mirror of
https://github.com/jointakahe/takahe.git
synced 2024-12-23 05:56:29 +00:00
451 lines
16 KiB
Python
451 lines
16 KiB
Python
import datetime
|
|
import traceback
|
|
from typing import ClassVar, cast
|
|
|
|
from asgiref.sync import sync_to_async
|
|
from django.db import models, transaction
|
|
from django.db.models.signals import class_prepared
|
|
from django.utils import timezone
|
|
from django.utils.functional import classproperty
|
|
|
|
from core import exceptions
|
|
from stator.exceptions import TryAgainLater
|
|
from stator.graph import State, StateGraph
|
|
|
|
|
|
class StateField(models.CharField):
|
|
"""
|
|
A special field that automatically gets choices from a state graph
|
|
"""
|
|
|
|
def __init__(self, graph: type[StateGraph], **kwargs):
|
|
# Sensible default for state length
|
|
kwargs.setdefault("max_length", 100)
|
|
# Add choices and initial
|
|
self.graph = graph
|
|
kwargs["choices"] = self.graph.choices
|
|
kwargs["default"] = self.graph.initial_state.name
|
|
super().__init__(**kwargs)
|
|
|
|
def deconstruct(self):
|
|
name, path, args, kwargs = super().deconstruct()
|
|
kwargs["graph"] = self.graph
|
|
return name, path, args, kwargs
|
|
|
|
def get_prep_value(self, value):
|
|
if isinstance(value, State):
|
|
return value.name
|
|
return value
|
|
|
|
|
|
def add_stator_indexes(sender, **kwargs):
|
|
"""
|
|
Inject Indexes used by StatorModel in to any subclasses. This sidesteps the
|
|
current Django inability to inherit indexes when the Model subclass defines
|
|
its own indexes.
|
|
"""
|
|
if issubclass(sender, StatorModel):
|
|
indexes = [
|
|
models.Index(
|
|
fields=["state", "state_attempted"],
|
|
name=f"ix_{sender.__name__.lower()[:11]}_state_attempted",
|
|
),
|
|
models.Index(
|
|
fields=["state_locked_until", "state"],
|
|
condition=models.Q(state_locked_until__isnull=False),
|
|
name=f"ix_{sender.__name__.lower()[:11]}_state_locked",
|
|
),
|
|
]
|
|
|
|
if not sender._meta.indexes:
|
|
# Meta.indexes needs to not be None to trigger Django behaviors
|
|
sender.Meta.indexes = []
|
|
|
|
for idx in indexes:
|
|
sender._meta.indexes.append(idx)
|
|
|
|
|
|
# class_prepared might become deprecated [1]. If it's removed, the named Index
|
|
# injection would need to happen in a metaclass subclass of ModelBase's _prepare()
|
|
#
|
|
# [1] https://code.djangoproject.com/ticket/24313
|
|
class_prepared.connect(add_stator_indexes)
|
|
|
|
|
|
class StatorModel(models.Model):
|
|
"""
|
|
A model base class that has a state machine backing it, with tasks to work
|
|
out when to move the state to the next one.
|
|
|
|
You need to provide a "state" field as an instance of StateField on the
|
|
concrete model yourself.
|
|
"""
|
|
|
|
state: StateField
|
|
|
|
# If this row is up for transition attempts (which it always is on creation!)
|
|
state_ready = models.BooleanField(default=True)
|
|
|
|
# When the state last actually changed, or the date of instance creation
|
|
state_changed = models.DateTimeField(auto_now_add=True)
|
|
|
|
# When the last state change for the current state was attempted
|
|
# (and not successful, as this is cleared on transition)
|
|
state_attempted = models.DateTimeField(blank=True, null=True)
|
|
|
|
# If a lock is out on this row, when it is locked until
|
|
# (we don't identify the lock owner, as there's no heartbeats)
|
|
state_locked_until = models.DateTimeField(null=True, blank=True)
|
|
|
|
# Collection of subclasses of us
|
|
subclasses: ClassVar[list[type["StatorModel"]]] = []
|
|
|
|
class Meta:
|
|
abstract = True
|
|
index_together = [("state_ready", "state_locked_until", "state")]
|
|
# Need this empty indexes to ensure child Models have a Meta.indexes
|
|
# that will look to add indexes (that we inject with class_prepared)
|
|
indexes: list = []
|
|
|
|
def __init_subclass__(cls) -> None:
|
|
if cls is not StatorModel:
|
|
cls.subclasses.append(cls)
|
|
|
|
@classproperty
|
|
def state_graph(cls) -> type[StateGraph]:
|
|
return cls._meta.get_field("state").graph
|
|
|
|
@property
|
|
def state_age(self) -> float:
|
|
return (timezone.now() - self.state_changed).total_seconds()
|
|
|
|
@classmethod
|
|
async def atransition_schedule_due(cls, now=None):
|
|
"""
|
|
Finds instances of this model that need to run and schedule them.
