Python库 | fdk-0.0.10.tar.gz

FN development kit for Python ============================= Purpose of this library to provide simple interface to parse HTTP 1.1 requests represented as string Following examples are showing how to use API of this library to work with streaming HTTP requests from Fn service. Handling Hot HTTP Functions --------------------------- A main loop is supplied that can repeatedly call a user function with a series of HTTP requests. In order to utilise this, you can write your `app.py` as follows: ```python import fdk from fdk import response def handler(context, data=None, loop=None): return response.RawResponse( context, status_code=200, headers={}, response_data=data.readall() ) if __name__ == "__main__": fdk.handle(handler) ``` Automatic input coercions ------------------------------ Decorators are provided that will attempt to coerce input values to Python types. Some attempt is made to coerce return values from these functions also: ```python import fdk @fdk.coerce_input_to_content_type def handler(context, data=None, loop=None): """ body is a request body, it's type depends on content type """ return data if __name__ == "__main__": fdk.handle(handler) ``` Working with async automatic input coercions ------------------------------------------------- Latest version supports async coroutines as a request body processors: ```python import asyncio import fdk from fdk import response @fdk.coerce_input_to_content_type async def handler(context, data=None, loop=None): headers = { "Content-Type": "text/plain", } return response.RawResponse( context, status_code=200, headers=headers, response_data="OK" ) if __name__ == "__main__": loop = asyncio.get_event_loop() fdk.handle(handler, loop=loop) ``` As you can see `app` function is no longer callable, because its type: coroutine, so we need to bypass event loop inside Handling Hot JSON Functions --------------------------- A main loop is supplied that can repeatedly call a user function with a series of HTTP requests. In order to utilise this, you can write your `app.py` as follows: ```python import fdk def handler(context, data=None, loop=None): return data if __name__ == "__main__": fdk.handle(handler) ``` Working with async Hot JSON Functions ------------------------------------- Latest version supports async coroutines as a request body processors: ```python import asyncio import fdk async def handler(context, data=None, loop=None): return data if __name__ == "__main__": loop = asyncio.get_event_loop() fdk.handle(handler, loop=loop) ``` Applications powered by Fn: Concept ----------------------------------- FDK is not only about developing functions, but providing necessary API to build serverless applications that look like nothing but classes with methods powered by Fn. ```python import requests from fdk.application import decorators @decorators.fn_app class Application(object): def __init__(self, *args, **kwargs): pass @decorators.with_fn(fn_image="denismakogon/os.environ:latest") def env(self, fn_data=None): return fn_data @decorators.with_fn(fn_image="denismakogon/py-traceback-test:0.0.1", fn_format="http") def traceback(self, fn_data=None): return fn_data @decorators.fn(fn_type="sync") def square(self, x, y, *args, **kwargs): return x * y @decorators.fn(fn_type="sync", dependencies={ "requests_get": requests.get }) def request(self, *args, **kwargs): requests_get = kwargs["dependencies"].get("requests_get") r = requests_get('https://api.github.com/events') r.raise_for_status() return r.text if __name__ == "__main__": app = Application(config={}) res, err = app.env() if err: raise err print(res) res, err = app.traceback() if err: raise err print(res) res, err = app.square(10, 20) if err: raise err print(res) res, err = app.request() if err: raise err print(res) ``` In order to identify to which Fn instance code needs to talk set following env var: ```bash export API_URL = http: // localhost: 8080 ``` with respect to IP address or domain name where Fn lives. Applications powered by Fn: supply data to a function ----------------------------------------------------- At this moment those helper - decorators let developers interact with Fn - powered functions as with regular class methods. In order to pass necessary data into a function developer just needs to do following ```python if __name__ == "__main__": app = Application(config={}) app.env(keyone="blah", keytwo="blah", somethingelse=3) ``` Key - value args will be turned into JSON instance and will be sent to a function as payload body. Applications powered by Fn: working with function's result ---------------------------------------------------------- In order to work with result from function you just need to read key - value argument `fn_data`: ```python @decorators.with_fn(fn_image="denismakogon/py-traceback-test:0.0.1", fn_format="http") def traceback(self, fn_data=None): return fn_data ``` Applications powered by Fn: advanced serverless functions --------------------------------------------------------- Since release v0.0.3 developer can consume new API to build truly serverless functions without taking care of Docker images, application, etc. ```python @decorators.fn(fn_type="sync") def square(self, x, y, *args, **kwargs): return x * y @decorators.fn(fn_type="sync", dependencies={ "requests_get": requests.get }) def request(self, *args, **kwargs): requests_get = kwargs["dependencies"].get("requests_get") r = requests_get('https://api.github.com/events') r.raise_for_status() return r.text ``` Each function decorated with `@decorator.fn` will become truly serverless and distributed. So, how it works? * A developer writes function * FDK(Fn - powered app) creates a recursive Pickle v4.0 with 3rd - party dependencies * FDK(Fn - powered app) transfers pickled object to a function based on Python3 GPI(general purpose image) * FDK unpickles function and its 3rd - party dependencies and runs it * Function sends response back to Fn - powered application function caller So, each CPU - intensive functions can be sent to Fn with the only load on networking(given example creates 7kB of traffic between app's host and Fn). Applications powered by Fn: exceptions -------------------------------------- Applications powered by Fn are following Go - like errors concept. It gives you full control on errors whether raise them or not. ```python res, err = app.env() if err: raise err print(res) ``` Each error is an instance fn `FnError` that encapsulates certain logic that makes hides HTTP errors and turns them into regular Python - like exceptions. TODOs ----- - generic response class - use fdk.headers.GoLikeHeaders in http