1# -*- coding: utf-8 -*-
2# Copyright 2020 Google LLC
3#
4# Licensed under the Apache License, Version 2.0 (the "License");
5# you may not use this file except in compliance with the License.
6# You may obtain a copy of the License at
7#
8#     http://www.apache.org/licenses/LICENSE-2.0
9#
10# Unless required by applicable law or agreed to in writing, software
11# distributed under the License is distributed on an "AS IS" BASIS,
12# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13# See the License for the specific language governing permissions and
14# limitations under the License.
15#
16from typing import (
17    Any,
18    Callable,
19    Iterator,
20    Sequence,
21    Tuple,
22)
23
24from google.longrunning import operations_pb2
25
26
27class ListOperationsPager:
28    """A pager for iterating through ``list_operations`` requests.
29
30    This class thinly wraps an initial
31    :class:`google.longrunning.operations_pb2.ListOperationsResponse` object, and
32    provides an ``__iter__`` method to iterate through its
33    ``operations`` field.
34
35    If there are more pages, the ``__iter__`` method will make additional
36    ``ListOperations`` requests and continue to iterate
37    through the ``operations`` field on the
38    corresponding responses.
39
40    All the usual :class:`google.longrunning.operations_pb2.ListOperationsResponse`
41    attributes are available on the pager. If multiple requests are made, only
42    the most recent response is retained, and thus used for attribute lookup.
43    """
44
45    def __init__(
46        self,
47        method: Callable[..., operations_pb2.ListOperationsResponse],
48        request: operations_pb2.ListOperationsRequest,
49        response: operations_pb2.ListOperationsResponse,
50        *,
51        metadata: Sequence[Tuple[str, str]] = ()
52    ):
53        """Instantiate the pager.
54
55        Args:
56            method (Callable): The method that was originally called, and
57                which instantiated this pager.
58            request (google.longrunning.operations_pb2.ListOperationsRequest):
59                The initial request object.
60            response (google.longrunning.operations_pb2.ListOperationsResponse):
61                The initial response object.
62            metadata (Sequence[Tuple[str, str]]): Strings which should be
63                sent along with the request as metadata.
64        """
65        self._method = method
66        self._request = request
67        self._response = response
68        self._metadata = metadata
69
70    def __getattr__(self, name: str) -> Any:
71        return getattr(self._response, name)
72
73    @property
74    def pages(self) -> Iterator[operations_pb2.ListOperationsResponse]:
75        yield self._response
76        while self._response.next_page_token:
77            self._request.page_token = self._response.next_page_token
78            self._response = self._method(self._request, metadata=self._metadata)
79            yield self._response
80
81    def __iter__(self) -> Iterator[operations_pb2.Operation]:
82        for page in self.pages:
83            yield from page.operations
84
85    def __repr__(self) -> str:
86        return "{0}<{1!r}>".format(self.__class__.__name__, self._response)
87