Import the async caches

projects/async_cache/BUILD

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+py_project(
+    name = "async_cache"
+)

projects/async_cache/LICENSE

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+MIT License
+
+Copyright (c) 2020 Rajat Singh
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

projects/async_cache/README.md

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+# Async cache
+
+An LRU and TTL cache for async functions in Python.
+
+- `alru_cache` provides an LRU cache decorator with configurable size.
+- `attl_cache` provides a TTL+LRU cache decorator with configurable size.
+
+Neither cache proactively expires keys.
+Maintenance occurs only when requesting keys out of the cache.
+
+## License
+
+Derived from https://github.com/iamsinghrajat/async-cache, published under the MIT license.

projects/async_cache/src/python/async_cache/__init__.py

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+"""The interface to the package. Just re-exports implemented caches."""
+
+from .lru import ALRU, alru_cache  # noqa
+from .ttl import ATTL, attl_cache  # noqa

projects/async_cache/src/python/async_cache/key.py

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+from typing import Any
+
+
+class KEY:
+    def __init__(self, *args, **kwargs):
+        self.args = args
+        self.kwargs = kwargs
+
+    def __eq__(self, obj):
+        return hash(self) == hash(obj)
+
+    def __hash__(self):
+        def _hash(param: Any):
+            if isinstance(param, tuple):
+                return tuple(map(_hash, param))
+            if isinstance(param, dict):
+                return tuple(map(_hash, param.items()))
+            elif hasattr(param, "__dict__"):
+                return str(vars(param))
+            else:
+                return str(param)
+
+        return hash(_hash(self.args) + _hash(self.kwargs))

projects/async_cache/src/python/async_cache/lru.py

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+from collections import OrderedDict
+
+from .key import KEY
+
+
+class LRU(OrderedDict):
+    def __init__(self, maxsize, *args, **kwargs):
+        self.maxsize = maxsize
+        super().__init__(*args, **kwargs)
+
+    def __getitem__(self, key):
+        value = super().__getitem__(key)
+        self.move_to_end(key)
+        return value
+
+    def __setitem__(self, key, value):
+        super().__setitem__(key, value)
+        if self.maxsize and len(self) > self.maxsize:
+            oldest = next(iter(self))
+            del self[oldest]
+
+
+class ALRU(object):
+    def __init__(self, maxsize=128):
+        """
+        :param maxsize: Use maxsize as None for unlimited size cache
+        """
+        self.lru = LRU(maxsize=maxsize)
+
+    def __call__(self, func):
+        async def wrapper(*args, **kwargs):
+            key = KEY(args, kwargs)
+            if key in self.lru:
+                return self.lru[key]
+            else:
+                self.lru[key] = await func(*args, **kwargs)
+                return self.lru[key]
+
+        wrapper.__name__ += func.__name__
+
+        return wrapper
+
+
+alru_cache = ALRU

projects/async_cache/src/python/async_cache/ttl.py

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+from typing import Union, Optional
+import datetime
+
+from .key import KEY
+from .lru import LRU
+
+
+class ATTL:
+    class _TTL(LRU):
+        def __init__(self, ttl: Optional[Union[datetime.timedelta, int, float]], maxsize: int):
+            super().__init__(maxsize=maxsize)
+
+            if isinstance(ttl, datetime.timedelta):
+                self.ttl = ttl
+            elif isinstance(ttl, (int, float)):
+                self.ttl = datetime.timedelta(seconds=ttl)
+            elif ttl is None:
+                self.ttl = None
+            else:
+                raise ValueError("TTL must be int or timedelta")
+
+            self.maxsize = maxsize
+
+        def __contains__(self, key):
+            if key not in self.keys():
+                return False
+            else:
+                key_expiration = super().__getitem__(key)[1]
+                if key_expiration and key_expiration < datetime.datetime.now():
+                    del self[key]
+                    return False
+                else:
+                    return True
+
+        def __getitem__(self, key):
+            if key in self:
+                value = super().__getitem__(key)[0]
+                return value
+            raise KeyError
+
+        def __setitem__(self, key, value):
+            ttl_value = (
+                    datetime.datetime.now() + self.ttl
+            ) if self.ttl else None
+            super().__setitem__(key, (value, ttl_value))
+
+    def __init__(
+            self,
+            ttl: Optional[Union[datetime.timedelta, int]] = datetime.timedelta(seconds=60),
+            maxsize: int = 1024,
+            skip_args: int = 0
+    ):
+        """
+        :param ttl: Use ttl as None for non expiring cache
+        :param maxsize: Use maxsize as None for unlimited size cache
+        :param skip_args: Use `1` to skip first arg of func in determining cache key
+        """
+        self.ttl = self._TTL(ttl=ttl, maxsize=maxsize)
+        self.skip_args = skip_args
+
+    def __call__(self, func):
+        async def wrapper(*args, **kwargs):
+            key = KEY(args[self.skip_args:], kwargs)
+            if key in self.ttl:
+                val = self.ttl[key]
+            else:
+                self.ttl[key] = await func(*args, **kwargs)
+                val = self.ttl[key]
+
+            return val
+
+        wrapper.__name__ += func.__name__
+
+        return wrapper
+
+
+attl_cache = ATTL

