InputProcessor

class InputProcessor

This class represents the input nodes of the pipeline's graph. It is a subclass of Processor and overrides the _process member coroutine. This class' object is instantiated by the Plumber when the input_srcs list is empty.

Methods

_process(...)

async def _process(self, *args, **kwargs):
    await self._processor_coro(self, self._output_queue, *args, **kwargs)

The role of _process is a little different from that of Processor._process. In this case, it calls the _processor_coro with the arguments - self, self._output_queue, *args, **kwargs.

_processor_coro is expected to be a coroutine that fills the provided self._output_queue with input data. It can be implemented as follows -

async def input_coro(self:Processor, q_out:asyncio.Queue, *args, **kwargs):
    while(True):
        inp = *get_input coro*
        await q_out.put(inp)

Note- Bear in mind that, since _processor_coro is an async function, it cannot be a long processor bound call as that will cause the other tasks to suffer. Furthermore, an overeager _processor_coro can lead to backpressure issues down the line.