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SP/web2py/gluon/scheduler.py

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#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
| This file is part of the web2py Web Framework
| Copyrighted by Massimo Di Pierro <mdipierro@cs.depaul.edu>
| License: LGPLv3 (http://www.gnu.org/licenses/lgpl.html)
Background processes made simple
---------------------------------
"""
from __future__ import print_function
import os
import re
import time
import multiprocessing
import sys
import threading
import traceback
import signal
import socket
import datetime
import logging
import optparse
import tempfile
import types
from functools import reduce
from json import loads, dumps
from gluon import DAL, Field, IS_NOT_EMPTY, IS_IN_SET, IS_NOT_IN_DB, IS_EMPTY_OR
from gluon import IS_INT_IN_RANGE, IS_DATETIME, IS_IN_DB
from gluon.utils import web2py_uuid
from gluon._compat import Queue, long, iteritems, PY2
from gluon.storage import Storage
USAGE = """
## Example
For any existing app
Create File: app/models/scheduler.py ======
from gluon.scheduler import Scheduler
def demo1(*args,**vars):
print('you passed args=%s and vars=%s' % (args, vars))
return 'done!'
def demo2():
1/0
scheduler = Scheduler(db,dict(demo1=demo1,demo2=demo2))
## run worker nodes with:
cd web2py
python web2py.py -K myapp
or
python gluon/scheduler.py -u sqlite://storage.sqlite \
-f applications/myapp/databases/ \
-t mytasks.py
(-h for info)
python scheduler.py -h
## schedule jobs using
http://127.0.0.1:8000/myapp/appadmin/insert/db/scheduler_task
## monitor scheduled jobs
http://127.0.0.1:8000/myapp/appadmin/select/db?query=db.scheduler_task.id>0
## view completed jobs
http://127.0.0.1:8000/myapp/appadmin/select/db?query=db.scheduler_run.id>0
## view workers
http://127.0.0.1:8000/myapp/appadmin/select/db?query=db.scheduler_worker.id>0
"""
path = os.getcwd()
if 'WEB2PY_PATH' not in os.environ:
os.environ['WEB2PY_PATH'] = path
IDENTIFIER = "%s#%s" % (socket.gethostname(), os.getpid())
logger = logging.getLogger('web2py.scheduler.%s' % IDENTIFIER)
QUEUED = 'QUEUED'
ASSIGNED = 'ASSIGNED'
RUNNING = 'RUNNING'
COMPLETED = 'COMPLETED'
FAILED = 'FAILED'
TIMEOUT = 'TIMEOUT'
STOPPED = 'STOPPED'
ACTIVE = 'ACTIVE'
TERMINATE = 'TERMINATE'
DISABLED = 'DISABLED'
KILL = 'KILL'
PICK = 'PICK'
STOP_TASK = 'STOP_TASK'
EXPIRED = 'EXPIRED'
SECONDS = 1
HEARTBEAT = 3 * SECONDS
MAXHIBERNATION = 10
CLEAROUT = '!clear!'
CALLABLETYPES = (types.LambdaType, types.FunctionType,
types.BuiltinFunctionType,
types.MethodType, types.BuiltinMethodType)
class Task(object):
"""Defines a "task" object that gets passed from the main thread to the
executor's one
"""
def __init__(self, app, function, timeout, args='[]', vars='{}', **kwargs):
logger.debug(' new task allocated: %s.%s', app, function)
self.app = app
self.function = function
self.timeout = timeout
self.args = args # json
self.vars = vars # json
self.__dict__.update(kwargs)
def __str__(self):
return '<Task: %s>' % self.function
class TaskReport(object):
"""Defines a "task report" object that gets passed from the executor's
thread to the main one
"""
def __init__(self, status, result=None, output=None, tb=None):
logger.debug(' new task report: %s', status)
if tb:
logger.debug(' traceback: %s', tb)
else:
logger.debug(' result: %s', result)
self.status = status
self.result = result
self.output = output
self.tb = tb
def __str__(self):
return '<TaskReport: %s>' % self.status
class JobGraph(object):
"""Experimental: dependencies amongs tasks."""
def __init__(self, db, job_name):
self.job_name = job_name or 'job_0'
self.db = db
def add_deps(self, task_parent, task_child):
"""Create a dependency between task_parent and task_child."""
self.db.scheduler_task_deps.insert(task_parent=task_parent,
task_child=task_child,
job_name=self.job_name)
def validate(self, job_name=None):
"""Validate if all tasks job_name can be completed.
Checks if there are no mutual dependencies among tasks.
Commits at the end if successfull, or it rollbacks the entire
transaction. Handle with care!
