import sys

import scrapy
from scrapy.crawler import AsyncCrawlerProcess


class CachingHostnameResolverSpider(scrapy.Spider):
    """
    Finishes in a finite amount of time (does not hang indefinitely in the DNS resolution)
    """

    name = "caching_hostname_resolver_spider"

    async def start(self):
        yield scrapy.Request(self.url)

    def parse(self, response):
        for _ in range(10):
            yield scrapy.Request(
                response.url, dont_filter=True, callback=self.ignore_response
            )

    def ignore_response(self, response):
        self.logger.info(repr(response.ip_address))


if __name__ == "__main__":
    process = AsyncCrawlerProcess(
        settings={
            "RETRY_ENABLED": False,
            "TWISTED_DNS_RESOLVER": "scrapy.resolver.CachingHostnameResolver",
        }
    )
    process.crawl(CachingHostnameResolverSpider, url=sys.argv[1])
    process.start()
