[checkmk-commits] Make loading/filtering persisted sections race condition free

Module: check_mk Branch: master Commit: 1a1984ef27dd019e464c547b0c4257db844160eb URL: http://git.mathias-kettner.de/git/?p=check_mk.git;a=commit;h=1a1984ef27dd01… Author: Simon Betz <si(a)mathias-kettner.de> Date: Thu Nov 29 12:44:07 2018 +0100 Make loading/filtering persisted sections race condition free Change-Id: Iecce769aac82f1455f97c9b24fef533b871cc5c5 --- cmk_base/data_sources/abstract.py | 37 ++++++++++++++----------------------- 1 file changed, 14 insertions(+), 23 deletions(-) diff --git a/cmk_base/data_sources/abstract.py b/cmk_base/data_sources/abstract.py index ff61691..d181e69 100644 --- a/cmk_base/data_sources/abstract.py +++ b/cmk_base/data_sources/abstract.py @@ -430,7 +430,7 @@ class DataSource(object): if not persisted_sections: return host_sections - for section_name, entry in persisted_sections.items(): + for section_name, entry in persisted_sections.iteritems(): if len(entry) == 2: continue # Skip entries of "old" format @@ -450,44 +450,35 @@ class DataSource(object): file_path = self._persisted_sections_file_path() persisted_sections = store.load_data_from_file(file_path, {}) - persisted_sections = self._filter_outdated_persisted_sections(persisted_sections) + filtered_persisted_sections = self._filter_outdated_persisted_sections(persisted_sections) - if not persisted_sections: + if not filtered_persisted_sections: self._logger.debug("No persisted sections loaded") - else: - self._logger.debug( - "Loaded persisted sections: %s" % (", ".join(persisted_sections.keys()))) + try: + os.remove(self._persisted_sections_file_path()) + except OSError: + pass - return persisted_sections + return filtered_persisted_sections # TODO: This is not race condition free when modifying the data. Either remove # the possible write here and simply ignore the outdated sections or lock when # reading and unlock after writing def _filter_outdated_persisted_sections(self, persisted_sections): + filtered_persisted_sections = {} now = time.time() - modified = False - for section_name, entry in persisted_sections.items(): + for section_name, entry in persisted_sections.iteritems(): if len(entry) == 2: persisted_until = entry[0] else: persisted_until = entry[1] if not self._use_outdated_persisted_sections and now > persisted_until: - self._logger.debug("Persisted section %s is outdated by %d seconds. Deleting it." % + self._logger.debug("Persisted section %s is outdated by %d seconds. Skipping it." % (section_name, now - persisted_until)) - del persisted_sections[section_name] - modified = True - - if not persisted_sections: - try: - os.remove(self._persisted_sections_file_path()) - except OSError: - pass - - elif modified: - self._store_persisted_sections(persisted_sections) - - return persisted_sections + continue + filtered_persisted_sections[section_name] = entry + return filtered_persisted_sections @classmethod def use_outdated_persisted_sections(cls):