shopify_app conflict with my rails server port

[HappyJoe21]

Hi friends here, I tried to get shopify app with a custom domain on Cloudflare:

Setup: I have Cloudflare to point a custom domain to localhost:6666, so I can just use the domain to access my local dev web application that runs on port 6666. It works for normal rails app.

The problem: cmd shopify app dev --tunnel-url=https://custom.domain:6666, it throws an error stating that port 6666 is already in use.

My procfile looks like below

web: bin/rails server -p 6666
js: yarn build --watch

What confused me is that, shopify app is the one uses the Procfile to start rails on port 6666,

• how come it complains the port 6666 is in use?
• My expectation is that the tunnel-url param is a way to tell shopify to use that url. No?
• Then only work around is to use a different port in the cmd like shopify app dev --tunnel-url=https://custom.domain:9999, then the app can successfully start. Then what's the extra port 9999 opened for?

Could someone explain what I might be doing wrong?

[sle-c]

Hi @HappyJoe21,

This is an issue with the CLI where it tries to run a proxy server on that port when you pass in the tunnel url with a port. Would you mind trying the solution in this issue thread?

Thank you

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