hbbft/tests/dynamic_honey_badger.rs

539 lines
20 KiB
Rust

use std::collections::{BTreeMap, BTreeSet};
use std::sync::Arc;
use std::time;
use hbbft::dynamic_honey_badger::{
Batch, Change, ChangeState, DynamicHoneyBadger, Input, JoinPlan,
};
use hbbft::sender_queue::{SenderQueue, Step};
use hbbft::{util, Epoched, PubKeyMap};
use hbbft_testing::adversary::{Adversary, ReorderingAdversary};
use hbbft_testing::proptest::{gen_seed, NetworkDimension, TestRng, TestRngSeed};
use hbbft_testing::{NetBuilder, NewNodeInfo, Node, VirtualNet};
use proptest::{prelude::ProptestConfig, prop_compose, proptest};
use rand::{seq::SliceRandom, SeedableRng};
type DHB = SenderQueue<DynamicHoneyBadger<Vec<usize>, usize>>;
/// Chooses a node's contribution for an epoch.
///
/// Selects randomly out of a slice, according to chosen batch and contribution sizes. The function
/// will not fail to do so, even if the queue is empty, returning a smaller or empty slice
/// `Vec` accordingly.
///
/// # Panics
///
/// The function asserts that `batch_size >= contribution_size`.
fn choose_contribution<R, T>(
rng: &mut R,
queue: &[T],
batch_size: usize,
contribution_size: usize,
) -> Vec<T>
where
R: rand::Rng,
T: Clone,
{
assert!(batch_size >= contribution_size);
let n = queue.len().min(batch_size);
let k = queue.len().min(contribution_size);
queue[0..n].choose_multiple(rng, k).cloned().collect()
}
/// Test configuration for dynamic honey badger tests.
#[derive(Debug)]
struct TestConfig {
/// The desired network dimension.
dimension: NetworkDimension,
/// Total number of transactions to execute before finishing.
total_txs: usize,
/// Epoch batch size.
batch_size: usize,
/// Individual nodes contribution size.
contribution_size: usize,
/// Random number generator to be passed to subsystems.
seed: TestRngSeed,
}
prop_compose! {
/// Strategy to generate a test configuration.
fn arb_config()
(dimension in NetworkDimension::range(3, 15),
total_txs in 20..60usize,
batch_size in 10..20usize,
contribution_size in 1..10usize,
seed in gen_seed())
-> TestConfig {
TestConfig {
dimension, total_txs, batch_size, contribution_size, seed
}
}
}
// Proptest wrapper for `do_drop_and_re_add`.
proptest! {
#![proptest_config(ProptestConfig::with_cases(1))]
#[test]
#[allow(clippy::unnecessary_operation)]
fn drop_and_re_add(cfg in arb_config()) {
do_drop_and_re_add(cfg)
}
}
/// Dynamic honey badger: Drop a validator node, demoting it to observer, then re-add it, all while
/// running a regular honey badger network.
// TODO: Add an observer node to the test network.
#[allow(clippy::needless_pass_by_value, clippy::cognitive_complexity)]
fn do_drop_and_re_add(cfg: TestConfig) {
// This returns an error in all but the first test.
let _ = env_logger::try_init();
let mut rng: TestRng = TestRng::from_seed(cfg.seed);
// First, we create a new test network with Honey Badger instances.
let num_faulty = cfg.dimension.faulty();
let (net, _) = NetBuilder::new(0..cfg.dimension.size())
.num_faulty(num_faulty)
// Limited to 20k messages per node.
.message_limit(20_000 * cfg.dimension.size() as usize)
// 30 secs per node.
.time_limit(time::Duration::from_secs(30 * cfg.dimension.size() as u64))
.adversary(ReorderingAdversary::new())
.using_step(move |node: NewNodeInfo<SenderQueue<_>>| {
let id = node.id;
println!(
"Constructing new {} dynamic honey badger node #{}",
if id < num_faulty { "faulty" } else { "correct" },
id
);
let netinfo = node.netinfo.clone();
let dhb = DynamicHoneyBadger::builder().build(netinfo, node.secret_key, node.pub_keys);
SenderQueue::builder(dhb, node.netinfo.other_ids().cloned()).build(node.id)
})
.build(&mut rng)
.expect("could not construct test network");
let mut state = TestState::new(net);
let nodes_for_remove = state.subset_for_remove(&mut rng);
println!("Will remove and re-add nodes {:?}", nodes_for_remove);
// We generate a list of total_txs transactions we want to propose, for each node.
