please test it (trunk version). I'm sending a patch to Massimo to include
it in trunk.
On Monday, March 11, 2013 11:35:23 PM UTC+1, dlypka wrote:
>
> Wow. That will be nice.
> Thanks.
>
> On Mon, Mar 11, 2013 at 5:28 PM, Niphlod <[email protected]
> <javascript:>>wrote:
>
>> PS: the task will end in FAILED status
>>
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#!/usr/bin/env python
# -*- coding: utf-8 -*-
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
## To install the scheduler as a permanent daemon on Linux (w/ Upstart), put
## the following into /etc/init/web2py-scheduler.conf:
## (This assumes your web2py instance is installed in <user>'s home directory,
## running as <user>, with app <myapp>, on network interface eth0.)
description "web2py task scheduler"
start on (local-filesystems and net-device-up IFACE=eth0)
stop on shutdown
respawn limit 8 60 # Give up if restart occurs 8 times in 60 seconds.
exec sudo -u <user> python /home/<user>/web2py/web2py.py -K <myapp>
respawn
## You can then start/stop/restart/check status of the daemon with:
sudo start web2py-scheduler
sudo stop web2py-scheduler
sudo restart web2py-scheduler
sudo status web2py-scheduler
"""
import os
import time
import multiprocessing
import sys
import threading
import traceback
import signal
import socket
import datetime
import logging
import optparse
import types
import Queue
if 'WEB2PY_PATH' in os.environ:
sys.path.append(os.environ['WEB2PY_PATH'])
else:
os.environ['WEB2PY_PATH'] = os.getcwd()
if not os.environ['WEB2PY_PATH'] in sys.path:
sys.path.append(os.environ['WEB2PY_PATH'])
try:
from gluon.contrib.simplejson import loads, dumps
except:
from simplejson import loads, dumps
IDENTIFIER = "%s#%s" % (socket.gethostname(),os.getpid())
logger = logging.getLogger('web2py.scheduler.%s' % IDENTIFIER)
from gluon import DAL, Field, IS_NOT_EMPTY, IS_IN_SET, IS_NOT_IN_DB, IS_INT_IN_RANGE, IS_DATETIME
from gluon.utils import web2py_uuid
from gluon.storage import Storage
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):
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):
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
def demo_function(*argv, **kwargs):
""" test function """
for i in range(argv[0]):
print 'click', i
time.sleep(1)
return 'done'
#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/how-to-get-string-objects-instead-unicode-ones-from-json-in-python
def _decode_list(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):
newdict = {}
for k, v in dct.iteritems():
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 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})
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)
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})
globals().update(_env)
args = 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))
queue.put(TaskReport(COMPLETED, result=result))
except BaseException, e:
tb = traceback.format_exc()
queue.put(TaskReport(FAILED, tb=tb))
del stdout
class MetaScheduler(threading.Thread):
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 async(self, task):
"""
starts the background process and returns:
('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()
self.have_heartbeat = False
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():
self.have_heartbeat = False
logger.debug(' task stopped')
tr = TaskReport(STOPPED)
else:
logger.debug(' task completed or failed')
tr = queue.get()
tr.output = task_output
return tr
def die(self):
logger.info('die!')
self.have_heartbeat = False
self.terminate_process()
def give_up(self):
logger.info('Giving up as soon as possible!')
self.have_heartbeat = False
def terminate_process(self):
try:
self.process.terminate()
except:
pass # no process to terminate
def run(self):
""" the thread that sends heartbeat """
counter = 0
while self.have_heartbeat:
self.send_heartbeat(counter)
counter += 1
def start_heartbeats(self):
self.start()
def send_heartbeat(self, counter):
print 'thum'
time.sleep(1)
def pop_task(self):
return Task(
app=None,
function='demo_function',
timeout=7,
args='[2]',
vars='{}')
def report_task(self, task, task_report):
print 'reporting task'
pass
def sleep(self):
pass
def loop(self):
try:
self.start_heartbeats()
while True and self.have_heartbeat:
logger.debug('looping...')
task = self.pop_task()
if task:
self.empty_runs = 0
self.report_task(task, self.async(task))
else:
self.empty_runs += 1
logger.debug('sleeping...')
if self.max_empty_runs != 0:
logger.debug('empty runs %s/%s',
self.empty_runs, self.max_empty_runs)
if self.empty_runs >= self.max_empty_runs:
logger.info(
'empty runs limit reached, killing myself')
self.die()
self.sleep()
except KeyboardInterrupt:
self.die()
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 TYPE(object):
"""
validator that check whether field is valid json and validate its type
"""
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):
def __init__(self, db, tasks=None, migrate=True,
worker_name=None, group_names=['main'], 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
self.heartbeat = heartbeat
self.worker_name = worker_name or IDENTIFIER
#list containing status as recorded in the table plus a boost parameter
#for hibernation (i.e. when someone stop the worker acting on the worker table)
self.worker_status = [RUNNING, 1]
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
from gluon import current
current._scheduler = self
self.define_tables(db, migrate=migrate)
def now(self):
return self.utc_time and datetime.datetime.utcnow() or datetime.datetime.now()
def set_requirements(self, scheduler_task):
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):
from gluon.dal 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', 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('timeout', 'integer', default=60, comment='seconds',
requires=IS_INT_IN_RANGE(0, 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=migrate, format='%(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=migrate)
db.define_table(
'scheduler_worker',
Field('worker_name', 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),#FIXME writable=False or give the chance to update dinamically the groups?
