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feat(bitcoind_rpc)!: emissions include checkpoint and connected_to data
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Previously, emissions are purely blocks + the block height. This means
emitted blocks can only connect to previous-adjacent blocks. Hence, sync
must start from genesis and include every block.
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@evanlinjin
evanlinjin committed Jan 15, 2024
1 parent 8f2d4d9 commit e0512ac
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Showing 3 changed files with 128 additions and 74 deletions.
70 changes: 59 additions & 11 deletions crates/bitcoind_rpc/src/lib.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -43,11 +43,13 @@ pub struct Emitter<'c, C> {
}

impl<'c, C: bitcoincore_rpc::RpcApi> Emitter<'c, C> {
/// Construct a new [`Emitter`] with the given RPC `client`, `last_cp` and `start_height`.
/// Construct a new [`Emitter`].
///
/// * `last_cp` is the check point used to find the latest block which is still part of the best
/// chain.
/// * `start_height` is the block height to start emitting blocks from.
/// `last_cp` informs the emitter of the chain we are starting off with. This way, the emitter
/// can start emission from a block that connects to the original chain.
///
/// `start_height` starts emission from a given height (if there are no conflicts with the
/// original chain).
pub fn new(client: &'c C, last_cp: CheckPoint, start_height: u32) -> Self {
Self {
client,
Expand Down Expand Up @@ -127,13 +129,58 @@ impl<'c, C: bitcoincore_rpc::RpcApi> Emitter<'c, C> {
}

/// Emit the next block height and header (if any).
pub fn next_header(&mut self) -> Result<Option<(u32, Header)>, bitcoincore_rpc::Error> {
poll(self, |hash| self.client.get_block_header(hash))
pub fn next_header(&mut self) -> Result<Option<BlockEvent<Header>>, bitcoincore_rpc::Error> {
Ok(poll(self, |hash| self.client.get_block_header(hash))?
.map(|(checkpoint, block)| BlockEvent { block, checkpoint }))
}

/// Emit the next block height and block (if any).
pub fn next_block(&mut self) -> Result<Option<(u32, Block)>, bitcoincore_rpc::Error> {
poll(self, |hash| self.client.get_block(hash))
pub fn next_block(&mut self) -> Result<Option<BlockEvent<Block>>, bitcoincore_rpc::Error> {
Ok(poll(self, |hash| self.client.get_block(hash))?
.map(|(checkpoint, block)| BlockEvent { block, checkpoint }))
}
}

/// A newly emitted block from [`Emitter`].
#[derive(Debug)]
pub struct BlockEvent<B> {
/// Either a full [`Block`] or [`Header`] of the new block.
pub block: B,

/// The checkpoint of the new block.
///
/// A [`CheckPoint`] is a node of a linked list of [`BlockId`]s. This checkpoint is linked to
/// all [`BlockId`]s originally passed in [`Emitter::new`] as well as emitted blocks since then.
/// These blocks are guaranteed to be of the same chain.
///
/// This is important as BDK structures require block-to-apply to be connected with another
/// block in the original chain.
pub checkpoint: CheckPoint,
}

impl<B> BlockEvent<B> {
/// The block height of this new block.
pub fn block_height(&self) -> u32 {
self.checkpoint.height()
}

/// The block hash of this new block.
pub fn block_hash(&self) -> BlockHash {
self.checkpoint.hash()
}

/// The [`BlockId`] of a previous block that this block connects to.
///
/// This either returns a [`BlockId`] of a previously emitted block or from the chain we started
/// with (passed in as `last_cp` in [`Emitter::new`]).
///
/// This value is derived from [`BlockEvent::checkpoint`].
pub fn connected_to(&self) -> BlockId {
match self.checkpoint.prev() {
Some(prev_cp) => prev_cp.block_id(),
// there is no previous checkpoint, so just connect with itself
None => self.checkpoint.block_id(),
}
}
}

