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Viewing changes to landscape/package/taskhandler.py

  • Committer: Bazaar Package Importer
  • Author(s): Free Ekanayaka
  • Date: 2010-02-10 18:50:53 UTC
  • mfrom: (1.1.13 upstream)
  • Revision ID: james.westby@ubuntu.com-20100210185053-kqyzavz3rkpkl7nx
Tags: 1.4.4-0ubuntu0.10.04
https://launchpad.net/bugs/519200
https://launchpad.net/bugs/514334
https://launchpad.net/bugs/517175
https://launchpad.net/bugs/509752
https://launchpad.net/bugs/518501
https://launchpad.net/bugs/218388
https://launchpad.net/bugs/517454
https://launchpad.net/bugs/517453
* New upstream release (LP: #519200):
  - Add a message for creating package locks (LP: #514334)
  - Add support for auto-approved change-packages messages (LP: #517175)
  - Add support for installing server-generated debian packages (LP: #509752)
  - Add support for reporting Eucalyptus topology information (LP: #518501)
  - Fix timeout while inserting large free-space message (LP: #218388)
  - Fix wrong log path in motd (LP: #517454)
  - Fix race condition in process excecution (LP: #517453)

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Lines of Context:
landscape/package/taskhandler.py
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from landscape.broker.remote import RemoteBroker
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class PackageTaskError(Exception):
 
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    """Raised when a task hasn't been successfully completed."""
 
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class PackageTaskHandlerConfiguration(Configuration):
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    """Specialized configuration for L{PackageTaskHandler}s."""
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        self._facade = package_facade
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        self._broker = remote_broker
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        self._config = config
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        self._channels_reloaded = False
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    def ensure_channels_reloaded(self):
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        if not self._channels_reloaded:
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            self._channels_reloaded = True
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            self._facade.reload_channels()
 
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        self._count = 0
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    def run(self):
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        return self.handle_tasks()
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    def handle_tasks(self):
 
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        """Handle the tasks in the queue.
 
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        The tasks will be handed over one by one to L{handle_task} until the
 
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        queue is empty or a task fails.
 
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        @see: L{handle_tasks}
 
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        """
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        return self._handle_next_task(None)
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    def _handle_next_task(self, result, last_task=None):
 
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        """Pick the next task from the queue and pass it to C{handle_task}."""
 
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        if last_task is not None:
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            # Last task succeeded.  We can safely kill it now.
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            last_task.remove()
 
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            self._count += 1
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        task = self._store.get_next_task(self.queue_name)
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        if task:
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            # We have another task.  Let's handle it.
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            result = self.handle_task(task)
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            result.addCallback(self._handle_next_task, task)
 
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            result.addCallback(self._handle_next_task, last_task=task)
 
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            result.addErrback(self._handle_task_failure)
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            return result
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        else:
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            # No more tasks!  We're done!
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            return succeed(None)
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    def _handle_task_failure(self, failure):
 
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        """Gracefully handle a L{PackageTaskError} and stop handling tasks."""
 
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        failure.trap(PackageTaskError)
 
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    def handle_task(self, task):
 
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        """Handle a sigle task.
 
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        Sub-classes must override this method in order to trigger task-specific
 
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        actions.
 
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        This method must return a L{Deferred} firing the task result. If the
 
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        deferred is successful the task will be removed from the queue and the
 
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        next one will be picked. If the task can't be completed, this method
 
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        must raise a L{PackageTaskError}, in this case the handler will stop
 
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        processing tasks and the failed task won't be removed from the queue.
 
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        """
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        return succeed(None)
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    @property
 
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    def handled_tasks_count(self):
 
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        """
 
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        Return the number of tasks that have been successfully handled so far.
 
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        """
 
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        return self._count
 
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    def use_hash_id_db(self):
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        """
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        Attach the appropriate pre-canned hash=>id database to our store.