codekingpro/portable-devtools

1# Copyright 2020 The gRPC Authors
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7#     http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14"""Abstract base classes for server-side classes."""
15
16import abc
17from typing import Generic, Iterable, Mapping, NoReturn, Optional, Sequence
18
19import grpc
20
21from ._metadata import Metadata  # pylint: disable=unused-import
22from ._typing import DoneCallbackType
23from ._typing import MetadataType
24from ._typing import RequestType
25from ._typing import ResponseType
26
27
28class Server(abc.ABC):
29    """Serves RPCs."""
30
31    @abc.abstractmethod
32    def add_generic_rpc_handlers(
33        self, generic_rpc_handlers: Sequence[grpc.GenericRpcHandler]
34    ) -> None:
35        """Registers GenericRpcHandlers with this Server.
36
37        This method is only safe to call before the server is started.
38
39        Args:
40          generic_rpc_handlers: A sequence of GenericRpcHandlers that will be
41          used to service RPCs.
42        """
43
44    @abc.abstractmethod
45    def add_insecure_port(self, address: str) -> int:
46        """Opens an insecure port for accepting RPCs.
47
48        A port is a communication endpoint that used by networking protocols,
49        like TCP and UDP. To date, we only support TCP.
50
51        This method may only be called before starting the server.
52
53        Args:
54          address: The address for which to open a port. If the port is 0,
55            or not specified in the address, then the gRPC runtime will choose a port.
56
57        Returns:
58          An integer port on which the server will accept RPC requests.
59        """
60
61    @abc.abstractmethod
62    def add_secure_port(
63        self, address: str, server_credentials: grpc.ServerCredentials
64    ) -> int:
65        """Opens a secure port for accepting RPCs.
66
67        A port is a communication endpoint that used by networking protocols,
68        like TCP and UDP. To date, we only support TCP.
69
70        This method may only be called before starting the server.
71
72        Args:
73          address: The address for which to open a port.
74            if the port is 0, or not specified in the address, then the gRPC
75            runtime will choose a port.
76          server_credentials: A ServerCredentials object.
77
78        Returns:
79          An integer port on which the server will accept RPC requests.
80        """
81
82    @abc.abstractmethod
83    async def start(self) -> None:
84        """Starts this Server.
85
86        This method may only be called once. (i.e. it is not idempotent).
87        """
88
89    @abc.abstractmethod
90    async def stop(self, grace: Optional[float]) -> None:
91        """Stops this Server.
92
93        This method immediately stops the server from servicing new RPCs in
94        all cases.
95
96        If a grace period is specified, this method waits until all active
97        RPCs are finished or until the grace period is reached. RPCs that haven't
98        been terminated within the grace period are aborted.
99        If a grace period is not specified (by passing None for grace), all
100        existing RPCs are aborted immediately and this method blocks until
101        the last RPC handler terminates.
102
103        This method is idempotent and may be called at any time. Passing a
104        smaller grace value in a subsequent call will have the effect of
105        stopping the Server sooner (passing None will have the effect of
106        stopping the server immediately). Passing a larger grace value in a
107        subsequent call will not have the effect of stopping the server later
108        (i.e. the most restrictive grace value is used).
109
110        Args:
111          grace: A duration of time in seconds or None.
112        """
113
114    @abc.abstractmethod
115    async def wait_for_termination(
116        self, timeout: Optional[float] = None
117    ) -> bool:
118        """Continues current coroutine once the server stops.
119
120        This is an EXPERIMENTAL API.
121
122        The wait will not consume computational resources during blocking, and
123        it will block until one of the two following conditions are met:
124
125        1) The server is stopped or terminated;
126        2) A timeout occurs if timeout is not `None`.
127
128        The timeout argument works in the same way as `threading.Event.wait()`.
129        https://docs.python.org/3/library/threading.html#threading.Event.wait
130
131        Args:
132          timeout: A floating point number specifying a timeout for the
133            operation in seconds.
134
135        Returns:
136          A bool indicates if the operation times out.
137        """
138
139    def add_registered_method_handlers(  # noqa: B027
140        self, service_name, method_handlers
141    ):
142        """Registers GenericRpcHandlers with this Server.
143
144        This method is only safe to call before the server is started.
145
146        Args:
147          service_name: The service name.
148          method_handlers: A dictionary that maps method names to corresponding
149            RpcMethodHandler.
150        """
151
152
153# pylint: disable=too-many-public-methods
154class ServicerContext(Generic[RequestType, ResponseType], abc.ABC):
155    """A context object passed to method implementations."""
156
157    @abc.abstractmethod
158    async def read(self) -> RequestType:
159        """Reads one message from the RPC.
160
161        Only one read operation is allowed simultaneously.
162
163        Returns:
164          A response message of the RPC.
165
166        Raises:
167          An RpcError exception if the read failed.
168        """
169
170    @abc.abstractmethod
171    async def write(self, message: ResponseType) -> None:
172        """Writes one message to the RPC.
173
174        Only one write operation is allowed simultaneously.
175
176        Raises:
177          An RpcError exception if the write failed.
178        """
179
180    @abc.abstractmethod
181    async def send_initial_metadata(
182        self, initial_metadata: MetadataType
183    ) -> None:
184        """Sends the initial metadata value to the client.
185
186        This method need not be called by implementations if they have no
187        metadata to add to what the gRPC runtime will transmit.
188
189        Args:
190          initial_metadata: The initial :term:`metadata`.
191        """
192
193    @abc.abstractmethod
194    async def abort(
195        self,
196        code: grpc.StatusCode,
197        details: str = "",
198        trailing_metadata: MetadataType = (),
199    ) -> NoReturn:
200        """Raises an exception to terminate the RPC with a non-OK status.