"""
db = self.db
sd = db.scheduler_task_deps
if job_name:
q = sd.job_name == job_name
else:
q = sd.id > 0
edges = db(q).select()
nested_dict = {}
for row in edges:
k = row.task_parent
if k in nested_dict:
nested_dict[k].add(row.task_child)
else:
nested_dict[k] = set((row.task_child,))
try:
rtn = []
for k, v in nested_dict.items():
v.discard(k) # Ignore self dependencies
extra_items_in_deps = reduce(set.union, nested_dict.values()) - set(nested_dict.keys())
nested_dict.update(dict((item, set()) for item in extra_items_in_deps))
while True:
ordered = set(item for item, dep in nested_dict.items() if not dep)
if not ordered:
break
rtn.append(ordered)
nested_dict = dict(
(item, (dep - ordered)) for item, dep in nested_dict.items()
if item not in ordered
)
assert not nested_dict, "A cyclic dependency exists amongst %r" % nested_dict
db.commit()
return rtn
except:
db.rollback()
return None
class CronParser(object):
def __init__(self, cronline, base=None):
self.cronline = cronline
self.sched = base or datetime.datetime.now()
self.task = None
@staticmethod
def _rangetolist(s, period='min'):
retval = []
if s.startswith('*'):
if period == 'min':
s = s.replace('*', '0-59', 1)
elif period == 'hr':
s = s.replace('*', '0-23', 1)
elif period == 'dom':
s = s.replace('*', '1-31', 1)
elif period == 'mon':
s = s.replace('*', '1-12', 1)
elif period == 'dow':
s = s.replace('*', '0-6', 1)
m = re.compile(r'(\d+)-(\d+)/(\d+)')
match = m.match(s)
if match:
min_, max_ = int(match.group(1)), int(match.group(2)) + 1
step_ = int(match.group(3))
else:
m = re.compile(r'(\d+)/(\d+)')
ranges_max = {'min': 59, 'hr': 23, 'mon': 12, 'dom': 31, 'dow': 7}
match = m.match(s)
if match:
min_, max_ = int(match.group(1)), ranges_max[period] + 1
step_ = int(match.group(2))
if match:
for i in range(min_, max_, step_):
retval.append(i)
return retval
@staticmethod
def _sanitycheck(values, period):
if period == 'min':
check = all(0 <= i <= 59 for i in values)
elif period == 'hr':
check = all(0 <= i <= 23 for i in values)
elif period == 'dom':
domrange = list(range(1, 32)) + ['l']
check = all(i in domrange for i in values)
elif period == 'mon':
check = all(1 <= i <= 12 for i in values)
elif period == 'dow':
check = all(0 <= i <= 7 for i in values)
return check
def _parse(self):
line = self.cronline.lower()
task = {}
if line.startswith('@yearly'):
line = line.replace('@yearly', '0 0 1 1 *')
elif line.startswith('@annually'):
line = line.replace('@annually', '0 0 1 1 *')
elif line.startswith('@monthly'):
line = line.replace('@monthly', '0 0 1 * *')
elif line.startswith('@weekly'):
line = line.replace('@weekly', '0 0 * * 0')
elif line.startswith('@daily'):
line = line.replace('@daily', '0 0 * * *')
elif line.startswith('@midnight'):
line = line.replace('@midnight', '0 0 * * *')
elif line.startswith('@hourly'):
line = line.replace('@hourly', '0 * * * *')
params = line.strip().split()
if len(params) < 5:
raise ValueError('Invalid cron line (too short)')
elif len(params) > 5:
raise ValueError('Invalid cron line (too long)')
daysofweek = {'sun': 0, 'mon': 1, 'tue': 2, 'wed': 3, 'thu': 4,
'fri': 5, 'sat': 6}
monthsofyear = {'jan': 1, 'feb': 2, 'mar': 3, 'apr': 4, 'may': 5,
'jun': 6, 'jul': 7, 'aug': 8, 'sep': 9, 'oct': 10,
'nov': 11, 'dec': 12, 'l': 'l'}
for (s, i) in zip(params[:5], ['min', 'hr', 'dom', 'mon', 'dow']):
if s not in [None, '*']:
task[i] = []
vals = s.split(',')
for val in vals:
if i == 'dow':
refdict = daysofweek
elif i == 'mon':
refdict = monthsofyear
if i in ('dow', 'mon') and '-' in val and '/' not in val:
isnum = val.split('-')[0].isdigit()
if isnum:
val = '%s/1' % val
else:
val = '-'.join([str(refdict[v])
for v in val.split('-')])
if val != '-1' and '-' in val and '/' not in val:
val = '%s/1' % val
if '/' in val:
task[i] += self._rangetolist(val, i)
elif val.isdigit() or val == '-1':
task[i].append(int(val))
elif i in ('dow', 'mon'):
if val in refdict:
task[i].append(refdict[val])
elif i == 'dom' and val == 'l':
task[i].append(val)
if not task[i]:
raise ValueError('Invalid cron value (%s)' % s)
if not self._sanitycheck(task[i], i):
raise ValueError('Invalid cron value (%s)' % s)
task[i] = sorted(task[i])
self.task = task
@staticmethod
def _get_next_dow(sched, task):
task_dow = [a % 7 for a in task['dow']]
while sched.isoweekday() % 7 not in task_dow:
sched += datetime.timedelta(days=1)
return sched
@staticmethod
def _get_next_dom(sched, task):
if task['dom'] == ['l']:
last_feb = 29 if sched.year % 4 == 0 else 28
lastdayofmonth = [
31, last_feb, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
]
task_dom = [lastdayofmonth[sched.month - 1]]
else:
task_dom = task['dom']
while sched.day not in task_dom:
sched += datetime.timedelta(days=1)
return sched
@staticmethod
def _get_next_mon(sched, task):
while sched.month not in task['mon']:
if sched.month < 12:
sched = sched.replace(month=sched.month + 1)
else:
sched = sched.replace(month=1, year=sched.year + 1)
return sched
@staticmethod
def _getnext_hhmm(sched, task, add_to=True):
if add_to:
sched += datetime.timedelta(minutes=1)
if 'min' in task:
while sched.minute not in task['min']:
sched += datetime.timedelta(minutes=1)
if 'hr' in task and sched.hour not in task['hr']:
while sched.hour not in task['hr']:
sched += datetime.timedelta(hours=1)
return sched
def _getnext_date(self, sched, task):
if 'dow' in task and 'dom' in task:
dow = self._get_next_dow(sched, task)
dom = self._get_next_dom(sched, task)
sched = min(dow, dom)
elif 'dow' in task:
sched = self._get_next_dow(sched, task)
elif 'dom' in task:
sched = self._get_next_dom(sched, task)
if 'mon' in task:
sched = self._get_next_mon(sched, task)
return sched.replace(hour=0, minute=0)
def get_next(self):
"""Get next date according to specs."""
if not self.task:
self._parse()
task = self.task
sched = self.sched
x = 0
while x < 1000: # avoid potential max recursions
x += 1
try:
next_date = self._getnext_date(sched, task)
except (ValueError, OverflowError) as e:
raise ValueError('Invalid cron expression (%s)' % e)
if next_date.date() > self.sched.date():
# we rolled date, check for valid hhmm
sched = self._getnext_hhmm(next_date, task, False)
break
else:
# same date, get next hhmm
sched_time = self._getnext_hhmm(sched, task, True)
if sched_time.date() > sched.date():
# we rolled date again :(
sched = sched_time
else:
sched = sched_time
break
else:
raise ValueError('Potential bug found, please submit your '
'cron expression to the authors')
self.sched = sched
return sched
def __iter__(self):
"""Support iteration."""
return self
__next__ = next = get_next
# the two functions below deal with simplejson decoding as unicode, esp for the dict decode
# and subsequent usage as function Keyword arguments unicode variable names won't work!
# borrowed from http://stackoverflow.com/questions/956867/
def _decode_list(lst):
if not PY2:
return lst
newlist = []
for i in lst:
if isinstance(i, unicode):
i = i.encode('utf-8')
elif isinstance(i, list):
i = _decode_list(i)
newlist.append(i)
return newlist
def _decode_dict(dct):
if not PY2:
return dct
newdict = {}
for k, v in iteritems(dct):
if isinstance(k, unicode):
k = k.encode('utf-8')
if isinstance(v, unicode):
v = v.encode('utf-8')
elif isinstance(v, list):
v = _decode_list(v)
newdict[k] = v
return newdict
def executor(queue, task, out):
"""The function used to execute tasks in the background process."""
