docker with cron job

README.md

ref. https://stackoverflow.com/a/37458519/868736

docker-compose up --build


curl localhost:5555

app.py

import os
import sys
from flask import Flask, jsonify


app = Flask(__name__)

@app.route('/')
def index():
    with open('/var/log/cron.log','r') as f:
        content = f.read()
    mydict = {"content":content}
    return jsonify(mydict)

if __name__ == "__main__":
    app.run(host='0.0.0.0', port=5555)

docker-compose.yml

version: '3'
services:
  cronjob:
    image: cronjob
    build:
      context: .
      dockerfile: Dockerfile    
    ports:
      - 5555:5555
    command: /bin/bash -c "cron && python app.py"

Dockerfile

FROM python:3.8-slim-buster

RUN apt-get update && apt-get -y install cron

# Copy hello-cron file to the cron.d directory
COPY hello-cron /etc/cron.d/hello-cron
 
# Give execution rights on the cron job
RUN chmod 0644 /etc/cron.d/hello-cron

# Apply cron job
RUN crontab /etc/cron.d/hello-cron
 
# Create the log file to be able to run tail
RUN touch /var/log/cron.log

# install flask
RUN pip install flask

COPY app.py /opt/app.py

WORKDIR /opt

hello-cron

* * * * * date >> /var/log/cron.log 2>&1