let mut queues: BTreeMap<_, Vec<usize>> = state
.net
.nodes()
.map(|node| (*node.id(), (0..cfg.total_txs).collect()))
.collect();
// For each node, select transactions randomly from the queue and propose them.
for (id, queue) in &mut queues {
let proposal = choose_contribution(&mut rng, queue, cfg.batch_size, cfg.contribution_size);
println!("Node {:?} will propose: {:?}", id, proposal);
// The step will have its messages added to the queue automatically, we ignore the output.
let _ = state
.net
.send_input(*id, Input::User(proposal), &mut rng)
.expect("could not send initial transaction");
}
// Afterwards, remove specific nodes from the dynamic honey badger network.
let old_pub_keys = state.get_pub_keys();
let not_removed = |(id, _): &(usize, _)| !nodes_for_remove.contains(id);
let old_pub_keys_iter = (*old_pub_keys).clone().into_iter();
let new_pub_keys: PubKeyMap<usize> = Arc::new(old_pub_keys_iter.filter(not_removed).collect());
let change = Input::Change(Change::NodeChange(new_pub_keys.clone()));
state
.net
.broadcast_input(&change, &mut rng)
.expect("broadcasting failed");
// We are tracking (correct) nodes' state through the process by ticking them off individually.
let correct_nodes: BTreeSet<_> = state.net.correct_nodes().map(|n| *n.id()).collect();
let non_rm_nodes = &correct_nodes - &nodes_for_remove;
let mut awaiting_apply_new_subset: BTreeSet<_> = correct_nodes.clone();
let mut awaiting_apply_old_subset: BTreeSet<_> = correct_nodes.clone();
let mut awaiting_apply_old_subset_input: BTreeSet<_> = non_rm_nodes.clone();
let mut awaiting_apply_old_subset_in_progress: BTreeSet<_> = non_rm_nodes;
let mut expected_outputs: BTreeMap<_, BTreeSet<_>> = correct_nodes
.iter()
.map(|id| (id, (0..cfg.total_txs).collect()))
.collect();
let mut received_batches: BTreeMap<u64, _> = BTreeMap::new();
// Run the network:
loop {
let (node_id, step) = state.net.crank_expect(&mut rng);
if !state.net[node_id].is_faulty() {
for batch in &step.output {
// Check that correct nodes don't output different batches for the same epoch.
if let Some(b) = received_batches.insert(batch.epoch(), batch.clone()) {
assert!(
batch.public_eq(&b),
"A batch of node {} doesn't match a previous batch for the same epoch {}",
node_id,
batch.epoch()
);
}
let expected_participants: Vec<_> = if awaiting_apply_new_subset.contains(&node_id)
{
// The node hasn't applied a new subset of nodes yet.
old_pub_keys.keys()
} else if awaiting_apply_old_subset.contains(&node_id) {
// The node has applied a new subset of nodes.
new_pub_keys.keys()
} else {
// The node has applied the old (previous) subset of nodes back.
old_pub_keys.keys()
}
.collect();
assert!(
batch.contributions().count() * 3 > expected_participants.len() * 2,
"The batch contains less than N - f contributions: {:?}",
batch
);
// Verify that only contributions from expected participants are present in the
// batch.
let batch_participants: Vec<_> = batch.contributions().map(|(id, _)| id).collect();
assert!(
batch_participants
.iter()
.all(|id| expected_participants.contains(id)),
"The batch at node {} contains an unexpected participant: {:?} (expected {:?})",
node_id,
batch_participants,
expected_participants,
);
}
}
for change in step.output.iter().map(Batch::change) {
match change {
ChangeState::Complete(Change::NodeChange(ref pub_keys))
if *pub_keys == new_pub_keys =>
{
println!("Node {} done applying a new subset.", node_id);
// Applying a new subset complete, tally:
awaiting_apply_new_subset.remove(&node_id);
}
ChangeState::InProgress(Change::NodeChange(ref pub_keys))
if *pub_keys == old_pub_keys =>
{
println!(
"Node {} is progressing for applying the old subset.",
node_id
);
awaiting_apply_old_subset_in_progress.remove(&node_id);
}
ChangeState::Complete(Change::NodeChange(ref pub_keys))
if *pub_keys == old_pub_keys =>
{
println!("Node {} done applying the old subset back.", node_id);
// Node has applied the old subset, ensure it has applied the new subset previously.
