Clock process as Docker container to prevent idling for free dyno on Heroku

clock.js

const axios = require('axios');

const HEROKU_APP = 'my-herokuapp';
const INTERVAL_MSEC = 10 * 60 * 1000; // every 10 minutes

setInterval(async () => {
  try {
    const response = await axios.get(`http://${HEROKU_APP}.herokuapp.com`);
    console.log(response.status, heroku_app);
  } catch (error) {
    console.log(error.response.status, heroku_app);
  }
}, INTERVAL_MSEC);

Dockerfile.clock

FROM node:9.11.1-alpine

LABEL maintainer="Keid"

RUN mkdir /app
WORKDIR /app

RUN npm install -g [email protected]
RUN chmod +x /usr/local/bin/yarn

COPY package.json package.json
COPY yarn.lock yarn.lock

RUN yarn install \
  && mv node_modules /node_modules

COPY clock.js clock.js

CMD node clock.js