X-Git-Url: https://wannabe.guru.org/gitweb/?a=blobdiff_plain;f=persistent.py;h=27aa4b32aed2fdb299e2c1031a041a19b3c385a5;hb=47ece7bceb442d70ddcc3c728533c4d4d2bccde4;hp=8832572e7b032ae71a7898ca6b21743cf7ce45bf;hpb=31c81f6539969a5eba864d3305f9fb7bf716a367;p=python_utils.git

diff --git a/persistent.py b/persistent.py
index 8832572..27aa4b3 100644
--- a/persistent.py
+++ b/persistent.py
@@ -1,5 +1,11 @@
 #!/usr/bin/env python3
 
+# © Copyright 2021-2022, Scott Gasch
+
+"""A Persistent is just a class with a load and save method.  This
+module defines the Persistent base and a decorator that can be used to
+create a persistent singleton that autoloads and autosaves."""
+
 import atexit
 import datetime
 import enum
@@ -64,7 +70,7 @@ def was_file_written_today(filename: str) -> bool:
         return False
 
     mtime = file_utils.get_file_mtime_as_datetime(filename)
-    assert mtime
+    assert mtime is not None
     now = datetime.datetime.now()
     return mtime.month == now.month and mtime.day == now.day and mtime.year == now.year
 
@@ -81,7 +87,7 @@ def was_file_written_within_n_seconds(
         return False
 
     mtime = file_utils.get_file_mtime_as_datetime(filename)
-    assert mtime
+    assert mtime is not None
     now = datetime.datetime.now()
     return (now - mtime).total_seconds() <= limit_seconds
 
@@ -136,34 +142,29 @@ class persistent_autoloaded_singleton(object):
             # memory.
             if self.instance is not None:
                 logger.debug(
-                    f'Returning already instantiated singleton instance of {cls.__name__}.'
+                    'Returning already instantiated singleton instance of %s.', cls.__name__
                 )
                 return self.instance
 
             # Otherwise, try to load it from persisted state.
             was_loaded = False
-            logger.debug(f'Attempting to load {cls.__name__} from persisted state.')
+            logger.debug('Attempting to load %s from persisted state.', cls.__name__)
             self.instance = cls.load()
             if not self.instance:
                 msg = 'Loading from cache failed.'
                 logger.warning(msg)
-                logger.debug(f'Attempting to instantiate {cls.__name__} directly.')
+                logger.debug('Attempting to instantiate %s directly.', cls.__name__)
                 self.instance = cls(*args, **kwargs)
             else:
-                logger.debug(
-                    f'Class {cls.__name__} was loaded from persisted state successfully.'
-                )
+                logger.debug('Class %s was loaded from persisted state successfully.', cls.__name__)
                 was_loaded = True
 
             assert self.instance is not None
 
             if self.persist_at_shutdown is PersistAtShutdown.ALWAYS or (
-                not was_loaded
-                and self.persist_at_shutdown is PersistAtShutdown.IF_NOT_LOADED
+                not was_loaded and self.persist_at_shutdown is PersistAtShutdown.IF_NOT_LOADED
             ):
-                logger.debug(
-                    'Scheduling a deferred called to save at process shutdown time.'
-                )
+                logger.debug('Scheduling a deferred called to save at process shutdown time.')
                 atexit.register(self.instance.save)
             return self.instance