201
202        The code and details passed as arguments will supersede any existing
203        ones.
204
205        Args:
206          code: A StatusCode object to be sent to the client.
207            It must not be StatusCode.OK.
208          details: A UTF-8-encodable string to be sent to the client upon
209            termination of the RPC.
210          trailing_metadata: A sequence of tuple represents the trailing
211            :term:`metadata`.
212
213        Raises:
214          Exception: An exception is always raised to signal the abortion the
215            RPC to the gRPC runtime.
216        """
217
218    @abc.abstractmethod
219    def set_trailing_metadata(self, trailing_metadata: MetadataType) -> None:
220        """Sends the trailing metadata for the RPC.
221
222        This method need not be called by implementations if they have no
223        metadata to add to what the gRPC runtime will transmit.
224
225        Args:
226          trailing_metadata: The trailing :term:`metadata`.
227        """
228
229    @abc.abstractmethod
230    def invocation_metadata(self) -> Optional[MetadataType]:
231        """Accesses the metadata sent by the client.
232
233        Returns:
234          The invocation :term:`metadata`.
235        """
236
237    @abc.abstractmethod
238    def set_code(self, code: grpc.StatusCode) -> None:
239        """Sets the value to be used as status code upon RPC completion.
240
241        This method need not be called by method implementations if they wish
242        the gRPC runtime to determine the status code of the RPC.
243
244        Args:
245          code: A StatusCode object to be sent to the client.
246        """
247
248    @abc.abstractmethod
249    def set_details(self, details: str) -> None:
250        """Sets the value to be used the as detail string upon RPC completion.
251
252        This method need not be called by method implementations if they have
253        no details to transmit.
254
255        Args:
256          details: A UTF-8-encodable string to be sent to the client upon
257            termination of the RPC.
258        """
259
260    @abc.abstractmethod
261    def set_compression(self, compression: grpc.Compression) -> None:
262        """Set the compression algorithm to be used for the entire call.
263
264        Args:
265          compression: An element of grpc.compression, e.g.
266            grpc.compression.Gzip.
267        """
268
269    @abc.abstractmethod
270    def disable_next_message_compression(self) -> None:
271        """Disables compression for the next response message.
272
273        This method will override any compression configuration set during
274        server creation or set on the call.
275        """
276
277    @abc.abstractmethod
278    def peer(self) -> str:
279        """Identifies the peer that invoked the RPC being serviced.
280
281        Returns:
282          A string identifying the peer that invoked the RPC being serviced.
283          The string format is determined by gRPC runtime.
284        """
285
286    @abc.abstractmethod
287    def peer_identities(self) -> Optional[Iterable[bytes]]:
288        """Gets one or more peer identity(s).
289
290        Equivalent to
291        servicer_context.auth_context().get(servicer_context.peer_identity_key())
292
293        Returns:
294          An iterable of the identities, or None if the call is not
295          authenticated. Each identity is returned as a raw bytes type.
296        """
297
298    @abc.abstractmethod
299    def peer_identity_key(self) -> Optional[str]:
300        """The auth property used to identify the peer.
301
302        For example, "x509_common_name" or "x509_subject_alternative_name" are
303        used to identify an SSL peer.
304
305        Returns:
306          The auth property (string) that indicates the
307          peer identity, or None if the call is not authenticated.
308        """
309
310    @abc.abstractmethod
311    def auth_context(self) -> Mapping[str, Iterable[bytes]]:
312        """Gets the auth context for the call.
313
314        Returns:
315          A map of strings to an iterable of bytes for each auth property.
316        """
317
318    def time_remaining(self) -> float:
319        """Describes the length of allowed time remaining for the RPC.
320
321        Returns:
322          A nonnegative float indicating the length of allowed time in seconds
323          remaining for the RPC to complete before it is considered to have
324          timed out, or None if no deadline was specified for the RPC.
325        """
326
327    def trailing_metadata(self):
328        """Access value to be used as trailing metadata upon RPC completion.
329
330        This is an EXPERIMENTAL API.
331
332        Returns:
333          The trailing :term:`metadata` for the RPC.
334        """
335        raise NotImplementedError()
336
337    def code(self):
338        """Accesses the value to be used as status code upon RPC completion.
339
340        This is an EXPERIMENTAL API.
341
342        Returns:
343          The StatusCode value for the RPC.
344        """
345        raise NotImplementedError()
346
347    def details(self):
348        """Accesses the value to be used as detail string upon RPC completion.
349
350        This is an EXPERIMENTAL API.
351
352        Returns:
353          The details string of the RPC.
354        """
355        raise NotImplementedError()
356
357    def add_done_callback(self, callback: DoneCallbackType) -> None:
358        """Registers a callback to be called on RPC termination.
359
360        This is an EXPERIMENTAL API.
361
362        Args:
363          callback: A callable object will be called with the servicer context
364            object as its only argument.
365        """
366
367    def cancelled(self) -> bool:
368        """Return True if the RPC is cancelled.
369
370        The RPC is cancelled when the cancellation was requested with cancel().
371
372        This is an EXPERIMENTAL API.
373
374        Returns:
375          A bool indicates whether the RPC is cancelled or not.
376        """
377
378    def done(self) -> bool:
379        """Return True if the RPC is done.
380
381        An RPC is done if the RPC is completed, cancelled or aborted.
382
383        This is an EXPERIMENTAL API.
384
385        Returns:
386          A bool indicates if the RPC is done.
387        """
388