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"""Kytos Napps Module.""" |
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import json |
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import os |
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import re |
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import sys |
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import tarfile |
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import urllib |
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from abc import ABCMeta, abstractmethod |
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from pathlib import Path |
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from random import randint |
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from threading import Event, Thread |
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from kytos.core.logs import NAppLog |
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__all__ = ('KytosNApp',) |
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LOG = NAppLog() |
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class NApp: |
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"""Class to represent a NApp.""" |
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# pylint: disable=too-many-arguments |
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def __init__(self, username=None, name=None, version=None, |
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repository=None, meta=False): |
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self.username = username |
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self.name = name |
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self.version = version if version else 'latest' |
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self.repository = repository |
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self.meta = meta |
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self.description = None |
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self.tags = [] |
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self.enabled = False |
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self.napp_dependencies = [] |
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def __str__(self): |
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return "{}/{}".format(self.username, self.name) |
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def __repr__(self): |
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return f"NApp({self.username}/{self.name})" |
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def __hash__(self): |
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return hash(self.id) |
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def __eq__(self, other): |
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"""Compare username/name strings.""" |
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return isinstance(other, self.__class__) and self.id == other.id |
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@property |
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def id(self): # pylint: disable=invalid-name |
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"""username/name string.""" |
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return str(self) |
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@property |
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def uri(self): |
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"""Return a unique identifier of this NApp.""" |
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version = self.version if self.version else 'latest' |
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if not self._has_valid_repository(): |
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return "" |
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# Use the next line after Diraol fix redirect using ":" for version |
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# return "{}/{}:{}".format(self.repository, self.id, version) |
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return "{}/{}-{}".format(self.repository, self.id, version) |
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@property |
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def package_url(self): |
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"""Return a fully qualified URL for a NApp package.""" |
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if not self.uri: |
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return "" |
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return "{}.napp".format(self.uri) |
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@classmethod |
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def create_from_uri(cls, uri): |
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"""Return a new NApp instance from an unique identifier.""" |
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regex = r'^(((https?://|file://)(.+))/)?(.+?)/(.+?)/?(:(.+))?$' |
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match = re.match(regex, uri) |
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if not match: |
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return None |
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return cls(username=match.groups()[4], |
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name=match.groups()[5], |
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version=match.groups()[7], |
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repository=match.groups()[1]) |
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@classmethod |
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def create_from_json(cls, filename): |
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"""Return a new NApp instance from a metadata file.""" |
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with open(filename, encoding='utf-8') as data_file: |
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data = json.loads(data_file.read()) |
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return cls.create_from_dict(data) |
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@classmethod |
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def create_from_dict(cls, data): |
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"""Return a new NApp instance from metadata.""" |
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napp = cls() |
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for attribute, value in data.items(): |
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setattr(napp, attribute, value) |
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return napp |
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def as_json(self): |
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"""Dump all NApp attributes on a json format.""" |
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return json.dumps(self.__dict__) |
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def match(self, pattern): |
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"""Whether a pattern is present on NApp id, description and tags.""" |
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try: |
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pattern = '.*{}.*'.format(pattern) |
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pattern = re.compile(pattern, re.IGNORECASE) |
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strings = [self.id, self.description] + self.tags |
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return any(pattern.match(string) for string in strings) |
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except TypeError: |
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return False |
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def download(self): |
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"""Download NApp package from his repository. |
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Raises: |
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urllib.error.HTTPError: If download is not successful. |
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Returns: |
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str: Downloaded temp filename. |
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""" |
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if not self.package_url: |
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return None |
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package_filename = urllib.request.urlretrieve(self.package_url)[0] |
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extracted = self._extract(package_filename) |
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Path(package_filename).unlink() |
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self._update_repo_file(extracted) |
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return extracted |
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@staticmethod |
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def _extract(filename): |
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"""Extract NApp package to a temporary folder. |
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Return: |
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pathlib.Path: Temp dir with package contents. |
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""" |
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random_string = '{:0d}'.format(randint(0, 10**6)) |
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tmp = '/tmp/kytos-napp-' + Path(filename).stem + '-' + random_string |
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os.mkdir(tmp) |
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with tarfile.open(filename, 'r:xz') as tar: |
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tar.extractall(tmp) |
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return Path(tmp) |
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def _has_valid_repository(self): |
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"""Whether this NApp has a valid repository or not.""" |
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return all([self.username, self.name, self.repository]) |
