Scrapy不会生成DNS查找失败网站的网站urls

nameserver 8.8.8.8
nameserver 8.8.4.4

import dns.resolver
from twisted.internet import defer, error
from scrapy.core.downloader.contextfactory import ScrapyHTTPClientContextFactory
from scrapy.utils.misc import load_object

class CustomDNSResolver(dns.resolver.Resolver):
    def query(self, qname, rdtype=dns.rdatatype.A, lifetime=None):
        try:
            return super().query(qname, rdtype, lifetime)
        except dns.resolver.NXDOMAIN:
            return defer.fail(error.DNSLookupError(qname))
        except dns.resolver.NoAnswer:
            return defer.fail(error.DNSLookupError(qname))
        except dns.resolver.Timeout:
            return defer.fail(error.DNSLookupError(qname))

class CustomHTTPClientContextFactory(ScrapyHTTPClientContextFactory):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.dns_resolver = CustomDNSResolver()

def custom_settings():
    return {
        'DOWNLOADER_CLIENT_TLS_CIPHERS': 'DEFAULT',
        'DOWNLOADER_CLIENT_TLS_METHOD': 'TLSv1.2',
        'DOWNLOADER_CLIENT_TLS_OPTIONS': {
            'ssl_version': ssl.PROTOCOL_TLSv1_2,
        },
        'DOWNLOADER_MIDDLEWARES': {
            'scrapy.downloadermiddlewares.retry.RetryMiddleware': 550,
        },
        'RETRY_ENABLED': True,
        'RETRY_TIMES': 3,
        'RETRY_HTTP_CODES': [500, 502, 503, 504, 408, 403, 404, 400],
        'DOWNLOAD_TIMEOUT': 15,
        'CONCURRENT_REQUESTS': 16,
        'CONCURRENT_REQUESTS_PER_DOMAIN': 8,
        'DNS_TIMEOUT': 5,
        'DNS_CACHE_ENABLED': True,
        'DNS_CACHE_SIZE': 900,
        'DNS_CACHE_EXPIRATION_SECS': 600,
        'HTTPCACHE_ENABLED': True,
        'HTTPCACHE_EXPIRATION_SECS': 0,
        'HTTPCACHE_DIR': 'httpcache',
        'HTTPCACHE_IGNORE_HTTP_CODES': [],
        'HTTPCACHE_STORAGE': 'scrapy.extensions.httpcache.FilesystemCacheStorage',
    }

# 在Scrapy项目中使用自定义设置
settings = custom_settings()