Fixed concurrent access to cache file when using tldextract in multip…

…le threads

pylintrc

@@ -358,7 +358,7 @@ max-statements=50
 max-parents=7
 
 # Maximum number of attributes for a class (see R0902).
-max-attributes=7
+max-attributes=8
 
 # Minimum number of public methods for a class (see R0903).
 min-public-methods=1

tldextract/tldextract.py

@@ -58,6 +58,7 @@
 import os
 import pkgutil
 import re
+import threading
 
 import idna
 
@@ -193,6 +194,7 @@ def __init__(self, cache_file=CACHE_FILE, suffix_list_urls=PUBLIC_SUFFIX_LIST_UR
         self.suffix_list_urls = tuple(url.strip() for url in suffix_list_urls if url.strip())
 
         self.cache_file = os.path.expanduser(cache_file or '')
+        self.cache_file_lock = threading.Lock()
         self.fallback_to_snapshot = fallback_to_snapshot
         if not (self.suffix_list_urls or self.cache_file or self.fallback_to_snapshot):
             raise ValueError("The arguments you have provided disable all ways for tldextract "
@@ -264,8 +266,8 @@ def _get_tld_extractor(self):
 
         if self._extractor:
             return self._extractor
-
-        tlds = self._get_cached_tlds()
+        with self.cache_file_lock:
+            tlds = self._get_cached_tlds()
         if tlds:
             tlds.extend(self.extra_suffixes)
             self._extractor = _PublicSuffixListTLDExtractor(tlds)
@@ -289,7 +291,8 @@ def _get_tld_extractor(self):
             raise Exception("tlds is empty, but fallback_to_snapshot is set"
                             " to false. Cannot proceed without tlds.")
 
-        self._cache_tlds(tlds)
+        with self.cache_file_lock:
+            self._cache_tlds(tlds)
 
         tlds.extend(self.extra_suffixes)
         self._extractor = _PublicSuffixListTLDExtractor(tlds)