Install Chromium (or a Package that needs it) inside Docker

I found a couple hints, but this one might be the best one. https://github.com/puppeteer/puppeteer/blob/master/docs/troubleshooting.md#running-puppeteer-in-docker I actually changed parts

RUN npm i puppeteer \
    # Add user so we don't need --no-sandbox.
    # same layer as npm install to keep re-chowned files from using up several hundred MBs more space
    && groupadd -r pptruser && useradd -r -g pptruser -G audio,video pptruser \

I replaced with

RUN mkdir /app/node_modules
RUN groupadd -r pptruser && useradd -r -g pptruser -G audio,video pptruser \

So that I let npm install install the package that has Chromium as a dependency (it might not be puppeteer itself).

Also I had to replace

     && chown -R pptruser:pptruser /node_modules

by

     && chown -R pptruser:pptruser /app/node_modules

since my WORKDIR=/app so node_modules will be inside that directory. Works well.