lagom.experimental.context_based.AwaitableSingleton.get() - Code Metrics - Inspection of "WIP Speed up context partials" - meadsteve/lagom - Measure and Improve Code Quality continuously with Scrutinizer

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Pull Request — master (#226)

by Steve

created 2023-03-07 13:22 UTC

AwaitableSingleton.get() A

↳ Parent: lagom.experimental.context_based

Complexity

Conditions

Size

Total Lines	6
Code Lines	6

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	6
CRAP Score	4

Importance

Changes

Metric	Value
cc	4
eloc	6
nop	1
dl	0
loc	6
ccs	6
cts	6
cp	1
crap	4
rs	10
c	0
b	0
f	0

import inspect
import logging
from asyncio import Lock
from contextlib import AsyncExitStack
from copy import copy
from typing import (
    Optional,
    Type,
    TypeVar,
    Awaitable,
    Generic,
    Collection,
    Union,
    ContextManager,
    AsyncContextManager,
    Iterator,
    Generator,
    AsyncGenerator,
    Callable,
    List,
)

from lagom.container import Container
from lagom.definitions import Alias, ConstructionWithContainer, SingletonWrapper
from lagom.exceptions import InvalidDependencyDefinition, MissingFeature
from lagom.experimental.definitions import AsyncConstructionWithContainer
from lagom.interfaces import (
    ReadableContainer,
    SpecialDepDefinition,
    CallTimeContainerUpdate,
    ContainerBoundFunction,
)

T = TypeVar("T")
X = TypeVar("X")


class AwaitableSingleton(Generic[T]):
    instance: Optional[T]
    constructor: ConstructionWithContainer[Awaitable[T]]
    container: Container
    _lock: Lock

    def __init__(self, constructor: ConstructionWithContainer, container: Container):
        self.instance = None
        self.constructor = constructor  # type: ignore
        self.container = container
        self._lock = Lock()

    async def get(self) -> T:
        if not self.instance:
            async with self._lock:
                if not self.instance:
                    self.instance = await self.constructor.get_instance(self.container)
        return self.instance


class _AsyncContextBoundFunction(ContainerBoundFunction[X]):
    """
    Represents an instance of a function bound to an async context container
    """

    async_context_container: "AsyncContextContainer"
    partially_bound_function: ContainerBoundFunction

    def __init__(
        self,
        async_context_container: "AsyncContextContainer",
        partially_bound_function: ContainerBoundFunction,
    ):
        self.async_context_container = async_context_container
        self.partially_bound_function = partially_bound_function

    def __call__(self, *args, **kwargs) -> X:
        return self.__async_call__(*args, **kwargs)

    async def __async_call__(self, *args, **kwargs):
        async with self.async_context_container as c:
            return await self.partially_bound_function.rebind(c)(*args, **kwargs)

    def rebind(self, container: ReadableContainer) -> "ContainerBoundFunction[X]":
        return _AsyncContextBoundFunction(
            self.async_context_container,
            self.partially_bound_function.rebind(container),
        )


class AsyncContextContainer(Container):
    async_exit_stack: Optional[AsyncExitStack] = None
    _context_types: Collection[Type]
    _context_singletons: Collection[Type]
    _root_context: bool = True

    def __init__(
        self,
        container: Container,
        context_types: Collection[Type],
        context_singletons: Collection[Type] = tuple(),
        log_undefined_deps: Union[bool, logging.Logger] = False,
    ):
        super().__init__(container, log_undefined_deps)
        self._context_types = set(context_types)
        self._context_singletons = set(context_singletons)

    def clone(self) -> "AsyncContextContainer":
        """returns a copy of the container
        :return:
        """
        return AsyncContextContainer(
            self,
            context_types=self._context_types,
            context_singletons=self._context_singletons,
            log_undefined_deps=self._undefined_logger,
        )

    async def __aenter__(self):
        if not self.async_exit_stack and self._root_context:
            self.async_exit_stack = AsyncExitStack()

        if self.async_exit_stack and self._root_context:
            # All actual context definitions happen on a clone so that there's isolation between invocations
            in_context = self.clone()
            in_context.async_exit_stack = AsyncExitStack()
            in_context._root_context = False

            for dep_type in self._context_types:
                managed_dep = self._context_type_def(dep_type)
                key = Awaitable[dep_type] if isinstance(managed_dep, AsyncConstructionWithContainer) else dep_type  # type: ignore
                in_context[key] = managed_dep  # type: ignore
            for dep_type in self._context_singletons:
                managed_singleton = self._singleton_type_def(dep_type)
                key = AwaitableSingleton[dep_type] if isinstance(managed_singleton, AwaitableSingleton) else dep_type  # type: ignore
                in_context[key] = managed_singleton  # type: ignore

