Added delete option to database storage.

venv/Lib/site-packages/grpc/framework/foundation/__init__.py

@@ -0,0 +1,13 @@
+# Copyright 2015 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.

venv/Lib/site-packages/grpc/framework/foundation/abandonment.py

@@ -0,0 +1,22 @@
+# Copyright 2015 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Utilities for indicating abandonment of computation."""
+
+
+class Abandoned(Exception):
+    """Indicates that some computation is being abandoned.
+
+  Abandoning a computation is different than returning a value or raising
+  an exception indicating some operational or programming defect.
+  """

venv/Lib/site-packages/grpc/framework/foundation/callable_util.py

@@ -0,0 +1,96 @@
+# Copyright 2015 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Utilities for working with callables."""
+
+import abc
+import collections
+import enum
+import functools
+import logging
+
+import six
+
+_LOGGER = logging.getLogger(__name__)
+
+
+class Outcome(six.with_metaclass(abc.ABCMeta)):
+    """A sum type describing the outcome of some call.
+
+  Attributes:
+    kind: One of Kind.RETURNED or Kind.RAISED respectively indicating that the
+      call returned a value or raised an exception.
+    return_value: The value returned by the call. Must be present if kind is
+      Kind.RETURNED.
+    exception: The exception raised by the call. Must be present if kind is
+      Kind.RAISED.
+  """
+
+    @enum.unique
+    class Kind(enum.Enum):
+        """Identifies the general kind of the outcome of some call."""
+
+        RETURNED = object()
+        RAISED = object()
+
+
+class _EasyOutcome(
+        collections.namedtuple('_EasyOutcome',
+                               ['kind', 'return_value', 'exception']), Outcome):
+    """A trivial implementation of Outcome."""
+
+
+def _call_logging_exceptions(behavior, message, *args, **kwargs):
+    try:
+        return _EasyOutcome(Outcome.Kind.RETURNED, behavior(*args, **kwargs),
+                            None)
+    except Exception as e:  # pylint: disable=broad-except
+        _LOGGER.exception(message)
+        return _EasyOutcome(Outcome.Kind.RAISED, None, e)
+
+
+def with_exceptions_logged(behavior, message):
+    """Wraps a callable in a try-except that logs any exceptions it raises.
+
+  Args:
+    behavior: Any callable.
+    message: A string to log if the behavior raises an exception.
+
+  Returns:
+    A callable that when executed invokes the given behavior. The returned
+      callable takes the same arguments as the given behavior but returns a
+      future.Outcome describing whether the given behavior returned a value or
+      raised an exception.
+  """
+
+    @functools.wraps(behavior)
+    def wrapped_behavior(*args, **kwargs):
+        return _call_logging_exceptions(behavior, message, *args, **kwargs)
+
+    return wrapped_behavior
+
+
+def call_logging_exceptions(behavior, message, *args, **kwargs):
+    """Calls a behavior in a try-except that logs any exceptions it raises.
+
+  Args:
+    behavior: Any callable.
+    message: A string to log if the behavior raises an exception.
+    *args: Positional arguments to pass to the given behavior.
+    **kwargs: Keyword arguments to pass to the given behavior.
+
+  Returns:
+    An Outcome describing whether the given behavior returned a value or raised
+      an exception.
+  """
+    return _call_logging_exceptions(behavior, message, *args, **kwargs)