logger.debug(' task started')
class LogOutput(object):
"""Facility to log output at intervals."""
def __init__(self, out_queue):
self.out_queue = out_queue
self.stdout = sys.stdout
sys.stdout = self
def __del__(self):
sys.stdout = self.stdout
def flush(self):
pass
def write(self, data):
self.out_queue.put(data)
W2P_TASK = Storage({
'id': task.task_id,
'uuid': task.uuid,
'run_id': task.run_id
})
stdout = LogOutput(out)
try:
if task.app:
os.chdir(os.environ['WEB2PY_PATH'])
from gluon.shell import env, parse_path_info
from gluon import current
level = logging.getLogger().getEffectiveLevel()
logging.getLogger().setLevel(logging.WARN)
# Get controller-specific subdirectory if task.app is of
# form 'app/controller'
(a, c, f) = parse_path_info(task.app)
_env = env(a=a, c=c, import_models=True,
extra_request={'is_scheduler': True})
logging.getLogger().setLevel(level)
f = task.function
functions = current._scheduler.tasks
if not functions:
# look into env
_function = _env.get(f)
else:
_function = functions.get(f)
if not isinstance(_function, CALLABLETYPES):
raise NameError(
"name '%s' not found in scheduler's environment" % f)
# Inject W2P_TASK into environment
_env.update({'W2P_TASK': W2P_TASK})
# Inject W2P_TASK into current
from gluon import current
current.W2P_TASK = W2P_TASK
globals().update(_env)
args = _decode_list(loads(task.args))
vars = loads(task.vars, object_hook=_decode_dict)
result = dumps(_function(*args, **vars))
else:
# for testing purpose only
result = eval(task.function)(
*loads(task.args, object_hook=_decode_dict),
**loads(task.vars, object_hook=_decode_dict))
if len(result) >= 1024:
fd, temp_path = tempfile.mkstemp(suffix='.w2p_sched')
with os.fdopen(fd, 'w') as f:
f.write(result)
result = 'w2p_special:%s' % temp_path
queue.put(TaskReport('COMPLETED', result=result))
except BaseException as e:
tb = traceback.format_exc()
queue.put(TaskReport('FAILED', tb=tb))
del stdout
class MetaScheduler(threading.Thread):
"""Base class documenting scheduler's base methods."""
def __init__(self):
threading.Thread.__init__(self)
self.process = None # the background process
self.have_heartbeat = True # set to False to kill
self.empty_runs = 0
def local_async(self, task):
"""Start the background process.
Args:
task : a `Task` object
Returns:
tuple: containing::
('ok',result,output)
('error',exception,None)
('timeout',None,None)
('terminated',None,None)
"""
db = self.db
sr = db.scheduler_run
out = multiprocessing.Queue()
queue = multiprocessing.Queue(maxsize=1)
p = multiprocessing.Process(target=executor, args=(queue, task, out))
self.process = p
logger.debug(' task starting')
p.start()
task_output = ""
tout = ""
try:
if task.sync_output > 0:
run_timeout = task.sync_output
else:
run_timeout = task.timeout
start = time.time()
while p.is_alive() and (not task.timeout or time.time() - start < task.timeout):
if tout:
try:
logger.debug(' partial output saved')
db(sr.id == task.run_id).update(run_output=task_output)
db.commit()
except:
pass
p.join(timeout=run_timeout)
tout = ""
while not out.empty():
tout += out.get()
if tout:
logger.debug(' partial output: "%s"', str(tout))
if CLEAROUT in tout:
task_output = tout[
tout.rfind(CLEAROUT) + len(CLEAROUT):]
else:
task_output += tout
except:
p.terminate()
p.join()
logger.debug(' task stopped by general exception')
tr = TaskReport(STOPPED)
else:
if p.is_alive():
p.terminate()
logger.debug(' task timeout')
try:
# we try to get a traceback here
tr = queue.get(timeout=2)
tr.status = TIMEOUT
tr.output = task_output
except Queue.Empty:
tr = TaskReport(TIMEOUT)
elif queue.empty():
logger.debug(' task stopped')
tr = TaskReport(STOPPED)
else:
logger.debug(' task completed or failed')
tr = queue.get()
result = tr.result
if result and result.startswith('w2p_special'):
temp_path = result.replace('w2p_special:', '', 1)
with open(temp_path) as f:
tr.result = f.read()
os.unlink(temp_path)
tr.output = task_output
return tr
def die(self):
"""Forces termination of the worker process along with any running
task"""
logger.info('die!')
self.have_heartbeat = False
self.terminate_process()
def give_up(self):
"""Waits for any running task to be executed, then exits the worker
process"""
logger.info('Giving up as soon as possible!')
self.have_heartbeat = False
def terminate_process(self):
"""Terminate any running tasks (internal use only)"""
try:
self.process.terminate()
except:
pass # no process to terminate
def run(self):
"""This is executed by the main thread to send heartbeats"""
counter = 0
while self.have_heartbeat:
self.send_heartbeat(counter)
counter += 1
def start_heartbeats(self):
self.start()
def send_heartbeat(self, counter):
raise NotImplementedError
def pop_task(self):
"""Fetches a task ready to be executed"""
raise NotImplementedError
def report_task(self, task, task_report):
"""Creates a task report"""
raise NotImplementedError
def sleep(self):
raise NotImplementedError
def loop(self):
"""Main loop, fetching tasks and starting executor's background
processes"""
raise NotImplementedError
TASK_STATUS = (QUEUED, RUNNING, COMPLETED, FAILED, TIMEOUT, STOPPED, EXPIRED)
RUN_STATUS = (RUNNING, COMPLETED, FAILED, TIMEOUT, STOPPED)
WORKER_STATUS = (ACTIVE, PICK, DISABLED, TERMINATE, KILL, STOP_TASK)
class IS_CRONLINE(object):
"""
Validates cronline
"""
def __init__(self, error_message=None):
self.error_message = error_message
def __call__(self, value):
recur = CronParser(value, datetime.datetime.now())
try:
recur.get_next()
return (value, None)
except (KeyError, ValueError) as e:
if not self.error_message:
return (value, e)
return (value, self.error_message)
class TYPE(object):
"""
Validator that checks whether field is valid json and validates its type.
