mylar/lib/apscheduler/jobstores/sqlalchemy.py

149 lines
5.6 KiB
Python

from __future__ import absolute_import
from apscheduler.jobstores.base import BaseJobStore, JobLookupError, ConflictingIdError
from apscheduler.util import maybe_ref, datetime_to_utc_timestamp, utc_timestamp_to_datetime
from apscheduler.job import Job
try:
import cPickle as pickle
except ImportError: # pragma: nocover
import pickle
try:
from sqlalchemy import (
create_engine, Table, Column, MetaData, Unicode, Float, LargeBinary, select)
from sqlalchemy.exc import IntegrityError
from sqlalchemy.sql.expression import null
except ImportError: # pragma: nocover
raise ImportError('SQLAlchemyJobStore requires SQLAlchemy installed')
class SQLAlchemyJobStore(BaseJobStore):
"""
Stores jobs in a database table using SQLAlchemy.
The table will be created if it doesn't exist in the database.
Plugin alias: ``sqlalchemy``
:param str url: connection string (see `SQLAlchemy documentation
<http://docs.sqlalchemy.org/en/latest/core/engines.html?highlight=create_engine#database-urls>`_
on this)
:param engine: an SQLAlchemy Engine to use instead of creating a new one based on ``url``
:param str tablename: name of the table to store jobs in
:param metadata: a :class:`~sqlalchemy.MetaData` instance to use instead of creating a new one
:param int pickle_protocol: pickle protocol level to use (for serialization), defaults to the
highest available
"""
def __init__(self, url=None, engine=None, tablename='apscheduler_jobs', metadata=None,
pickle_protocol=pickle.HIGHEST_PROTOCOL):
super(SQLAlchemyJobStore, self).__init__()
self.pickle_protocol = pickle_protocol
metadata = maybe_ref(metadata) or MetaData()
if engine:
self.engine = maybe_ref(engine)
elif url:
self.engine = create_engine(url)
else:
raise ValueError('Need either "engine" or "url" defined')
# 191 = max key length in MySQL for InnoDB/utf8mb4 tables,
# 25 = precision that translates to an 8-byte float
self.jobs_t = Table(
tablename, metadata,
Column('id', Unicode(191, _warn_on_bytestring=False), primary_key=True),
Column('next_run_time', Float(25), index=True),
Column('job_state', LargeBinary, nullable=False)
)
def start(self, scheduler, alias):
super(SQLAlchemyJobStore, self).start(scheduler, alias)
self.jobs_t.create(self.engine, True)
def lookup_job(self, job_id):
selectable = select([self.jobs_t.c.job_state]).where(self.jobs_t.c.id == job_id)
job_state = self.engine.execute(selectable).scalar()
return self._reconstitute_job(job_state) if job_state else None
def get_due_jobs(self, now):
timestamp = datetime_to_utc_timestamp(now)
return self._get_jobs(self.jobs_t.c.next_run_time <= timestamp)
def get_next_run_time(self):
selectable = select([self.jobs_t.c.next_run_time]).\
where(self.jobs_t.c.next_run_time != null()).\
order_by(self.jobs_t.c.next_run_time).limit(1)
next_run_time = self.engine.execute(selectable).scalar()
return utc_timestamp_to_datetime(next_run_time)
def get_all_jobs(self):
jobs = self._get_jobs()
self._fix_paused_jobs_sorting(jobs)
return jobs
def add_job(self, job):
insert = self.jobs_t.insert().values(**{
'id': job.id,
'next_run_time': datetime_to_utc_timestamp(job.next_run_time),
'job_state': pickle.dumps(job.__getstate__(), self.pickle_protocol)
})
try:
self.engine.execute(insert)
except IntegrityError:
raise ConflictingIdError(job.id)
def update_job(self, job):
update = self.jobs_t.update().values(**{
'next_run_time': datetime_to_utc_timestamp(job.next_run_time),
'job_state': pickle.dumps(job.__getstate__(), self.pickle_protocol)
}).where(self.jobs_t.c.id == job.id)
result = self.engine.execute(update)
if result.rowcount == 0:
raise JobLookupError(id)
def remove_job(self, job_id):
delete = self.jobs_t.delete().where(self.jobs_t.c.id == job_id)
result = self.engine.execute(delete)
if result.rowcount == 0:
raise JobLookupError(job_id)
def remove_all_jobs(self):
delete = self.jobs_t.delete()
self.engine.execute(delete)
def shutdown(self):
self.engine.dispose()
def _reconstitute_job(self, job_state):
job_state = pickle.loads(job_state)
job_state['jobstore'] = self
job = Job.__new__(Job)
job.__setstate__(job_state)
job._scheduler = self._scheduler
job._jobstore_alias = self._alias
return job
def _get_jobs(self, *conditions):
jobs = []
selectable = select([self.jobs_t.c.id, self.jobs_t.c.job_state]).\
order_by(self.jobs_t.c.next_run_time)
selectable = selectable.where(*conditions) if conditions else selectable
failed_job_ids = set()
for row in self.engine.execute(selectable):
try:
jobs.append(self._reconstitute_job(row.job_state))
except:
self._logger.exception('Unable to restore job "%s" -- removing it', row.id)
failed_job_ids.add(row.id)
# Remove all the jobs we failed to restore
if failed_job_ids:
delete = self.jobs_t.delete().where(self.jobs_t.c.id.in_(failed_job_ids))
self.engine.execute(delete)
return jobs
def __repr__(self):
return '<%s (url=%s)>' % (self.__class__.__name__, self.engine.url)