Docker ports shadow local ones and can cause bugs

This is part of the Semicolon&Sons Code Diary - consisting of lessons learned on the job. You're in the containerization category.

Last Updated: 2024-11-23

I had the error "unable to connect to chromedriver 127.0.0.1:9515"

I went online and Googled for generic (and useless info)

Ultimately I should have inspected what was going on in my computer at that port

and I'd have seen that a stray docker instance was there.

Lessons

Stop docker on your host system if something else has broken.
When you cannot connect to a port, use command line tools to inspect what is happening there (e.g. $ lsof -i :80)

Get Episode Alerts and Freebies

We publish a video once every week, on Sundays. Every 2nd video is completely free to watch.

If you'd like, we can remind you via email when a new episode is released. We'll also keep you up to date about the top-secret game we're developing for learning programming.

Semicolon & Sons