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Stop awaiting the previous block in the block verifier 

Instead, the state should cache blocks until the previous block has been
committed.
This commit is contained in:
teor 2020-09-04 20:54:14 +10:00 committed by Henry de Valence
parent 8463b705c8
commit 7f2bebb97d
1 changed files with 2 additions and 62 deletions
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64
zebra-consensus/src/block.rs
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@ -22,9 +22,7 @@ use std::{
pin::Pin,
sync::Arc,
task::{Context, Poll},
time::Duration,
};
use tokio::time;
use tower::{buffer::Buffer, Service, ServiceExt};
use zebra_chain::block::{self, Block};
@ -125,42 +123,6 @@ where
// TODO: context-free header verification: merkle root
// As a temporary solution for chain gaps, wait for the previous block,
// and check its height.
//
// TODO: replace this check with the contextual verification RFC design
//
// Skip contextual checks for the genesis block
let previous_block_hash = block.header.previous_block_hash;
if previous_block_hash != crate::parameters::GENESIS_PREVIOUS_BLOCK_HASH {
if height == block::Height(0) {
Err(format!("invalid block {:?}: height is 0, but previous block hash {:?} is not null",
hash,
previous_block_hash))?;
}
let expected_height = block::Height(height.0 - 1);
tracing::trace!(?expected_height, ?previous_block_hash, "Waiting for previous block");
metrics::gauge!("block.waiting.block.height", expected_height.0 as i64);
metrics::counter!("block.waiting.count", 1);
let previous_block = BlockVerifier::await_block(
&mut state_service,
previous_block_hash,
expected_height,
)
.await?;
let previous_height = previous_block.coinbase_height().unwrap();
if previous_height != expected_height {
Err(format!("invalid block height {:?} for {:?}: must be 1 more than the previous block height {:?} in {:?}",
height,
hash,
previous_height,
previous_block_hash))?;
}
}
tracing::trace!("verified block");
metrics::gauge!(
"block.verified.block.height",
@ -168,9 +130,8 @@ where
);
metrics::counter!("block.verified.block.count", 1);
// We need to add the block after the previous block is in the state,
// and before this future returns. Otherwise, blocks could be
// committed out of order.
// Commit the block in the future - the state will handle out of
// order blocks.
let ready_state = state_service
.ready_and()
.await?;
@ -221,27 +182,6 @@ where
Ok(block)
}
/// Wait until a block with `hash` is in `state_service`.
///
/// Returns an error if `state_service.poll_ready` errors.
async fn await_block(
state_service: &mut S,
hash: block::Hash,
height: block::Height,
) -> Result<Arc<Block>, Report> {
loop {
match BlockVerifier::get_block(state_service, hash).await? {
Some(block) => return Ok(block),
// Busy-waiting is only a temporary solution to waiting for blocks.
// Replace with the contextual verification RFC design
None => {
tracing::debug!(?height, ?hash, "Waiting for state to have block");
time::delay_for(Duration::from_millis(50)).await
}
};
}
}
}
/// Return a block verification service, using the provided state service.