Used for `args` and `vars` of the scheduler_task table
"""
def __init__(self, myclass=list, parse=False):
self.myclass = myclass
self.parse = parse
def __call__(self, value):
from gluon import current
try:
obj = loads(value)
except:
return (value, current.T('invalid json'))
else:
if isinstance(obj, self.myclass):
if self.parse:
return (obj, None)
else:
return (value, None)
else:
return (value, current.T('Not of type: %s') % self.myclass)
class Scheduler(MetaScheduler):
"""Scheduler object
Args:
db: DAL connection where Scheduler will create its tables
tasks(dict): either a dict containing name-->func or None.
If None, functions will be searched in the environment
migrate(bool): turn migration on/off for the Scheduler's tables
worker_name(str): force worker_name to identify each process.
Leave it to None to autoassign a name (hostname#pid)
group_names(list): process tasks belonging to this group
defaults to ['main'] if nothing gets passed
heartbeat(int): how many seconds the worker sleeps between one
execution and the following one. Indirectly sets how many seconds
will pass between checks for new tasks
max_empty_runs(int): how many loops are allowed to pass without
processing any tasks before exiting the process. 0 to keep always
the process alive
discard_results(bool): Scheduler stores executions's details into the
scheduler_run table. By default, only if there is a result the
details are kept. Turning this to True means discarding results
even for tasks that return something
utc_time(bool): do all datetime calculations assuming UTC as the
timezone. Remember to pass `start_time` and `stop_time` to tasks
accordingly
"""
def __init__(self, db, tasks=None, migrate=True,
worker_name=None, group_names=None, heartbeat=HEARTBEAT,
max_empty_runs=0, discard_results=False, utc_time=False):
MetaScheduler.__init__(self)
self.db = db
self.db_thread = None
self.tasks = tasks
self.group_names = group_names or ['main']
self.heartbeat = heartbeat
self.worker_name = worker_name or IDENTIFIER
self.max_empty_runs = max_empty_runs
self.discard_results = discard_results
self.is_a_ticker = False
self.do_assign_tasks = False
self.greedy = False
self.utc_time = utc_time
self.w_stats = Storage(
dict(
status=RUNNING,
sleep=heartbeat,
total=0,
errors=0,
empty_runs=0,
queue=0,
distribution=None,
workers=0)
) # dict holding statistics
from gluon import current
current._scheduler = self
self.define_tables(db, migrate=migrate)
def __get_migrate(self, tablename, migrate=True):
if migrate is False:
return False
elif migrate is True:
return True
elif isinstance(migrate, str):
return "%s%s.table" % (migrate, tablename)
return True
def now(self):
"""Shortcut that fetches current time based on UTC preferences."""
return self.utc_time and datetime.datetime.utcnow() or datetime.datetime.now()
def set_requirements(self, scheduler_task):
"""Called to set defaults for lazy_tables connections."""
from gluon import current
if hasattr(current, 'request'):
scheduler_task.application_name.default = '%s/%s' % (
current.request.application, current.request.controller
)
def define_tables(self, db, migrate):
"""Define Scheduler tables structure."""
from pydal.base import DEFAULT
logger.debug('defining tables (migrate=%s)', migrate)
now = self.now
db.define_table(
'scheduler_task',
Field('application_name', requires=IS_NOT_EMPTY(),
default=None, writable=False),
Field('task_name', default=None),
Field('group_name', default='main'),
Field('status', requires=IS_IN_SET(TASK_STATUS),
default=QUEUED, writable=False),
Field('function_name',
requires=IS_IN_SET(sorted(self.tasks.keys()))
if self.tasks else DEFAULT),
Field('uuid', length=255,
requires=IS_NOT_IN_DB(db, 'scheduler_task.uuid'),
unique=True, default=web2py_uuid),
Field('args', 'text', default='[]', requires=TYPE(list)),
Field('vars', 'text', default='{}', requires=TYPE(dict)),
Field('enabled', 'boolean', default=True),
Field('start_time', 'datetime', default=now,
requires=IS_DATETIME()),
Field('next_run_time', 'datetime', default=now),
Field('stop_time', 'datetime'),
Field('repeats', 'integer', default=1, comment="0=unlimited",
requires=IS_INT_IN_RANGE(0, None)),
Field('retry_failed', 'integer', default=0, comment="-1=unlimited",
requires=IS_INT_IN_RANGE(-1, None)),
Field('period', 'integer', default=60, comment='seconds',
requires=IS_INT_IN_RANGE(0, None)),
Field('prevent_drift', 'boolean', default=False,
comment='Exact start_times between runs'),
Field('cronline', default=None,
comment='Discard "period", use this cron expr instead',
requires=IS_EMPTY_OR(IS_CRONLINE())),
Field('timeout', 'integer', default=60, comment='seconds',
requires=IS_INT_IN_RANGE(1, None)),
Field('sync_output', 'integer', default=0,
comment="update output every n sec: 0=never",
requires=IS_INT_IN_RANGE(0, None)),
Field('times_run', 'integer', default=0, writable=False),
Field('times_failed', 'integer', default=0, writable=False),
Field('last_run_time', 'datetime', writable=False, readable=False),
Field('assigned_worker_name', default='', writable=False),
on_define=self.set_requirements,
migrate=self.__get_migrate('scheduler_task', migrate),
format='(%(id)s) %(task_name)s')
db.define_table(
'scheduler_run',
Field('task_id', 'reference scheduler_task'),
Field('status', requires=IS_IN_SET(RUN_STATUS)),
Field('start_time', 'datetime'),
Field('stop_time', 'datetime'),
Field('run_output', 'text'),
Field('run_result', 'text'),
Field('traceback', 'text'),
Field('worker_name', default=self.worker_name),
migrate=self.__get_migrate('scheduler_run', migrate)
)
db.define_table(
'scheduler_worker',
Field('worker_name', length=255, unique=True),
Field('first_heartbeat', 'datetime'),
Field('last_heartbeat', 'datetime'),
Field('status', requires=IS_IN_SET(WORKER_STATUS)),
Field('is_ticker', 'boolean', default=False, writable=False),
Field('group_names', 'list:string', default=self.group_names),
Field('worker_stats', 'json'),
migrate=self.__get_migrate('scheduler_worker', migrate)
)
db.define_table(
'scheduler_task_deps',
Field('job_name', default='job_0'),
Field('task_parent', 'integer',
requires=IS_IN_DB(db, 'scheduler_task.id', '%(task_name)s')
),
Field('task_child', 'reference scheduler_task'),
Field('can_visit', 'boolean', default=False),
migrate=self.__get_migrate('scheduler_task_deps', migrate)
)
if migrate is not False:
db.commit()
def loop(self, worker_name=None):
"""Main loop.