|
|
"""
|
|
if now is None:
|
|
now = timezone.now()
|
|
q = models.Q()
|
|
for state in cls.state_graph.states.values():
|
|
state = cast(State, state)
|
|
if not state.externally_progressed:
|
|
q = q | models.Q(
|
|
(
|
|
models.Q(
|
|
state_attempted__lte=(
|
|
now
|
|
- datetime.timedelta(
|
|
seconds=cast(float, state.try_interval)
|
|
)
|
|
)
|
|
)
|
|
| models.Q(state_attempted__isnull=True)
|
|
),
|
|
state=state.name,
|
|
)
|
|
await cls.objects.filter(q).aupdate(state_ready=True)
|
|
|
|
@classmethod
|
|
async def atransition_delete_due(cls, now=None):
|
|
"""
|
|
Finds instances of this model that need to be deleted and deletes them.
|
|
"""
|
|
if now is None:
|
|
now = timezone.now()
|
|
for state in cls.state_graph.states.values():
|
|
state = cast(State, state)
|
|
if state.delete_after:
|
|
await cls.objects.filter(
|
|
state=state,
|
|
state_changed__lte=(
|
|
now - datetime.timedelta(seconds=state.delete_after)
|
|
),
|
|
).adelete()
|
|
|
|
@classmethod
|
|
def transition_get_with_lock(
|
|
cls, number: int, lock_expiry: datetime.datetime
|
|
) -> list["StatorModel"]:
|
|
"""
|
|
Returns up to `number` tasks for execution, having locked them.
|
|
"""
|
|
with transaction.atomic():
|
|
selected = list(
|
|
cls.objects.filter(
|
|
state_locked_until__isnull=True,
|
|
state_ready=True,
|
|
state__in=cls.state_graph.automatic_states,
|
|
)[:number].select_for_update()
|
|
)
|
|
cls.objects.filter(pk__in=[i.pk for i in selected]).update(
|
|
state_locked_until=lock_expiry
|
|
)
|
|
return selected
|
|
|
|
@classmethod
|
|
async def atransition_get_with_lock(
|
|
cls, number: int, lock_expiry: datetime.datetime
|
|
) -> list["StatorModel"]:
|
|
return await sync_to_async(cls.transition_get_with_lock)(number, lock_expiry)
|
|
|
|
@classmethod
|
|
async def atransition_ready_count(cls) -> int:
|
|
"""
|
|
Returns how many instances are "queued"
|
|
"""
|
|
return await (
|
|
cls.objects.filter(
|
|
state_locked_until__isnull=True,
|
|
state_ready=True,
|
|
state__in=cls.state_graph.automatic_states,
|
|
).acount()
|
|
)
|
|
|
|
@classmethod
|
|
async def atransition_clean_locks(cls):
|
|
await cls.objects.filter(state_locked_until__lte=timezone.now()).aupdate(
|
|
state_locked_until=None
|
|
)
|
|
|
|
def transition_schedule(self):
|
|
"""
|
|
Adds this instance to the queue to get its state transition attempted.
|
|
|
|
The scheduler will call this, but you can also call it directly if you
|
|
know it'll be ready and want to lower latency.
|
|
"""
|
|
self.state_ready = True
|
|
self.save()
|
|
|
|
async def atransition_attempt(self) -> State | None:
|
|
"""
|
|
Attempts to transition the current state by running its handler(s).
|
|
"""
|
|
current_state: State = self.state_graph.states[self.state]
|
|
# If it's a manual progression state don't even try
|
|
# We shouldn't really be here in this case, but it could be a race condition
|
|
if current_state.externally_progressed:
|
|
print(
|
|
f"Warning: trying to progress externally progressed state {self.state}!"
