Files
aitbc/apps/blockchain-node/src/aitbc_chain/consensus/poa.py
aitbc 6a7258941a
Some checks failed
Blockchain Synchronization Verification / sync-verification (push) Failing after 5s
Integration Tests / test-service-integration (push) Failing after 10s
Multi-Node Blockchain Health Monitoring / health-check (push) Successful in 4s
P2P Network Verification / p2p-verification (push) Successful in 4s
Python Tests / test-python (push) Successful in 12s
Security Scanning / security-scan (push) Successful in 30s
Fix: Initialize _last_block_timestamp from head block on startup
This fixes the hybrid mode heartbeat logic which was unable to
calculate time since last block after service restart because
_last_block_timestamp was None.
2026-04-23 11:02:03 +02:00

521 lines
23 KiB
Python
Executable File

import asyncio
import hashlib
import json
import re
from datetime import datetime
from pathlib import Path
from typing import Callable, ContextManager, Optional
from sqlmodel import Session, select
from ..gossip import gossip_broker
from ..logger import get_logger
from ..state.merkle_patricia_trie import StateManager
logger = get_logger(__name__)
from ..state.state_transition import get_state_transition
from ..config import ProposerConfig
from ..metrics import metrics_registry
from ..models import Block, Account
_METRIC_KEY_SANITIZE = re.compile(r"[^a-zA-Z0-9_]")
def _sanitize_metric_suffix(value: str) -> str:
sanitized = _METRIC_KEY_SANITIZE.sub("_", value).strip("_")
return sanitized or "unknown"
def _compute_state_root(session: Session, chain_id: str) -> str:
"""Compute state root from current account state."""
try:
state_manager = StateManager()
# Get all accounts for this chain
accounts = session.exec(
select(Account).where(Account.chain_id == chain_id)
).all()
# Convert to dictionary
account_dict = {acc.address: acc for acc in accounts}
# Compute state root
root = state_manager.compute_state_root(account_dict)
# Return as hex string
return '0x' + root.hex()
except Exception as e:
# If state root computation fails, return None for now
# This can happen during genesis block creation when accounts don't exist yet
logger.warning(f"Failed to compute state root: {e}")
return None
import time
class CircuitBreaker:
def __init__(self, threshold: int, timeout: int):
self._threshold = threshold
self._timeout = timeout
self._failures = 0
self._last_failure_time = 0.0
self._state = "closed"
@property
def state(self) -> str:
if self._state == "open":
if time.time() - self._last_failure_time > self._timeout:
self._state = "half-open"
return self._state
def allow_request(self) -> bool:
state = self.state
if state == "closed":
return True
if state == "half-open":
return True
return False
def record_failure(self) -> None:
self._failures += 1
self._last_failure_time = time.time()
if self._failures >= self._threshold:
self._state = "open"
def record_success(self) -> None:
self._failures = 0
self._state = "closed"
class PoAProposer:
"""Proof-of-Authority block proposer.
Responsible for periodically proposing blocks if this node is configured as a proposer.
In the real implementation, this would involve checking the mempool, validating transactions,
and signing the block.
"""
def __init__(
self,
*,
config: ProposerConfig,
session_factory: Callable[[], ContextManager[Session]],
) -> None:
self._config = config
self._session_factory = session_factory
self._logger = get_logger(__name__)
self._stop_event = asyncio.Event()
self._task: Optional[asyncio.Task[None]] = None
self._last_proposer_id: Optional[str] = None
self._last_block_timestamp: Optional[datetime] = None
async def start(self) -> None:
if self._task is not None:
return
self._logger.info("Starting PoA proposer loop", extra={"interval": self._config.interval_seconds})
await self._ensure_genesis_block()
# Initialize last block timestamp from head block for heartbeat logic
head = self._fetch_chain_head()
if head is not None:
self._last_block_timestamp = head.timestamp
self._logger.info("Initialized last block timestamp from head", extra={"height": head.height})
self._stop_event.clear()
self._task = asyncio.create_task(self._run_loop())
async def stop(self) -> None:
if self._task is None:
return
self._logger.info("Stopping PoA proposer loop")
self._stop_event.set()
await self._task
self._task = None
async def _run_loop(self) -> None:
# Initial sleep so we don't start proposing immediately
await asyncio.sleep(self._config.interval_seconds)