This works basically as a neverending loop that:
- checks if the worker is ready to process tasks (is not DISABLED)
- pops a task from the queue
- if there is a task:
- spawns the executor background process
- waits for the process to be finished
- sleeps `heartbeat` seconds
- if there is not a task:
- checks for max_empty_runs
- sleeps `heartbeat` seconds
"""
signal.signal(signal.SIGTERM, lambda signum, stack_frame: sys.exit(1))
try:
self.start_heartbeats()
while self.have_heartbeat:
if self.w_stats.status == DISABLED:
logger.debug('Someone stopped me, sleeping until better'
' times come (%s)', self.w_stats.sleep)
self.sleep()
continue
logger.debug('looping...')
task = self.wrapped_pop_task()
if task:
self.w_stats.empty_runs = 0
self.w_stats.status = RUNNING
self.w_stats.total += 1
self.wrapped_report_task(task, self.local_async(task))
if not self.w_stats.status == DISABLED:
self.w_stats.status = ACTIVE
else:
self.w_stats.empty_runs += 1
logger.debug('sleeping...')
if self.max_empty_runs != 0:
logger.debug('empty runs %s/%s',
self.w_stats.empty_runs,
self.max_empty_runs)
if self.w_stats.empty_runs >= self.max_empty_runs:
logger.info(
'empty runs limit reached, killing myself')
self.die()
self.sleep()
except (KeyboardInterrupt, SystemExit):
logger.info('catched')
self.die()
def wrapped_assign_tasks(self, db):
"""Commodity function to call `assign_tasks` and trap exceptions.
If an exception is raised, assume it happened because of database
contention and retries `assign_task` after 0.5 seconds
"""
logger.debug('Assigning tasks...')
db.commit() # db.commit() only for Mysql
x = 0
while x < 10:
try:
self.assign_tasks(db)
db.commit()
logger.debug('Tasks assigned...')
break
except:
self.w_stats.errors += 1
db.rollback()
logger.error('TICKER: error assigning tasks (%s)', x)
x += 1
time.sleep(0.5)
def wrapped_pop_task(self):
"""Commodity function to call `pop_task` and trap exceptions.
If an exception is raised, assume it happened because of database
contention and retries `pop_task` after 0.5 seconds
"""
db = self.db
db.commit() # another nifty db.commit() only for Mysql
x = 0
while x < 10:
try:
rtn = self.pop_task(db)
return rtn
break
except:
self.w_stats.errors += 1
db.rollback()
logger.error(' error popping tasks')
x += 1
time.sleep(0.5)
def pop_task(self, db):
"""Grab a task ready to be executed from the queue."""
now = self.now()
st = self.db.scheduler_task
if self.is_a_ticker and self.do_assign_tasks:
# I'm a ticker, and 5 loops passed without reassigning tasks,
# let's do that and loop again
self.wrapped_assign_tasks(db)
return None
# ready to process something
grabbed = db(
(st.assigned_worker_name == self.worker_name) &
(st.status == ASSIGNED)
)
task = grabbed.select(limitby=(0, 1), orderby=st.next_run_time).first()
if task:
task.update_record(status=RUNNING, last_run_time=now)
# noone will touch my task!
db.commit()
logger.debug(' work to do %s', task.id)
else:
if self.is_a_ticker and self.greedy:
# there are other tasks ready to be assigned
logger.info('TICKER: greedy loop')
self.wrapped_assign_tasks(db)
else:
logger.info('nothing to do')
return None
times_run = task.times_run + 1
if task.cronline:
cron_recur = CronParser(task.cronline, now.replace(second=0))
next_run_time = cron_recur.get_next()
elif not task.prevent_drift:
next_run_time = task.last_run_time + datetime.timedelta(
seconds=task.period
)
else:
# calc next_run_time based on available slots
# see #1191
next_run_time = task.start_time
secondspassed = (now - next_run_time).total_seconds()
steps = secondspassed // task.period + 1
next_run_time += datetime.timedelta(seconds=task.period * steps)
if times_run < task.repeats or task.repeats == 0:
# need to run (repeating task)
run_again = True
else:
# no need to run again
run_again = False
run_id = 0
while True and not self.discard_results:
logger.debug(' new scheduler_run record')
try:
run_id = db.scheduler_run.insert(
task_id=task.id,
status=RUNNING,
start_time=now,
worker_name=self.worker_name)
db.commit()
break
except:
time.sleep(0.5)
db.rollback()
logger.info('new task %(id)s "%(task_name)s"'
' %(application_name)s.%(function_name)s' % task)
return Task(
app=task.application_name,
function=task.function_name,
timeout=task.timeout,
args=task.args, # in json
vars=task.vars, # in json
task_id=task.id,
run_id=run_id,
run_again=run_again,
next_run_time=next_run_time,
times_run=times_run,
stop_time=task.stop_time,
retry_failed=task.retry_failed,
times_failed=task.times_failed,
sync_output=task.sync_output,
uuid=task.uuid)
def wrapped_report_task(self, task, task_report):
"""Commodity function to call `report_task` and trap exceptions.
If an exception is raised, assume it happened because of database
contention and retries `pop_task` after 0.5 seconds
"""
db = self.db
while True:
try:
self.report_task(task, task_report)
db.commit()
break
except:
self.w_stats.errors += 1
db.rollback()
logger.error(' error storing result')
time.sleep(0.5)
def report_task(self, task, task_report):
"""Take care of storing the result according to preferences.
Deals with logic for repeating tasks.
