CODEWITHSUNDEEP
dockerheroku
Jay Jung
Jay Jung

Reputation: 1885

Docker env vars + Heroku; Heroku requires ENV while local build requires ARG

My understanding of Heroku's Docker container-registry CLI was that it was a wrapper around the Docker cli.

When I build locally I'll use, for example: docker build -f Dockerfile.example --build-arg SECRET_KEY=abc. And I'll have set ARG SECRET_KEY in my Dockerfile.example.

However if I want to push up to heroku's docker container-registry, I found out that I need to declare ENV SECRET_KEY=abc in my Dockerfile.example, and then run the command heroku container:push example --recursive.

Why is the case? What sets them apart? Isn't hardcoding the ENV bad security practice? Does Heroku offer a way around this?

Upvotes: 7

Views: 1999

Answers (2)

Peter Lada
Peter Lada

Reputation: 393

The config vars (per app) override whatever values you hard-code in the Dockerfile. Put a placeholder value in your Dockerfile (personal favotite: notsecret) and set the actual secret values on the Heroku UI or CLI.

Upvotes: 0

Sudharsan Ravikumar
Sudharsan Ravikumar

Reputation: 433

You can run something like
heroku container:push web --arg SECRET_KEY=xxxSecret123

In that way, You don't have to feed information in your Dockerfile directly.

Upvotes: 5

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