a5953e0349
Add an example that will use a sqlite layer for persisting flow and task information, and will use the layer for future resumption. Show how to output what a logbook contains as well. Change-Id: If5f936fe100cb43ed857b99e3fae0c6e6baba5ed
123 lines
3.3 KiB
Python
123 lines
3.3 KiB
Python
# -*- coding: utf-8 -*-
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# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright (C) 2012-2013 Yahoo! Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import contextlib
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import logging
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import os
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import sys
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import traceback
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logging.basicConfig(level=logging.ERROR)
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top_dir = os.path.abspath(os.path.join(os.path.dirname(__file__),
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os.pardir,
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os.pardir))
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sys.path.insert(0, top_dir)
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from taskflow import engines
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from taskflow.patterns import linear_flow as lf
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from taskflow.persistence import backends
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from taskflow.persistence import logbook
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from taskflow import task
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import tempfile
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class HiTask(task.Task):
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def execute(self):
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print("Hi!")
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def revert(self, **kwargs):
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print("Whooops, said hi to early, take that back!")
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class ByeTask(task.Task):
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def __init__(self, blowup):
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super(ByeTask, self).__init__()
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self._blowup = blowup
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def execute(self):
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if self._blowup:
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raise Exception("Fail!")
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print("Bye!")
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def make_flow(blowup=False):
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flo = lf.Flow("hello-world")
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flo.add(HiTask(), ByeTask(blowup))
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return flo
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def dump_book(book):
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for fd in book:
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print("+ Ran '%s' (%s)" % (fd.name, fd.state))
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for td in fd:
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print(" - name = %s" % (td.name))
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print(" state = %s" % (td.state))
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print(" results = %s" % (td.results))
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print(" failure = %s" % (bool(td.failure)))
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if td.meta and 'progress' in td.meta:
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print(" progress = %0.2f%%" % (td.meta['progress'] * 100))
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def print_wrapped(text):
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print("-" * (len(text)))
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print(text)
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print("-" * (len(text)))
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persist_filename = os.path.join(tempfile.gettempdir(), "persisting.db")
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if os.path.isfile(persist_filename):
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blowup = False
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else:
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blowup = True
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# Ensure schema upgraded before we continue working.
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backend_config = {
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'connection': "sqlite:///%s" % (persist_filename),
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}
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with contextlib.closing(backends.fetch(backend_config)) as be:
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with contextlib.closing(be.get_connection()) as conn:
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conn.upgrade()
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# Now we can run.
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engine_config = {
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'backend': backend_config,
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'engine_conf': 'serial',
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'book': logbook.LogBook("my-test"),
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}
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# Make a flow that will blowup if the file doesn't exist previously, if it
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# did exist, assume we won't blowup (and therefore this shows the undo
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# and redo that a flow will go through).
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flo = make_flow(blowup=blowup)
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print_wrapped("Running")
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try:
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eng = engines.load(flo, **engine_config)
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eng.run()
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try:
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os.unlink(persist_filename)
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except (OSError, IOError):
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pass
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except Exception:
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traceback.print_exc(file=sys.stdout)
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print_wrapped("Book contents")
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dump_book(engine_config['book'])
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