venv/Lib/site-packages/grpc/framework/foundation/future.py

@@ -0,0 +1,221 @@
+# Copyright 2015 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""A Future interface.
+
+Python doesn't have a Future interface in its standard library. In the absence
+of such a standard, three separate, incompatible implementations
+(concurrent.futures.Future, ndb.Future, and asyncio.Future) have appeared. This
+interface attempts to be as compatible as possible with
+concurrent.futures.Future. From ndb.Future it adopts a traceback-object accessor
+method.
+
+Unlike the concrete and implemented Future classes listed above, the Future
+class defined in this module is an entirely abstract interface that anyone may
+implement and use.
+
+The one known incompatibility between this interface and the interface of
+concurrent.futures.Future is that this interface defines its own CancelledError
+and TimeoutError exceptions rather than raising the implementation-private
+concurrent.futures._base.CancelledError and the
+built-in-but-only-in-3.3-and-later TimeoutError.
+"""
+
+import abc
+
+import six
+
+
+class TimeoutError(Exception):
+    """Indicates that a particular call timed out."""
+
+
+class CancelledError(Exception):
+    """Indicates that the computation underlying a Future was cancelled."""
+
+
+class Future(six.with_metaclass(abc.ABCMeta)):
+    """A representation of a computation in another control flow.
+
+  Computations represented by a Future may be yet to be begun, may be ongoing,
+  or may have already completed.
+  """
+
+    # NOTE(nathaniel): This isn't the return type that I would want to have if it
+    # were up to me. Were this interface being written from scratch, the return
+    # type of this method would probably be a sum type like:
+    #
+    # NOT_COMMENCED
+    # COMMENCED_AND_NOT_COMPLETED
+    # PARTIAL_RESULT<Partial_Result_Type>
+    # COMPLETED<Result_Type>
+    # UNCANCELLABLE
+    # NOT_IMMEDIATELY_DETERMINABLE
+    @abc.abstractmethod
+    def cancel(self):
+        """Attempts to cancel the computation.
+
+    This method does not block.
+
+    Returns:
+      True if the computation has not yet begun, will not be allowed to take
+        place, and determination of both was possible without blocking. False
+        under all other circumstances including but not limited to the
+        computation's already having begun, the computation's already having
+        finished, and the computation's having been scheduled for execution on a
+        remote system for which a determination of whether or not it commenced
+        before being cancelled cannot be made without blocking.
+    """
+        raise NotImplementedError()
+
+    # NOTE(nathaniel): Here too this isn't the return type that I'd want this
+    # method to have if it were up to me. I think I'd go with another sum type
+    # like:
+    #
+    # NOT_CANCELLED (this object's cancel method hasn't been called)
+    # NOT_COMMENCED
+    # COMMENCED_AND_NOT_COMPLETED
+    # PARTIAL_RESULT<Partial_Result_Type>
+    # COMPLETED<Result_Type>
+    # UNCANCELLABLE
+    # NOT_IMMEDIATELY_DETERMINABLE
+    #
+    # Notice how giving the cancel method the right semantics obviates most
+    # reasons for this method to exist.
+    @abc.abstractmethod
+    def cancelled(self):
+        """Describes whether the computation was cancelled.
+
+    This method does not block.
+
+    Returns:
+      True if the computation was cancelled any time before its result became
+        immediately available. False under all other circumstances including but
+        not limited to this object's cancel method not having been called and
+        the computation's result having become immediately available.
+    """
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def running(self):
+        """Describes whether the computation is taking place.
+
+    This method does not block.
+
+    Returns:
+      True if the computation is scheduled to take place in the future or is
+        taking place now, or False if the computation took place in the past or
+        was cancelled.
+    """
+        raise NotImplementedError()
+
+    # NOTE(nathaniel): These aren't quite the semantics I'd like here either. I
+    # would rather this only returned True in cases in which the underlying
+    # computation completed successfully. A computation's having been cancelled
+    # conflicts with considering that computation "done".
+    @abc.abstractmethod
+    def done(self):
+        """Describes whether the computation has taken place.
+
+    This method does not block.
+
+    Returns:
+      True if the computation is known to have either completed or have been
+        unscheduled or interrupted. False if the computation may possibly be
+        executing or scheduled to execute later.
+    """
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def result(self, timeout=None):
+        """Accesses the outcome of the computation or raises its exception.
+
+    This method may return immediately or may block.
+
+    Args:
+      timeout: The length of time in seconds to wait for the computation to
+        finish or be cancelled, or None if this method should block until the
+        computation has finished or is cancelled no matter how long that takes.
+
+    Returns:
+      The return value of the computation.
+
+    Raises:
+      TimeoutError: If a timeout value is passed and the computation does not
+        terminate within the allotted time.
+      CancelledError: If the computation was cancelled.
+      Exception: If the computation raised an exception, this call will raise
+        the same exception.
+    """
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def exception(self, timeout=None):
+        """Return the exception raised by the computation.
+
+    This method may return immediately or may block.
+
+    Args:
+      timeout: The length of time in seconds to wait for the computation to
+        terminate or be cancelled, or None if this method should block until
+        the computation is terminated or is cancelled no matter how long that
+        takes.
+
+    Returns:
+      The exception raised by the computation, or None if the computation did
+        not raise an exception.
+
+    Raises:
+      TimeoutError: If a timeout value is passed and the computation does not
+        terminate within the allotted time.
+      CancelledError: If the computation was cancelled.
+    """
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def traceback(self, timeout=None):
+        """Access the traceback of the exception raised by the computation.
+
+    This method may return immediately or may block.
+
+    Args:
+      timeout: The length of time in seconds to wait for the computation to
+        terminate or be cancelled, or None if this method should block until
+        the computation is terminated or is cancelled no matter how long that
+        takes.
+
+    Returns:
+      The traceback of the exception raised by the computation, or None if the
+        computation did not raise an exception.
+
+    Raises:
+      TimeoutError: If a timeout value is passed and the computation does not
+        terminate within the allotted time.
+      CancelledError: If the computation was cancelled.
+    """
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def add_done_callback(self, fn):
+        """Adds a function to be called at completion of the computation.
+
+    The callback will be passed this Future object describing the outcome of
+    the computation.
+
+    If the computation has already completed, the callback will be called
+    immediately.
+
+    Args:
+      fn: A callable taking this Future object as its single parameter.
+    """
+        raise NotImplementedError()

