Method _write_files_cache

src/borg/cache.py:576–618

write files cache to cache directory

(self, files)

        return files

    def _write_files_cache(self, files):
        """write files cache to cache directory"""
        max_time_ns = 2**63 - 1  # nanoseconds, good until y2262
        # _self._newest_cmtime might be None if it was never set because no files were modified/added.
        newest_cmtime = self._newest_cmtime if self._newest_cmtime is not None else max_time_ns
        start_backup_time = self.start_backup - TIME_DIFFERS2_NS if self.start_backup is not None else max_time_ns
        # we don't want to persist files cache entries of potentially problematic files:
        discard_after = min(newest_cmtime, start_backup_time)
        ttl = int(os.environ.get("BORG_FILES_CACHE_TTL", 2))
        files_cache_logger.debug("FILES-CACHE-SAVE: starting...")
        cache_path = str(self.path / self.files_cache_name())
        with SaveFile(cache_path, binary=True) as sync_file:
            with IntegrityCheckedFile(path=cache_path, write=True, override_fd=sync_file) as fd:
                entries = 0
                age_discarded = 0
                race_discarded = 0
                for path_hash, entry in files.items():
                    entry = self.decompress_entry(entry)
                    if entry.age == 0:  # current entries
                        if max(timestamp_to_int(entry.ctime), timestamp_to_int(entry.mtime)) < discard_after:
                            # Only keep files seen in this backup that old enough not to suffer race conditions
                            # relating to filesystem snapshots and ctime/mtime granularity or being modified
                            # while we read them.
                            keep = True
                        else:
                            keep = False
                            race_discarded += 1
                    else:  # old entries
                        if entry.age < ttl:
                            # Also keep files from older backups that have not reached BORG_FILES_CACHE_TTL yet.
                            keep = True
                        else:
                            keep = False
                            age_discarded += 1
                    if keep:
                        msgpack.pack((path_hash, entry), fd)
                        entries += 1
            integrity_data = fd.integrity_data
        files_cache_logger.debug(f"FILES-CACHE-KILL: removed {age_discarded} entries with age >= TTL [{ttl}]")
        t_str = datetime.fromtimestamp(discard_after / 1e9, timezone.utc).isoformat()
        files_cache_logger.debug(f"FILES-CACHE-KILL: removed {race_discarded} entries with ctime/mtime >= {t_str}")
        files_cache_logger.debug(f"FILES-CACHE-SAVE: finished, {entries} remaining entries saved.")
        return integrity_data

    def file_known_and_unchanged(self, hashed_path, path_hash, st):
        """