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Diffstat (limited to '.venv/lib/python3.12/site-packages/asgiref/server.py')
| -rw-r--r-- | .venv/lib/python3.12/site-packages/asgiref/server.py | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/.venv/lib/python3.12/site-packages/asgiref/server.py b/.venv/lib/python3.12/site-packages/asgiref/server.py new file mode 100644 index 00000000..43c28c6c --- /dev/null +++ b/.venv/lib/python3.12/site-packages/asgiref/server.py @@ -0,0 +1,157 @@ +import asyncio +import logging +import time +import traceback + +from .compatibility import guarantee_single_callable + +logger = logging.getLogger(__name__) + + +class StatelessServer: + """ + Base server class that handles basic concepts like application instance + creation/pooling, exception handling, and similar, for stateless protocols + (i.e. ones without actual incoming connections to the process) + + Your code should override the handle() method, doing whatever it needs to, + and calling get_or_create_application_instance with a unique `scope_id` + and `scope` for the scope it wants to get. + + If an application instance is found with the same `scope_id`, you are + given its input queue, otherwise one is made for you with the scope provided + and you are given that fresh new input queue. Either way, you should do + something like: + + input_queue = self.get_or_create_application_instance( + "user-123456", + {"type": "testprotocol", "user_id": "123456", "username": "andrew"}, + ) + input_queue.put_nowait(message) + + If you try and create an application instance and there are already + `max_application` instances, the oldest/least recently used one will be + reclaimed and shut down to make space. + + Application coroutines that error will be found periodically (every 100ms + by default) and have their exceptions printed to the console. Override + application_exception() if you want to do more when this happens. + + If you override run(), make sure you handle things like launching the + application checker. + """ + + application_checker_interval = 0.1 + + def __init__(self, application, max_applications=1000): + # Parameters + self.application = application + self.max_applications = max_applications + # Initialisation + self.application_instances = {} + + ### Mainloop and handling + + def run(self): + """ + Runs the asyncio event loop with our handler loop. + """ + event_loop = asyncio.get_event_loop() + asyncio.ensure_future(self.application_checker()) + try: + event_loop.run_until_complete(self.handle()) + except KeyboardInterrupt: + logger.info("Exiting due to Ctrl-C/interrupt") + + async def handle(self): + raise NotImplementedError("You must implement handle()") + + async def application_send(self, scope, message): + """ + Receives outbound sends from applications and handles them. + """ + raise NotImplementedError("You must implement application_send()") + + ### Application instance management + + def get_or_create_application_instance(self, scope_id, scope): + """ + Creates an application instance and returns its queue. + """ + if scope_id in self.application_instances: + self.application_instances[scope_id]["last_used"] = time.time() + return self.application_instances[scope_id]["input_queue"] + # See if we need to delete an old one + while len(self.application_instances) > self.max_applications: + self.delete_oldest_application_instance() + # Make an instance of the application + input_queue = asyncio.Queue() + application_instance = guarantee_single_callable(self.application) + # Run it, and stash the future for later checking + future = asyncio.ensure_future( + application_instance( + scope=scope, + receive=input_queue.get, + send=lambda message: self.application_send(scope, message), + ), + ) + self.application_instances[scope_id] = { + "input_queue": input_queue, + "future": future, + "scope": scope, + "last_used": time.time(), + } + return input_queue + + def delete_oldest_application_instance(self): + """ + Finds and deletes the oldest application instance + """ + oldest_time = min( + details["last_used"] for details in self.application_instances.values() + ) + for scope_id, details in self.application_instances.items(): + if details["last_used"] == oldest_time: + self.delete_application_instance(scope_id) + # Return to make sure we only delete one in case two have + # the same oldest time + return + + def delete_application_instance(self, scope_id): + """ + Removes an application instance (makes sure its task is stopped, + then removes it from the current set) + """ + details = self.application_instances[scope_id] + del self.application_instances[scope_id] + if not details["future"].done(): + details["future"].cancel() + + async def application_checker(self): + """ + Goes through the set of current application instance Futures and cleans up + any that are done/prints exceptions for any that errored. + """ + while True: + await asyncio.sleep(self.application_checker_interval) + for scope_id, details in list(self.application_instances.items()): + if details["future"].done(): + exception = details["future"].exception() + if exception: + await self.application_exception(exception, details) + try: + del self.application_instances[scope_id] + except KeyError: + # Exception handling might have already got here before us. That's fine. + pass + + async def application_exception(self, exception, application_details): + """ + Called whenever an application coroutine has an exception. + """ + logging.error( + "Exception inside application: %s\n%s%s", + exception, + "".join(traceback.format_tb(exception.__traceback__)), + f" {exception}", + ) |