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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 logging
27import threading
28import uuid
29from typing import TypeVar, Generic, Any, Callable, Optional, Tuple, List
30from azure.core.exceptions import AzureError
31from azure.core.tracing.decorator import distributed_trace
32from azure.core.tracing.common import with_current_context
33from ._utils import _encode_continuation_token, _decode_continuation_token
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 return _encode_continuation_token(self._initial_response)
167 @classmethod
168 def from_continuation_token(
169 cls, continuation_token: str, **kwargs: Any
170 ) -> Tuple[Any, Any, Callable[[Any], PollingReturnType_co]]:
171 """Recreate the poller from a continuation token.
173 :param continuation_token: The continuation token to recreate the poller from.
174 :type continuation_token: str
175 :rtype: Tuple[Any, Any, Callable[[Any], PollingReturnType_co]]
176 :return: A tuple containing the client, initial response, and deserialization callback.
177 :raises ValueError: If 'deserialization_callback' is not provided in kwargs.
178 """
179 try:
180 deserialization_callback = kwargs["deserialization_callback"]
181 except KeyError:
182 raise ValueError("Need kwarg 'deserialization_callback' to be recreated from continuation_token") from None
184 initial_response = _decode_continuation_token(continuation_token)
185 return None, initial_response, deserialization_callback
188class NoPolling(_SansIONoPolling[PollingReturnType_co], PollingMethod[PollingReturnType_co]):
189 """An empty poller that returns the deserialized initial response."""
191 def run(self) -> None:
192 """Empty run, no polling."""
195class LROPoller(Generic[PollingReturnType_co]):
196 """Poller for long running operations.
198 :param client: A pipeline service client
199 :type client: ~azure.core.PipelineClient
200 :param initial_response: The initial call response
201 :type initial_response: ~azure.core.pipeline.PipelineResponse
202 :param deserialization_callback: A callback that takes a Response and return a deserialized object.
203 If a subclass of Model is given, this passes "deserialize" as callback.
204 :type deserialization_callback: callable or msrest.serialization.Model
205 :param polling_method: The polling strategy to adopt
206 :type polling_method: ~azure.core.polling.PollingMethod
207 """
209 def __init__(
210 self,
211 client: Any,
212 initial_response: Any,
213 deserialization_callback: Callable[[Any], PollingReturnType_co],
214 polling_method: PollingMethod[PollingReturnType_co],
215 ) -> None:
216 self._callbacks: List[Callable] = []
217 self._polling_method = polling_method
219 # This implicit test avoids bringing in an explicit dependency on Model directly
220 try:
221 deserialization_callback = deserialization_callback.deserialize # type: ignore
222 except AttributeError:
223 pass
225 # Might raise a CloudError
226 self._polling_method.initialize(client, initial_response, deserialization_callback)
228 # Prepare thread execution
229 self._thread = None
230 self._done = threading.Event()
231 self._exception = None
232 if self._polling_method.finished():
233 self._done.set()
234 else:
235 self._thread = threading.Thread(
236 target=with_current_context(self._start),
237 name="LROPoller({})".format(uuid.uuid4()),
238 )
239 self._thread.daemon = True
240 self._thread.start()
242 def _start(self):
243 """Start the long running operation.
244 On completion, runs any callbacks.
245 """
246 try:
247 self._polling_method.run()
248 except AzureError as error:
249 if not error.continuation_token:
250 try:
251 error.continuation_token = self.continuation_token()
252 except Exception: # pylint: disable=broad-except
253 _LOGGER.warning("Unable to retrieve continuation token.")
254 error.continuation_token = None
256 self._exception = error
257 except Exception as error: # pylint: disable=broad-except
258 self._exception = error
260 finally:
261 self._done.set()
263 callbacks, self._callbacks = self._callbacks, []
264 while callbacks:
265 for call in callbacks:
266 call(self._polling_method)
267 callbacks, self._callbacks = self._callbacks, []
269 def polling_method(self) -> PollingMethod[PollingReturnType_co]:
270 """Return the polling method associated to this poller.
272 :return: The polling method
273 :rtype: ~azure.core.polling.PollingMethod
274 """
275 return self._polling_method
277 def continuation_token(self) -> str:
278 """Return a continuation token that allows to restart the poller later.
280 :returns: An opaque continuation token
281 :rtype: str
282 """
283 return self._polling_method.get_continuation_token()
285 @classmethod
286 def from_continuation_token(
287 cls, polling_method: PollingMethod[PollingReturnType_co], continuation_token: str, **kwargs: Any
288 ) -> "LROPoller[PollingReturnType_co]":
289 """Create a poller from a continuation token.
291 :param polling_method: The polling strategy to adopt
292 :type polling_method: ~azure.core.polling.PollingMethod
293 :param continuation_token: An opaque continuation token
294 :type continuation_token: str
295 :return: An instance of LROPoller
296 :rtype: ~azure.core.polling.LROPoller
297 :raises ~azure.core.exceptions.HttpResponseError: If the continuation token is invalid.
298 """
299 (
300 client,
301 initial_response,
302 deserialization_callback,
303 ) = polling_method.from_continuation_token(continuation_token, **kwargs)
304 return cls(client, initial_response, deserialization_callback, polling_method)
306 def status(self) -> str:
307 """Returns the current status string.
309 :returns: The current status string
310 :rtype: str
311 """
312 return self._polling_method.status()
314 def result(self, timeout: Optional[float] = None) -> PollingReturnType_co:
315 """Return the result of the long running operation, or
316 the result available after the specified timeout.
318 :param float timeout: Period of time to wait before getting back control.
319 :returns: The deserialized resource of the long running operation, if one is available.
320 :rtype: any or None
321 :raises ~azure.core.exceptions.HttpResponseError: Server problem with the query.
322 """
323 self.wait(timeout)
324 return self._polling_method.resource()
326 @distributed_trace
327 def wait(self, timeout: Optional[float] = None) -> None:
328 """Wait on the long running operation for a specified length
329 of time. You can check if this call as ended with timeout with the
330 "done()" method.
332 :param float timeout: Period of time to wait for the long running
333 operation to complete (in seconds).
334 :raises ~azure.core.exceptions.HttpResponseError: Server problem with the query.
335 """
336 if self._thread is None:
337 return
338 self._thread.join(timeout=timeout)
339 try:
340 # Let's handle possible None in forgiveness here
341 # https://github.com/python/mypy/issues/8165
342 raise self._exception # type: ignore
343 except TypeError: # Was None
344 pass
346 def done(self) -> bool:
347 """Check status of the long running operation.
349 :returns: 'True' if the process has completed, else 'False'.
350 :rtype: bool
351 """
352 return self._thread is None or not self._thread.is_alive()
354 def add_done_callback(self, func: Callable) -> None:
355 """Add callback function to be run once the long running operation
356 has completed - regardless of the status of the operation.
358 :param callable func: Callback function that takes at least one
359 argument, a completed LongRunningOperation.
360 """
361 # Still use "_done" and not "done", since CBs are executed inside the thread.
362 if self._done.is_set():
363 func(self._polling_method)
364 # Let's add them still, for consistency (if you wish to access to it for some reasons)
365 self._callbacks.append(func)
367 def remove_done_callback(self, func: Callable) -> None:
368 """Remove a callback from the long running operation.
370 :param callable func: The function to be removed from the callbacks.
371 :raises ValueError: if the long running operation has already completed.
372 """
373 if self._done is None or self._done.is_set():
374 raise ValueError("Process is complete.")
375 self._callbacks = [c for c in self._callbacks if c != func]