|
|
)
|
|
return None
|
|
try:
|
|
next_state = await current_state.handler(self) # type: ignore
|
|
except TryAgainLater:
|
|
pass
|
|
except BaseException as e:
|
|
await exceptions.acapture_exception(e)
|
|
traceback.print_exc()
|
|
else:
|
|
if next_state:
|
|
# Ensure it's a State object
|
|
if isinstance(next_state, str):
|
|
next_state = self.state_graph.states[next_state]
|
|
# Ensure it's a child
|
|
if next_state not in current_state.children:
|
|
raise ValueError(
|
|
f"Cannot transition from {current_state} to {next_state} - not a declared transition"
|
|
)
|
|
await self.atransition_perform(next_state)
|
|
return next_state
|
|
# See if it timed out
|
|
if (
|
|
current_state.timeout_value
|
|
and current_state.timeout_value
|
|
<= (timezone.now() - self.state_changed).total_seconds()
|
|
):
|
|
await self.atransition_perform(current_state.timeout_state)
|
|
return current_state.timeout_state
|
|
await self.__class__.objects.filter(pk=self.pk).aupdate(
|
|
state_attempted=timezone.now(),
|
|
state_locked_until=None,
|
|
state_ready=False,
|
|
)
|
|
return None
|
|
|
|
def transition_perform(self, state: State | str):
|
|
"""
|
|
Transitions the instance to the given state name, forcibly.
|
|
"""
|
|
self.transition_perform_queryset(
|
|
self.__class__.objects.filter(pk=self.pk),
|
|
state,
|
|
)
|
|
|
|
atransition_perform = sync_to_async(transition_perform)
|
|
|
|
def transition_set_state(self, state: State | str):
|
|
"""
|
|
Sets the instance to the given state name for when it is saved.
|
|
"""
|
|
if isinstance(state, State):
|
|
state = state.name
|
|
if state not in self.state_graph.states:
|
|
raise ValueError(f"Invalid state {state}")
|
|
self.state = state # type: ignore
|
|
self.state_changed = timezone.now()
|
|
self.state_locked_until = None
|
|
|
|
if self.state_graph.states[state].attempt_immediately:
|
|
self.state_attempted = None
|
|
self.state_ready = True
|
|
else:
|
|
self.state_attempted = timezone.now()
|
|
self.state_ready = False
|
|
|
|
@classmethod
|
|
def transition_perform_queryset(
|
|
cls,
|
|
queryset: models.QuerySet,
|
|
state: State | str,
|
|
):
|
|
"""
|
|
Transitions every instance in the queryset to the given state name, forcibly.
|
|
"""
|
|
if isinstance(state, State):
|
|
state = state.name
|
|
if state not in cls.state_graph.states:
|
|
raise ValueError(f"Invalid state {state}")
|
|
# See if it's ready immediately (if not, delay until first try_interval)
|
|
if cls.state_graph.states[state].attempt_immediately:
|
|
queryset.update(
|
|
state=state,
|
|
state_changed=timezone.now(),
|
|
state_attempted=None,
|
|
state_locked_until=None,
|
|
state_ready=True,
|
|
)
|
|
else:
|
|
queryset.update(
|
|
state=state,
|
|
state_changed=timezone.now(),
|
|
state_attempted=timezone.now(),
|
|
state_locked_until=None,
|
|
state_ready=False,
|
|
)
|
|
|
|
|
|
class Stats(models.Model):
|
|
"""
|
|
Tracks summary statistics of each model over time.
|
|
"""
|
|
|
|
# appname.modelname (lowercased) label for the model this represents
|
|
model_label = models.CharField(max_length=200, primary_key=True)
|
|
|
|
statistics = models.JSONField()
|
|
|
|
created = models.DateTimeField(auto_now_add=True)
|
|
updated = models.DateTimeField(auto_now=True)
|
|
|
|
class Meta:
|
|
verbose_name_plural = "Stats"
|
|
|
|
@classmethod
|
|
def get_for_model(cls, model: type[StatorModel]) -> "Stats":
|
|
instance = cls.objects.filter(model_label=model._meta.label_lower).first()
|
|
if instance is None:
|
|
instance = cls(model_label=model._meta.label_lower)
|
|
if not instance.statistics:
|
|
instance.statistics = {}
|
|
# Ensure there are the right keys
|
|
for key in ["queued", "hourly", "daily", "monthly"]:
|
|
if key not in instance.statistics:
|
|
instance.statistics[key] = {}
|
|
return instance
|
|
|
|
@classmethod
|
|
async def aget_for_model(cls, model: type[StatorModel]) -> "Stats":
|
|
return await sync_to_async(cls.get_for_model)(model)
|
|
|
|
def set_queued(self, number: int):
|
|
"""
|
|
Sets the current queued amount.
