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1# --------------------------------------------------------------------------
2#
3# Copyright (c) Microsoft Corporation. All rights reserved.
4#
5# The MIT License (MIT)
6#
7# Permission is hereby granted, free of charge, to any person obtaining a copy
8# of this software and associated documentation files (the ""Software""), to
9# deal in the Software without restriction, including without limitation the
10# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
11# sell copies of the Software, and to permit persons to whom the Software is
12# furnished to do so, subject to the following conditions:
13#
14# The above copyright notice and this permission notice shall be included in
15# all copies or substantial portions of the Software.
16#
17# THE SOFTWARE IS PROVIDED *AS IS*, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
20# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
22# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
23# IN THE SOFTWARE.
24#
25# --------------------------------------------------------------------------
26import base64
27import logging
28import threading
29import uuid
30from typing import TypeVar, Generic, Any, Callable, Optional, Tuple, List
31from azure.core.exceptions import AzureError
32from azure.core.tracing.decorator import distributed_trace
33from azure.core.tracing.common import with_current_context
36PollingReturnType_co = TypeVar("PollingReturnType_co", covariant=True)
37DeserializationCallbackType = Any
39_LOGGER = logging.getLogger(__name__)
42class PollingMethod(Generic[PollingReturnType_co]):
43 """ABC class for polling method."""
45 def initialize(
46 self, client: Any, initial_response: Any, deserialization_callback: DeserializationCallbackType
47 ) -> None:
48 raise NotImplementedError("This method needs to be implemented")
50 def run(self) -> None:
51 raise NotImplementedError("This method needs to be implemented")
53 def status(self) -> str:
54 raise NotImplementedError("This method needs to be implemented")
56 def finished(self) -> bool:
57 raise NotImplementedError("This method needs to be implemented")
59 def resource(self) -> PollingReturnType_co:
60 raise NotImplementedError("This method needs to be implemented")
62 def get_continuation_token(self) -> str:
63 raise TypeError("Polling method '{}' doesn't support get_continuation_token".format(self.__class__.__name__))
65 @classmethod
66 def from_continuation_token(
67 cls, continuation_token: str, **kwargs: Any
68 ) -> Tuple[Any, Any, DeserializationCallbackType]:
69 raise TypeError("Polling method '{}' doesn't support from_continuation_token".format(cls.__name__))
72class _SansIONoPolling(Generic[PollingReturnType_co]):
73 _deserialization_callback: Callable[[Any], PollingReturnType_co]
74 """Deserialization callback passed during initialization"""
76 def __init__(self):
77 self._initial_response = None
79 def initialize(
80 self,
81 _: Any,
82 initial_response: Any,
83 deserialization_callback: Callable[[Any], PollingReturnType_co],
84 ) -> None:
85 self._initial_response = initial_response
86 self._deserialization_callback = deserialization_callback
88 def status(self) -> str:
89 """Return the current status.
91 :rtype: str
92 :return: The current status
93 """
94 return "succeeded"
96 def finished(self) -> bool:
97 """Is this polling finished?
99 :rtype: bool
100 :return: Whether this polling is finished
101 """
102 return True
104 def resource(self) -> PollingReturnType_co:
105 return self._deserialization_callback(self._initial_response)
107 def get_continuation_token(self) -> str:
108 import pickle
110 return base64.b64encode(pickle.dumps(self._initial_response)).decode("ascii")
112 @classmethod
113 def from_continuation_token(
114 cls, continuation_token: str, **kwargs: Any
115 ) -> Tuple[Any, Any, Callable[[Any], PollingReturnType_co]]:
116 try:
117 deserialization_callback = kwargs["deserialization_callback"]
118 except KeyError:
119 raise ValueError("Need kwarg 'deserialization_callback' to be recreated from continuation_token") from None
120 import pickle
122 initial_response = pickle.loads(base64.b64decode(continuation_token)) # nosec
123 return None, initial_response, deserialization_callback
126class NoPolling(_SansIONoPolling[PollingReturnType_co], PollingMethod[PollingReturnType_co]):
127 """An empty poller that returns the deserialized initial response."""
129 def run(self) -> None:
130 """Empty run, no polling."""
133class LROPoller(Generic[PollingReturnType_co]):
134 """Poller for long running operations.
136 :param client: A pipeline service client
137 :type client: ~azure.core.PipelineClient
138 :param initial_response: The initial call response
139 :type initial_response: ~azure.core.pipeline.PipelineResponse
140 :param deserialization_callback: A callback that takes a Response and return a deserialized object.