migrate=migrate)
if migrate:
db.commit()
def loop(self, worker_name=None):
signal.signal(signal.SIGTERM, lambda signum, stack_frame: sys.exit(1))
try:
self.start_heartbeats()
while True and self.have_heartbeat:
if self.worker_status[0] == DISABLED:
logger.debug('Someone stopped me, sleeping until better times come (%s)', self.worker_status[1])
self.sleep()
continue
logger.debug('looping...')
task = self.wrapped_pop_task()
if task:
self.empty_runs = 0
self.worker_status[0] = RUNNING
self.report_task(task, self.async(task))
self.worker_status[0] = ACTIVE
else:
self.empty_runs += 1
logger.debug('sleeping...')
if self.max_empty_runs != 0:
logger.debug('empty runs %s/%s',
self.empty_runs, self.max_empty_runs)
if self.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):
db.commit() #db.commit() only for Mysql
x = 0
while x < 10:
try:
self.assign_tasks(db)
db.commit()
break
except:
db.rollback()
logger.error('TICKER: error assigning tasks')
x += 1
time.sleep(0.5)
def wrapped_pop_task(self):
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:
db.rollback()
logger.error(' error popping tasks')
x += 1
time.sleep(0.5)
def pop_task(self, db):
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.greedy and self.is_a_ticker:
#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
next_run_time = task.last_run_time + datetime.timedelta(
seconds=task.period)
times_run = task.times_run + 1
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 report_task(self, task, task_report):
db = self.db
now = self.now()
while True:
try:
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(db.scheduler_run.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(db.scheduler_run.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(db.scheduler_task.id == task.task_id)(
db.scheduler_task.status == RUNNING).update(**d)
else:
st_mapping = {'FAILED': 'FAILED',
'TIMEOUT': 'TIMEOUT',
'STOPPED': 'QUEUED'}[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(
(db.scheduler_task.id == task.task_id) &
(db.scheduler_task.status == RUNNING)
).update(
times_failed=db.scheduler_task.times_failed + 1,
next_run_time=task.next_run_time,
status=status
)
db.commit()
logger.info('task completed (%s)', task_report.status)
break
except:
db.rollback()
time.sleep(0.5)
def adj_hibernation(self):
if self.worker_status[0] == DISABLED:
wk_st = self.worker_status[1]
hibernation = wk_st + 1 if wk_st < MAXHIBERNATION else MAXHIBERNATION
self.worker_status[1] = hibernation
def send_heartbeat(self, counter):
if not self.db_thread:
logger.debug('thread building own DAL object')
self.db_thread = DAL(
self.db._uri, folder=self.db._adapter.folder)
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)
self.worker_status = [ACTIVE, 1] # activating the process
mybackedstatus = ACTIVE
else:
mybackedstatus = mybackedstatus.status
if mybackedstatus == DISABLED:
# keep sleeping
self.worker_status[0] = DISABLED
if self.worker_status[1] == MAXHIBERNATION:
logger.debug('........recording heartbeat (%s)', self.worker_status[0])
db(sw.worker_name == self.worker_name).update(
last_heartbeat=now)
elif mybackedstatus == TERMINATE:
self.worker_status[0] = TERMINATE
logger.debug("Waiting to terminate the current task")
self.give_up()
return
elif mybackedstatus == KILL:
self.worker_status[0] = KILL
self.die()
else:
if mybackedstatus == STOP_TASK:
logger.info('Asked to kill the current task')
self.terminate_process()
logger.debug('........recording heartbeat (%s)', self.worker_status[0])
db(sw.worker_name == self.worker_name).update(
last_heartbeat=now, status=ACTIVE)
self.worker_status[1] = 1 # re-activating the process
if self.worker_status[0] <> RUNNING:
self.worker_status[0] = ACTIVE
self.do_assign_tasks = False
if counter % 5 == 0 or mybackedstatus == PICK:
try:
# delete inactive workers
expiration = now - datetime.timedelta(seconds=self.heartbeat * 3)
departure = now - datetime.timedelta(
seconds=self.heartbeat * 3 * MAXHIBERNATION)
logger.debug(
' freeing workers that have not sent heartbeat')
inactive_workers = db(
((sw.last_heartbeat < expiration) & (sw.status == ACTIVE)) |
((sw.last_heartbeat < departure) & (sw.status != ACTIVE))
)
db(st.assigned_worker_name.belongs(
inactive_workers._select(sw.worker_name)))(st.status == RUNNING)\
.update(assigned_worker_name='', status=QUEUED)
inactive_workers.delete()
self.is_a_ticker = self.being_a_ticker()
if self.worker_status[0] == ACTIVE:
self.do_assign_tasks = True
except:
pass
db.commit()
except:
db.rollback()
self.adj_hibernation()
self.sleep()
def being_a_ticker(self):
db = self.db_thread
sw = db.scheduler_worker
all_active = db(
(sw.worker_name != self.worker_name) & (sw.status == ACTIVE)
).select()
ticker = all_active.find(lambda row: row.is_ticker is True).first()
not_busy = self.worker_status[0] == ACTIVE
if not ticker:
if not_busy:
#only if this worker isn't busy, otherwise wait for a free one
