Dash App on shinyproxy Connection to mariadb database

ShinyProxy
#1

Hi,
Im trying to deploy a python dash app via shinyproxy. The app queries data from Mariadb database (not hosted on localhost).

The problem

I have tried using sqlALchemy to make a connection to database. when I make a docker image out of the app and deploy it i get:

Error 500 : Container did not respond in time

the contents of my docker file are as follows:

FROM ubuntu:20.04

RUN apt-get update && \
    apt-get install -y python3 python3-pip && \
    rm -rf /var/lib/apt/lists/*



RUN pip3 install mariadb
RUN pip3 install dash==1.19.0 && \
    pip3 install pandas && \
    pip3 install SQLAlchemy && \
    pip3 install pyyaml  
    

RUN mkdir app
COPY app/ /app
RUN ls

EXPOSE 8050

WORKDIR /app
CMD ["python3", "app.py"]

Furthermore, My application.yml includes the following contents

- id: shinyproxy-dash-myapp
    display-name: My App
    container-cmd:
    - python3
    - app.py
    container-image: shinyproxy-python-test
    access-groups:
    - my_access_group
    container-volumes:
    - /srv/myvol/Volume:/srv/myvol/Volume
    docker-network: host
    port: 8050

Important observation:

while debugging I have noticed everything works ok until I used the create_engine() method to make a connection to the database. So in my opinion it it somehow the culprit.

Furthermore, when I run it on local host as just a app.py python app. it runs fine, also when I run the image with docker run it runs fine. It only starts to ‘not work’ when I deploy it on shinyproxy.

1 Like
#2

Hi Fareeha,

for debugging of your case first try to see what output your app will write on console (hope that python code will write some error on console similar as r code does). Find container id (with docker ps) and try with
docker logs --follow <container_id>
You have to be fast with commands to before container die.

Also, some options from your application.yml should be inspected also.

1 Like