Python docker crontab

ddm — Fri, 28 Feb 2025 14:05:34 +0000

My goal is to create a docker container to use as crontab container.
First Dockerfile:

FROM python:3.9-slim-bullseye as python

# Prevents Python from writing .pyc files
ENV PYTHONDONTWRITEBYTECODE 1

# Causes all output to stdout to be flushed immediately
ENV PYTHONUNBUFFERED 1

RUN apt update -yqq \ 
  && apt install -y cron build-essential libssl-dev gcc g++ curl wget freetds-dev freetds-bin gnupg apt-transport-https lsb-release vim \
  && apt install -y unixodbc unixodbc-dev libgss3 odbcinst default-libmysqlclient-dev libmagic1 \ 
  && curl https://packages.microsoft.com/keys/microsoft.asc | apt-key add - \
  && curl https://packages.microsoft.com/config/debian/10/prod.list > /etc/apt/sources.list.d/mssql-release.list \
  && exit \
  && apt update -yqq \
  && ACCEPT_EULA=Y apt install -yqq msodbcsql17 \ 
  && ACCEPT_EULA=Y apt install -yqq mssql-tools

RUN useradd --create-home --shell /bin/bash danilo

# Update pip
RUN /usr/local/bin/python -m pip install --upgrade pip

WORKDIR /app

COPY docker/* ./

RUN pip install --no-cache-dir -r requirements.txt

WORKDIR /app/scripts

#COPY scripts/* ./

#RUN chmod a+x *.py

RUN crontab /app/crontab

# Do not use this image as 'root' user
#USER danilo
RUN chmod 777 /app/entrypoint.sh
ENTRYPOINT ["/app/entrypoint.sh"]
CMD ["/bin/bash"]

then, add relative stanza to docker-compose.yml file:

crontab:
  image: registry.waltertosto.it/wt-python:latest
tty: true # docker run -t
stdin_open: true # docker run -i
restart: always
volumes:
  - ./crontab/crontab:/app/crontab
  - ./crontab/scripts:/app/scripts

Add crontab file and be careful to leave am empty line at the end, otherwise it will not work!

* * * * * /usr/bin/python3 -u /app/scripts/test.py > /dev/console

Entrypoint.sh

#!/bin/sh
set -e
crontab /app/crontab
printenv  > /etc/environment
cron -f
sleep infinity

Remote debug on Chrome in 2025

ddm — Fri, 28 Feb 2025 13:31:32 +0000

Sometimes I need to access to my remote kioks running Chrome/Chromium browsers and check developer tools.
In kiosk mode you don't have F12 key and right click available, so even with VNC remote control screen you cannot access to dev tools.

What to do then? Well, suppose with have to different hosts:
Host A with IP: 192.168.160.140 runnning kiosk app (with running SSH server)
Host B with IP: 192.168.160.100 our local machine

First of all, adjust kiosk host launching Chrome/Chromium with this option:
chromium --remote-debugging-port=9222 --kiosk "https://my-cool-app"
Then establish an SSH connection between two hosts using this command on your local machine:
ssh -L 9222:127.0.0.1:9222 <user>@192.168.160.140 where is a valid user in your kiosk host. Once launched

Now, on your local machine open a new tab and load chrome://inspect/#devices > check "Discover network targets" > press "Configure..." button and check "Enable port forwarding" option.

You're done!
On "Remote target" list you'll see remote Dev tools 🥂

Click on "Inspect" link and start to inspect on your remote kiosk.

There is another way to get Developer tools: go to http://localhost:9222/json to get a list of debugging URLs like this one in the picture

Click on link to open debugging URL.

Cheers!

DEV Community: ddm

Python docker crontab

Remote debug on Chrome in 2025