0af733757c
get_working_directory has been updated to raise an IOError if it is not able to create and/or access a working directory. Additional checks have been added to catch these cases: - If a plugin tries to execute, and the working directory fails, it will not execute. - If the cron plugin is registered, it will confirm that the working directory is accesible before reporting that it is enabled. - Working directory no longer attempts to fall back to a non-configured value, and instead fails cleanly. Change-Id: I04011cdb1cec24f4621c1ff1f0090a59d56509c8
147 lines
5.0 KiB
Python
147 lines
5.0 KiB
Python
# Copyright (c) 2014 Hewlett-Packard Development Company, L.P.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain 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,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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# implied. See the License for the specific language governing permissions and
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# limitations under the License.
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from crontab import CronTab
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from oslo.config import cfg
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from oslo_log import log
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from storyboard.common.working_dir import get_working_directory
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from storyboard.plugin.base import StoryboardPluginLoader
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from storyboard.plugin.cron.base import CronPluginBase
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LOG = log.getLogger(__name__)
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CRON_MANAGEMENT_OPTS = [
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cfg.BoolOpt('enable',
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default=False,
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help='Enable StoryBoard\'s Crontab management.')
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]
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CONF = cfg.CONF
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CONF.register_opts(CRON_MANAGEMENT_OPTS, 'cron')
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class CronManager(CronPluginBase):
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"""A Cron Plugin serves both as the manager for other storyboard
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cron tasks, and as an example plugin for storyboard. It checks every
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5 minutes or so to see what storyboard cron plugins are registered vs.
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running, and enables/disables them accordingly.
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"""
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def __init__(self, config, tabfile=None):
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super(CronManager, self).__init__(config=config)
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self.tabfile = tabfile
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def enabled(self):
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"""Indicate whether this plugin is enabled. This indicates whether
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this plugin alone is runnable, as opposed to the entire cron system.
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Note that this plugin cannot operate if the system cannot create a
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working directory.
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"""
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try:
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# This will raise an exception if the working directory cannot
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# be created.
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get_working_directory()
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# Return the configured cron flag.
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return self.config.cron.enable
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except IOError as e:
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LOG.error("Cannot enable crontab management: Working directory is"
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" not available: %s" % (e,))
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return False
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def interval(self):
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"""This plugin executes every 5 minutes.
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:return: "*/5 * * * *"
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"""
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return "*/5 * * * *"
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def run(self, start_time, end_time):
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"""Execute a periodic task.
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:param start_time: The last time the plugin was run.
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:param end_time: The current timestamp.
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"""
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# First, go through the stevedore registration and update the plugins
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# we know about.
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loader = StoryboardPluginLoader(namespace="storyboard.plugin.cron")
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handled_plugins = dict()
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if loader.extensions:
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loader.map(self._manage_plugins, handled_plugins)
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# Now manually go through the cron list and remove anything that
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# isn't registered.
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cron = CronTab(tabfile=self.tabfile)
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not_handled = lambda x: x.comment not in handled_plugins
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jobs = filter(not_handled, cron.find_command('storyboard-cron'))
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cron.remove(*jobs)
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cron.write()
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def _manage_plugins(self, ext, handled_plugins=dict()):
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"""Adds a plugin instance to crontab."""
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plugin = ext.obj
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cron = CronTab(tabfile=self.tabfile)
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plugin_name = plugin.get_name()
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plugin_interval = plugin.interval()
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command = "storyboard-cron --plugin %s" % (plugin_name,)
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# Pull any existing jobs.
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job = None
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for item in cron.find_comment(plugin_name):
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LOG.info("Found existing cron job: %s" % (plugin_name,))
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job = item
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job.set_command(command)
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job.set_comment(plugin_name)
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job.setall(plugin_interval)
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break
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if not job:
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LOG.info("Adding cron job: %s" % (plugin_name,))
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job = cron.new(command=command, comment=plugin_name)
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job.setall(plugin_interval)
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# Update everything.
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job.set_command(command)
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job.set_comment(plugin_name)
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job.setall(plugin_interval)
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# This code us usually not triggered, because the stevedore plugin
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# loader harness already filters based on the results of the
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# enabled() method, however we're keeping it in here since plugin
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# loading and individual plugin functionality are independent, and may
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# change independently.
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if plugin.enabled():
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job.enable()
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else:
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LOG.info("Disabled cron plugin: %s", (plugin_name,))
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job.enable(False)
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# Remember the state of this plugin
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handled_plugins[plugin_name] = True
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# Save it.
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cron.write()
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def remove(self):
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"""Remove all storyboard cron extensions.
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"""
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# Flush all orphans
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cron = CronTab(tabfile=self.tabfile)
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cron.remove_all(command='storyboard-cron')
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cron.write()
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