log_file_analysis_3.py

import socket
log_file = pd.read_pickle('log.pkl')
log_file = log_file.ip_address.apply(lambda ip: socket.gethostbyaddr(ip)[0])

# Alternative 
from crawlerdetect import CrawlerDetect
crawler_detect = CrawlerDetect()
validate = []
for crawl in log_file.user_agent:
    data = {'valid':crawler_detect.isCrawler(crawl),
           'bot_type':crawler_detect.getMatches()}
    validate.append(data)
log_file[['valid', 'bot_type']] = pd.DataFrame(validate)[['valid', 'bot_type']]
log_file = log_file[log_file['valid']==True]