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"""Module to handle the storehouse.""" |
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import time |
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from kytos.core import log |
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from kytos.core.events import KytosEvent |
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from napps.kytos.flow_manager import settings |
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DEFAULT_BOX_RESTORE_TIMER = 0.1 |
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BOX_RESTORE_ATTEMPTS = 10 |
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class StoreHouse: |
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"""Class to handle storehouse.""" |
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@classmethod |
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def __new__(cls, *args, **kwargs): |
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# pylint: disable=unused-argument |
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"""Make this class a Singleton.""" |
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instance = cls.__dict__.get("__instance__") |
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if instance is not None: |
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return instance |
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cls.__instance__ = instance = object.__new__(cls) |
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return instance |
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def __init__(self, controller): |
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"""Create a storehouse client instance.""" |
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self.controller = controller |
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self.namespace = 'kytos.flow.persistence' |
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self.box_restore_timer = getattr(settings, 'BOX_RESTORE_TIMER', |
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DEFAULT_BOX_RESTORE_TIMER) |
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if 'box' not in self.__dict__: |
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self.box = None |
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self.list_stored_boxes() |
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def get_data(self): |
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"""Return the persistence box data.""" |
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# Wait retrieve or create box in storehouse |
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i = 0 |
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while not self.box and i < BOX_RESTORE_ATTEMPTS: |
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time.sleep(self.box_restore_timer) |
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i += 1 |
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if not self.box: |
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error = 'Error retrieving persistence box from storehouse.' |
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log.error(error) |
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raise FileNotFoundError(error) |
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return self.box.data |
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def create_box(self): |
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"""Create a persistence box to store administrative changes.""" |
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content = {'namespace': self.namespace, |
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'callback': self._create_box_callback, |
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'data': {}} |
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event = KytosEvent(name='kytos.storehouse.create', content=content) |
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self.controller.buffers.app.put(event) |
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def _create_box_callback(self, _event, data, error): |
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"""Execute the callback to handle create_box.""" |
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if error: |
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log.error(f'Can\'t create persistence' |
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f'box with namespace {self.namespace}') |
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self.box = data |
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def list_stored_boxes(self): |
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"""List all persistence box stored in storehouse.""" |
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name = 'kytos.storehouse.list' |
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content = {'namespace': self.namespace, |
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'callback': self._get_or_create_a_box_from_list_of_boxes} |
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event = KytosEvent(name=name, content=content) |
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self.controller.buffers.app.put(event) |
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def _get_or_create_a_box_from_list_of_boxes(self, _event, data, _error): |
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"""Create a persistence box or retrieve the stored box.""" |
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if data: |
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self.get_stored_box(data[0]) |
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else: |
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self.create_box() |
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def get_stored_box(self, box_id): |
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"""Get persistence box from storehouse.""" |
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content = {'namespace': self.namespace, |
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'callback': self._get_box_callback, |
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'box_id': box_id, |
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'data': {}} |
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name = 'kytos.storehouse.retrieve' |
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event = KytosEvent(name=name, content=content) |
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self.controller.buffers.app.put(event) |
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def _get_box_callback(self, _event, data, error): |
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"""Handle get_box method saving the box or logging with the error.""" |
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if error: |
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log.error('Persistence box not found.') |
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self.box = data |
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def save_flow(self, flows): |
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"""Save flows in storehouse.""" |
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self.box.data[flows['id']] = flows |
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content = {'namespace': self.namespace, |
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'box_id': self.box.box_id, |
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'data': self.box.data, |
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'callback': self._save_flow_callback} |
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event = KytosEvent(name='kytos.storehouse.update', content=content) |
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self.controller.buffers.app.put(event) |
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def _save_flow_callback(self, _event, data, error): |
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"""Display stored flow.""" |
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if error: |
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log.error(f'Can\'t update persistence box {data.box_id}.') |
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log.info(f'Flow saved in {self.namespace}.{data.box_id}') |
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