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def _update_repo_file(self, destination=None): |
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"""Create or update the file '.repo' inside NApp package.""" |
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with open("{}/.repo".format(destination), 'w') as repo_file: |
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repo_file.write(self.repository + '\n') |
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class KytosNApp(Thread, metaclass=ABCMeta): |
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"""Base class for any KytosNApp to be developed.""" |
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def __init__(self, controller, **kwargs): |
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"""Contructor of KytosNapps. |
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Go through all of the instance methods and selects those that have |
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the events attribute, then creates a dict containing the event_name |
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and the list of methods that are responsible for handling such event. |
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At the end, the setup method is called as a complement of the init |
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process. |
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""" |
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Thread.__init__(self, daemon=False) |
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self.controller = controller |
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self.username = None # loaded from json |
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self.name = None # loaded from json |
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self.meta = False # loaded from json |
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self._load_json() |
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# Force a listener with a private method. |
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self._listeners = { |
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'kytos/core.shutdown': [self._shutdown_handler], |
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'kytos/core.shutdown.' + self.napp_id: [self._shutdown_handler]} |
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self.__event = Event() |
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#: int: Seconds to sleep before next call to :meth:`execute`. If |
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#: negative, run :meth:`execute` only once. |
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self.__interval = -1 |
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self.setup() |
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#: Add non-private methods that listen to events. |
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handler_methods = [getattr(self, method_name) for method_name in |
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dir(self) if method_name[0] != '_' and |
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callable(getattr(self, method_name)) and |
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hasattr(getattr(self, method_name), 'events')] |
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# Building the listeners dictionary |
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for method in handler_methods: |
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for event_name in method.events: |
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if event_name not in self._listeners: |
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self._listeners[event_name] = [] |
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self._listeners[event_name].append(method) |
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@property |
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def napp_id(self): |
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"""username/name string.""" |
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return "{}/{}".format(self.username, self.name) |
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def listeners(self): |
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"""Return all listeners registered.""" |
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return list(self._listeners.keys()) |
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def _load_json(self): |
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"""Update object attributes based on kytos.json.""" |
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current_file = sys.modules[self.__class__.__module__].__file__ |
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json_path = os.path.join(os.path.dirname(current_file), 'kytos.json') |
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with open(json_path, encoding='utf-8') as data_file: |
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data = json.loads(data_file.read()) |
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for attribute, value in data.items(): |
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setattr(self, attribute, value) |
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def execute_as_loop(self, interval): |
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"""Run :meth:`execute` within a loop. Call this method during setup. |
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By calling this method, the application does not need to worry about |
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loop details such as sleeping and stopping the loop when |
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:meth:`shutdown` is called. Just call this method during :meth:`setup` |
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and implement :meth:`execute` as a single execution. |
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Args: |
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interval (int): Seconds between each call to :meth:`execute`. |
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""" |
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self.__interval = interval |
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def run(self): |
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"""Call the execute method, looping as needed. |
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It should not be overriden. |
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""" |
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LOG.info("Running NApp: %s", self) |
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self.execute() |
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while self.__interval > 0 and not self.__event.is_set(): |
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self.__event.wait(self.__interval) |
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self.execute() |
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# all listeners receive event |
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def _shutdown_handler(self, event): # pylint: disable=unused-argument |
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"""Listen shutdown event from kytos. |
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This method listens the kytos/core.shutdown event and call the shutdown |
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method from napp subclass implementation. |
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Paramters |
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event (:class:`KytosEvent`): event to be listened. |
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""" |
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if not self.__event.is_set(): |
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self.__event.set() |
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self.shutdown() |
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@abstractmethod |
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def setup(self): |
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"""Replace the 'init' method for the KytosApp subclass. |
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The setup method is automatically called on the NApp __init__(). |
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Users aren't supposed to call this method directly. |
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""" |
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pass |
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@abstractmethod |
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def execute(self): |
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"""Execute in a loop until 'kytos/core.shutdown' is received. |
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The execute method is called by KytosNApp class. |
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Users shouldn't call this method directly. |
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""" |
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pass |
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@abstractmethod |
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def shutdown(self): |
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"""Run before the app is unloaded and the controller, stopped. |
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The user implementation of this method should do the necessary routine |
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for the user App and also it is a good moment to break the loop of the |
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execute method if it is in a loop. |
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This methods is not going to be called directly, it is going to be |
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called by the _shutdown_handler method when a KytosShutdownEvent is |
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sent. |
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""" |
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pass |
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