Expand Down Expand Up @@ -203,7 +250,7 @@ where
fn poll<C, V, F>(
emitter: &mut Emitter<C>,
get_item: F,
) -> Result<Option<(u32, V)>, bitcoincore_rpc::Error>
) -> Result<Option<(CheckPoint, V)>, bitcoincore_rpc::Error>
where
C: bitcoincore_rpc::RpcApi,
F: Fn(&BlockHash) -> Result<V, bitcoincore_rpc::Error>,
Expand All @@ -215,13 +262,14 @@ where
let hash = res.hash;
let item = get_item(&hash)?;

emitter.last_cp = emitter
let new_cp = emitter
.last_cp
.clone()
.push(BlockId { height, hash })
.expect("must push");
emitter.last_cp = new_cp.clone();
emitter.last_block = Some(res);
return Ok(Some((height, item)));
return Ok(Some((new_cp, item)));
}
PollResponse::NoMoreBlocks => {
emitter.last_block = None;
Expand Down
98 changes: 48 additions & 50 deletions crates/bitcoind_rpc/tests/test_emitter.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -157,28 +157,6 @@ impl TestEnv {
}
}

fn block_to_chain_update(block: &bitcoin::Block, height: u32) -> local_chain::Update {
let this_id = BlockId {
height,
hash: block.block_hash(),
};
let tip = if block.header.prev_blockhash == BlockHash::all_zeros() {
CheckPoint::new(this_id)
} else {
CheckPoint::new(BlockId {
height: height - 1,
hash: block.header.prev_blockhash,
})
.extend(core::iter::once(this_id))
.expect("must construct checkpoint")
};

local_chain::Update {
tip,
introduce_older_blocks: false,
}
}

/// Ensure that blocks are emitted in order even after reorg.
///
/// 1. Mine 101 blocks.
Expand All @@ -200,17 +178,21 @@ pub fn test_sync_local_chain() -> anyhow::Result<()> {

// see if the emitter outputs the right blocks
println!("first sync:");
while let Some((height, block)) = emitter.next_block()? {
while let Some(emission) = emitter.next_block()? {
let height = emission.block_height();
let hash = emission.block_hash();
assert_eq!(
block.block_hash(),
emission.block_hash(),
exp_hashes[height as usize],
"emitted block hash is unexpected"
);

let chain_update = block_to_chain_update(&block, height);
assert_eq!(
local_chain.apply_update(chain_update)?,
BTreeMap::from([(height, Some(block.block_hash()))]),
local_chain.apply_update(local_chain::Update {
tip: emission.checkpoint,
introduce_older_blocks: false,
})?,
BTreeMap::from([(height, Some(hash))]),
"chain update changeset is unexpected",
);
}
Expand All @@ -237,27 +219,30 @@ pub fn test_sync_local_chain() -> anyhow::Result<()> {
// see if the emitter outputs the right blocks
println!("after reorg:");
let mut exp_height = exp_hashes.len() - reorged_blocks.len();
while let Some((height, block)) = emitter.next_block()? {
while let Some(emission) = emitter.next_block()? {
let height = emission.block_height();
let hash = emission.block_hash();
assert_eq!(
height, exp_height as u32,
"emitted block has unexpected height"
);

assert_eq!(
block.block_hash(),
exp_hashes[height as usize],
hash, exp_hashes[height as usize],
"emitted block is unexpected"
);

let chain_update = block_to_chain_update(&block, height);
assert_eq!(
local_chain.apply_update(chain_update)?,
local_chain.apply_update(local_chain::Update {
tip: emission.checkpoint,
introduce_older_blocks: false,
})?,
if exp_height == exp_hashes.len() - reorged_blocks.len() {
core::iter::once((height, Some(block.block_hash())))
core::iter::once((height, Some(hash)))
.chain((height + 1..exp_hashes.len() as u32).map(|h| (h, None)))
.collect::<bdk_chain::local_chain::ChangeSet>()
} else {
BTreeMap::from([(height, Some(block.block_hash()))])
BTreeMap::from([(height, Some(hash))])
},
"chain update changeset is unexpected",
);
Expand Down Expand Up @@ -307,9 +292,13 @@ fn test_into_tx_graph() -> anyhow::Result<()> {

let emitter = &mut Emitter::new(&env.client, chain.tip(), 0);

while let Some((height, block)) = emitter.next_block()? {
let _ = chain.apply_update(block_to_chain_update(&block, height))?;
let indexed_additions = indexed_tx_graph.apply_block_relevant(block, height);
while let Some(emission) = emitter.next_block()? {
let height = emission.block_height();
let _ = chain.apply_update(local_chain::Update {
tip: emission.checkpoint,
introduce_older_blocks: false,
})?;
let indexed_additions = indexed_tx_graph.apply_block_relevant(emission.block, height);
assert!(indexed_additions.is_empty());
}

