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78 lines
2.5 KiB
Python
78 lines
2.5 KiB
Python
"""
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This code has been taken from
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https://blog.hypertrack.io/2016/10/08/dealing-with-database-transactions-in-django-celery/
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Usage:
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from pretix.base.services.async import TransactionAwareTask
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@task(base=TransactionAwareTask)
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def task_…():
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"""
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import cProfile
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import os
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import random
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import time
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from django.conf import settings
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from django.db import transaction
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from pretix.base.metrics import (
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pretix_task_duration_seconds, pretix_task_runs_total,
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)
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from pretix.celery_app import app
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class ProfiledTask(app.Task):
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def __call__(self, *args, **kwargs):
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if settings.PROFILING_RATE > 0 and random.random() < settings.PROFILING_RATE / 100:
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profiler = cProfile.Profile()
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profiler.enable()
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t0 = time.perf_counter()
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ret = super().__call__(*args, **kwargs)
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tottime = time.perf_counter() - t0
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profiler.disable()
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profiler.dump_stats(os.path.join(settings.PROFILE_DIR, '{time:.0f}_{tottime:.3f}_celery_{t}.pstat'.format(
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t=self.name, tottime=tottime, time=time.time()
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)))
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else:
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t0 = time.perf_counter()
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ret = super().__call__(*args, **kwargs)
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tottime = time.perf_counter() - t0
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if settings.METRICS_ENABLED:
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pretix_task_duration_seconds.observe(tottime, task_name=self.name)
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return ret
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def on_failure(self, exc, task_id, args, kwargs, einfo):
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if settings.METRICS_ENABLED:
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expected = False
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for t in self.throws:
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if isinstance(exc, t):
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expected = True
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break
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pretix_task_runs_total.inc(1, task_name=self.name, status="expected-error" if expected else "error")
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return super().on_failure(exc, task_id, args, kwargs, einfo)
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def on_success(self, retval, task_id, args, kwargs):
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if settings.METRICS_ENABLED:
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pretix_task_runs_total.inc(1, task_name=self.name, status="success")
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return super().on_success(retval, task_id, args, kwargs)
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class TransactionAwareTask(ProfiledTask):
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"""
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Task class which is aware of django db transactions and only executes tasks
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after transaction has been committed
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"""
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def apply_async(self, *args, **kwargs):
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"""
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Unlike the default task in celery, this task does not return an async
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result
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"""
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transaction.on_commit(
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lambda: super(TransactionAwareTask, self).apply_async(*args, **kwargs)
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)
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