoterSet;
use codec::{Encode, Decode};
use log::{debug, info};
use substrate_telemetry::{telemetry, CONSENSUS_INFO};
use fg_primitives::AuthorityId;
use fg_primitives::{AuthorityId, AuthorityList};

use std::cmp::Ord;
use std::fmt::Debug;
Expand Down Expand Up @@ -86,7 +86,7 @@ pub(crate) struct Status<H, N> {
/// A set of authorities.
#[derive(Debug, Clone, Encode, Decode, PartialEq)]
pub(crate) struct AuthoritySet<H, N> {
pub(crate) current_authorities: Vec<(AuthorityId, u64)>,
pub(crate) current_authorities: AuthorityList,
pub(crate) set_id: u64,
// Tree of pending standard changes across forks. Standard changes are
// enacted on finality and must be enacted (i.e. finalized) in-order across
Expand All @@ -103,7 +103,7 @@ where H: PartialEq,
N: Ord,
{
/// Get a genesis set with given authorities.
pub(crate) fn genesis(initial: Vec<(AuthorityId, u64)>) -> Self {
pub(crate) fn genesis(initial: AuthorityList) -> Self {
AuthoritySet {
current_authorities: initial,
set_id: 0,
Expand Down Expand Up @@ -390,7 +390,7 @@ pub(crate) enum DelayKind<N> {
#[derive(Debug, Clone, Encode, PartialEq)]
pub(crate) struct PendingChange<H, N> {
/// The new authorities and weights to apply.
pub(crate) next_authorities: Vec<(AuthorityId, u64)>,
pub(crate) next_authorities: AuthorityList,
/// How deep in the chain the announcing block must be
/// before the change is applied.
pub(crate) delay: N,
Expand Down
9 changes: 5 additions & 4 deletions core/finality-grandpa/src/aux_schema.rs
Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,7 @@ use fork_tree::ForkTree;
use grandpa::round::State as RoundState;
use sr_primitives::traits::{Block as BlockT, NumberFor};
use log::{info, warn};
use fg_primitives::{AuthorityId, AuthorityWeight, SetId, RoundNumber};
use fg_primitives::{AuthorityList, SetId, RoundNumber};

use crate::authorities::{AuthoritySet, SharedAuthoritySet, PendingChange, DelayKind};
use crate::consensus_changes::{SharedConsensusChanges, ConsensusChanges};
Expand Down Expand Up @@ -55,15 +55,15 @@ type V0VoterSetState<H, N> = (RoundNumber, RoundState<H, N>);

#[derive(Debug, Clone, Encode, Decode, PartialEq)]
struct V0PendingChange<H, N> {
next_authorities: Vec<(AuthorityId, AuthorityWeight)>,
next_authorities: AuthorityList,
delay: N,
canon_height: N,
canon_hash: H,
}

#[derive(Debug, Clone, Encode, Decode, PartialEq)]
struct V0AuthoritySet<H, N> {
current_authorities: Vec<(AuthorityId, AuthorityWeight)>,
current_authorities: AuthorityList,
set_id: SetId,
pending_changes: Vec<V0PendingChange<H, N>>,
}
Expand Down Expand Up @@ -266,7 +266,7 @@ pub(crate) fn load_persistent<Block: BlockT, B, G>(
-> ClientResult<PersistentData<Block>>
where
B: AuxStore,
G: FnOnce() -> ClientResult<Vec<(AuthorityId, AuthorityWeight)>>,
G: FnOnce() -> ClientResult<AuthorityList>,
{
let version: Option<u32> = load_decode(backend, VERSION_KEY)?;
let consensus_changes = load_decode(backend, CONSENSUS_CHANGES_KEY)?
Expand Down Expand Up @@ -426,6 +426,7 @@ pub(crate) fn load_authorities<B: AuxStore, H: Decode, N: Decode>(backend: &B)

#[cfg(test)]
mod test {
use fg_primitives::AuthorityId;
use primitives::H256;
use test_client;
use super::*;
Expand Down
3 changes: 2 additions & 1 deletion core/finality-grandpa/src/communication/tests.rs
Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,7 @@ use codec::Encode;
use sr_primitives::traits::NumberFor;

use crate::environment::SharedVoterSetState;
use fg_primitives::AuthorityList;
use super::gossip::{self, GossipValidator};
use super::{AuthorityId, VoterSet, Round, SetId};

Expand Down Expand Up @@ -200,7 +201,7 @@ fn make_test_network() -> (
)
}

fn make_ids(keys: &[Ed25519Keyring]) -> Vec<(AuthorityId, u64)> {
fn make_ids(keys: &[Ed25519Keyring]) -> AuthorityList {
keys.iter()
.map(|key| key.clone().public().into())
.map(|id| (id, 1))
Expand Down
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