ProgrammaticAgentDefinitioninFaust

Hello everyone,

I am currently working with Faust version 1.4.5 and facing challenges when attempting to define multiple agents programmatically. The issue arises when more than one agent is defined; messages intended for one agent are incorrectly delivered to another, despite the topic-agent associations appearing correct when listed using the associated command. This suggests that the dynamic definition process might be disrupting some internal mechanisms, leading to incorrect bindings.

Below is the approach I've taken:

for transformation in get_transformations():
    async def _func(messages):
        service = Service(transformation, config)
        async for message in messages:
            # Process the message
            yield result

    _func.__name__ = transformation.name
    locals()[transformation.name] = _func
    app.agent(app.topic(transformation.input_topic, value_serializer='raw'))(locals()[transformation.name])

Note: The use of locals() is not essential for the operation and can be disregarded.

While the code works perfectly with a single agent, the problem emerges with multiple agents. The input-function associations are accurate, as I am migrating existing services to Faust, and these were previously functioning correctly.

It appears that during each iteration of the loop, some definitions are being overwritten, resulting in the last defined agent being incorrectly associated with all topics. To debug this, I am looking for internal variables or mechanisms that could help identify where the issue lies, as the standard debug messages and the agents command do not reveal any obvious problems.

An additional point to note is that if the above code is executed after the application has started, the new agents must be manually started. Simply attaching them to the application is insufficient. Here’s how to ensure they start properly:

new_agent = app.agent(channel=..., name=...)(agent_coro)
new_agent.start()

This detail was crucial for resolving the issue and is shared here for the benefit of others who may encounter similar problems.