assert!(
!awaiting_apply_new_subset.contains(&node_id),
"Node {} reported a success applying the old subset before applying the new subset.",
node_id,
);
awaiting_apply_old_subset.remove(&node_id);
}
ChangeState::None => (),
_ => {
println!("Unhandled change: {:?}", change);
}
}
}
let (era, hb_epoch) = state.net[node_id].algorithm().algo().epoch();
if !nodes_for_remove.contains(&node_id)
&& awaiting_apply_old_subset_input.contains(&node_id)
&& state.re_add_epoch.is_some()
&& era + hb_epoch >= state.re_add_epoch.unwrap()
{
// Now we apply old subset of node back. Public keys will be reused.
let step = state
.net
.send_input(
node_id,
Input::Change(Change::NodeChange(old_pub_keys.clone())),
&mut rng,
)
.expect("failed to send `apply old subset` input");
assert!(step.output.is_empty());
awaiting_apply_old_subset_input.remove(&node_id);
println!("Node {} started to apply old subset.", node_id);
}
// Record whether or not we received some output.
let has_output = !step.output.is_empty();
// Find the node's input queue.
let queue: &mut Vec<_> = queues
.get_mut(&node_id)
.expect("queue for node disappeared");
// Examine potential algorithm output.
for batch in step.output {
println!(
"Received epoch {} batch on node {:?}.",
batch.epoch(),
node_id,
);
// If this is a batch applying the new subset of nodes, record the epoch
// in which 'nodes_for_remove' will shut down.
if let ChangeState::Complete(Change::NodeChange(ref pub_keys)) = batch.change() {
if *pub_keys == new_pub_keys {
state.re_add_epoch = Some(batch.epoch() + 1);
}
}
for tx in batch.iter() {
// Remove the confirmed contribution from the input queue.
let index = queue.iter().position(|v| v == tx);
if let Some(idx) = index {
assert_eq!(queue.remove(idx), *tx);
}
// Add it to the set of received outputs.
if !state.net[node_id].is_faulty() {
expected_outputs
.get_mut(&node_id)
.expect("output set disappeared")
.remove(tx);
// Also, delete expected output from the 'nodes_for_remove' if those nodes are
// currently removed. They do not output any values in epochs in which they
// are not a participant.
if !nodes_for_remove.contains(&node_id)
&& awaiting_apply_new_subset.is_empty()
&& !state.old_subset_applied
{
nodes_for_remove.iter().for_each(|id| {
expected_outputs
.get_mut(&id)
.map(|output| output.remove(tx));
});
}
}
}
// If this is the first batch from a correct node with a vote to apply the old subset
// back, take the join plan of the batch and use it to restart removed nodes.
if !state.old_subset_applied
&& !state.net[node_id].is_faulty()
&& state.join_plan.is_none()
{
if let ChangeState::InProgress(Change::NodeChange(pub_keys)) = batch.change() {
if *pub_keys == old_pub_keys {
state.join_plan = Some(
batch
.join_plan()
.expect("failed to get the join plan of the batch"),
);
}
}
}
// Restart removed nodes having checked that they can be correctly restarted.
if !state.old_subset_applied && awaiting_apply_old_subset_in_progress.is_empty() {
if let Some(join_plan) = state.join_plan.take() {
let saved_nodes: Vec<_> = state.saved_nodes.drain(..).collect();
assert!(!saved_nodes.is_empty(), "removed nodes wasn't saved");
saved_nodes.into_iter().for_each(|node| {
let node_id = *node.id();
let step =
restart_node_for_add(&mut state.net, node, join_plan.clone(), &mut rng);
state
.net
.process_step(node_id, &step)
.expect("processing a step failed");
});
state.old_subset_applied = true;
}
}
}
let all_removed = |nodes: &BTreeSet<usize>| {
nodes
.iter()
.all(|id| state.net[*id].algorithm().is_removed())
};
// Decide - from the point of view of removed nodes - whether they are ready to go offline.
if !state.old_subset_applied
&& state.saved_nodes.is_empty()
&& all_removed(&nodes_for_remove)
{
println!(
"Removing nodes {:?} from the test network.",
nodes_for_remove
);
state.saved_nodes = state.net.remove_nodes(&nodes_for_remove);
if nodes_for_remove.contains(&node_id) {
// Further operations on the cranked node are not possible. Continue with
// processing other nodes.