from ..config import settings
block_generation_mode = getattr(settings, "block_generation_mode", "hybrid")
while not self._stop_event.is_set():
if self._stop_event.is_set():
break
try:
proposed = await self._propose_block()
if proposed:
await self._wait_until_next_slot()
else:
# If we skipped proposing, wait based on mode
if block_generation_mode == "hybrid":
# Check more frequently in hybrid mode to catch heartbeat timing
# Use 1/4 of normal interval for responsive heartbeat checks
check_interval = self._config.interval_seconds / 4
try:
await asyncio.wait_for(self._stop_event.wait(), timeout=check_interval)
except asyncio.TimeoutError:
pass
else:
# Regular interval for other modes
try:
await asyncio.wait_for(self._stop_event.wait(), timeout=self._config.interval_seconds)
except asyncio.TimeoutError:
pass
except Exception as exc: # pragma: no cover - defensive logging
self._logger.exception("Failed to propose block", extra={"error": str(exc)})
await asyncio.sleep(1.0)
async def _wait_until_next_slot(self) -> None:
head = self._fetch_chain_head()
if head is None:
return
now = datetime.utcnow()
elapsed = (now - head.timestamp).total_seconds()
sleep_for = max(self._config.interval_seconds - elapsed, 0.1)
if sleep_for <= 0:
sleep_for = 0.1
try:
await asyncio.wait_for(self._stop_event.wait(), timeout=sleep_for)
except asyncio.TimeoutError:
return
async def _propose_block(self) -> bool:
# Check internal mempool and include transactions
from ..mempool import get_mempool
from ..models import Transaction, Account
from ..config import settings
mempool = get_mempool()
# Hybrid block generation logic
block_generation_mode = getattr(settings, "block_generation_mode", "hybrid")
max_empty_block_interval = getattr(settings, "max_empty_block_interval", 60)
if block_generation_mode in ["mempool-only", "hybrid"]:
mempool_size = mempool.size(self._config.chain_id)
if block_generation_mode == "mempool-only":
# Strict mempool-only mode: skip if empty
if mempool_size == 0:
self._logger.info(f"[PROPOSE] Skipping block proposal: mempool is empty (chain={self._config.chain_id}, mode=mempool-only)")
metrics_registry.increment("sync_empty_blocks_skipped_total")
return False
elif block_generation_mode == "hybrid":
# Hybrid mode: check heartbeat interval
if self._last_block_timestamp:
time_since_last_block = (datetime.utcnow() - self._last_block_timestamp).total_seconds()
if mempool_size == 0 and time_since_last_block < max_empty_block_interval:
self._logger.info(f"[PROPOSE] Skipping block proposal: mempool empty, heartbeat not yet due (chain={self._config.chain_id}, mode=hybrid, idle_time={time_since_last_block:.1f}s)")
metrics_registry.increment("sync_empty_blocks_skipped_total")
return False
elif mempool_size == 0 and time_since_last_block >= max_empty_block_interval:
self._logger.info(f"[PROPOSE] Forcing heartbeat block: idle for {time_since_last_block:.1f}s (chain={self._config.chain_id}, mode=hybrid)")
metrics_registry.increment("sync_heartbeat_blocks_forced_total")
metrics_registry.observe("sync_time_since_last_block_seconds", time_since_last_block)
elif mempool_size == 0:
# No previous block timestamp, skip (will be set after genesis)
self._logger.info(f"[PROPOSE] Skipping block proposal: no previous block timestamp (chain={self._config.chain_id}, mode=hybrid)")
metrics_registry.increment("sync_empty_blocks_skipped_total")
return False
with self._session_factory() as session:
head = session.exec(select(Block).where(Block.chain_id == self._config.chain_id).order_by(Block.height.desc()).limit(1)).first()
next_height = 0
parent_hash = "0x00"
interval_seconds: Optional[float] = None
if head is not None:
next_height = head.height + 1
parent_hash = head.hash
interval_seconds = (datetime.utcnow() - head.timestamp).total_seconds()
timestamp = datetime.utcnow()
# Pull transactions from mempool
max_txs = self._config.max_txs_per_block
max_bytes = self._config.max_block_size_bytes
pending_txs = mempool.drain(max_txs, max_bytes, self._config.chain_id)
self._logger.info(f"[PROPOSE] drained {len(pending_txs)} txs from mempool, chain={self._config.chain_id}")
# Process transactions and update balances
processed_txs = []
for tx in pending_txs:
try:
# Parse transaction data
tx_data = tx.content
sender = tx_data.get("from")
recipient = tx_data.get("to")
value = tx_data.get("amount", 0)
fee = tx_data.get("fee", 0)
self._logger.info(f"[PROPOSE] Processing tx {tx.tx_hash}: from={sender}, to={recipient}, amount={value}, fee={fee}")
