下面是job.py源代码，做了一点修改。
这是我第一篇文章，请大家支持。
主要属性：
- 一个job（有唯一id）就是在trigger 的激发下执行
func(args, kwargs)的任务. 具体执行由executor来做。
job 执行流程：时间读入 -> trigger 激发 -> executor执行job -> 计算下一次运行时间 - 一个job会被某个scheduler安排，必要的话会被存储在某个jobstore里。下一次执行程序时候, scheduler会考虑jobstore的执行。
- 初始化时，间接由方法
_modify实现
次要属性： - 错过执行时间的处理
- 下一次执行时间
- 提供job名称
方法：
间接使用scheduler的方法，如 job.pause 就是调用self._scheduler.pause_job（scheduler通过id, jobstore_alias查询job）
from collections import Iterable, Mapping
from uuid import uuid4
from apscheduler.triggers.base import BaseTrigger
from apscheduler.util import (
ref_to_obj, obj_to_ref, datetime_repr, repr_escape, get_callable_name, check_callable_args,
convert_to_datetime)
class Job(object):
"""
Contains the options given when scheduling callables and its current schedule and other state.
This class should never be instantiated by the user.
:var str id: the unique identifier of this job
:var str name: the description of this job
:var func: the callable to execute
:var tuple|list args: positional arguments to the callable
:var dict kwargs: keyword arguments to the callable
:var bool coalesce: whether to only run the job once when several run times are due
:var trigger: the trigger object that controls the schedule of this job
:var str executor: the name of the executor that will run this job
:var int misfire_grace_time: the time (in seconds) how much this job's execution is allowed to
be late
:var int max_instances: the maximum number of concurrently executing instances allowed for this
job
:var datetime.datetime next_run_time: the next scheduled run time of this job
.. note::
The ``misfire_grace_time`` has some non-obvious effects on job execution. See the
:ref:`missed-job-executions` section in the documentation for an in-depth explanation.
"""
__slots__ = ('_scheduler', '_jobstore_alias', 'id', 'trigger', 'executor', 'func', 'func_ref',
'args', 'kwargs', 'name', 'misfire_grace_time', 'coalesce', 'max_instances',
'next_run_time')
def __init__(self, scheduler, id=None, **kwargs):
super(Job, self).__init__()
self._scheduler = scheduler
self._jobstore_alias = None
self._modify(id=id or uuid4().hex, **kwargs)
# 间接使用scheduler 的方法：中止、重启、删除等。具体看scheduler 模块
def modify(self, **changes):
"""
Makes the given changes to this job and saves it in the associated job store.
Accepted keyword arguments are the same as the variables on this class.
.. seealso:: :meth:`~apscheduler.schedulers.base.BaseScheduler.modify_job`
:return Job: this job instance
"""
self._scheduler.modify_job(self.id, self._jobstore_alias, **changes)
return self
def reschedule(self, trigger, **trigger_args):
"""
Shortcut for switching the trigger on this job.
.. seealso:: :meth:`~apscheduler.schedulers.base.BaseScheduler.reschedule_job`
:return Job: this job instance
"""
self._scheduler.reschedule_job(self.id, self._jobstore_alias, trigger, **trigger_args)
return self
def pause(self):
"""
Temporarily suspend the execution of this job.
.. seealso:: :meth:`~apscheduler.schedulers.base.BaseScheduler.pause_job`
:return Job: this job instance
"""
self._scheduler.pause_job(self.id, self._jobstore_alias)
return self
def resume(self):
"""
Resume the schedule of this job if previously paused.
.. seealso:: :meth:`~apscheduler.schedulers.base.BaseScheduler.resume_job`
:return Job: this job instance
"""
self._scheduler.resume_job(self.id, self._jobstore_alias)
return self
def remove(self):
"""
Unschedules this job and removes it from its associated job store.
.. seealso:: :meth:`~apscheduler.schedulers.base.BaseScheduler.remove_job`
"""
self._scheduler.remove_job(self.id, self._jobstore_alias)
@property
def pending(self):
"""
Returns ``True`` if the referenced job is still waiting to be added to its designated job
store.
"""
return self._jobstore_alias is None
#
# Private API
#
def _get_run_times(self, now):
# 利用trigger获得next run times
"""
Computes the scheduled run times between ``next_run_time`` and ``now`` (inclusive).
:type now: datetime.datetime
:rtype: list[datetime.datetime]
"""
run_times = []
next_run_time = self.next_run_time
while next_run_time and next_run_time <= now:
run_times.append(next_run_time)
next_run_time = self.trigger.get_next_fire_time(next_run_time, now)
return run_times
# 初始化具体实现，也被用来modify
def _modify(self, **changes):
"""
Validates the changes to the Job and makes the modifications if and only if all of them
validate.
"""
approved = {}
if 'id' in changes:
value = changes.pop('id')
if not isinstance(value, str):
raise TypeError("id must be a nonempty string")
if hasattr(self, 'id'):
raise ValueError('The job ID may not be changed')
approved['id'] = value
if 'func' in changes or 'args' in changes or 'kwargs' in changes:
func = changes.pop('func') if 'func' in changes else self.func
args = changes.pop('args') if 'args' in changes else self.args
kwargs = changes.pop('kwargs') if 'kwargs' in changes else self.kwargs
if isinstance(func, str):
func_ref = func
func = ref_to_obj(func)
elif callable(func):
try:
func_ref = obj_to_ref(func)
except ValueError:
# If this happens, this Job won't be serializable
func_ref = None
else:
raise TypeError('func must be a callable or a textual reference to one')
if not hasattr(self, 'name') and changes.get('name', None) is None:
changes['name'] = get_callable_name(func)
if isinstance(args, str) or not isinstance(args, Iterable):
raise TypeError('args must be a non-string iterable')
if isinstance(kwargs, str) or not isinstance(kwargs, Mapping):
raise TypeError('kwargs must be a dict-like object')
check_callable_args(func, args, kwargs)
approved['func'] = func
approved['func_ref'] = func_ref
approved['args'] = args
approved['kwargs'] = kwargs
if 'name' in changes:
value = changes.pop('name')
if not value or not isinstance(value, str):
raise TypeError("name must be a nonempty string")
approved['name'] = value
if 'misfire_grace_time' in changes:
value = changes.pop('misfire_grace_time')
if value is not None and (not isinstance(value, int) or value <= 0):
raise TypeError('misfire_grace_time must be either None or a positive integer')
approved['misfire_grace_time'] = value
if 'coalesce' in changes:
value = bool(changes.pop('coalesce'))
approved['coalesce'] = value
if 'max_instances' in changes:
value = changes.pop('max_instances')
if not isinstance(value, int) or value <= 0:
raise TypeError('max_instances must be a positive integer')
approved['max_instances'] = value
if 'trigger' in changes:
trigger = changes.pop('trigger')
if not isinstance(trigger, BaseTrigger):
raise TypeError('Expected a trigger instance, got %s instead' %
trigger.__class__.__name__)
approved['trigger'] = trigger
if 'executor' in changes:
value = changes.pop('executor')
if not isinstance(value, str):
raise TypeError('executor must be a string')
approved['executor'] = value
if 'next_run_time' in changes:
value = changes.pop('next_run_time')
approved['next_run_time'] = convert_to_datetime(value, self._scheduler.timezone,
'next_run_time')
if changes:
raise AttributeError('The following are not modifiable attributes of Job: %s' %
', '.join(changes))
for key, value in approved.items():
setattr(self, key, value)
# 下面是序列化和字符串格式
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