Expand Down Expand Up @@ -367,10 +356,13 @@ fn test_into_tx_graph() -> anyhow::Result<()> {

// must receive mined block which will confirm the transactions.
{
let (height, block) = emitter.next_block()?.expect("must get mined block");
let _ = chain
.apply_update(CheckPoint::from_header(&block.header, height).into_update(false))?;
let indexed_additions = indexed_tx_graph.apply_block_relevant(block, height);
let emission = emitter.next_block()?.expect("must get mined block");
let height = emission.block_height();
let _ = chain.apply_update(local_chain::Update {
tip: emission.checkpoint,
introduce_older_blocks: false,
})?;
let indexed_additions = indexed_tx_graph.apply_block_relevant(emission.block, height);
assert!(indexed_additions.graph.txs.is_empty());
assert!(indexed_additions.graph.txouts.is_empty());
assert_eq!(indexed_additions.graph.anchors, exp_anchors);
Expand Down Expand Up @@ -407,9 +399,12 @@ fn ensure_block_emitted_after_reorg_is_at_reorg_height() -> anyhow::Result<()> {

for reorg_count in 1..=10 {
let replaced_blocks = env.reorg_empty_blocks(reorg_count)?;
let (height, next_header) = emitter.next_header()?.expect("must emit block after reorg");
let next_emission = emitter.next_header()?.expect("must emit block after reorg");
assert_eq!(
(height as usize, next_header.block_hash()),
(
next_emission.block_height() as usize,
next_emission.block_hash()
),
replaced_blocks[0],
"block emitted after reorg should be at the reorg height"
);
Expand Down Expand Up @@ -439,8 +434,9 @@ fn sync_from_emitter<C>(
where
C: bitcoincore_rpc::RpcApi,
{
while let Some((height, block)) = emitter.next_block()? {
process_block(recv_chain, recv_graph, block, height)?;
while let Some(emission) = emitter.next_block()? {
let height = emission.block_height();
process_block(recv_chain, recv_graph, emission.block, height)?;
}
Ok(())
}
Expand Down Expand Up @@ -660,7 +656,8 @@ fn mempool_re_emits_if_tx_introduction_height_not_reached() -> anyhow::Result<()

// At this point, the emitter has seen all mempool transactions. It should only re-emit those
// that have introduction heights less than the emitter's last-emitted block tip.
while let Some((height, _)) = emitter.next_header()? {
while let Some(emission) = emitter.next_header()? {
let height = emission.block_height();
// We call `mempool()` twice.
// The second call (at height `h`) should skip the tx introduced at height `h`.
for try_index in 0..2 {
Expand Down Expand Up @@ -754,7 +751,8 @@ fn mempool_during_reorg() -> anyhow::Result<()> {
.collect::<BTreeMap<_, _>>());

// `next_header` emits the replacement block of the reorg
if let Some((height, _)) = emitter.next_header()? {
if let Some(emission) = emitter.next_header()? {
let height = emission.block_height();
println!("\t- replacement height: {}", height);

// the mempool emission (that follows the first block emission after reorg) should only
Expand Down Expand Up @@ -835,12 +833,12 @@ fn no_agreement_point() -> anyhow::Result<()> {
env.mine_blocks(PREMINE_COUNT, None)?;

// emit block 99a
let (_, block_header_99a) = emitter.next_header()?.expect("block 99a header");
let block_header_99a = emitter.next_header()?.expect("block 99a header").block;
let block_hash_99a = block_header_99a.block_hash();
let block_hash_98a = block_header_99a.prev_blockhash;

