frappe/frappe/utils/background_jobs.py

import os
import socket
import time
from functools import lru_cache
from uuid import uuid4
from collections import defaultdict
from typing import List


import redis
from redis.exceptions import BusyLoadingError, ConnectionError
from rq import Connection, Queue, Worker
from rq.logutils import setup_loghandlers
from tenacity import retry, retry_if_exception_type, stop_after_attempt, wait_fixed

import frappe
from frappe import _
import frappe.monitor
from frappe.utils import cstr, get_bench_id
from frappe.utils.redis_queue import RedisQueue
from frappe.utils.commands import log



@lru_cache()
def get_queues_timeout():
	common_site_config = frappe.get_conf()
	custom_workers_config = common_site_config.get("workers", {})
	default_timeout = 300

	return {
		"default": default_timeout,
		"short": default_timeout,
		"long": 1500,
		**{
			worker: config.get("timeout", default_timeout)
			for worker, config in custom_workers_config.items()
		}
	}

redis_connection = None

def enqueue(method, queue='default', timeout=None, event=None,
	is_async=True, job_name=None, now=False, enqueue_after_commit=False, **kwargs):
	'''
		Enqueue method to be executed using a background worker

		:param method: method string or method object
		:param queue: should be either long, default or short
		:param timeout: should be set according to the functions
		:param event: this is passed to enable clearing of jobs from queues
		:param is_async: if is_async=False, the method is executed immediately, else via a worker
		:param job_name: can be used to name an enqueue call, which can be used to prevent duplicate calls
		:param now: if now=True, the method is executed via frappe.call
		:param kwargs: keyword arguments to be passed to the method
	'''
	# To handle older implementations
	is_async = kwargs.pop('async', is_async)

	if now or frappe.flags.in_migrate:
		return frappe.call(method, **kwargs)

	q = get_queue(queue, is_async=is_async)
	if not timeout:
		timeout = get_queues_timeout().get(queue) or 300
	queue_args = {
		"site": frappe.local.site,
		"user": frappe.session.user,
		"method": method,
		"event": event,
		"job_name": job_name or cstr(method),
		"is_async": is_async,
		"kwargs": kwargs
	}
	if enqueue_after_commit:
		if not frappe.flags.enqueue_after_commit:
			frappe.flags.enqueue_after_commit = []

		frappe.flags.enqueue_after_commit.append({
			"queue": queue,
			"is_async": is_async,
			"timeout": timeout,
			"queue_args":queue_args
		})
		return frappe.flags.enqueue_after_commit
	else:
		return q.enqueue_call(execute_job, timeout=timeout,
			kwargs=queue_args)

def enqueue_doc(doctype, name=None, method=None, queue='default', timeout=300,
	now=False, **kwargs):
	'''Enqueue a method to be run on a document'''
	return enqueue('frappe.utils.background_jobs.run_doc_method', doctype=doctype, name=name,
		doc_method=method, queue=queue, timeout=timeout, now=now, **kwargs)

def run_doc_method(doctype, name, doc_method, **kwargs):
	getattr(frappe.get_doc(doctype, name), doc_method)(**kwargs)

def execute_job(site, method, event, job_name, kwargs, user=None, is_async=True, retry=0):
	'''Executes job in a worker, performs commit/rollback and logs if there is any error'''
	if is_async:
		frappe.connect(site)
		if os.environ.get('CI'):
			frappe.flags.in_test = True

		if user:
			frappe.set_user(user)

	if isinstance(method, str):
		method_name = method
		method = frappe.get_attr(method)
	else:
		method_name = cstr(method.__name__)

	frappe.monitor.start("job", method_name, kwargs)
	try:
		method(**kwargs)

	except (frappe.db.InternalError, frappe.RetryBackgroundJobError) as e:
		frappe.db.rollback()

		if (retry < 5 and
			(isinstance(e, frappe.RetryBackgroundJobError) or
				(frappe.db.is_deadlocked(e) or frappe.db.is_timedout(e)))):
			# retry the job if
			# 1213 = deadlock
			# 1205 = lock wait timeout
			# or RetryBackgroundJobError is explicitly raised
			frappe.destroy()
			time.sleep(retry+1)

			return execute_job(site, method, event, job_name, kwargs,
				is_async=is_async, retry=retry+1)

		else:
			frappe.log_error(title=method_name)
			raise

	except:
		frappe.db.rollback()
		frappe.log_error(title=method_name)
		frappe.db.commit()
		print(frappe.get_traceback())
		raise

	else:
		frappe.db.commit()

	finally:
		frappe.monitor.stop()
		if is_async:
			frappe.destroy()

def start_worker(queue=None, quiet = False, rq_username=None, rq_password=None):
	'''Wrapper to start rq worker. Connects to redis and monitors these queues.'''
	with frappe.init_site():
		# empty init is required to get redis_queue from common_site_config.json
		redis_connection = get_redis_conn(username=rq_username, password=rq_password)
		queues = get_queue_list(queue, build_queue_name=True)
		queue_name = queue and generate_qname(queue)

	if os.environ.get('CI'):
		setup_loghandlers('ERROR')