            # The parent context manager keeps track of the inner clone
            await self.async_exit_stack.enter_async_context(in_context)
            return in_context
        return self

    async def __aexit__(self, exc_type, exc_val, exc_tb):
        if self.async_exit_stack:
            await self.async_exit_stack.aclose()
            self.async_exit_stack = None

    def partial(
        self,
        func: Callable[..., X],
        shared: Optional[List[Type]] = None,
        container_updater: Optional[CallTimeContainerUpdate] = None,
    ) -> ContainerBoundFunction[X]:
        if not inspect.iscoroutinefunction(func):
            raise MissingFeature(
                "AsyncContextManager currently can only deal with async functions"
            )
        base_partial = super(AsyncContextContainer, self).partial(
            func, shared, container_updater
        )

        return _AsyncContextBoundFunction(self, base_partial)

    def magic_partial(
        self,
        func: Callable[..., X],
        shared: Optional[List[Type]] = None,
        keys_to_skip: Optional[List[str]] = None,
        skip_pos_up_to: int = 0,
        container_updater: Optional[CallTimeContainerUpdate] = None,
    ) -> ContainerBoundFunction[X]:
        if not inspect.iscoroutinefunction(func):
            raise MissingFeature(
                "AsyncContextManager currently can only deal with async functions"
            )
        base_partial = super(AsyncContextContainer, self).magic_partial(
            func, shared, keys_to_skip, skip_pos_up_to, container_updater
        )

        return _AsyncContextBoundFunction(self, base_partial)

    def _context_type_def(self, dep_type: Type):
        type_def = self.get_definition(ContextManager[dep_type]) or self.get_definition(Iterator[dep_type]) or self.get_definition(Generator[dep_type, None, None]) or self.get_definition(AsyncGenerator[dep_type, None]) or self.get_definition(AsyncContextManager[dep_type])  # type: ignore
        if type_def is None:
            raise InvalidDependencyDefinition(
                f"A ContextManager[{dep_type}] should be defined. "
                f"This could be an Iterator[{dep_type}] or Generator[{dep_type}, None, None] "
                f"with the @contextmanager decorator"
            )
        if isinstance(type_def, Alias):
            # Without this we create a definition that points to
            # itself.
            type_def = copy(type_def)
            type_def.skip_definitions = True
        if self.get_definition(AsyncGenerator[dep_type, None]) or self.get_definition(AsyncContextManager[dep_type]):  # type: ignore
            return AsyncConstructionWithContainer(lambda c: self._async_context_resolver(c, type_def))  # type: ignore
        return ConstructionWithContainer(lambda c: self._context_resolver(c, type_def))  # type: ignore

    def _context_resolver(self, c: ReadableContainer, type_def: SpecialDepDefinition):
        """
        Takes an existing definition which must be a context manager. Returns
        the value of the context manager from __enter__ and then places the
        __exit__ in this container's exit stack
        """
        assert self.async_exit_stack, "Types can only be resolved within an async with"
        context_manager = type_def.get_instance(c)
        return self.async_exit_stack.enter_context(context_manager)

    def _async_context_resolver(
        self, c: ReadableContainer, type_def: SpecialDepDefinition
    ):
        """
        Takes an existing definition which must be a context manager. Returns
        the value of the context manager from __aenter__ and then places the
        __aexit__ in this container's exit stack
        """
        assert self.async_exit_stack, "Types can only be resolved within an async with"
        context_manager = type_def.get_instance(c)
        return self.async_exit_stack.enter_async_context(context_manager)

    def _singleton_type_def(self, dep_type: Type):
        """
        The same as context_type_def but acts as a singleton within this container
        """
        type_def = self._context_type_def(dep_type)
        if isinstance(type_def, AsyncConstructionWithContainer):
            return AwaitableSingleton(type_def, self)
        return SingletonWrapper(type_def)


