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Pickle worker state machine exceptions #6702

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Merged
crusaderky merged 1 commit into from
Jul 11, 2022
Merged

Pickle worker state machine exceptions #6702

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29 changes: 29 additions & 0 deletions distributed/tests/test_worker_state_machine.py
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Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,8 @@
GatherDep,
GatherDepSuccessEvent,
Instruction,
InvalidTaskState,
InvalidTransition,
PauseEvent,
RecommendationsConflict,
RefreshWhoHasEvent,
Expand All @@ -44,6 +46,7 @@
SerializedTask,
StateMachineEvent,
TaskState,
TransitionCounterMaxExceeded,
UnpauseEvent,
UpdateDataEvent,
merge_recs_instructions,
Expand Down Expand Up @@ -194,6 +197,32 @@ def test_WorkerState_pickle(ws):
assert ws2.data == {"y": 123}


@pytest.mark.parametrize(
"cls,kwargs",
[
(
InvalidTransition,
dict(key="x", start="released", finish="waiting", story=[]),

@hendrikmakait hendrikmakait Jul 11, 2022

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I personally prefer dict literals over their constructors, do we have any rule of thumb around what to use? It looks like nothing enforces one or the other.

@crusaderky crusaderky Jul 11, 2022

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These are function parameters, so it felt more natural to use a dict constructor. YMMV.

),
(
TransitionCounterMaxExceeded,
dict(key="x", start="released", finish="waiting", story=[]),
),
(InvalidTaskState, dict(key="x", state="released", story=[])),
],
)
@pytest.mark.parametrize("positional", [False, True])
def test_pickle_exceptions(cls, kwargs, positional):
if positional:
e = cls(*kwargs.values())
else:
e = cls(**kwargs)
e2 = pickle.loads(pickle.dumps(e))
assert type(e2) is type(e)
for k, v in kwargs.items():

@hendrikmakait hendrikmakait Jul 11, 2022

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Should we instead make use of self.args (and initialize it properly) to compare the two instances?

@crusaderky crusaderky Jul 11, 2022

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Exception has a weird design. Yes it would be cleaner to initialise args to the parameters and then offer @property accessors, but it would also be very verbose and IMHO overkill.

assert getattr(e2, k) == v

@crusaderky crusaderky Jul 11, 2022

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positional=True passes without any changes to worker_state_machine.py; positional=False crashes with TypeError



def traverse_subclasses(cls: type) -> Iterator[type]:
yield cls
for subcls in cls.__subclasses__():
Expand Down
11 changes: 10 additions & 1 deletion distributed/worker_state_machine.py
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Original file line number Diff line number Diff line change
Expand Up @@ -130,6 +130,9 @@ def __init__(
self.finish = finish
self.story = story

def __reduce__(self) -> tuple[Callable, tuple]:
return type(self), (self.key, self.start, self.finish, self.story)

def __repr__(self) -> str:
return (
f"{self.__class__.__name__}: {self.key} :: {self.start}->{self.finish}"
Expand Down Expand Up @@ -169,6 +172,9 @@ def __init__(
self.state = state
self.story = story

def __reduce__(self) -> tuple[Callable, tuple]:
return type(self), (self.key, self.state, self.story)

def __repr__(self) -> str:
return (
f"{self.__class__.__name__}: {self.key} :: {self.state}"
Expand Down Expand Up @@ -2415,7 +2421,10 @@ def _transition(
# final
ts.state,
# new recommendations
{ts.key: new for ts, new in recs.items()},
{
ts.key: new[0] if isinstance(new, tuple) else new
for ts, new in recs.items()
},
stimulus_id,
time(),
)
Expand Down