import logging
from scrapy.log import ScrapyFileLogObserver

logfile = open('testlog.log', 'w')
log_observer = ScrapyFileLogObserver(logfile, level=logging.DEBUG)
log_observer.start()

import logging

class AbcSpider(scrapy.Spider):
    name: str = 'abc_spider'
    start_urls = ['you_url']
    custom_settings = {
         'LOG_FILE': 'my_log.log',
         'LOG_LEVEL': 'INFO',
         ... # you can add more settings
     }
     logging.getLogger().addHandler(logging.StreamHandler())

     def parse(self, response):
        pass