if not sender or not recipient:
self._logger.warning(f"[PROPOSE] Skipping tx {tx.tx_hash}: missing sender or recipient")
continue
# Get sender account
sender_account = session.get(Account, (self._config.chain_id, sender))
if not sender_account:
self._logger.warning(f"[PROPOSE] Skipping tx {tx.tx_hash}: sender account not found for {sender}")
continue
# Check sufficient balance
total_cost = value + fee
if sender_account.balance < total_cost:
self._logger.warning(f"[PROPOSE] Skipping tx {tx.tx_hash}: insufficient balance (has {sender_account.balance}, needs {total_cost})")
continue
# Get or create recipient account
recipient_account = session.get(Account, (self._config.chain_id, recipient))
if not recipient_account:
self._logger.info(f"[PROPOSE] Creating recipient account for {recipient}")
recipient_account = Account(chain_id=self._config.chain_id, address=recipient, balance=0, nonce=0)
session.add(recipient_account)
session.flush()
else:
self._logger.info(f"[PROPOSE] Recipient account exists for {recipient}")
# Apply state transition through validated transaction
state_transition = get_state_transition()
# Use original tx_data from mempool to preserve type and payload
tx_data_for_transition = tx.content.copy()
tx_data_for_transition["nonce"] = sender_account.nonce
success, error_msg = state_transition.apply_transaction(
session, self._config.chain_id, tx_data_for_transition, tx.tx_hash
)
if not success:
self._logger.warning(f"[PROPOSE] Failed to apply transaction {tx.tx_hash}: {error_msg}")
continue
# Check if transaction already exists in database
existing_tx = session.exec(
select(Transaction).where(
Transaction.chain_id == self._config.chain_id,
Transaction.tx_hash == tx.tx_hash
)
).first()
if existing_tx:
self._logger.warning(f"[PROPOSE] Skipping tx {tx.tx_hash}: already exists in database at block {existing_tx.block_height}")
continue
# Create transaction record
# Extract type from normalized tx_data (which should have the type field)
tx_type = tx.content.get("type", "TRANSFER")
if tx_type:
tx_type = tx_type.upper()
else:
tx_type = "TRANSFER"
# Store only the original payload, not the full normalized data
original_payload = tx.content.get("payload", {})
transaction = Transaction(
chain_id=self._config.chain_id,
tx_hash=tx.tx_hash,
sender=sender,
recipient=recipient,
payload=original_payload,
value=value,
fee=fee,
nonce=sender_account.nonce - 1,
timestamp=timestamp,
block_height=next_height,
status="confirmed",
type=tx_type
)
session.add(transaction)
processed_txs.append(tx)
self._logger.info(f"[PROPOSE] Successfully processed tx {tx.tx_hash}: updated balances")
except Exception as e:
self._logger.warning(f"Failed to process transaction {tx.tx_hash}: {e}")
continue
if pending_txs and not processed_txs and getattr(settings, "propose_only_if_mempool_not_empty", True):
self._logger.warning(
f"[PROPOSE] Skipping block proposal: all drained transactions were invalid (count={len(pending_txs)}, chain={self._config.chain_id})"
)
return False
# Compute block hash with transaction data
block_hash = self._compute_block_hash(next_height, parent_hash, timestamp, processed_txs)
# Compute state root from account state
state_root = _compute_state_root(session, self._config.chain_id)
block = Block(
chain_id=self._config.chain_id,
height=next_height,
hash=block_hash,
parent_hash=parent_hash,
proposer=self._config.proposer_id,
timestamp=timestamp,
tx_count=len(processed_txs),
state_root=state_root,
)
session.add(block)
session.commit()
metrics_registry.increment("blocks_proposed_total")
metrics_registry.set_gauge("chain_head_height", float(next_height))
if interval_seconds is not None and interval_seconds >= 0:
metrics_registry.observe("block_interval_seconds", interval_seconds)
metrics_registry.set_gauge("poa_last_block_interval_seconds", float(interval_seconds))
proposer_suffix = _sanitize_metric_suffix(self._config.proposer_id)
metrics_registry.increment(f"poa_blocks_proposed_total_{proposer_suffix}")
if self._last_proposer_id is not None and self._last_proposer_id != self._config.proposer_id:
metrics_registry.increment("poa_proposer_switches_total")
self._last_proposer_id = self._config.proposer_id
# Update last block timestamp for heartbeat logic
self._last_block_timestamp = timestamp
self._logger.info(
"Proposed block",
extra={
"height": block.height,
"hash": block.hash,
"proposer": block.proposer,
},
)