"""
db = self.db
now = self.now()
st = db.scheduler_task
sr = db.scheduler_run
if not self.discard_results:
if task_report.result != 'null' or task_report.tb:
# result is 'null' as a string if task completed
# if it's stopped it's None as NoneType, so we record
# the STOPPED "run" anyway
logger.debug(' recording task report in db (%s)',
task_report.status)
db(sr.id == task.run_id).update(
status=task_report.status,
stop_time=now,
run_result=task_report.result,
run_output=task_report.output,
traceback=task_report.tb)
else:
logger.debug(' deleting task report in db because of no result')
db(sr.id == task.run_id).delete()
# if there is a stop_time and the following run would exceed it
is_expired = (task.stop_time and
task.next_run_time > task.stop_time and
True or False)
status = (task.run_again and is_expired and EXPIRED or
task.run_again and not is_expired and
QUEUED or COMPLETED)
if task_report.status == COMPLETED:
d = dict(status=status,
next_run_time=task.next_run_time,
times_run=task.times_run,
times_failed=0
)
db(st.id == task.task_id).update(**d)
if status == COMPLETED:
self.update_dependencies(db, task.task_id)
else:
st_mapping = {'FAILED': 'FAILED',
'TIMEOUT': 'TIMEOUT',
'STOPPED': 'FAILED'}[task_report.status]
status = (task.retry_failed
and task.times_failed < task.retry_failed
and QUEUED or task.retry_failed == -1
and QUEUED or st_mapping)
db(st.id == task.task_id).update(
times_failed=st.times_failed + 1,
next_run_time=task.next_run_time,
status=status
)
logger.info('task completed (%s)', task_report.status)
def update_dependencies(self, db, task_id):
"""Unblock execution paths for Jobs."""
db(db.scheduler_task_deps.task_child == task_id).update(can_visit=True)
def adj_hibernation(self):
"""Used to increase the "sleep" interval for DISABLED workers."""
if self.w_stats.status == DISABLED:
wk_st = self.w_stats.sleep
hibernation = wk_st + HEARTBEAT if wk_st < MAXHIBERNATION else MAXHIBERNATION
self.w_stats.sleep = hibernation
def send_heartbeat(self, counter):
"""Coordination among available workers.
It:
- sends the heartbeat
- elects a ticker among available workers (the only process that
effectively dispatch tasks to workers)
- deals with worker's statuses
- does "housecleaning" for dead workers
- triggers tasks assignment to workers
"""
if not self.db_thread:
logger.debug('thread building own DAL object')
self.db_thread = DAL(
self.db._uri, folder=self.db._adapter.folder, decode_credentials=True)
self.define_tables(self.db_thread, migrate=False)
try:
db = self.db_thread
sw, st = db.scheduler_worker, db.scheduler_task
now = self.now()
# record heartbeat
mybackedstatus = db(sw.worker_name == self.worker_name).select().first()
if not mybackedstatus:
sw.insert(status=ACTIVE, worker_name=self.worker_name,
first_heartbeat=now, last_heartbeat=now,
group_names=self.group_names,
worker_stats=self.w_stats)
self.w_stats.status = ACTIVE
self.w_stats.sleep = self.heartbeat
mybackedstatus = ACTIVE
else:
mybackedstatus = mybackedstatus.status
if mybackedstatus == DISABLED:
# keep sleeping
self.w_stats.status = DISABLED
logger.debug('........recording heartbeat (%s)',
self.w_stats.status)
db(sw.worker_name == self.worker_name).update(
last_heartbeat=now,
worker_stats=self.w_stats)
elif mybackedstatus == TERMINATE:
self.w_stats.status = TERMINATE
logger.debug("Waiting to terminate the current task")
self.give_up()
elif mybackedstatus == KILL:
self.w_stats.status = KILL
self.die()
return
else:
if mybackedstatus == STOP_TASK:
logger.info('Asked to kill the current task')
self.terminate_process()
logger.debug('........recording heartbeat (%s)',
self.w_stats.status)
db(sw.worker_name == self.worker_name).update(
last_heartbeat=now, status=ACTIVE,
worker_stats=self.w_stats)
self.w_stats.sleep = self.heartbeat # re-activating the process
if self.w_stats.status != RUNNING:
self.w_stats.status = ACTIVE
self.do_assign_tasks = False
if counter % 5 == 0 or mybackedstatus == PICK:
try:
# delete dead workers
expiration = now - datetime.timedelta(
seconds=self.heartbeat * 3)
departure = now - datetime.timedelta(
seconds=self.heartbeat * 3 * 15)
logger.debug(
' freeing workers that have not sent heartbeat')
dead_workers = db(
((sw.last_heartbeat < expiration) & (sw.status == ACTIVE)) |
((sw.last_heartbeat < departure) & (sw.status != ACTIVE))
)
dead_workers_name = dead_workers._select(sw.worker_name)
db(
(st.assigned_worker_name.belongs(dead_workers_name)) &
(st.status == RUNNING)
).update(assigned_worker_name='', status=QUEUED)
dead_workers.delete()
try:
self.is_a_ticker = self.being_a_ticker()
except:
logger.error('Error coordinating TICKER')
if self.w_stats.status == ACTIVE:
self.do_assign_tasks = True
except:
logger.error('Error cleaning up')
db.commit()
except:
logger.error('Error retrieving status')
db.rollback()
self.adj_hibernation()
self.sleep()
def being_a_ticker(self):
"""Elect a TICKER process that assigns tasks to available workers.
Does its best to elect a worker that is not busy processing other tasks
to allow a proper distribution of tasks among all active workers ASAP
"""
db = self.db_thread
sw = db.scheduler_worker
my_name = self.worker_name
all_active = db(
(sw.worker_name != my_name) & (sw.status == ACTIVE)
).select(sw.is_ticker, sw.worker_name)
ticker = all_active.find(lambda row: row.is_ticker is True).first()
not_busy = self.w_stats.status == ACTIVE
if not ticker:
# if no other tickers are around
if not_busy:
# only if I'm not busy
db(sw.worker_name == my_name).update(is_ticker=True)
db(sw.worker_name != my_name).update(is_ticker=False)
logger.info("TICKER: I'm a ticker")
else:
# I'm busy
if len(all_active) >= 1:
# so I'll "downgrade" myself to a "poor worker"
db(sw.worker_name == my_name).update(is_ticker=False)
else:
not_busy = True
db.commit()
return not_busy
else:
logger.info(
"%s is a ticker, I'm a poor worker" % ticker.worker_name)
return False
def assign_tasks(self, db):
"""Assign task to workers, that can then pop them from the queue.
