"""
Extension for collecting core stats like items scraped and start/finish times
"""
from __future__ import annotations
from datetime import datetime, timezone
from typing import TYPE_CHECKING, Any, Optional
from scrapy import Spider, signals
from scrapy.crawler import Crawler
from scrapy.statscollectors import StatsCollector
if TYPE_CHECKING:
# typing.Self requires Python 3.11
from typing_extensions import Self
[docs]class CoreStats:
def __init__(self, stats: StatsCollector):
self.stats: StatsCollector = stats
self.start_time: Optional[datetime] = None
@classmethod
def from_crawler(cls, crawler: Crawler) -> Self:
assert crawler.stats
o = cls(crawler.stats)
crawler.signals.connect(o.spider_opened, signal=signals.spider_opened)
crawler.signals.connect(o.spider_closed, signal=signals.spider_closed)
crawler.signals.connect(o.item_scraped, signal=signals.item_scraped)
crawler.signals.connect(o.item_dropped, signal=signals.item_dropped)
crawler.signals.connect(o.response_received, signal=signals.response_received)
return o
def spider_opened(self, spider: Spider) -> None:
self.start_time = datetime.now(tz=timezone.utc)
self.stats.set_value("start_time", self.start_time, spider=spider)
def spider_closed(self, spider: Spider, reason: str) -> None:
assert self.start_time is not None
finish_time = datetime.now(tz=timezone.utc)
elapsed_time = finish_time - self.start_time
elapsed_time_seconds = elapsed_time.total_seconds()
self.stats.set_value(
"elapsed_time_seconds", elapsed_time_seconds, spider=spider
)
self.stats.set_value("finish_time", finish_time, spider=spider)
self.stats.set_value("finish_reason", reason, spider=spider)
def item_scraped(self, item: Any, spider: Spider) -> None:
self.stats.inc_value("item_scraped_count", spider=spider)
def response_received(self, spider: Spider) -> None:
self.stats.inc_value("response_received_count", spider=spider)
def item_dropped(self, item: Any, spider: Spider, exception: BaseException) -> None:
reason = exception.__class__.__name__
self.stats.inc_value("item_dropped_count", spider=spider)
self.stats.inc_value(f"item_dropped_reasons_count/{reason}", spider=spider)