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Environment variables

A variable is configuration the application reads from its environment: log level, feature flag, a service's address. The value is visible on screen — it is not a secret.

For sensitive values, use secrets.

Declaring​

  1. Open the project and go to Variables.
  2. Choose the scope: organization, project, or environment.
  3. Enter the name and the value.
  4. Save.

The screen shows the variable with a badge indicating which scope it was declared in.

Inheritance in plain sight​

When the same name exists in more than one scope, the most specific one wins. The screen shows the whole chain, with the effective value highlighted:

Organization   LOG_LEVEL = info
Project        LOG_LEVEL = debug     ← this is the one the application reads
Environment    (not declared)

Without seeing the chain, changing LOG_LEVEL at organization level and seeing no effect would look like a platform defect.

Variables the platform supplies​

The platform injects the values the application needs in order to work, among them:

VariableWhat it holds
PORTThe service's port, which the application must listen on, on 0.0.0.0. Default 8080
HOME/tmp — the only writable directory while the application runs

Your application should read the port from the environment rather than hard-coding a number. EXPOSE in the Dockerfile does not change the port. See How the application runs.

Changing and removing​

  • Changing replaces the value in the scope where it was declared.
  • Removing deletes the declaration in that scope. If the same name exists in a more general scope, that one takes over — the screen shows which value becomes effective.

When it takes effect​

On the next deployment. The screen warns when a change has been declared and not yet applied. To apply it now, deploy the service — the new version uses the same image with the new configuration.

Good practice​

  • Declare at the most general scope that still makes sense: what applies to every project belongs at the organization.
  • Use the environment scope only for what genuinely differs between environments.
  • A sensitive-sounding name is not a secret. If the value is sensitive, the right object is a secret, even when the name looks harmless.

Next steps​