continue;
}
}
// Check if we are done.
if expected_outputs.values().all(BTreeSet::is_empty)
&& awaiting_apply_old_subset.is_empty()
&& awaiting_apply_new_subset.is_empty()
{
// All outputs are empty, the old subset was applied back after that
// new subset was applied.
break;
}
// If not done, check if we still want to propose something.
if has_output {
// Out of the remaining transactions, select a suitable amount.
let proposal =
choose_contribution(&mut rng, queue, cfg.batch_size, cfg.contribution_size);
let _ = state
.net
.send_input(node_id, Input::User(proposal), &mut rng)
.expect("could not send follow-up transaction");
}
}
// As a final step, we verify that all nodes have arrived at the same conclusion.
// Removed nodes can miss some batches while they were removed.
let result: Vec<_> = state
.net
.correct_nodes()
.filter(|node| !nodes_for_remove.contains(node.id()))
.map(|node| {
state.net.verify_batches(&node);
node.outputs()
})
.collect();
assert!(!result.is_empty(), "Could not find a full node");
println!("End result: {:?}", result);
}
/// Restarts specified node on the test network for adding it back as a validator.
fn restart_node_for_add<R, A>(
net: &mut VirtualNet<DHB, A>,
mut node: Node<DHB>,
join_plan: JoinPlan<usize>,
rng: &mut R,
) -> Step<DynamicHoneyBadger<Vec<usize>, usize>>
where
R: rand::Rng,
A: Adversary<DHB>,
{
println!("Restarting node {} with {:?}", node.id(), join_plan);
// TODO: When an observer node is added to the network, it should also be added to peer_ids.
let peer_ids: Vec<_> = net
.nodes()
.map(Node::id)
.filter(|id| *id != node.id())
.cloned()
.collect();
let step = node
.algorithm_mut()
.restart(join_plan, peer_ids.into_iter(), rng)
.expect("failed to restart the node");
net.insert_node(node);
step
}
/// Internal state of the test.
struct TestState<A>
where
A: Adversary<DHB>,
{
/// The test network.
net: VirtualNet<DHB, A>,
/// The join plan for adding nodes.
join_plan: Option<JoinPlan<usize>>,
/// The epoch in which the removed nodes should go offline.
re_add_epoch: Option<u64>,
/// The removed nodes which are to be restarted as soon as all remaining
/// validators agree to add them back.
saved_nodes: Vec<Node<DHB>>,
/// Whether the old subset of validators was applied back to the network.
old_subset_applied: bool,
}
impl<A> TestState<A>
where
A: Adversary<DHB>,
{
/// Constructs a new `VirtualNetState`.
fn new(net: VirtualNet<DHB, A>) -> Self {
TestState {
net,
join_plan: None,
re_add_epoch: None,
saved_nodes: Vec::new(),
old_subset_applied: false,
}
}
/// Selects random subset of validators which can be safely removed from the network.
///
/// The cluster always remain correct after removing this subset from the cluster.
/// This method may select correct nodes as well as malicious ones.
fn subset_for_remove<R>(&self, rng: &mut R) -> BTreeSet<usize>
where
R: rand::Rng,
{
let net = &self.net;
let (faulty, correct): (Vec<_>, Vec<_>) = net.nodes().partition(|n| n.is_faulty());
let f = faulty.len();
let n = correct.len() + f;
assert!(n > 2, "cannot remove any more nodes");
assert!(
n > f * 3,
"the network is already captured by the faulty nodes"
);
let new_n = rng.gen_range(2, n); // new_n is between 2 and n-1
let min_new_f = f.saturating_sub(n - new_n);
let new_f = rng.gen_range(min_new_f, f.min(util::max_faulty(new_n)) + 1);
let remove_from_faulty = f - new_f;
let remove_from_correct = n - new_n - remove_from_faulty;
let result: BTreeSet<usize> = correct
.choose_multiple(rng, remove_from_correct)
.map(|n| *n.id())
.chain(
faulty
.choose_multiple(rng, remove_from_faulty)
.map(|n| *n.id()),
)
.collect();
assert!(
!result.is_empty(),
"subset for remove should have at least one node"
);
println!("{} nodes were chosen for removing", result.len());
result
}
/// Returns clone of all public keys for this network.
fn get_pub_keys(&self) -> PubKeyMap<usize> {
self.net
.get(0)
.expect("network should have at least one node")
.algorithm()
.algo()
.public_keys()
.clone()
}
}