taskflow/taskflow/examples/resume_from_backend.py

118 lines
3.3 KiB
Python

# -*- coding: utf-8 -*-
# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright (C) 2013 Yahoo! Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import logging
import os
import sys
logging.basicConfig(level=logging.ERROR)
top_dir = os.path.abspath(os.path.join(os.path.dirname(__file__),
os.pardir,
os.pardir))
sys.path.insert(0, top_dir)
import taskflow.engines
from taskflow.patterns import linear_flow as lf
from taskflow.persistence import backends
from taskflow import task
from taskflow.utils import persistence_utils as p_utils
### UTILITY FUNCTIONS #########################################
def print_task_states(flowdetail, msg):
print(msg)
print('Flow state: %s' % flowdetail.state)
items = sorted((td.name, td.version, td.state, td.results)
for td in flowdetail)
for item in items:
print("%s==%s: %s, result=%r" % item)
def get_backend():
try:
backend_uri = sys.argv[1]
except Exception:
backend_uri = 'sqlite://'
backend = backends.fetch({'connection': backend_uri})
backend.get_connection().upgrade()
return backend
def find_flow_detail(backend, lb_id, fd_id):
conn = backend.get_connection()
lb = conn.get_logbook(lb_id)
return lb.find(fd_id)
### CREATE FLOW ###############################################
class InterruptTask(task.Task):
def execute(self):
# DO NOT TRY THIS AT HOME
engine.suspend()
class TestTask(task.Task):
def execute(self):
print 'executing %s' % self
return 'ok'
def flow_factory():
return lf.Flow('resume from backend example').add(
TestTask(name='first'),
InterruptTask(name='boom'),
TestTask(name='second'))
### INITIALIZE PERSISTENCE ####################################
backend = get_backend()
logbook = p_utils.temporary_log_book(backend)
### CREATE AND RUN THE FLOW: FIRST ATTEMPT ####################
flow = flow_factory()
flowdetail = p_utils.create_flow_detail(flow, logbook, backend)
engine = taskflow.engines.load(flow, flow_detail=flowdetail,
backend=backend)
print_task_states(flowdetail, "\nAt the beginning, there is no state:")
print("\nRunning:")
engine.run()
print_task_states(flowdetail, "\nAfter running:")
### RE-CREATE, RESUME, RUN ####################################
print("\nResuming and running again:")
# reload flowdetail from backend
flowdetail2 = find_flow_detail(backend, logbook.uuid,
flowdetail.uuid)
engine2 = taskflow.engines.load(flow_factory(),
flow_detail=flowdetail,
backend=backend)
engine2.run()
print_task_states(flowdetail, "\nAt the end:")