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import threading
import time
import uuid
try:
from urlparse import urlparse
except ImportError:
from urllib.parse import urlparse
from typing import Any, Callable, Union, List, Optional, TYPE_CHECKING
if TYPE_CHECKING:
import requests
from ..serialization import Model
from ..service_client import ServiceClient
from ..pipeline import ClientRawResponse
class PollingMethod(object):
"""ABC class for polling method.
"""
def initialize(self, client, initial_response, deserialization_callback):
# type: (Any, Any, Any) -> None
raise NotImplementedError("This method needs to be implemented")
def run(self):
# type: () -> None
raise NotImplementedError("This method needs to be implemented")
def status(self):
# type: () -> str
raise NotImplementedError("This method needs to be implemented")
def finished(self):
# type: () -> bool
raise NotImplementedError("This method needs to be implemented")
def resource(self):
# type: () -> Any
raise NotImplementedError("This method needs to be implemented")
class NoPolling(PollingMethod):
"""An empty poller that returns the deserialized initial response.
"""
def __init__(self):
self._initial_response = None
self._deserialization_callback = None
def initialize(self, _, initial_response, deserialization_callback):
# type: (Any, requests.Response, Callable) -> None
self._initial_response = initial_response
self._deserialization_callback = deserialization_callback
def run(self):
# type: () -> None
"""Empty run, no polling.
"""
pass
def status(self):
# type: () -> str
"""Return the current status as a string.
:rtype: str
"""
return "succeeded"
def finished(self):
# type: () -> bool
"""Is this polling finished?
:rtype: bool
"""
return True
def resource(self):
# type: () -> Any
return self._deserialization_callback(self._initial_response)
class LROPoller(object):
"""Poller for long running operations.
:param client: A msrest service client. Can be a SDK client and it will be casted to a ServiceClient.
:type client: msrest.service_client.ServiceClient
:param initial_response: The initial call response
:type initial_response: requests.Response or msrest.pipeline.ClientRawResponse
:param deserialization_callback: A callback that takes a Response and return a deserialized object. If a subclass of Model is given, this passes "deserialize" as callback.
:type deserialization_callback: callable or msrest.serialization.Model
:param polling_method: The polling strategy to adopt
:type polling_method: msrest.polling.PollingMethod
"""
def __init__(self, client, initial_response, deserialization_callback, polling_method):
# type: (Any, Union[ClientRawResponse, requests.Response], Union[Model, Callable[[requests.Response], Model]], PollingMethod) -> None
try:
self._client = client if isinstance(client, ServiceClient) else client._client # type: ServiceClient
except AttributeError:
raise ValueError("Poller client parameter must be a low-level msrest Service Client or a SDK client.")
self._response = initial_response.response if isinstance(initial_response, ClientRawResponse) else initial_response
self._callbacks = [] # type: List[Callable]
self._polling_method = polling_method
if isinstance(deserialization_callback, type) and issubclass(deserialization_callback, Model):
deserialization_callback = deserialization_callback.deserialize # type: ignore
# Might raise a CloudError
self._polling_method.initialize(self._client, self._response, deserialization_callback)
# Prepare thread execution
self._thread = None
self._done = None
self._exception = None
if not self._polling_method.finished():
self._done = threading.Event()
self._thread = threading.Thread(
target=self._start,
name="LROPoller({})".format(uuid.uuid4()))
self._thread.daemon = True
self._thread.start()
def _start(self):
"""Start the long running operation.
On completion, runs any callbacks.
:param callable update_cmd: The API request to check the status of
the operation.
"""
try:
self._polling_method.run()
except Exception as err:
self._exception = err
finally:
self._done.set()
callbacks, self._callbacks = self._callbacks, []
while callbacks:
for call in callbacks:
call(self._polling_method)
callbacks, self._callbacks = self._callbacks, []
def status(self):
# type: () -> str
"""Returns the current status string.
:returns: The current status string
:rtype: str
"""
return self._polling_method.status()
def result(self, timeout=None):
# type: (Optional[float]) -> Model
"""Return the result of the long running operation, or
the result available after the specified timeout.
:returns: The deserialized resource of the long running operation,
if one is available.
:raises CloudError: Server problem with the query.
"""
self.wait(timeout)
return self._polling_method.resource()
def wait(self, timeout=None):
# type: (Optional[float]) -> None
"""Wait on the long running operation for a specified length
of time. You can check if this call as ended with timeout with the
"done()" method.
:param float timeout: Period of time to wait for the long running
operation to complete (in seconds).
:raises CloudError: Server problem with the query.
"""
if self._thread is None:
return
self._thread.join(timeout=timeout)
try:
# Let's handle possible None in forgiveness here
raise self._exception # type: ignore
except TypeError: # Was None
pass
def done(self):
# type: () -> bool
"""Check status of the long running operation.
:returns: 'True' if the process has completed, else 'False'.
"""
return self._thread is None or not self._thread.is_alive()
def add_done_callback(self, func):
# type: (Callable) -> None
"""Add callback function to be run once the long running operation
has completed - regardless of the status of the operation.
:param callable func: Callback function that takes at least one
argument, a completed LongRunningOperation.
"""
# Still use "_done" and not "done", since CBs are executed inside the thread.
if self._done is None or self._done.is_set():
func(self._polling_method)
# Let's add them still, for consistency (if you wish to access to it for some reasons)
self._callbacks.append(func)
def remove_done_callback(self, func):
# type: (Callable) -> None
"""Remove a callback from the long running operation.
:param callable func: The function to be removed from the callbacks.
:raises: ValueError if the long running operation has already
completed.
"""
if self._done is None or self._done.is_set():
raise ValueError("Process is complete.")
self._callbacks = [c for c in self._callbacks if c != func]
