[Python] No text message in logs or console when my flask app runs in a container

I am currently packaging an old python/flask/pandas application (MyApp) into a podman container.

When MyApp runs directly in Ubuntu Console, text messages (e.g. user defined warnings and errors from pandas) are printed in the terminal. The application works smoothly. The prompts are:

conda activate my_env
python run.py


When I build a podman image and run the container attached to a console, not a single text message is printed in the console or stored in logs. Some of the functions (e.g. download) of the application fails. The prompts are:

podman build -t my_app .
podman run -p 5000:5000 my_app
podman logs -f {container_id}


When I start the container and terminate it with Ctrl+C, only the "keyboard interrupt" error is recorded in logs - nothing else.

What could be the reason? I am very new with container, Thanks!

PS. the Dockerfile is:

# Dockerfile
FROM docker.io/continuumio/miniconda3:24.11.1-0
ENV CONDA_ENV_NAME=my_env
ENV ENV_FILE=environment.yml
ENV APP_ENV_FILE=.env.dev
ENV FLASK_APP=run.py
ENV FLASK_ENV=development
ENV PYTHONUNBUFFERED=1

RUN echo Flask environment name: "$FLASK_ENV" # && true
RUN echo Conda environment name: "$CONDA_ENV_NAME" && true

RUN \
apt-get update && \
apt-get install -y zip

WORKDIR /deployment

COPY ./$ENV_FILE /deployment/$ENV_FILE
RUN conda env create -y -n $CONDA_ENV_NAME -f /deployment/$ENV_FILE
RUN conda run -n "$CONDA_ENV_NAME" conda info --envs
RUN conda run -n "$CONDA_ENV_NAME" python --version
RUN conda run -n "$CONDA_ENV_NAME" python -m flask --version

COPY ./app /deployment/app
COPY ./doc /deployment/doc
COPY ./web /deployment/web
COPY ./upload /deployment/upload
COPY ./run.py /deployment/run.py
COPY ./$APP_ENV_FILE /deployment/$APP_ENV_FILE

EXPOSE 5000
CMD ["/bin/bash", "-c", "conda run -n $CONDA_ENV_NAME python -u -m flask run --host=0.0.0.0"]

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