venv/Lib/site-packages/grpc/framework/foundation/logging_pool.py

@@ -0,0 +1,72 @@
+# Copyright 2015 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""A thread pool that logs exceptions raised by tasks executed within it."""
+
+import logging
+
+from concurrent import futures
+
+_LOGGER = logging.getLogger(__name__)
+
+
+def _wrap(behavior):
+    """Wraps an arbitrary callable behavior in exception-logging."""
+
+    def _wrapping(*args, **kwargs):
+        try:
+            return behavior(*args, **kwargs)
+        except Exception:
+            _LOGGER.exception(
+                'Unexpected exception from %s executed in logging pool!',
+                behavior)
+            raise
+
+    return _wrapping
+
+
+class _LoggingPool(object):
+    """An exception-logging futures.ThreadPoolExecutor-compatible thread pool."""
+
+    def __init__(self, backing_pool):
+        self._backing_pool = backing_pool
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self._backing_pool.shutdown(wait=True)
+
+    def submit(self, fn, *args, **kwargs):
+        return self._backing_pool.submit(_wrap(fn), *args, **kwargs)
+
+    def map(self, func, *iterables, **kwargs):
+        return self._backing_pool.map(_wrap(func),
+                                      *iterables,
+                                      timeout=kwargs.get('timeout', None))
+
+    def shutdown(self, wait=True):
+        self._backing_pool.shutdown(wait=wait)
+
+
+def pool(max_workers):
+    """Creates a thread pool that logs exceptions raised by the tasks within it.
+
+  Args:
+    max_workers: The maximum number of worker threads to allow the pool.
+
+  Returns:
+    A futures.ThreadPoolExecutor-compatible thread pool that logs exceptions
+      raised by the tasks executed within it.
+  """
+    return _LoggingPool(futures.ThreadPoolExecutor(max_workers))