projects/async_cache/test/python/__init__.py

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+#!/usr/bin/env python3

projects/async_cache/test/python/test_lru.py

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+import asyncio
+import time
+
+from async_cache import ALRU, ATTL
+
+
+@ALRU(maxsize=128)
+async def func(wait: int):
+    await asyncio.sleep(wait)
+
+
+class TestClassFunc:
+    @ALRU(maxsize=128)
+    async def obj_func(self, wait: int):
+        await asyncio.sleep(wait)
+
+    @staticmethod
+    @ATTL(maxsize=128, ttl=None, skip_args=1)
+    async def skip_arg_func(arg: int, wait: int):
+        await asyncio.sleep(wait)
+
+    @classmethod
+    @ALRU(maxsize=128)
+    async def class_func(cls, wait: int):
+        await asyncio.sleep(wait)
+
+
+def test():
+    t1 = time.time()
+    asyncio.get_event_loop().run_until_complete(func(4))
+    t2 = time.time()
+    asyncio.get_event_loop().run_until_complete(func(4))
+    t3 = time.time()
+    t_first_exec = (t2 - t1) * 1000
+    t_second_exec = (t3 - t2) * 1000
+    print(t_first_exec)
+    print(t_second_exec)
+    assert t_first_exec > 4000
+    assert t_second_exec < 4000
+
+
+def test_obj_fn():
+    t1 = time.time()
+    obj = TestClassFunc()
+    asyncio.get_event_loop().run_until_complete(obj.obj_func(4))
+    t2 = time.time()
+    asyncio.get_event_loop().run_until_complete(obj.obj_func(4))
+    t3 = time.time()
+    t_first_exec = (t2 - t1) * 1000
+    t_second_exec = (t3 - t2) * 1000
+    print(t_first_exec)
+    print(t_second_exec)
+    assert t_first_exec > 4000
+    assert t_second_exec < 4000
+
+
+def test_class_fn():
+    t1 = time.time()
+    asyncio.get_event_loop().run_until_complete(TestClassFunc.class_func(4))
+    t2 = time.time()
+    asyncio.get_event_loop().run_until_complete(TestClassFunc.class_func(4))
+    t3 = time.time()
+    t_first_exec = (t2 - t1) * 1000
+    t_second_exec = (t3 - t2) * 1000
+    print(t_first_exec)
+    print(t_second_exec)
+    assert t_first_exec > 4000
+    assert t_second_exec < 4000
+
+
+def test_skip_args():
+    t1 = time.time()
+    asyncio.get_event_loop().run_until_complete(TestClassFunc.skip_arg_func(5, 4))
+    t2 = time.time()
+    asyncio.get_event_loop().run_until_complete(TestClassFunc.skip_arg_func(6, 4))
+    t3 = time.time()
+    t_first_exec = (t2 - t1) * 1000
+    t_second_exec = (t3 - t2) * 1000
+    print(t_first_exec)
+    print(t_second_exec)
+    assert t_first_exec > 4000
+    assert t_second_exec < 4000

projects/async_cache/test/python/test_ttl.py

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+import asyncio
+import time
+
+from async_cache import ATTL
+
+
+@ATTL(ttl=60)
+async def long_expiration_fn(wait: int):
+    await asyncio.sleep(wait)
+    return wait
+
+
+@ATTL(ttl=5)
+async def short_expiration_fn(wait: int):
+    await asyncio.sleep(wait)
+    return wait
+
+
+@ATTL(ttl=3)
+async def short_cleanup_fn(wait: int):
+    await asyncio.sleep(wait)
+    return wait
+
+
+def test_cache_hit():
+    t1 = time.time()
+    asyncio.get_event_loop().run_until_complete(long_expiration_fn(4))
+    t2 = time.time()
+    asyncio.get_event_loop().run_until_complete(long_expiration_fn(4))
+    t3 = time.time()
+    t_first_exec = (t2 - t1) * 1000
+    t_second_exec = (t3 - t2) * 1000
+    print(t_first_exec)
+    print(t_second_exec)
+    assert t_first_exec > 4000
+    assert t_second_exec < 4000
+
+
+def test_cache_expiration():
+    t1 = time.time()
+    asyncio.get_event_loop().run_until_complete(short_expiration_fn(1))
+    t2 = time.time()
+    asyncio.get_event_loop().run_until_complete(short_expiration_fn(1))
+    t3 = time.time()
+    time.sleep(5)
+    t4 = time.time()
+    asyncio.get_event_loop().run_until_complete(short_expiration_fn(1))
+    t5 = time.time()
+    t_first_exec = (t2 - t1) * 1000
+    t_second_exec = (t3 - t2) * 1000
+    t_third_exec = (t5 - t4) * 1000
+    print(t_first_exec)
+    print(t_second_exec)
+    print(t_third_exec)
+    assert t_first_exec > 1000
+    assert t_second_exec < 1000
+    assert t_third_exec > 1000