|
|
|
|
The queue is an instantaneous value (a "gauge") rather than a
|
|
sum ("counter"). It's mostly used for reporting what things are right
|
|
now, but basic trend analysis is also used to see if we think the
|
|
queue is backing up.
|
|
"""
|
|
self.statistics["queued"][
|
|
int(timezone.now().replace(second=0, microsecond=0).timestamp())
|
|
] = number
|
|
|
|
def add_handled(self, number: int):
|
|
"""
|
|
Adds the "handled" number to the current stats.
|
|
"""
|
|
hour = timezone.now().replace(minute=0, second=0, microsecond=0)
|
|
day = hour.replace(hour=0)
|
|
hour_timestamp = str(int(hour.timestamp()))
|
|
day_timestamp = str(int(day.timestamp()))
|
|
month_timestamp = str(int(day.replace(day=1).timestamp()))
|
|
self.statistics["hourly"][hour_timestamp] = (
|
|
self.statistics["hourly"].get(hour_timestamp, 0) + number
|
|
)
|
|
self.statistics["daily"][day_timestamp] = (
|
|
self.statistics["daily"].get(day_timestamp, 0) + number
|
|
)
|
|
self.statistics["monthly"][month_timestamp] = (
|
|
self.statistics["monthly"].get(month_timestamp, 0) + number
|
|
)
|
|
|
|
def trim_data(self):
|
|
"""
|
|
Removes excessively old data from the field
|
|
"""
|
|
queued_horizon = int((timezone.now() - datetime.timedelta(hours=2)).timestamp())
|
|
hourly_horizon = int(
|
|
(timezone.now() - datetime.timedelta(hours=50)).timestamp()
|
|
)
|
|
daily_horizon = int((timezone.now() - datetime.timedelta(days=62)).timestamp())
|
|
monthly_horizon = int(
|
|
(timezone.now() - datetime.timedelta(days=3653)).timestamp()
|
|
)
|
|
self.statistics["queued"] = {
|
|
ts: v
|
|
for ts, v in self.statistics["queued"].items()
|
|
if int(ts) >= queued_horizon
|
|
}
|
|
self.statistics["hourly"] = {
|
|
ts: v
|
|
for ts, v in self.statistics["hourly"].items()
|
|
if int(ts) >= hourly_horizon
|
|
}
|
|
self.statistics["daily"] = {
|
|
ts: v
|
|
for ts, v in self.statistics["daily"].items()
|
|
if int(ts) >= daily_horizon
|
|
}
|
|
self.statistics["monthly"] = {
|
|
ts: v
|
|
for ts, v in self.statistics["monthly"].items()
|
|
if int(ts) >= monthly_horizon
|
|
}
|
|
|
|
def most_recent_queued(self) -> int:
|
|
"""
|
|
Returns the most recent number of how many were queued
|
|
"""
|
|
queued = [(int(ts), v) for ts, v in self.statistics["queued"].items()]
|
|
queued.sort(reverse=True)
|
|
if queued:
|
|
return queued[0][1]
|
|
else:
|
|
return 0
|
|
|
|
def most_recent_handled(self) -> tuple[int, int, int]:
|
|
"""
|
|
Returns the current handling numbers for hour, day, month
|
|
"""
|
|
hour = timezone.now().replace(minute=0, second=0, microsecond=0)
|
|
day = hour.replace(hour=0)
|
|
hour_timestamp = str(int(hour.timestamp()))
|
|
day_timestamp = str(int(day.timestamp()))
|
|
month_timestamp = str(int(day.replace(day=1).timestamp()))
|
|
return (
|
|
self.statistics["hourly"].get(hour_timestamp, 0),
|
|
self.statistics["daily"].get(day_timestamp, 0),
|
|
self.statistics["monthly"].get(month_timestamp, 0),
|
|
)
|