venv/Lib/site-packages/grpc/framework/foundation/stream.py

@@ -0,0 +1,45 @@
+# Copyright 2015 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Interfaces related to streams of values or objects."""
+
+import abc
+
+import six
+
+
+class Consumer(six.with_metaclass(abc.ABCMeta)):
+    """Interface for consumers of finite streams of values or objects."""
+
+    @abc.abstractmethod
+    def consume(self, value):
+        """Accepts a value.
+
+    Args:
+      value: Any value accepted by this Consumer.
+    """
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def terminate(self):
+        """Indicates to this Consumer that no more values will be supplied."""
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def consume_and_terminate(self, value):
+        """Supplies a value and signals that no more values will be supplied.
+
+    Args:
+      value: Any value accepted by this Consumer.
+    """
+        raise NotImplementedError()

venv/Lib/site-packages/grpc/framework/foundation/stream_util.py

@@ -0,0 +1,148 @@
+# Copyright 2015 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Helpful utilities related to the stream module."""
+
+import logging
+import threading
+
+from grpc.framework.foundation import stream
+
+_NO_VALUE = object()
+_LOGGER = logging.getLogger(__name__)
+
+
+class TransformingConsumer(stream.Consumer):
+    """A stream.Consumer that passes a transformation of its input to another."""
+
+    def __init__(self, transformation, downstream):
+        self._transformation = transformation
+        self._downstream = downstream
+
+    def consume(self, value):
+        self._downstream.consume(self._transformation(value))
+
+    def terminate(self):
+        self._downstream.terminate()
+
+    def consume_and_terminate(self, value):
+        self._downstream.consume_and_terminate(self._transformation(value))
+
+
+class IterableConsumer(stream.Consumer):
+    """A Consumer that when iterated over emits the values it has consumed."""
+
+    def __init__(self):
+        self._condition = threading.Condition()
+        self._values = []
+        self._active = True
+
+    def consume(self, value):
+        with self._condition:
+            if self._active:
+                self._values.append(value)
+                self._condition.notify()
+
+    def terminate(self):
+        with self._condition:
+            self._active = False
+            self._condition.notify()
+
+    def consume_and_terminate(self, value):
+        with self._condition:
+            if self._active:
+                self._values.append(value)
+                self._active = False
+                self._condition.notify()
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        return self.next()
+
+    def next(self):
+        with self._condition:
+            while self._active and not self._values:
+                self._condition.wait()
+            if self._values:
+                return self._values.pop(0)
+            else:
+                raise StopIteration()
+
+
+class ThreadSwitchingConsumer(stream.Consumer):
+    """A Consumer decorator that affords serialization and asynchrony."""
+
+    def __init__(self, sink, pool):
+        self._lock = threading.Lock()
+        self._sink = sink
+        self._pool = pool
+        # True if self._spin has been submitted to the pool to be called once and
+        # that call has not yet returned, False otherwise.
+        self._spinning = False
+        self._values = []
+        self._active = True
+
+    def _spin(self, sink, value, terminate):
+        while True:
+            try:
+                if value is _NO_VALUE:
+                    sink.terminate()
+                elif terminate:
+                    sink.consume_and_terminate(value)
+                else:
+                    sink.consume(value)
+            except Exception as e:  # pylint:disable=broad-except
+                _LOGGER.exception(e)
+
+            with self._lock:
+                if terminate:
+                    self._spinning = False
+                    return
+                elif self._values:
+                    value = self._values.pop(0)
+                    terminate = not self._values and not self._active
+                elif not self._active:
+                    value = _NO_VALUE
+                    terminate = True
+                else:
+                    self._spinning = False
+                    return
+
+    def consume(self, value):
+        with self._lock:
+            if self._active:
+                if self._spinning:
+                    self._values.append(value)
+                else:
+                    self._pool.submit(self._spin, self._sink, value, False)
+                    self._spinning = True
+
+    def terminate(self):
+        with self._lock:
+            if self._active:
+                self._active = False
+                if not self._spinning:
+                    self._pool.submit(self._spin, self._sink, _NO_VALUE, True)
+                    self._spinning = True
+
+    def consume_and_terminate(self, value):
+        with self._lock:
+            if self._active:
+                self._active = False
+                if self._spinning:
+                    self._values.append(value)
+                else:
+                    self._pool.submit(self._spin, self._sink, value, True)
+                    self._spinning = True