1	1	import inspect
2	1	import logging
3	1	from asyncio import Lock
4	1	from contextlib import AsyncExitStack
5	1	from copy import copy
6	1	from typing import (
7		Optional,
8		Type,
9		TypeVar,
10		Awaitable,
11		Generic,
12		Collection,
13		Union,
14		ContextManager,
15		AsyncContextManager,
16		Iterator,
17		Generator,
18		AsyncGenerator,
19		Callable,
20		List,
21		)
22
23	1	from lagom.container import Container
24	1	from lagom.definitions import Alias, ConstructionWithContainer, SingletonWrapper
25	1	from lagom.exceptions import InvalidDependencyDefinition, MissingFeature
26	1	from lagom.experimental.definitions import AsyncConstructionWithContainer
27	1	from lagom.interfaces import (
28		ReadableContainer,
29		SpecialDepDefinition,
30		CallTimeContainerUpdate,
31		ContainerBoundFunction,
32		)
33
34	1	T = TypeVar("T")
35	1	X = TypeVar("X")
36
37
38	1	class AwaitableSingleton(Generic[T]):
39	1	instance: Optional[T]
40	1	constructor: ConstructionWithContainer[Awaitable[T]]
41	1	container: Container
42	1	_lock: Lock
43
44	1	def __init__(self, constructor: ConstructionWithContainer, container: Container):
45	1	self.instance = None
46	1	self.constructor = constructor # type: ignore
47	1	self.container = container
48	1	self._lock = Lock()
49
50	1	async def get(self) -> T:
51	1	if not self.instance:
52	1	async with self._lock:
53	1	if not self.instance:
54	1	self.instance = await self.constructor.get_instance(self.container)
55	1	return self.instance
56
57
58	1	class _AsyncContextBoundFunction(ContainerBoundFunction[X]):
59		"""
60		Represents an instance of a function bound to an async context container
61		"""
62
63	1	async_context_container: "AsyncContextContainer"
64	1	partially_bound_function: ContainerBoundFunction
65
66	1	def __init__(
67		self,
68		async_context_container: "AsyncContextContainer",
69		partially_bound_function: ContainerBoundFunction,
70		):
71	1	self.async_context_container = async_context_container
72	1	self.partially_bound_function = partially_bound_function
73
74	1	def __call__(self, args, *kwargs) -> X:
75	1	return self.__async_call__(args, *kwargs)
76
77	1	async def __async_call__(self, args, *kwargs):
78	1	async with self.async_context_container as c:
79	1	return await self.partially_bound_function.rebind(c)(args, *kwargs)
80
81	1	def rebind(self, container: ReadableContainer) -> "ContainerBoundFunction[X]":
82		return _AsyncContextBoundFunction(
83		self.async_context_container,
84		self.partially_bound_function.rebind(container),
85		)
86
87
88	1	class AsyncContextContainer(Container):
89	1	async_exit_stack: Optional[AsyncExitStack] = None
90	1	_context_types: Collection[Type]
91	1	_context_singletons: Collection[Type]
92	1	_root_context: bool = True
93
94	1	def __init__(
95		self,
96		container: Container,
97		context_types: Collection[Type],
98		context_singletons: Collection[Type] = tuple(),
99		log_undefined_deps: Union[bool, logging.Logger] = False,
100		):
101	1	super().__init__(container, log_undefined_deps)
102	1	self._context_types = set(context_types)
103	1	self._context_singletons = set(context_singletons)
104
105	1	def clone(self) -> "AsyncContextContainer":
106		"""returns a copy of the container
107		:return:
108		"""
109	1	return AsyncContextContainer(
110		self,
111		context_types=self._context_types,
112		context_singletons=self._context_singletons,
113		log_undefined_deps=self._undefined_logger,
114		)
115
116	1	async def __aenter__(self):
117	1	if not self.async_exit_stack and self._root_context:
118	1	self.async_exit_stack = AsyncExitStack()
119
120	1	if self.async_exit_stack and self._root_context:
121		# All actual context definitions happen on a clone so that there's isolation between invocations
122	1	in_context = self.clone()
123	1	in_context.async_exit_stack = AsyncExitStack()
124	1	in_context._root_context = False
125
126	1	for dep_type in self._context_types:
127	1	managed_dep = self._context_type_def(dep_type)
128	1	key = Awaitable[dep_type] if isinstance(managed_dep, AsyncConstructionWithContainer) else dep_type # type: ignore
129	1	in_context[key] = managed_dep # type: ignore
130	1	for dep_type in self._context_singletons:
131	1	managed_singleton = self._singleton_type_def(dep_type)
132	1	key = AwaitableSingleton[dep_type] if isinstance(managed_singleton, AwaitableSingleton) else dep_type # type: ignore