Deals with group_name(s) logic, in order to assign linearly tasks
to available workers for those groups
"""
sw, st, sd = db.scheduler_worker, db.scheduler_task, db.scheduler_task_deps
now = self.now()
all_workers = db(sw.status == ACTIVE).select()
# build workers as dict of groups
wkgroups = {}
for w in all_workers:
if w.worker_stats['status'] == 'RUNNING':
continue
group_names = w.group_names
for gname in group_names:
if gname not in wkgroups:
wkgroups[gname] = dict(
workers=[{'name': w.worker_name, 'c': 0}])
else:
wkgroups[gname]['workers'].append(
{'name': w.worker_name, 'c': 0})
# set queued tasks that expired between "runs" (i.e., you turned off
# the scheduler): then it wasn't expired, but now it is
db(
(st.status.belongs((QUEUED, ASSIGNED))) &
(st.stop_time < now)
).update(status=EXPIRED)
# calculate dependencies
deps_with_no_deps = db(
(sd.can_visit == False) &
(~sd.task_child.belongs(
db(sd.can_visit == False)._select(sd.task_parent)
)
)
)._select(sd.task_child)
no_deps = db(
(st.status.belongs((QUEUED, ASSIGNED))) &
(
(sd.id == None) | (st.id.belongs(deps_with_no_deps))
)
)._select(st.id, distinct=True, left=sd.on(
(st.id == sd.task_parent) &
(sd.can_visit == False)
)
)
all_available = db(
(st.status.belongs((QUEUED, ASSIGNED))) &
(st.next_run_time <= now) &
(st.enabled == True) &
(st.id.belongs(no_deps))
)
limit = len(all_workers) * (50 / (len(wkgroups) or 1))
# if there are a moltitude of tasks, let's figure out a maximum of
# tasks per worker. This can be further tuned with some added
# intelligence (like esteeming how many tasks will a worker complete
# before the ticker reassign them around, but the gain is quite small
# 50 is a sweet spot also for fast tasks, with sane heartbeat values
# NB: ticker reassign tasks every 5 cycles, so if a worker completes
# its 50 tasks in less than heartbeat*5 seconds,
# it won't pick new tasks until heartbeat*5 seconds pass.
# If a worker is currently elaborating a long task, its tasks needs to
# be reassigned to other workers
# this shuffles up things a bit, in order to give a task equal chances
# to be executed
# let's freeze it up
db.commit()
x = 0
for group in wkgroups.keys():
tasks = all_available(st.group_name == group).select(
limitby=(0, limit), orderby=st.next_run_time)
# let's break up the queue evenly among workers
for task in tasks:
x += 1
gname = task.group_name
ws = wkgroups.get(gname)
if ws:
counter = 0
myw = 0
for i, w in enumerate(ws['workers']):
if w['c'] < counter:
myw = i
counter = w['c']
assigned_wn = wkgroups[gname]['workers'][myw]['name']
d = dict(
status=ASSIGNED,
assigned_worker_name=assigned_wn
)
db(
(st.id == task.id) &
(st.status.belongs((QUEUED, ASSIGNED)))
).update(**d)
wkgroups[gname]['workers'][myw]['c'] += 1
db.commit()
# I didn't report tasks but I'm working nonetheless!!!!
if x > 0:
self.w_stats.empty_runs = 0
self.w_stats.queue = x
self.w_stats.distribution = wkgroups
self.w_stats.workers = len(all_workers)
# I'll be greedy only if tasks assigned are equal to the limit
# (meaning there could be others ready to be assigned)
self.greedy = x >= limit
logger.info('TICKER: workers are %s', len(all_workers))
logger.info('TICKER: tasks are %s', x)
def sleep(self):
"""Calculate the number of seconds to sleep."""
time.sleep(self.w_stats.sleep)
# should only sleep until next available task
def set_worker_status(self, group_names=None, action=ACTIVE,
exclude=None, limit=None, worker_name=None):
"""Internal function to set worker's status."""
ws = self.db.scheduler_worker
if not group_names:
group_names = self.group_names
elif isinstance(group_names, str):
group_names = [group_names]
if worker_name:
self.db(ws.worker_name == worker_name).update(status=action)
return
exclusion = exclude and exclude.append(action) or [action]
if not limit:
for group in group_names:
self.db(
(ws.group_names.contains(group)) &
(~ws.status.belongs(exclusion))
).update(status=action)
else:
for group in group_names:
workers = self.db((ws.group_names.contains(group)) &
(~ws.status.belongs(exclusion))
)._select(ws.id, limitby=(0, limit))
self.db(ws.id.belongs(workers)).update(status=action)
def disable(self, group_names=None, limit=None, worker_name=None):
"""Set DISABLED on the workers processing `group_names` tasks.
A DISABLED worker will be kept alive but it won't be able to process
any waiting tasks, essentially putting it to sleep.
By default, all group_names of Scheduler's instantation are selected
"""
self.set_worker_status(
group_names=group_names,
action=DISABLED,
exclude=[DISABLED, KILL, TERMINATE],
limit=limit)
def resume(self, group_names=None, limit=None, worker_name=None):
"""Wakes a worker up (it will be able to process queued tasks)"""
self.set_worker_status(
group_names=group_names,
action=ACTIVE,
exclude=[KILL, TERMINATE],
limit=limit)
def terminate(self, group_names=None, limit=None, worker_name=None):
"""Sets TERMINATE as worker status. The worker will wait for any
currently running tasks to be executed and then it will exit gracefully
"""
self.set_worker_status(
group_names=group_names,
action=TERMINATE,
exclude=[KILL],
limit=limit)
def kill(self, group_names=None, limit=None, worker_name=None):
"""Sets KILL as worker status. The worker will be killed even if it's
processing a task."""
self.set_worker_status(
group_names=group_names,
action=KILL,
limit=limit)
def queue_task(self, function, pargs=[], pvars={}, **kwargs):
"""
Queue tasks. This takes care of handling the validation of all
parameters
Args:
function: the function (anything callable with a __name__)
pargs: "raw" args to be passed to the function. Automatically
jsonified.
pvars: "raw" kwargs to be passed to the function. Automatically
jsonified
kwargs: all the parameters available (basically, every
`scheduler_task` column). If args and vars are here, they
should be jsonified already, and they will override pargs
and pvars
Returns:
a dict just as a normal validate_and_insert(), plus a uuid key
holding the uuid of the queued task. If validation is not passed
( i.e. some parameters are invalid) both id and uuid will be None,
and you'll get an "error" dict holding the errors found.
