Deprecate clock_tick context manager #39

multigl · 2017-08-31T23:50:46Z

backwards compatible deprecation of clock_tick context manager
ensure activity set when changing temporal properties and model clocked with activity_cls
session and mapper event life cycle tests

…ivities

multigl · 2017-09-06T20:49:33Z

Resolves #28

dargueta-work · 2017-10-04T23:39:58Z

temporal_sqlalchemy/bases.py

+
+    def __get__(self, instance, owner):
+        if not instance:
+            return None


You might want to use return self here, because otherwise any attempt to access reset_activity or activity_required from an instance of a class using it will crash with an AttributeError:

A minimal example:

import types ns = types.SimpleNamespace(activity=1) # This works ActivityState.reset_activity(ns, None) class B: astate = ActivityState() # This crashes B.astate.reset_activity(ns, None)

dargueta-work · 2017-10-04T23:40:13Z

temporal_sqlalchemy/bases.py

+
+    def __get__(self, instance, owner):
+        if not instance:
+            return None


Same idea here about returning self.

multigl · 2017-10-23T19:52:52Z

temporal_sqlalchemy/clock.py

@@ -78,6 +80,10 @@ def temporal_map(*track, mapper: orm.Mapper, activity_class=None, schema=None):
        backref_name = '%s_clock' % entity_table.name
        clock_properties['activity'] = \
            orm.relationship(lambda: activity_class, backref=backref_name)
+        cls.activity = ActivityState()
+        event.listen(cls, 'expire', ActivityState.reset_activity)


@NicoleZuckerman this the expire for the activity descriptor

multigl · 2017-10-23T19:53:13Z

temporal_sqlalchemy/clock.py

@@ -94,24 +100,19 @@ def temporal_map(*track, mapper: orm.Mapper, activity_class=None, schema=None):
        clock_model=clock_model,
        activity_cls=activity_class
    )
-
+    cls.current_clock = ClockState()
+    event.listen(cls, 'expire', ClockState.reset_tick)


@NicoleZuckerman this is the expire for the current_clock descriptor

multigl · 2017-10-23T19:55:30Z

relevant sqlalchemy documentation on instance events: http://docs.sqlalchemy.org/en/rel_1_1/orm/events.html#instance-events

dargueta-work · 2017-10-24T16:16:34Z

temporal_sqlalchemy/bases.py

+        if not instance:
+            return self
+
+        vclock = getattr(instance, 'vclock') or 0


Using getattr with a string constant like this is equivalent to instance.vclock. This will still crash with an AttributeError unless you pass a default value as the third argument. Did you mean to do that?

vclock = getattr(instance, 'vclock', 0)

dargueta-work · 2017-10-24T16:22:29Z

temporal_sqlalchemy/bases.py

+            setattr(instance, '__temporal_current_tick', clock_tick)
+            instance.clock.append(clock_tick)
+
+        return getattr(instance, '__temporal_current_tick')


Same note here about using getattr without a default argument.

However, be warned: attributes starting with double underscores may not behave as you expect. Python has a concept of "private variables" that may result in an AttributeError getting thrown.

From the docs:

Any identifier of the form __spam (at least two leading underscores, at most one trailing underscore) is textually replaced with _classname__spam, where classname is the current class name with leading underscore(s) stripped. This mangling is done without regard to the syntactic position of the identifier, as long as it occurs within the definition of a class.

Because it's required to occur inside the class definition I think this will be okay, but I thought I'd point it out.

yeah, I think in this case it's okay, but it's a good call out

dargueta-work · 2017-10-24T16:23:57Z

temporal_sqlalchemy/bases.py

+                      DeprecationWarning)
+        if self.temporal_options.activity_cls:
+            if not activity:
+                raise ValueError


Can we put an error message here please? It'll make debugging easier. I think the original error message might suffice.

👍 should probably be:

raise ValueError("activity is missing on edit") from None

dargueta-work · 2017-10-24T16:24:27Z

temporal_sqlalchemy/bases.py


-            session.add(new_clock_tick)
+        return


return isn't necessary at the end of a function. You can remove this.

I left it in so it looks less confusing to me, but I'm strange that way 😆

multigl

looking good, looking real good

multigl · 2017-10-27T18:39:48Z

tests/test_session.py

+
+        # clear out db
+        transaction.rollback()
+        second_session.close()


this is pretty neat, might also want to refetch the model from the first session and see that the vclock is two there

multigl · 2017-10-27T18:40:45Z

tests/test_temporal_with_activity.py

+                                             activity=create_activity)
+        session.add(t)
+
+        assert getattr(t, '__temporal_current_tick', None)


I wonder if we want to assert that it's an instance of ClockTick (or whatever it actually is) and has properties we expect?

multigl · 2017-10-27T18:40:57Z

tests/test_temporal_with_activity.py

+        assert t.activity
+        session.commit()
+        assert not getattr(t, '__temporal_current_tick', None)
+        assert not t.activity


dargueta-work · 2017-10-27T18:57:00Z

temporal_sqlalchemy/bases.py


 T_PROPS = typing.TypeVar(
    'T_PROP', orm.RelationshipProperty, orm.ColumnProperty)


+class ActivityState:
+    def __set__(self, instance, value):
+        assert instance.temporal_options.activity_cls, "Make this better Joey"


Can we change this error message to something a bit more helpful? 🙂 Perhaps:

if instance.temporal_options.activity_cls: raise RuntimeError( "Can't set activity state on instance of %r because the activity class is None." % type(instance).__name__)

(That's assuming that my interpretation of this assertion is correct.)

…ntext manager

first pass on simple model state to keep track of clock ticks and act…

5ed28fb

…ivities

multigl added enhancement wip labels Aug 31, 2017

multigl added this to the Version 1.0 milestone Aug 31, 2017

Joey Leingang added 3 commits September 20, 2017 18:10

cleanup to __temporal_ state management

f2c2229

cleanup strict mode session stuff

6512d60

make them tests pass

3df510d

dargueta-work reviewed Oct 4, 2017

View reviewed changes

descriptors return something meaningful

9afe85b

multigl commented Oct 23, 2017

View reviewed changes

dargueta-work reviewed Oct 24, 2017

View reviewed changes

Nicole Zuckerman added 2 commits October 25, 2017 11:59

Rename atrribute that's reset for clarity

d7e52ad

Add tests for session/clock behavior & expiring tick and activity

c97443e

multigl commented Oct 27, 2017

View reviewed changes

dargueta-work reviewed Oct 27, 2017

View reviewed changes

Nicole Zuckerman and others added 3 commits October 30, 2017 13:37

Add some more asserts to session & activity tests

de145e4

some polish on bases.py -- better error messages, and more concise co…

e06df10

…ntext manager

Merge branch 'master' into deprecate-clock-tick

44eb508

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Deprecate clock_tick context manager #39

Deprecate clock_tick context manager #39

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Deprecate clock_tick context manager #39

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Deprecate clock_tick context manager #39

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