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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,
47 client: Any,
48 initial_response: Any,
49 deserialization_callback: DeserializationCallbackType,
50 ) -> None:
51 raise NotImplementedError("This method needs to be implemented")
53 def run(self) -> None:
54 """Run the polling method.
55 This method should be implemented to perform the actual polling logic.
57 :return: None
58 :rtype: None
59 """
60 raise NotImplementedError("This method needs to be implemented")
62 def status(self) -> str:
63 """Return the current status of the polling operation.
65 :rtype: str
66 :return: The current status of the polling operation.
67 """
68 raise NotImplementedError("This method needs to be implemented")
70 def finished(self) -> bool:
71 """Check if the polling operation is finished.
73 :rtype: bool
74 :return: True if the polling operation is finished, False otherwise.
75 """
76 raise NotImplementedError("This method needs to be implemented")
78 def resource(self) -> PollingReturnType_co:
79 """Return the resource built by the polling operation.
81 :rtype: any
82 :return: The resource built by the polling operation.
83 """
84 raise NotImplementedError("This method needs to be implemented")
86 def get_continuation_token(self) -> str:
87 """Return a continuation token that allows to restart the poller later.
89 :rtype: str
90 :return: An opaque continuation token.
91 """
92 raise TypeError("Polling method '{}' doesn't support get_continuation_token".format(self.__class__.__name__))
94 @classmethod
95 def from_continuation_token(
96 cls, continuation_token: str, **kwargs: Any
97 ) -> Tuple[Any, Any, DeserializationCallbackType]:
98 """Recreate the poller from a continuation token.
100 :param continuation_token: The continuation token to recreate the poller from.
101 :type continuation_token: str
102 :rtype: Tuple[Any, Any, DeserializationCallbackType]
103 :return: A tuple containing the client, initial response, and deserialization callback.
104 """
105 raise TypeError("Polling method '{}' doesn't support from_continuation_token".format(cls.__name__))
108class _SansIONoPolling(Generic[PollingReturnType_co]):
109 _deserialization_callback: Callable[[Any], PollingReturnType_co]
110 """Deserialization callback passed during initialization"""
112 def __init__(self):
113 self._initial_response = None
115 def initialize(
116 self,
117 _: Any,
118 initial_response: Any,
119 deserialization_callback: Callable[[Any], PollingReturnType_co],
120 ) -> None:
121 """Initialize the poller with the initial response and deserialization callback.
123 :param _: The client, not used in this polling method.
124 :type _: Any
125 :param initial_response: The initial response from the long-running operation.
126 :type initial_response: Any
127 :param deserialization_callback: A callback that takes a response and returns a deserialized object.
128 :type deserialization_callback: Callable[[Any], PollingReturnType_co]
129 :return: None
130 :rtype: None
131 """
132 self._initial_response = initial_response
133 self._deserialization_callback = deserialization_callback
135 def status(self) -> str:
136 """Return the current status.
138 :rtype: str
139 :return: The current status
140 """
141 return "succeeded"
143 def finished(self) -> bool:
144 """Is this polling finished?
146 :rtype: bool
147 :return: Whether this polling is finished
148 """
149 return True
151 def resource(self) -> PollingReturnType_co:
152 """Return the built resource.
154 :rtype: any
155 :return: The built resource.
156 """
157 return self._deserialization_callback(self._initial_response)
159 def get_continuation_token(self) -> str:
160 """Return a continuation token that allows to restart the poller later.
162 :rtype: str
163 :return: An opaque continuation token
164 """
165 import pickle
167 return base64.b64encode(pickle.dumps(self._initial_response)).decode("ascii")
169 @classmethod
170 def from_continuation_token(
171 cls, continuation_token: str, **kwargs: Any
172 ) -> Tuple[Any, Any, Callable[[Any], PollingReturnType_co]]:
173 """Recreate the poller from a continuation token.
175 :param continuation_token: The continuation token to recreate the poller from.
176 :type continuation_token: str
177 :rtype: Tuple[Any, Any, Callable[[Any], PollingReturnType_co]]
178 :return: A tuple containing the client, initial response, and deserialization callback.
179 :raises ValueError: If 'deserialization_callback' is not provided in kwargs.
180 """
181 try:
182 deserialization_callback = kwargs["deserialization_callback"]
183 except KeyError:
184 raise ValueError("Need kwarg 'deserialization_callback' to be recreated from continuation_token") from None
185 import pickle
187 initial_response = pickle.loads(base64.b64decode(continuation_token)) # nosec
188 return None, initial_response, deserialization_callback
191class NoPolling(_SansIONoPolling[PollingReturnType_co], PollingMethod[PollingReturnType_co]):
192 """An empty poller that returns the deserialized initial response."""
194 def run(self) -> None:
195 """Empty run, no polling."""
198class LROPoller(Generic[PollingReturnType_co]):
199 """Poller for long running operations.
201 :param client: A pipeline service client
202 :type client: ~azure.core.PipelineClient
203 :param initial_response: The initial call response
204 :type initial_response: ~azure.core.pipeline.PipelineResponse
205 :param deserialization_callback: A callback that takes a Response and return a deserialized object.