// emit block 100a
let (_, block_header_100a) = emitter.next_header()?.expect("block 100a header");
let block_header_100a = emitter.next_header()?.expect("block 100a header").block;
let block_hash_100a = block_header_100a.block_hash();

// get hash for block 101a
Expand All @@ -855,7 +853,7 @@ fn no_agreement_point() -> anyhow::Result<()> {
env.mine_blocks(3, None)?;

// emit block header 99b
let (_, block_header_99b) = emitter.next_header()?.expect("block 99b header");
let block_header_99b = emitter.next_header()?.expect("block 99b header").block;
let block_hash_99b = block_header_99b.block_hash();
let block_hash_98b = block_header_99b.prev_blockhash;

Expand Down
34 changes: 21 additions & 13 deletions example-crates/example_bitcoind_rpc_polling/src/main.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,7 @@ use bdk_bitcoind_rpc::{
use bdk_chain::{
bitcoin::{constants::genesis_block, Block, Transaction},
indexed_tx_graph, keychain,
local_chain::{self, CheckPoint, LocalChain},
local_chain::{self, LocalChain},
ConfirmationTimeHeightAnchor, IndexedTxGraph,
};
use example_cli::{
Expand Down Expand Up @@ -42,7 +42,7 @@ type ChangeSet = (

#[derive(Debug)]
enum Emission {
Block { height: u32, block: Block },
Block(bdk_bitcoind_rpc::BlockEvent<Block>),
Mempool(Vec<(Transaction, u64)>),
Tip(u32),
}
Expand Down Expand Up @@ -178,17 +178,20 @@ fn main() -> anyhow::Result<()> {
let mut last_db_commit = Instant::now();
let mut last_print = Instant::now();

while let Some((height, block)) = emitter.next_block()? {
while let Some(emission) = emitter.next_block()? {
let height = emission.block_height();

let mut chain = chain.lock().unwrap();
let mut graph = graph.lock().unwrap();
let mut db = db.lock().unwrap();

let chain_update =
CheckPoint::from_header(&block.header, height).into_update(false);
let chain_changeset = chain
.apply_update(chain_update)
.apply_update(local_chain::Update {
tip: emission.checkpoint,
introduce_older_blocks: false,
})
.expect("must always apply as we receive blocks in order from emitter");
let graph_changeset = graph.apply_block_relevant(block, height);
let graph_changeset = graph.apply_block_relevant(emission.block, height);
db.stage((chain_changeset, graph_changeset));

// commit staged db changes in intervals
Expand Down Expand Up @@ -256,15 +259,16 @@ fn main() -> anyhow::Result<()> {

loop {
match emitter.next_block()? {
Some((height, block)) => {
Some(block_emission) => {
let height = block_emission.block_height();
if sigterm_flag.load(Ordering::Acquire) {
break;
}
if height > block_count {
block_count = rpc_client.get_block_count()? as u32;
tx.send(Emission::Tip(block_count))?;
}
tx.send(Emission::Block { height, block })?;
tx.send(Emission::Block(block_emission))?;
}
None => {
if await_flag(&sigterm_flag, MEMPOOL_EMIT_DELAY) {
Expand Down Expand Up @@ -293,13 +297,17 @@ fn main() -> anyhow::Result<()> {
let mut chain = chain.lock().unwrap();

let changeset = match emission {
Emission::Block { height, block } => {
let chain_update =
CheckPoint::from_header(&block.header, height).into_update(false);
Emission::Block(block_emission) => {
let height = block_emission.block_height();
let chain_update = local_chain::Update {
tip: block_emission.checkpoint,
introduce_older_blocks: false,
};
let chain_changeset = chain
.apply_update(chain_update)
.expect("must always apply as we receive blocks in order from emitter");
let graph_changeset = graph.apply_block_relevant(block, height);
let graph_changeset =
graph.apply_block_relevant(block_emission.block, height);
(chain_changeset, graph_changeset)
}
Emission::Mempool(mempool_txs) => {
Expand Down

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