141 If a subclass of Model is given, this passes "deserialize" as callback.
142 :type deserialization_callback: callable or msrest.serialization.Model
143 :param polling_method: The polling strategy to adopt
144 :type polling_method: ~azure.core.polling.PollingMethod
145 """
147 def __init__(
148 self,
149 client: Any,
150 initial_response: Any,
151 deserialization_callback: Callable[[Any], PollingReturnType_co],
152 polling_method: PollingMethod[PollingReturnType_co],
153 ) -> None:
154 self._callbacks: List[Callable] = []
155 self._polling_method = polling_method
157 # This implicit test avoids bringing in an explicit dependency on Model directly
158 try:
159 deserialization_callback = deserialization_callback.deserialize # type: ignore
160 except AttributeError:
161 pass
163 # Might raise a CloudError
164 self._polling_method.initialize(client, initial_response, deserialization_callback)
166 # Prepare thread execution
167 self._thread = None
168 self._done = threading.Event()
169 self._exception = None
170 if self._polling_method.finished():
171 self._done.set()
172 else:
173 self._thread = threading.Thread(
174 target=with_current_context(self._start),
175 name="LROPoller({})".format(uuid.uuid4()),
176 )
177 self._thread.daemon = True
178 self._thread.start()
180 def _start(self):
181 """Start the long running operation.
182 On completion, runs any callbacks.
183 """
184 try:
185 self._polling_method.run()
186 except AzureError as error:
187 if not error.continuation_token:
188 try:
189 error.continuation_token = self.continuation_token()
190 except Exception as err: # pylint: disable=broad-except
191 _LOGGER.warning("Unable to retrieve continuation token: %s", err)
192 error.continuation_token = None
194 self._exception = error
195 except Exception as error: # pylint: disable=broad-except
196 self._exception = error
198 finally:
199 self._done.set()
201 callbacks, self._callbacks = self._callbacks, []
202 while callbacks:
203 for call in callbacks:
204 call(self._polling_method)
205 callbacks, self._callbacks = self._callbacks, []
207 def polling_method(self) -> PollingMethod[PollingReturnType_co]:
208 """Return the polling method associated to this poller.
210 :return: The polling method
211 :rtype: ~azure.core.polling.PollingMethod
212 """
213 return self._polling_method
215 def continuation_token(self) -> str:
216 """Return a continuation token that allows to restart the poller later.
218 :returns: An opaque continuation token
219 :rtype: str
220 """
221 return self._polling_method.get_continuation_token()
223 @classmethod
224 def from_continuation_token(
225 cls, polling_method: PollingMethod[PollingReturnType_co], continuation_token: str, **kwargs: Any
226 ) -> "LROPoller[PollingReturnType_co]":
227 (
228 client,
229 initial_response,
230 deserialization_callback,
231 ) = polling_method.from_continuation_token(continuation_token, **kwargs)
232 return cls(client, initial_response, deserialization_callback, polling_method)
234 def status(self) -> str:
235 """Returns the current status string.
237 :returns: The current status string
238 :rtype: str
239 """
240 return self._polling_method.status()
242 def result(self, timeout: Optional[float] = None) -> PollingReturnType_co:
243 """Return the result of the long running operation, or
244 the result available after the specified timeout.
246 :param float timeout: Period of time to wait before getting back control.
247 :returns: The deserialized resource of the long running operation, if one is available.
248 :rtype: any or None
249 :raises ~azure.core.exceptions.HttpResponseError: Server problem with the query.
250 """
251 self.wait(timeout)
252 return self._polling_method.resource()
254 @distributed_trace
255 def wait(self, timeout: Optional[float] = None) -> None:
256 """Wait on the long running operation for a specified length
257 of time. You can check if this call as ended with timeout with the
258 "done()" method.
260 :param float timeout: Period of time to wait for the long running
261 operation to complete (in seconds).
262 :raises ~azure.core.exceptions.HttpResponseError: Server problem with the query.
263 """
264 if self._thread is None:
265 return
266 self._thread.join(timeout=timeout)
267 try:
268 # Let's handle possible None in forgiveness here
269 # https://github.com/python/mypy/issues/8165
270 raise self._exception # type: ignore
271 except TypeError: # Was None
272 pass
274 def done(self) -> bool:
275 """Check status of the long running operation.
277 :returns: 'True' if the process has completed, else 'False'.
278 :rtype: bool
279 """
280 return self._thread is None or not self._thread.is_alive()
282 def add_done_callback(self, func: Callable) -> None:
283 """Add callback function to be run once the long running operation
284 has completed - regardless of the status of the operation.
286 :param callable func: Callback function that takes at least one
287 argument, a completed LongRunningOperation.
288 """
289 # Still use "_done" and not "done", since CBs are executed inside the thread.
290 if self._done.is_set():
291 func(self._polling_method)
292 # Let's add them still, for consistency (if you wish to access to it for some reasons)
293 self._callbacks.append(func)
295 def remove_done_callback(self, func: Callable) -> None:
296 """Remove a callback from the long running operation.
298 :param callable func: The function to be removed from the callbacks.
299 :raises ValueError: if the long running operation has already completed.
300 """
301 if self._done is None or self._done.is_set():
302 raise ValueError("Process is complete.")
303 self._callbacks = [c for c in self._callbacks if c != func]