# Broadcast the new block
tx_list = [tx.content for tx in processed_txs] if processed_txs else []
await gossip_broker.publish(
"blocks",
{
"chain_id": self._config.chain_id,
"height": block.height,
"hash": block.hash,
"parent_hash": block.parent_hash,
"proposer": block.proposer,
"timestamp": block.timestamp.isoformat(),
"tx_count": block.tx_count,
"state_root": block.state_root,
"transactions": tx_list,
},
)
return True
async def _ensure_genesis_block(self) -> None:
with self._session_factory() as session:
# Check if genesis block already exists
genesis = session.exec(select(Block).where(Block.chain_id == self._config.chain_id).where(Block.height == 0).limit(1)).first()
if genesis is not None:
self._logger.info(f"Genesis block already exists: height={genesis.height}, hash={genesis.hash}, proposer={genesis.proposer}")
return
# Use a deterministic genesis timestamp so all nodes agree on the genesis block hash
timestamp = datetime(2025, 1, 1, 0, 0, 0)
block_hash = self._compute_block_hash(0, "0x00", timestamp)
# Check if block with this hash already exists (duplicate check)
existing = session.exec(select(Block).where(Block.chain_id == self._config.chain_id).where(Block.hash == block_hash).limit(1)).first()
if existing is not None:
self._logger.info(f"Genesis block with hash {block_hash} already exists, skipping creation")
return
# Compute state root for genesis block
state_root = _compute_state_root(session, self._config.chain_id)
genesis = Block(
chain_id=self._config.chain_id,
height=0,
hash=block_hash,
parent_hash="0x00",
proposer="genesis", # Use "genesis" as the proposer for genesis block to avoid hash conflicts
timestamp=timestamp,
tx_count=0,
state_root=state_root,
)
session.add(genesis)
try:
session.commit()
except Exception as e:
self._logger.warning(f"Failed to create genesis block: {e}")
session.rollback()
return
# Initialize accounts from genesis allocations file (if present)
await self._initialize_genesis_allocations(session)
# Recompute state root after accounts are initialized
new_state_root = _compute_state_root(session, self._config.chain_id)
if new_state_root:
genesis.state_root = new_state_root
session.add(genesis)
session.commit()
self._logger.info(f"Updated genesis block state_root: {new_state_root}")
# Broadcast genesis block for initial sync
await gossip_broker.publish(
"blocks",
{
"chain_id": self._config.chain_id,
"height": genesis.height,
"hash": genesis.hash,
"parent_hash": genesis.parent_hash,
"proposer": genesis.proposer,
"timestamp": genesis.timestamp.isoformat(),
"tx_count": genesis.tx_count,
"state_root": genesis.state_root,
}
)
async def _initialize_genesis_allocations(self, session: Session) -> None:
"""Create Account entries from the genesis allocations file."""
# Use standardized data directory from configuration
from ..config import settings
genesis_paths = [
Path(f"/var/lib/aitbc/data/{self._config.chain_id}/genesis.json"), # Standard location
]
genesis_path = None
for path in genesis_paths:
if path.exists():
genesis_path = path
break
if not genesis_path:
self._logger.warning("Genesis allocations file not found; skipping account initialization", extra={"paths": str(genesis_paths)})
return
with open(genesis_path) as f:
genesis_data = json.load(f)
allocations = genesis_data.get("allocations", [])
created = 0
for alloc in allocations:
addr = alloc["address"]
balance = int(alloc["balance"])
nonce = int(alloc.get("nonce", 0))
# Check if account already exists (idempotent)
acct = session.get(Account, (self._config.chain_id, addr))
if acct is None:
acct = Account(chain_id=self._config.chain_id, address=addr, balance=balance, nonce=nonce)
session.add(acct)
created += 1
session.commit()
self._logger.info("Initialized genesis accounts", extra={"count": created, "total": len(allocations), "path": str(genesis_path)})
def _fetch_chain_head(self) -> Optional[Block]:
with self._session_factory() as session:
return session.exec(
select(Block)
.where(Block.chain_id == self._config.chain_id)
.order_by(Block.height.desc())
.limit(1)
).first()
def _compute_block_hash(self, height: int, parent_hash: str, timestamp: datetime, transactions: list = None) -> str:
# Include transaction hashes in block hash computation
tx_hashes = []
if transactions:
tx_hashes = [tx.tx_hash for tx in transactions]
payload = f"{self._config.chain_id}|{height}|{parent_hash}|{timestamp.isoformat()}|{'|'.join(sorted(tx_hashes))}".encode()
return "0x" + hashlib.sha256(payload).hexdigest()