hub/scribe/readers/interface.py
Jack Robison dfef80d9c2
initial
2022-03-08 12:41:51 -05:00

119 lines
5 KiB
Python

import logging
import asyncio
import typing
from concurrent.futures.thread import ThreadPoolExecutor
from prometheus_client import Gauge, Histogram
from scribe import PROMETHEUS_NAMESPACE
from scribe.db.prefixes import DBState
from scribe.db import HubDB
HISTOGRAM_BUCKETS = (
.005, .01, .025, .05, .075, .1, .25, .5, .75, 1.0, 2.5, 5.0, 7.5, 10.0, 15.0, 20.0, 30.0, 60.0, float('inf')
)
NAMESPACE = f"{PROMETHEUS_NAMESPACE}_reader"
class BaseBlockchainReader:
block_count_metric = Gauge(
"block_count", "Number of processed blocks", namespace=NAMESPACE
)
block_update_time_metric = Histogram(
"block_time", "Block update times", namespace=NAMESPACE, buckets=HISTOGRAM_BUCKETS
)
reorg_count_metric = Gauge(
"reorg_count", "Number of reorgs", namespace=NAMESPACE
)
def __init__(self, env, secondary_name: str, thread_workers: int = 1, thread_prefix: str = 'blockchain-reader'):
self.env = env
self.log = logging.getLogger(__name__).getChild(self.__class__.__name__)
self.shutdown_event = asyncio.Event()
self.cancellable_tasks = []
self._thread_workers = thread_workers
self._thread_prefix = thread_prefix
self._executor = ThreadPoolExecutor(thread_workers, thread_name_prefix=thread_prefix)
self.db = HubDB(
env.coin, env.db_dir, env.cache_MB, env.reorg_limit, env.cache_all_claim_txos, env.cache_all_tx_hashes,
secondary_name=secondary_name, max_open_files=-1, blocking_channel_ids=env.blocking_channel_ids,
filtering_channel_ids=env.filtering_channel_ids, executor=self._executor
)
self.last_state: typing.Optional[DBState] = None
self._refresh_interval = 0.1
self._lock = asyncio.Lock()
def _detect_changes(self):
try:
self.db.prefix_db.try_catch_up_with_primary()
except:
self.log.exception('failed to update secondary db')
raise
state = self.db.prefix_db.db_state.get()
if not state or state.height <= 0:
return
if self.last_state and self.last_state.height > state.height:
self.log.warning("reorg detected, waiting until the writer has flushed the new blocks to advance")
return
last_height = 0 if not self.last_state else self.last_state.height
rewound = False
if self.last_state:
while True:
if self.db.headers[-1] == self.db.prefix_db.header.get(last_height, deserialize_value=False):
self.log.debug("connects to block %i", last_height)
break
else:
self.log.warning("disconnect block %i", last_height)
self.unwind()
rewound = True
last_height -= 1
if rewound:
self.reorg_count_metric.inc()
self.db.read_db_state()
if not self.last_state or last_height < state.height:
for height in range(last_height + 1, state.height + 1):
self.log.info("advancing to %i", height)
self.advance(height)
self.clear_caches()
self.last_state = state
self.block_count_metric.set(self.last_state.height)
self.db.blocked_streams, self.db.blocked_channels = self.db.get_streams_and_channels_reposted_by_channel_hashes(
self.db.blocking_channel_hashes
)
self.db.filtered_streams, self.db.filtered_channels = self.db.get_streams_and_channels_reposted_by_channel_hashes(
self.db.filtering_channel_hashes
)
async def poll_for_changes(self):
await asyncio.get_event_loop().run_in_executor(self._executor, self._detect_changes)
async def refresh_blocks_forever(self, synchronized: asyncio.Event):
while True:
try:
async with self._lock:
await self.poll_for_changes()
except asyncio.CancelledError:
raise
except:
self.log.exception("blockchain reader main loop encountered an unexpected error")
raise
await asyncio.sleep(self._refresh_interval)
synchronized.set()
def clear_caches(self):
pass
def advance(self, height: int):
tx_count = self.db.prefix_db.tx_count.get(height).tx_count
assert tx_count not in self.db.tx_counts, f'boom {tx_count} in {len(self.db.tx_counts)} tx counts'
assert len(self.db.tx_counts) == height, f"{len(self.db.tx_counts)} != {height}"
self.db.tx_counts.append(tx_count)
self.db.headers.append(self.db.prefix_db.header.get(height, deserialize_value=False))
def unwind(self):
self.db.tx_counts.pop()
self.db.headers.pop()
async def start(self):
if not self._executor:
self._executor = ThreadPoolExecutor(self._thread_workers, thread_name_prefix=self._thread_prefix)
self.db._executor = self._executor