Source code for jina.peapods.runtimes.base

import argparse

from ...excepts import RuntimeTerminated
from ...logging.logger import JinaLogger


[docs]class BaseRuntime: """A Jina Runtime is a procedure that blocks the main process once running (i.e. :meth:`run_forever`), therefore should be put into a separated thread/process, or inside the main process of a docker container. Any program/library/package/module that blocks the main process, can be formulated into a :class:`BaseRuntime` class and then be started from a :class:`BasePea`. In the sequel, we call the main process/thread as ``M``, the process/thread blocked :class:`Runtime` as ``S``. In Jina, a :class:`BasePea` object is used to manage a :class:`Runtime` object's lifecycle. A :class:`BasePea` acts as a :class:`multiprocessing.Process` or :class:`threading.Thread`, it starts from ``M`` and once the ``S`` is spawned, it uses :class:`Runtime` as a context manager: 0. :meth:`__init__` 1. :meth: `__enter__` 2. :meth:`run_forever`. Note that this will block ``S``, step 3 won't be reached until it is unblocked by :meth:`cancel`. 3. When an error occurs during `run_forever` or `cancel` signal is reached by the `runtime`. The `run_forever` method is cancelled and the managed context is closed. The `__exit__` of `Runtime` guarantees that the `Runtime` is properly shut by calling `teardown`. The :meth:`__init__` and :meth:`teardown` pair together, which defines instructions that will be executed before and after. In subclasses, `teardown` is optional. In order to cancel the `run_forever` method of a `Runtime`, you can use their `static` `cancel` method that will make sure that the runtime is properly cancelled. - Use :class:`threading.Event` or `multiprocessing.Event`, while :meth:`run_forever` polls for this event - Use ZMQ to send a TERMINATE message, while :meth:`run_forever` polls for this message Note, another way to jump out from :meth:`run_forever` is raise exceptions from it. This will immediately move to :meth:`teardown`. .. note:: Rule of thumb on exception handling: if you are not sure if you should handle exception inside :meth:`run_forever`, :meth:`cancel`, :meth:`teardown`, then DO NOT catch exception in them. Exception is MUCH better handled by :class:`BasePea`. .. seealso:: :class:`BasePea` for managing a :class:`Runtime` object's lifecycle. """ def __init__( self, args: 'argparse.Namespace', **kwargs, ): super().__init__() self.args = args if args.name: self.name = f'{args.name}/{self.__class__.__name__}' else: self.name = self.__class__.__name__ self.logger = JinaLogger(self.name, **vars(self.args))
[docs] def run_forever(self): """Running the blocking procedure inside ``S``. Note, once this method is called, ``S`` is blocked. .. note:: If this method raises any exception, :meth:`teardown` will be called. .. seealso:: :meth:`cancel` for cancelling the forever loop. """ raise NotImplementedError
[docs] def teardown(self): """Method called immediately after :meth:`run_forever` is unblocked. You can tidy up things here. Optional in subclasses. The default implementation does nothing. """ self.logger.close()
def __enter__(self): return self def __exit__(self, exc_type, exc_val, exc_tb): if exc_type == RuntimeTerminated: self.logger.debug(f'{self!r} is ended') elif exc_type == KeyboardInterrupt: self.logger.debug(f'{self!r} is interrupted by user') elif exc_type and issubclass(exc_type, Exception): self.logger.error( f'{exc_val!r} during {self.run_forever!r}' + f'\n add "--quiet-error" to suppress the exception details' if not self.args.quiet_error else '', exc_info=not self.args.quiet_error, ) try: self.teardown() except OSError: # OSError(Stream is closed) already pass except Exception as ex: self.logger.error( f'{ex!r} during {self.teardown!r}' + f'\n add "--quiet-error" to suppress the exception details' if not self.args.quiet_error else '', exc_info=not self.args.quiet_error, ) # https://stackoverflow.com/a/28158006 # return True will silent all exception stack trace here, silence is desired here as otherwise it is too # noisy # # doc: If an exception is supplied, and the method wishes to suppress the exception (i.e., prevent it # from being propagated), it should return a true value. Otherwise, the exception will be processed normally # upon exit from this method. return True