Lock the cache file

This commit is contained in:
Stephane Bortzmeyer 2021-07-07 11:13:36 +02:00
parent 79032c1021
commit a3a1f8c0d4

View File

@ -12,6 +12,7 @@ import datetime
import json
import os
import sys
import fcntl
IANABASE = "https://data.iana.org/rdap/dns.json"
CACHE = os.environ["HOME"] + "/.ianardapcache.json"
@ -22,7 +23,9 @@ class IanaRDAPDatabase():
def __init__(self, maxage=MAXAGE, cachefile=CACHE):
""" Retrieves the IANA databse, if not already cached. maxage is in hours. """
cache_valid = False
# TODO we should lock it
self.cachefile = cachefile
self.lockname = self.cachefile + ".lock"
self.lock()
if os.path.exists(cachefile) and \
datetime.datetime.fromtimestamp(os.path.getmtime(cachefile)) >= \
(datetime.datetime.utcnow() - datetime.timedelta(hours = maxage)):
@ -30,7 +33,9 @@ class IanaRDAPDatabase():
content = cache.read()
cache.close()
cache_valid = True
self.unlock()
else:
self.unlock()
response = requests.get(IANABASE)
if response.status_code != 200:
raise Exception("Invalid HTTPS return code when trying to get %s: %s" % (IANABASE, response.status_code))
@ -45,11 +50,20 @@ class IanaRDAPDatabase():
for server in service[1]:
self.services[tld] = server
if not cache_valid:
# TODO we should lock it
self.lock()
cache = open(cachefile, "wb")
cache.write(content)
cache.close()
self.unlock()
def lock(self):
self.lockhandle = open(self.lockname, 'w')
fcntl.lockf(self.lockhandle, fcntl.LOCK_EX)
def unlock(self):
fcntl.lockf(self.lockhandle, fcntl.LOCK_UN)
self.lockhandle.close()
def find(self, domain):
""" Get the RDAP server for a given domain name. None if there is none."""
labels = domain.split(".")