db(sw.worker_name == self.worker_name).update(is_ticker=True)
db(sw.worker_name != self.worker_name).update(is_ticker=False)
logger.info("TICKER: I'm a ticker")
else:
#giving up, only if I'm not alone
if len(all_active) > 1:
db(sw.worker_name == self.worker_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):
sw, st = db.scheduler_worker, db.scheduler_task
now = self.now()
all_workers = db(sw.status == ACTIVE).select()
#build workers as dict of groups
wkgroups = {}
for w in all_workers:
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)
all_available = db(
(st.status.belongs((QUEUED, ASSIGNED))) &
((st.times_run < st.repeats) | (st.repeats == 0)) &
(st.start_time <= now) &
((st.stop_time == None) | (st.stop_time > now)) &
(st.next_run_time <= now) &
(st.enabled == True)
)
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 adjusted 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 quite a sweet spot also for fast tasks, with sane heartbeat values
#NB: ticker reassign tasks every 5 cycles, so if a worker completes his 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, all other tasks assigned
#to him needs to be reassigned "freely" to other workers, that may be free.
#this shuffles up things a bit, in order to maintain the idea of a semi-linear scalability
#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']
d = dict(
status=ASSIGNED,
assigned_worker_name=wkgroups[gname]['workers'][myw]['name']
)
if not task.task_name:
d['task_name'] = task.function_name
task.update_record(**d)
wkgroups[gname]['workers'][myw]['c'] += 1
db.commit()
#I didn't report tasks but I'm working nonetheless!!!!
if x > 0:
self.empty_runs = 0
#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 and True or False
logger.info('TICKER: workers are %s', len(all_workers))
logger.info('TICKER: tasks are %s', x)
def sleep(self):
time.sleep(self.heartbeat * self.worker_status[1])
# should only sleep until next available task
def set_worker_status(self, group_names=None, action=ACTIVE):
if not group_names:
group_names = self.group_names
elif isinstance(group_names, str):
group_names = [group_names]
for group in group_names:
self.db(
self.db.scheduler_worker.group_names.contains(group)
).update(status=action)
def disable(self, group_names=None):
self.set_worker_status(group_names=group_names,action=DISABLED)
def resume(self, group_names=None):
self.set_worker_status(group_names=group_names,action=ACTIVE)
def terminate(self, group_names=None):
self.set_worker_status(group_names=group_names,action=TERMINATE)
def kill(self, group_names=None):
self.set_worker_status(group_names=group_names,action=KILL)
def queue_task(self, function, pargs=[], pvars={}, **kwargs):
"""
Queue tasks. This takes care of handling the validation of all
values.
:param function: the function (anything callable with a __name__)
:param pargs: "raw" args to be passed to the function. Automatically
jsonified.
:param pvars: "raw" kwargs to be passed to the function. Automatically
jsonified
:param kwargs: all the scheduler_task columns. args and vars here should be
in json format already, 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, 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
rtn = self.db.scheduler_task.validate_and_insert(
function_name=function,
task_name=tname,
args=targs,
vars=tvars,
uuid=tuuid,
**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):
"""
Shortcut for task status retrieval
:param ref: can be
- integer --> lookup will be done by scheduler_task.id
- string --> lookup will be done by scheduler_task.uuid
- query --> lookup as you wish (as in db.scheduler_task.task_name == 'test1')
:param output: 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
scheduler_run record is fetched by a left join, so it can
have all fields == None
"""
from gluon.dal import Query
sr, st = self.db.scheduler_run, self.db.scheduler_task
if isinstance(ref, int):
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):
"""
Experimental!!!
Shortcut for task termination.
If the task is RUNNING it will terminate it --> execution 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, status to STOPPED
:param ref: can be
- integer --> lookup will be done by scheduler_task.id
- 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
"""
from gluon.dal import Query
st, sw = self.db.scheduler_task, self.db.scheduler_worker
if isinstance(ref, int):
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).first()
rtn = None
if not task:
return rtn
if task.status == 'RUNNING':
rtn = self.db(sw.worker_name == task.assigned_worker_name).update(status=STOP_TASK)
elif task.status == 'QUEUED':
rtn = self.db(q).update(stop_time=self.now(), enabled=False, status=STOPPED)
return rtn
def main():
"""
allows to run worker without python web2py.py .... by simply python this.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)
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()
