Package: aiolifecycle
aiolifecycleSafely use asyncio handlers in synchronous context.Use caseIf you want to run an asyncio-based program in a synchronous context - such as
a command line invocation - you can useasyncio.runfrom the standard library.
But it immediately spins up and terminates an event loop. What if you want to a
continuous workflow, where you can initialise and re-use resources?The original need for this project arose when adapting an asyncio-based system
to AWS Lambda, which makes multiple synchronous function calls in the same
interpreter environment.InstallationRunpip install aiolifecycle, or add it to your package dependencies.UsageHandlerDefine your handler as anasyncfunction, and add thesyncannotation. Then
it can safely be called synchronously. An event loop will automatically be
initialised with its associated resources.importasynciofromaiolifecycleimportsync@sync()asyncdefmy_handler()->None:awaitasyncio.sleep(1)By default, handlers areeager, meaning an event loop will be created and
initialisation functions will be immediately run on module import.If you want to initialise resources only when a handler is first called, do:importasynciofromaiolifecycleimportsync@sync(eager=False)asyncdefmy_handler()->None:awaitasyncio.sleep(1)InitialisationYou can defineasyncinitialisation functions to prepare resources for use by
handlers. These can be simpleasync defs returning nothing.In the following example,my_initwill be called exactly once, before any handlers
run.importasynciofromaiolifecycleimportsync,init@initasyncdefmy_init()->None:print('Hello, world!')@syncasyncdefmy_handler()->None:awaitasyncio.sleep(1)Initialisation order can be controlled with theorderparameter. In the following
example,hellowill be called beforeworld. Functions with the same order (or
undefined order) are called in the order they were defined.importasynciofromaiolifecycleimportsync,init@init(order=20)asyncdefworld()->None:print('World!')@init(order=10)asyncdefhello()->None:print('Hello!')@sync()asyncdefmy_handler()->None:awaitasyncio.sleep(1)Initialisation functions can manage resources. You can simply return the resource
from aninitfunction (if no finalisation is necessary), or define it as anasynccontextmanagerOr you can useAsyncContextManagers, and access the resources they create by
refering to the handler function. Proper lifetime will be managed internally, such
that the initialisation will happen once.importjsonfromcontextlibimportasynccontextmanagerfromtypingimportAsyncIteratorimportaiofilesfromaiofiles.threadpool.textimportAsyncTextIOWrapperfromaiolifecycleimportsyncfromaiolifecycleimportinit@initasyncdefjson_log_path()->str:# Run complicated logic to determine path, only once!# ....return'/tmp/my-file.json'@init()@asynccontextmanagerasyncdefjson_log_file()->AsyncIterator[AsyncTextIOWrapper]:log_path=awaitjson_log_path()# File will be open before any handler is called, and cleaned up on shutdownasyncwithaiofiles.open(log_path,mode='a')asf:yieldf@sync()asyncdefhandler():log_file=awaitjson_log_file()awaitlog_file.write(json.dumps(event)+"\n")awaitlog_file.flush()Changelogv0.1.8 (2022-05-11)Fixinit:Fix cycle checking scope (9e76ea7)v0.1.7 (2022-05-11)Fixinit:Raise terminating exception on init function failure bubbling up (69c0f88)init:Raise terminating exception on init function failure bubbling up (024734d)v0.1.6 (2022-05-11)Fixinit:Exit immediately on init failure (8abe43b)v0.1.5 (2022-05-11)Fixinit:Exit immediately on init failure (9652c7c)v0.1.4 (2022-05-10)Fixinit:Fix threading atexit registration order (0a3a861)v0.1.3 (2022-05-09)Fixloop:Wait for loop on interpreter termination (e6b9825)v0.1.2 (2022-05-09)Fixinit:Add missing reset for context var (#1) (fc7f654)v0.1.1 (2022-05-05)Fixlicense:Update copyright (588e5a3)v0.1.0 (2022-05-05)Featureall:Remove remaining lambda references (c003c73)v0.0.4 (2022-05-05)Fixhandlers:Cycle detection (018ba95)handlers:Rename handlers to remove lambda references (de9643b)tests:For new resource management (5f30e6d)metadata:Use Markdown version of Apache License [skip ci] (bfaf82e)v0.0.3 (2022-05-04)Fixcd:Fix long_description Markdown content type (b3479ee)v0.0.2 (2022-05-04)Fixcd:Don't release on new tags (581d5ff)v0.0.1 (2022-05-04)Fixcd:Force release (7bbac93)cd:Force release (dd9f209)cd:Force release (e621555)Copyright 2022 Daniel Miranda and contributors.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 athttp://www.apache.org/licenses/LICENSE-2.0Unless 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.-------------------------------------------------------------------------
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