def get_lock_if_job_is_runnable(app_name, job_id):
"""Return a lock instance or False. If returning False,
the job is not ready to execute.
"""
available = qb.check_state(
app_name, job_id, pending=True, raise_if_not_exists=True)
if not available:
try:
raise RuntimeError(
"I found a job in queue that wasn't"
" in state pending. This might be a code bug. You"
" probably queued 2+ of the same job!")
except RuntimeError as err:
# force a traceback in the logs
log.exception(
err, extra=dict(
app_name=app_name,
job_id=job_id,
state=qb.check_state(
app_name, job_id, _get=True)))
return False
l = qb.obtain_execute_lock(app_name, job_id, blocking=False)
if l is False:
log.warn('Could not obtain execute lock for task because'
' something is already processing this job_id',
extra=dict(app_name=app_name, job_id=job_id))
return False
return l
def get_lock_if_job_is_runnable(app_name, job_id):
"""Return a lock instance or False. If returning False,
the job is not ready to execute.
"""
available = qb.check_state(app_name,
job_id,
pending=True,
raise_if_not_exists=True)
if not available:
try:
raise RuntimeError(
"I found a job in queue that wasn't"
" in state pending. This might be a code bug. You"
" probably queued 2+ of the same job!")
except RuntimeError as err:
# force a traceback in the logs
log.exception(err,
extra=dict(app_name=app_name,
job_id=job_id,
state=qb.check_state(app_name,
job_id,
_get=True)))
return False
l = qb.obtain_execute_lock(app_name, job_id, blocking=False)
if l is False:
log.warn(
'Could not obtain execute lock for task because'
' something is already processing this job_id',
extra=dict(app_name=app_name, job_id=job_id))
return False
return l
def main(ns):
"""
Fetch a job_id from the `app_name` queue and figure out what to with it.
If the job is runnable, execute it and then queue its children into their
respective queues. If it's not runnable, queue its parents into respective
parent queues and remove the job from its own queue.
If the job fails, either requeue it or mark it as permanently failed
"""
assert ns.app_name in dt.get_task_names()
if ns.bypass_scheduler:
log.info(
"Running a task without scheduling anything"
" or fetching from a queue", extra=dict(
app_name=ns.app_name, job_id=ns.job_id))
assert ns.job_id
ns.job_type_func(ns=ns)
return
log.info("Beginning Stolos", extra=dict(**ns.__dict__))
q = qb.get_qbclient().LockingQueue(ns.app_name)
if ns.job_id:
lock = _handle_manually_given_job_id(ns)
q.consume = object # do nothing
else:
ns.job_id = q.get(timeout=ns.timeout)
if not validate_job_id(app_name=ns.app_name, job_id=ns.job_id,
q=q, timeout=ns.timeout):
return
try:
lock = get_lock_if_job_is_runnable(
app_name=ns.app_name, job_id=ns.job_id)
except exceptions.NoNodeError:
q.consume()
log.exception(
"Job failed. The job is queued, so why does its state not"
" exist? The Queue backend may be in an inconsistent state."
" Consuming this job",
extra=dict(app_name=ns.app_name, job_id=ns.job_id))
return
log.debug(
"Stolos got a job_id.", extra=dict(
app_name=ns.app_name, job_id=ns.job_id, acquired_lock=bool(lock)))
if lock is False:
# infinite loop: some jobs will always requeue if lock is unobtainable
log.info("Could not obtain a lock. Will requeue and try again later",
extra=dict(app_name=ns.app_name, job_id=ns.job_id))
_send_to_back_of_queue(
q=q, app_name=ns.app_name, job_id=ns.job_id)
return
if not parents_completed(ns.app_name, ns.job_id, q=q, lock=lock):
return
log.info(
"Job starting!", extra=dict(app_name=ns.app_name, job_id=ns.job_id))
try:
ns.job_type_func(ns=ns)
except exceptions.CodeError: # assume error is previously logged
_handle_failure(ns, q, lock)
return
except Exception as err:
log.exception(
("Job failed! Unhandled exception in an application!"
" Fix ASAP because"
" it is unclear how to handle this failure. %s: %s")
% (err.__class__.__name__, err), extra=dict(
app_name=ns.app_name, job_id=ns.job_id, failed=True))
return
_handle_success(ns, q, lock)
def main(ns):
"""
Fetch a job_id from the `app_name` queue and figure out what to with it.
If the job is runnable, execute it and then queue its children into their
respective queues. If it's not runnable, queue its parents into respective
parent queues and remove the job from its own queue.
If the job fails, either requeue it or mark it as permanently failed
"""
assert ns.app_name in dt.get_task_names()
if ns.bypass_scheduler:
log.info(
"Running a task without scheduling anything"
" or fetching from a queue",
extra=dict(app_name=ns.app_name, job_id=ns.job_id))
assert ns.job_id
ns.job_type_func(ns=ns)
return
log.info("Beginning Stolos", extra=dict(**ns.__dict__))
q = qb.get_qbclient().LockingQueue(ns.app_name)
if ns.job_id:
lock = _handle_manually_given_job_id(ns)
q.consume = object # do nothing
else:
ns.job_id = q.get(timeout=ns.timeout)
if not validate_job_id(
app_name=ns.app_name, job_id=ns.job_id, q=q,
timeout=ns.timeout):
return
try:
lock = get_lock_if_job_is_runnable(app_name=ns.app_name,
job_id=ns.job_id)
except exceptions.NoNodeError:
q.consume()
log.exception(
"Job failed. The job is queued, so why does its state not"
" exist? The Queue backend may be in an inconsistent state."
" Consuming this job",
extra=dict(app_name=ns.app_name, job_id=ns.job_id))
return
log.debug("Stolos got a job_id.",
extra=dict(app_name=ns.app_name,
job_id=ns.job_id,
acquired_lock=bool(lock)))
if lock is False:
# infinite loop: some jobs will always requeue if lock is unobtainable
log.info("Could not obtain a lock. Will requeue and try again later",
extra=dict(app_name=ns.app_name, job_id=ns.job_id))
_send_to_back_of_queue(q=q, app_name=ns.app_name, job_id=ns.job_id)
return
if not parents_completed(ns.app_name, ns.job_id, q=q, lock=lock):
return
log.info("Job starting!",
extra=dict(app_name=ns.app_name, job_id=ns.job_id))
try:
ns.job_type_func(ns=ns)
except exceptions.CodeError: # assume error is previously logged
_handle_failure(ns, q, lock)
return
except Exception as err:
log.exception(("Job failed! Unhandled exception in an application!"
" Fix ASAP because"
" it is unclear how to handle this failure. %s: %s") %
(err.__class__.__name__, err),
extra=dict(app_name=ns.app_name,
job_id=ns.job_id,
failed=True))
return
_handle_success(ns, q, lock)