"""
if hasattr(function, '__name__'):
function = function.__name__
targs = 'args' in kwargs and kwargs.pop('args') or dumps(pargs)
tvars = 'vars' in kwargs and kwargs.pop('vars') or dumps(pvars)
tuuid = 'uuid' in kwargs and kwargs.pop('uuid') or web2py_uuid()
tname = 'task_name' in kwargs and kwargs.pop('task_name') or function
immediate = 'immediate' in kwargs and kwargs.pop('immediate') or None
cronline = kwargs.get('cronline')
kwargs.update(
function_name=function,
task_name=tname,
args=targs,
vars=tvars,
uuid=tuuid,
)
if cronline:
try:
start_time = kwargs.get('start_time', self.now)
next_run_time = CronParser(cronline, start_time).get_next()
kwargs.update(start_time=start_time, next_run_time=next_run_time)
except:
pass
if 'start_time' in kwargs and 'next_run_time' not in kwargs:
kwargs.update(next_run_time=kwargs['start_time'])
rtn = self.db.scheduler_task.validate_and_insert(**kwargs)
if not rtn.errors:
rtn.uuid = tuuid
if immediate:
self.db(
(self.db.scheduler_worker.is_ticker == True)
).update(status=PICK)
else:
rtn.uuid = None
return rtn
def task_status(self, ref, output=False):
"""
Retrieves task status and optionally the result of the task
Args:
ref: can be
- an integer : lookup will be done by scheduler_task.id
- a string : lookup will be done by scheduler_task.uuid
- a `Query` : lookup as you wish, e.g. ::
db.scheduler_task.task_name == 'test1'
output(bool): if `True`, fetch also the scheduler_run record
Returns:
a single Row object, for the last queued task.
If output == True, returns also the last scheduler_run record.
The scheduler_run record is fetched by a left join, so it can
have all fields == None
"""
from pydal.objects import Query
sr, st = self.db.scheduler_run, self.db.scheduler_task
if isinstance(ref, (int, long)):
q = st.id == ref
elif isinstance(ref, str):
q = st.uuid == ref
elif isinstance(ref, Query):
q = ref
else:
raise SyntaxError(
"You can retrieve results only by id, uuid or Query")
fields = [st.ALL]
left = False
orderby = ~st.id
if output:
fields = st.ALL, sr.ALL
left = sr.on(sr.task_id == st.id)
orderby = ~st.id | ~sr.id
row = self.db(q).select(
*fields,
**dict(orderby=orderby,
left=left,
limitby=(0, 1))
).first()
if row and output:
row.result = row.scheduler_run.run_result and \
loads(row.scheduler_run.run_result,
object_hook=_decode_dict) or None
return row
def stop_task(self, ref):
"""Shortcut for task termination.
If the task is RUNNING it will terminate it, meaning that status
will be set as FAILED.
If the task is QUEUED, its stop_time will be set as to "now",
the enabled flag will be set to False, and the status to STOPPED
Args:
ref: can be
- an integer : lookup will be done by scheduler_task.id
- a string : lookup will be done by scheduler_task.uuid
Returns:
- 1 if task was stopped (meaning an update has been done)
- None if task was not found, or if task was not RUNNING or QUEUED
Note:
Experimental
"""
st, sw = self.db.scheduler_task, self.db.scheduler_worker
if isinstance(ref, (int, long)):
q = st.id == ref
elif isinstance(ref, str):
q = st.uuid == ref
else:
raise SyntaxError(
"You can retrieve results only by id or uuid")
task = self.db(q).select(st.id, st.status, st.assigned_worker_name)
task = task.first()
rtn = None
if not task:
return rtn
if task.status == 'RUNNING':
q = sw.worker_name == task.assigned_worker_name
rtn = self.db(q).update(status=STOP_TASK)
elif task.status == 'QUEUED':
rtn = self.db(q).update(
stop_time=self.now(),
enabled=False,
status=STOPPED)
return rtn
def get_workers(self, only_ticker=False):
""" Returns a dict holding `worker_name : {**columns}`
representing all "registered" workers
only_ticker returns only the workers running as a TICKER,
if there are any
"""
db = self.db
if only_ticker:
workers = db(db.scheduler_worker.is_ticker == True).select()
else:
workers = db(db.scheduler_worker.id > 0).select()
all_workers = {}
for row in workers:
all_workers[row.worker_name] = Storage(
status=row.status,
first_heartbeat=row.first_heartbeat,
last_heartbeat=row.last_heartbeat,
group_names=row.group_names,
is_ticker=row.is_ticker,
worker_stats=row.worker_stats
)
return all_workers
def main():
"""
allows to run worker without python web2py.py .... by simply::
python gluon/scheduler.py
"""
parser = optparse.OptionParser()
parser.add_option(
"-w", "--worker_name", dest="worker_name", default=None,
help="start a worker with name")
parser.add_option(
"-b", "--heartbeat", dest="heartbeat", default=10,
type='int', help="heartbeat time in seconds (default 10)")
parser.add_option(
"-L", "--logger_level", dest="logger_level",
default=30,
type='int',
help="set debug output level (0-100, 0 means all, 100 means none;default is 30)")
parser.add_option("-E", "--empty-runs",
dest="max_empty_runs",
type='int',
default=0,
help="max loops with no grabbed tasks permitted (0 for never check)")
parser.add_option(
"-g", "--group_names", dest="group_names",
default='main',
help="comma separated list of groups to be picked by the worker")
parser.add_option(
"-f", "--db_folder", dest="db_folder",
default='/Users/mdipierro/web2py/applications/scheduler/databases',
help="location of the dal database folder")
parser.add_option(
"-u", "--db_uri", dest="db_uri",
default='sqlite://storage.sqlite',
help="database URI string (web2py DAL syntax)")
parser.add_option(
"-t", "--tasks", dest="tasks", default=None,
help="file containing task files, must define" +
"tasks = {'task_name':(lambda: 'output')} or similar set of tasks")
parser.add_option(
"-U", "--utc-time", dest="utc_time", default=False,
help="work with UTC timestamps"
)
(options, args) = parser.parse_args()
if not options.tasks or not options.db_uri:
print(USAGE)
if options.tasks:
path, filename = os.path.split(options.tasks)
if filename.endswith('.py'):
filename = filename[:-3]
sys.path.append(path)
print('importing tasks...')
tasks = __import__(filename, globals(), locals(), [], -1).tasks
print('tasks found: ' + ', '.join(tasks.keys()))
else:
tasks = {}
group_names = [x.strip() for x in options.group_names.split(',')]
logging.getLogger().setLevel(options.logger_level)
print('groups for this worker: ' + ', '.join(group_names))
print('connecting to database in folder: ' + options.db_folder or './')
print('using URI: ' + options.db_uri)
db = DAL(options.db_uri, folder=options.db_folder, decode_credentials=True)
print('instantiating scheduler...')
scheduler = Scheduler(db=db,
worker_name=options.worker_name,
tasks=tasks,
migrate=True,
group_names=group_names,
heartbeat=options.heartbeat,
max_empty_runs=options.max_empty_runs,
utc_time=options.utc_time)
signal.signal(signal.SIGTERM, lambda signum, stack_frame: sys.exit(1))
print('starting main worker loop...')
scheduler.loop()
if __name__ == '__main__':
main()
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