206 If a subclass of Model is given, this passes "deserialize" as callback.
207 :type deserialization_callback: callable or msrest.serialization.Model
208 :param polling_method: The polling strategy to adopt
209 :type polling_method: ~azure.core.polling.PollingMethod
210 """
212 def __init__(
213 self,
214 client: Any,
215 initial_response: Any,
216 deserialization_callback: Callable[[Any], PollingReturnType_co],
217 polling_method: PollingMethod[PollingReturnType_co],
218 ) -> None:
219 self._callbacks: List[Callable] = []
220 self._polling_method = polling_method
222 # This implicit test avoids bringing in an explicit dependency on Model directly
223 try:
224 deserialization_callback = deserialization_callback.deserialize # type: ignore
225 except AttributeError:
226 pass
228 # Might raise a CloudError
229 self._polling_method.initialize(client, initial_response, deserialization_callback)
231 # Prepare thread execution
232 self._thread = None
233 self._done = threading.Event()
234 self._exception = None
235 if self._polling_method.finished():
236 self._done.set()
237 else:
238 self._thread = threading.Thread(
239 target=with_current_context(self._start),
240 name="LROPoller({})".format(uuid.uuid4()),
241 )
242 self._thread.daemon = True
243 self._thread.start()
245 def _start(self):
246 """Start the long running operation.
247 On completion, runs any callbacks.
248 """
249 try:
250 self._polling_method.run()
251 except AzureError as error:
252 if not error.continuation_token:
253 try:
254 error.continuation_token = self.continuation_token()
255 except Exception: # pylint: disable=broad-except
256 _LOGGER.warning("Unable to retrieve continuation token.")
257 error.continuation_token = None
259 self._exception = error
260 except Exception as error: # pylint: disable=broad-except
261 self._exception = error
263 finally:
264 self._done.set()
266 callbacks, self._callbacks = self._callbacks, []
267 while callbacks:
268 for call in callbacks:
269 call(self._polling_method)
270 callbacks, self._callbacks = self._callbacks, []
272 def polling_method(self) -> PollingMethod[PollingReturnType_co]:
273 """Return the polling method associated to this poller.
275 :return: The polling method
276 :rtype: ~azure.core.polling.PollingMethod
277 """
278 return self._polling_method
280 def continuation_token(self) -> str:
281 """Return a continuation token that allows to restart the poller later.
283 :returns: An opaque continuation token
284 :rtype: str
285 """
286 return self._polling_method.get_continuation_token()
288 @classmethod
289 def from_continuation_token(
290 cls, polling_method: PollingMethod[PollingReturnType_co], continuation_token: str, **kwargs: Any
291 ) -> "LROPoller[PollingReturnType_co]":
292 """Create a poller from a continuation token.
294 :param polling_method: The polling strategy to adopt
295 :type polling_method: ~azure.core.polling.PollingMethod
296 :param continuation_token: An opaque continuation token
297 :type continuation_token: str
298 :return: An instance of LROPoller
299 :rtype: ~azure.core.polling.LROPoller
300 :raises ~azure.core.exceptions.HttpResponseError: If the continuation token is invalid.
301 """
302 (
303 client,
304 initial_response,
305 deserialization_callback,
306 ) = polling_method.from_continuation_token(continuation_token, **kwargs)
307 return cls(client, initial_response, deserialization_callback, polling_method)
309 def status(self) -> str:
310 """Returns the current status string.
312 :returns: The current status string
313 :rtype: str
314 """
315 return self._polling_method.status()
317 def result(self, timeout: Optional[float] = None) -> PollingReturnType_co:
318 """Return the result of the long running operation, or
319 the result available after the specified timeout.
321 :param float timeout: Period of time to wait before getting back control.
322 :returns: The deserialized resource of the long running operation, if one is available.
323 :rtype: any or None
324 :raises ~azure.core.exceptions.HttpResponseError: Server problem with the query.
325 """
326 self.wait(timeout)
327 return self._polling_method.resource()
329 @distributed_trace
330 def wait(self, timeout: Optional[float] = None) -> None:
331 """Wait on the long running operation for a specified length
332 of time. You can check if this call as ended with timeout with the
333 "done()" method.
335 :param float timeout: Period of time to wait for the long running
336 operation to complete (in seconds).
337 :raises ~azure.core.exceptions.HttpResponseError: Server problem with the query.
338 """
339 if self._thread is None:
340 return
341 self._thread.join(timeout=timeout)
342 try:
343 # Let's handle possible None in forgiveness here
344 # https://github.com/python/mypy/issues/8165
345 raise self._exception # type: ignore
346 except TypeError: # Was None
347 pass
349 def done(self) -> bool:
350 """Check status of the long running operation.
352 :returns: 'True' if the process has completed, else 'False'.
353 :rtype: bool
354 """
355 return self._thread is None or not self._thread.is_alive()
357 def add_done_callback(self, func: Callable) -> None:
358 """Add callback function to be run once the long running operation
359 has completed - regardless of the status of the operation.
361 :param callable func: Callback function that takes at least one
362 argument, a completed LongRunningOperation.
363 """
364 # Still use "_done" and not "done", since CBs are executed inside the thread.
365 if self._done.is_set():
366 func(self._polling_method)
367 # Let's add them still, for consistency (if you wish to access to it for some reasons)
368 self._callbacks.append(func)
370 def remove_done_callback(self, func: Callable) -> None:
371 """Remove a callback from the long running operation.
373 :param callable func: The function to be removed from the callbacks.
374 :raises ValueError: if the long running operation has already completed.
375 """
376 if self._done is None or self._done.is_set():
377 raise ValueError("Process is complete.")
378 self._callbacks = [c for c in self._callbacks if c != func]