	with Connection(redis_connection):
		logging_level = "INFO"
		if quiet:
			logging_level = "WARNING"
		Worker(queues, name=get_worker_name(queue_name)).work(logging_level = logging_level)

def get_worker_name(queue):
	'''When limiting worker to a specific queue, also append queue name to default worker name'''
	name = None

	if queue:
		# hostname.pid is the default worker name
		name = '{uuid}.{hostname}.{pid}.{queue}'.format(
			uuid=uuid4().hex,
			hostname=socket.gethostname(),
			pid=os.getpid(),
			queue=queue)

	return name

def get_jobs(site=None, queue=None, key='method'):
	'''Gets jobs per queue or per site or both'''
	jobs_per_site = defaultdict(list)

	def add_to_dict(job):
		if key in job.kwargs:
			jobs_per_site[job.kwargs['site']].append(job.kwargs[key])

		elif key in job.kwargs.get('kwargs', {}):
			# optional keyword arguments are stored in 'kwargs' of 'kwargs'
			jobs_per_site[job.kwargs['site']].append(job.kwargs['kwargs'][key])

	for queue in get_queue_list(queue):
		q = get_queue(queue)
		jobs = q.jobs + get_running_jobs_in_queue(q)
		for job in jobs:
			if job.kwargs.get('site'):
				# if job belongs to current site, or if all jobs are requested
				if (job.kwargs['site'] == site) or site is None:
					add_to_dict(job)
			else:
				print('No site found in job', job.__dict__)

	return jobs_per_site

def get_queue_list(queue_list=None, build_queue_name=False):
	'''Defines possible queues. Also wraps a given queue in a list after validating.'''
	default_queue_list = list(get_queues_timeout())
	if queue_list:
		if isinstance(queue_list, str):
			queue_list = [queue_list]

		for queue in queue_list:
			validate_queue(queue, default_queue_list)
	else:
		queue_list = default_queue_list
	return [generate_qname(qtype) for qtype in queue_list] if build_queue_name else queue_list

def get_workers(queue=None):
	'''Returns a list of Worker objects tied to a queue object if queue is passed, else returns a list of all workers'''
	if queue:
		return Worker.all(queue=queue)
	else:
		return Worker.all(get_redis_conn())

def get_running_jobs_in_queue(queue):
	'''Returns a list of Jobs objects that are tied to a queue object and are currently running'''
	jobs = []
	workers = get_workers(queue)
	for worker in workers:
		current_job = worker.get_current_job()
		if current_job:
			jobs.append(current_job)
	return jobs

def get_queue(qtype, is_async=True):
	'''Returns a Queue object tied to a redis connection'''
	validate_queue(qtype)
	return Queue(generate_qname(qtype), connection=get_redis_conn(), is_async=is_async)

def validate_queue(queue, default_queue_list=None):
	if not default_queue_list:
		default_queue_list = list(get_queues_timeout())

	if queue not in default_queue_list:
		frappe.throw(_("Queue should be one of {0}").format(', '.join(default_queue_list)))

@retry(
	retry=retry_if_exception_type(BusyLoadingError) | retry_if_exception_type(ConnectionError),
	stop=stop_after_attempt(10),
	wait=wait_fixed(1)
)
def get_redis_conn(username=None, password=None):
	if not hasattr(frappe.local, 'conf'):
		raise Exception('You need to call frappe.init')

	elif not frappe.local.conf.redis_queue:
		raise Exception('redis_queue missing in common_site_config.json')

	global redis_connection

	cred = frappe._dict()
	if frappe.conf.get('use_rq_auth'):
		if username:
			cred['username'] = username
			cred['password'] = password
		else:
			cred['username'] = frappe.get_site_config().rq_username or get_bench_id()
			cred['password'] = frappe.get_site_config().rq_password

	elif os.environ.get('RQ_ADMIN_PASWORD'):
		cred['username'] = 'default'
		cred['password'] = os.environ.get('RQ_ADMIN_PASWORD')
	try:
		redis_connection = RedisQueue.get_connection(**cred)
	except (redis.exceptions.AuthenticationError, redis.exceptions.ResponseError):
		log(f'Wrong credentials used for {cred.username or "default user"}. '
			'You can reset credentials using `bench create-rq-users` CLI and restart the server',
			colour='red')
		raise
	except Exception:
		log(f'Please make sure that Redis Queue runs @ {frappe.get_conf().redis_queue}', colour='red')
		raise

	return redis_connection

def get_queues() -> List[Queue]:
	"""Get all the queues linked to the current bench.
	"""
	queues = Queue.all(connection=get_redis_conn())
	return [q for q in queues if is_queue_accessible(q)]

def generate_qname(qtype: str) -> str:
	"""Generate qname by combining bench ID and queue type.

	qnames are useful to define namespaces of customers.
	"""
	return f"{get_bench_id()}:{qtype}"

def is_queue_accessible(qobj: Queue) -> bool:
	"""Checks whether queue is relate to current bench or not.
	"""
	accessible_queues = [generate_qname(q) for q in list(get_queues_timeout())]
	return qobj.name in accessible_queues

def enqueue_test_job():
	enqueue('frappe.utils.background_jobs.test_job', s=100)

def test_job(s):
	import time
	print('sleeping...')
	time.sleep(s)