errors.py

# Copyright (c) 2013 Red Hat, Inc.
#
# 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.


class ExceptionBase(Exception):

    msg_format = ''

    def __init__(self, **kwargs):
        msg = self.msg_format.format(**kwargs)
        super(ExceptionBase, self).__init__(msg)


class ConnectionError(ExceptionBase):
    """Raised when the connection with the back-end
    was lost.
    """


class DoesNotExist(ExceptionBase):
    """Resource does not exist."""


class NotPermitted(ExceptionBase):
    """Operation not permitted."""


class Conflict(ExceptionBase):
    """Resource could not be created due to a conflict
    with an existing resource.
    """


class MessageConflict(Conflict):

    msg_format = (u'Message could not be enqueued due to a conflict '
                  u'with another message that is already in '
                  u'queue {queue} for project {project}')

    def __init__(self, queue, project, message_ids):
        """Initializes the error with contextual information.
        :param queue: name of the queue to which the message was posted

        :param project: name of the project to which the queue belongs
        :param message_ids: list of IDs for messages successfully
        posted. Note that these must be in the same order as the
        list of messages originally submitted to be enqueued.
        """
        super(MessageConflict, self).__init__(queue=queue, project=project)
        self._succeeded_ids = message_ids

        @property
        def succeeded_ids(self):
            return self._succeeded_ids


class QueueDoesNotExist(DoesNotExist):

    msg_format = u'Queue {name} does not exist for project {project}'

    def __init__(self, name, project):
        super(QueueDoesNotExist, self).__init__(name=name, project=project)


class QueueIsEmpty(ExceptionBase):

    msg_format = u'Queue {name} in project {project} is empty'

    def __init__(self, name, project):
        super(QueueIsEmpty, self).__init__(name=name, project=project)


class MessageDoesNotExist(DoesNotExist):

    msg_format = (u'Message {mid} does not exist in '
                  u'queue {queue} for project {project}')

    def __init__(self, mid, queue, project):
        super(MessageDoesNotExist, self).__init__(mid=mid, queue=queue,
                                                  project=project)


class MessageIsClaimed(NotPermitted):

    msg_format = u'Message {mid} is claimed'

    def __init__(self, mid):
        super(MessageIsClaimed, self).__init__(mid=mid)


class ClaimDoesNotExist(DoesNotExist):

    msg_format = (u'Claim {cid} does not exist in '
                  u'queue {queue} for project {project}')

    def __init__(self, cid, queue, project):
        super(ClaimDoesNotExist, self).__init__(cid=cid, queue=queue,
                                                project=project)


class QueueNotMapped(DoesNotExist):

    msg_format = (u'No pool found for '
                  u'queue {queue} for project {project}')

    def __init__(self, queue, project):
        super(QueueNotMapped, self).__init__(queue=queue, project=project)


class MessageIsClaimedBy(NotPermitted):

    msg_format = u'Message {mid} is not claimed by {cid}'

    def __init__(self, mid, cid):
        super(MessageIsClaimedBy, self).__init__(cid=cid, mid=mid)


class PoolDoesNotExist(DoesNotExist):

    msg_format = u'Pool {pool} does not exist'

    def __init__(self, pool):
        super(PoolDoesNotExist, self).__init__(pool=pool)


class NoPoolFound(ExceptionBase):

    msg_format = u'No pools registered'

    def __init__(self):
        super(NoPoolFound, self).__init__()