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I have a base resource class

../baselayer/baseresource/resource.py

class Resource:

    def __init__(self, *args, service_name: str, client_name: str = "Resource", log: Logger = None,
                 error_notifier: ErrorNotifier = None, **kwargs):
        super().__init__(*args, **kwargs)
        self.service_name: str = service_name
        self.client_name: str = client_name
        self.log: Logger = log
        self.error_notifier: ErrorNotifier = error_notifier

And I have a utility class inherting the above class


../baselayer/kafka/producer.py

from confluent_kafka import Producer


class CustomKafkaProducer(Resource, Producer):

    #custom functions

    @classmethod
    def get_client(cls, *, service_name, logger, error_notifier, config: KafkaCred):
        config = {
            "bootstrap.servers": config.BROKER,
            "security.protocol": "SASL_SSL",
            "sasl.mechanisms": "PLAIN",
            "sasl.username": config.USERNAME,
            "sasl.password": config.PASSWORD,
            "client.id": f"{service_name}-{uuid4().hex}"
        }
        client = cls(config, log=logger, service_name=service_name, error_notifier=error_notifier)
        return client

This is part of a fastapi project and the CustomKafkaProducer.get_client is called during app setup

../tests/app.py


from dotenv import load_dotenv
print("ENV load status test", load_dotenv(".env"))

from src.app.deployment import http_server, kafka_client

gunicorn tests.app:http_server --workers 4 --worker-class uvicorn.workers.UvicornWorker --bind 0.0.0.0:3000 --log-file - --access-logfile -

With the above command I am able to run the server with Python 3.10.4

I am building the image for the code with the following docker file

FROM python:3.10.4-slim-bullseye as base
RUN apt-get update
RUN apt-get install  build-essential -y
RUN python -m pip install --upgrade pip
COPY ./requirements.txt /tmp/requirements.txt
WORKDIR /myapp
RUN pip install -r /tmp/requirements.txt
COPY ./src /myapp/src
COPY ./baselayer /myapp/baselayer
EXPOSE 3000

FROM base AS http

CMD ["ddtrace-run", "gunicorn", "src.app.deployment:http_server","--workers", "4", "--worker-class", "uvicorn.workers.UvicornWorker",  "--bind", "0.0.0.0:3000", "--log-file" , "-", "--access-logfile", "-"]

When running the container I get the following error

File "/myapp/src/app/deployment/ddtrace_deployment.py", line 15, in <module>
    http_server = create_http_app()
  File "/myapp/src/app/app.py", line 80, in create_http_app
    return create_app(config=config, cls=HTTPServer)
  File "/myapp/src/app/app.py", line 75, in create_app
    app = cls.get_app(config, aws_session=Session())
  File "/myapp/baselayer/app.py", line 104, in get_app
    app.setup_app()
  File "/myapp/src/app/app.py", line 49, in setup_app
    super().setup_app()
  File "/myapp/src/app/app.py", line 34, in setup_app
    self.kafka_producer = CustomKafkaProducer.get_client(service_name=self.config.SERVICE_NAME,
  File "/myapp/baselayer/kafka/producer.py", line 62, in get_client
    client = cls(config, log=logger, service_name=service_name, error_notifier=error_notifier)
  File "/myapp/baselayer/baseresource/resource.py", line 11, in __init__
    self.service_name: str = service_name
AttributeError: 'cimpl.Producer' object has no attribute 'service_name'
Sab
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  • I think the error here is that you're trying to inherit from `confluent_kafka.Producer`, which comes from a C extension. In addition to that, anything involving multiple inheritance usually ends up biting you. I would highly recommend not subclassing and creating your `Producer` separately. See e.g. [this article](https://python-patterns.guide/gang-of-four/composition-over-inheritance/) – M.O. Apr 19 '23 at 10:02
  • @M.O. I changed to composition and its working, Is there a way to debug the issue with this inheritance to get a better understanding on where it went wrong – Sab Apr 19 '23 at 11:36

0 Answers0