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import asyncio
import datetime
import time
import traceback
import uuid
from typing import List, Optional, Type
from asgiref.sync import sync_to_async
from django.conf import settings
from django.utils import timezone
from stator.models import StatorModel
class StatorRunner:
"""
Runs tasks on models that are looking for state changes.
Designed to run for a determinate amount of time, and then exit.
"""
def __init__(
self,
models: List[Type[StatorModel]],
concurrency: int = 50,
concurrency_per_model: int = 10,
liveness_file: Optional[str] = None,
schedule_interval: int = 30,
lock_expiry: int = 300,
):
self.models = models
self.runner_id = uuid.uuid4().hex
self.concurrency = concurrency
self.concurrency_per_model = concurrency_per_model
self.liveness_file = liveness_file
self.schedule_interval = schedule_interval
self.lock_expiry = lock_expiry
async def run(self):
self.handled = 0
self.last_clean = time.monotonic() - self.schedule_interval
self.tasks = []
# For the first time period, launch tasks
print("Running main task loop")
try:
while True:
# Do we need to do cleaning?
if (time.monotonic() - self.last_clean) >= self.schedule_interval:
print(f"{self.handled} tasks processed so far")
print("Running cleaning and scheduling")
for model in self.models:
asyncio.create_task(model.atransition_clean_locks())
asyncio.create_task(model.atransition_schedule_due())
self.last_clean = time.monotonic()
# Calculate space left for tasks
self.remove_completed_tasks()
space_remaining = self.concurrency - len(self.tasks)
# Fetch new tasks
for model in self.models:
if space_remaining > 0:
for instance in await model.atransition_get_with_lock(
number=min(space_remaining, self.concurrency_per_model),
lock_expiry=(
timezone.now()
+ datetime.timedelta(seconds=self.lock_expiry)
),
):
self.tasks.append(
asyncio.create_task(self.run_transition(instance))
)
self.handled += 1
space_remaining -= 1
# Prevent busylooping
await asyncio.sleep(0.1)
except KeyboardInterrupt:
# Wait for tasks to finish
print("Waiting for tasks to complete")
while True:
self.remove_completed_tasks()
if not self.tasks:
break
# Prevent busylooping
await asyncio.sleep(1)
print("Complete")
return self.handled
async def run_transition(self, instance: StatorModel):
"""
Wrapper for atransition_attempt with fallback error handling
"""
try:
print(
f"Attempting transition on {instance._meta.label_lower}#{instance.pk} from state {instance.state}"
)
await instance.atransition_attempt()
except BaseException as e:
if settings.SENTRY_ENABLED:
from sentry_sdk import capture_exception
await sync_to_async(capture_exception, thread_sensitive=False)(e)
traceback.print_exc()
def remove_completed_tasks(self):
"""
Removes all completed asyncio.Tasks from our local in-progress list
"""
self.tasks = [t for t in self.tasks if not t.done()]
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