133	1	in_context[key] = managed_singleton # type: ignore
134
135		# The parent context manager keeps track of the inner clone
136	1	await self.async_exit_stack.enter_async_context(in_context)
137	1	return in_context
138	1	return self
139
140	1	async def __aexit__(self, exc_type, exc_val, exc_tb):
141	1	if self.async_exit_stack:
142	1	await self.async_exit_stack.aclose()
143	1	self.async_exit_stack = None
144
145	1	def partial(
146		self,
147		func: Callable[..., X],
148		shared: Optional[List[Type]] = None,
149		container_updater: Optional[CallTimeContainerUpdate] = None,
150		) -> ContainerBoundFunction[X]:
151	1	if not inspect.iscoroutinefunction(func):
152		raise MissingFeature(
153		"AsyncContextManager currently can only deal with async functions"
154		)
155	1	base_partial = super(AsyncContextContainer, self).partial(
156		func, shared, container_updater
157		)
158
159	1	return _AsyncContextBoundFunction(self, base_partial)
160
161	1	def magic_partial(
162		self,
163		func: Callable[..., X],
164		shared: Optional[List[Type]] = None,
165		keys_to_skip: Optional[List[str]] = None,
166		skip_pos_up_to: int = 0,
167		container_updater: Optional[CallTimeContainerUpdate] = None,
168		) -> ContainerBoundFunction[X]:
169	1	if not inspect.iscoroutinefunction(func):
170		raise MissingFeature(
171		"AsyncContextManager currently can only deal with async functions"
172		)
173	1	base_partial = super(AsyncContextContainer, self).magic_partial(
174		func, shared, keys_to_skip, skip_pos_up_to, container_updater
175		)
176
177	1	return _AsyncContextBoundFunction(self, base_partial)
178
179	1	def _context_type_def(self, dep_type: Type):
180	1	type_def = self.get_definition(ContextManager[dep_type]) or self.get_definition(Iterator[dep_type]) or self.get_definition(Generator[dep_type, None, None]) or self.get_definition(AsyncGenerator[dep_type, None]) or self.get_definition(AsyncContextManager[dep_type]) # type: ignore
181	1	if type_def is None:
182	1	raise InvalidDependencyDefinition(
183		f"A ContextManager[{dep_type}] should be defined. "
184		f"This could be an Iterator[{dep_type}] or Generator[{dep_type}, None, None] "
185		f"with the @contextmanager decorator"
186		)
187	1	if isinstance(type_def, Alias):
188		# Without this we create a definition that points to
189		# itself.
190	1	type_def = copy(type_def)
191	1	type_def.skip_definitions = True
192	1	if self.get_definition(AsyncGenerator[dep_type, None]) or self.get_definition(AsyncContextManager[dep_type]): # type: ignore
193	1	return AsyncConstructionWithContainer(lambda c: self._async_context_resolver(c, type_def)) # type: ignore
194	1	return ConstructionWithContainer(lambda c: self._context_resolver(c, type_def)) # type: ignore
195
196	1	def _context_resolver(self, c: ReadableContainer, type_def: SpecialDepDefinition):
197		"""
198		Takes an existing definition which must be a context manager. Returns
199		the value of the context manager from __enter__ and then places the
200		__exit__ in this container's exit stack
201		"""
202	1	assert self.async_exit_stack, "Types can only be resolved within an async with"
203	1	context_manager = type_def.get_instance(c)
204	1	return self.async_exit_stack.enter_context(context_manager)
205
206	1	def _async_context_resolver(
207		self, c: ReadableContainer, type_def: SpecialDepDefinition
208		):
209		"""
210		Takes an existing definition which must be a context manager. Returns
211		the value of the context manager from __aenter__ and then places the
212		__aexit__ in this container's exit stack
213		"""
214	1	assert self.async_exit_stack, "Types can only be resolved within an async with"
215	1	context_manager = type_def.get_instance(c)
216	1	return self.async_exit_stack.enter_async_context(context_manager)
217
218	1	def _singleton_type_def(self, dep_type: Type):
219		"""
220		The same as context_type_def but acts as a singleton within this container
221		"""
222	1	type_def = self._context_type_def(dep_type)
223	1	if isinstance(type_def, AsyncConstructionWithContainer):
224	1	return AwaitableSingleton(type_def, self)
225		return SingletonWrapper(type_def)
226

meadsteve / lagom

Pull Request — master (#226)

AwaitableSingleton.get() A

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Duplication

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