Configuration & domains

The rule: no domain, account ID, region, or resource name appears in application code. The placeholder domain frond.cntnus.app will be replaced by the real brand domain — that change is pure configuration, no code changes.

Layers of configuration

Layer	File	Consumers
Environments	infra/config/environments.json	CDK (infrastructure)
Accounts	infra/config/accounts.json	CDK (deploy targets)
Runtime config	config.json injected into each site’s S3 bucket at deploy	the canvas app, marketing links
Schema + loader	packages/config	all frontends
Lambda env vars	set by infra/lib/stacks/api-stack.ts	services/api
CI/CD context	-c githubConnectionArn, -c githubRepo at pipeline deploy	infra/bin/pipeline.ts

environments.json

{
  "prod": {
    "account": "prod",
    "productName": "Frond",
    "zoneDomain": "frond.cntnus.app",
    "appDomain": "app.frond.cntnus.app",
    "wwwDomain": "frond.cntnus.app",
    "wwwAliases": ["www.frond.cntnus.app"],
    "docsDomain": "docs.frond.cntnus.app",
    "apiDomain": "api.frond.cntnus.app",
    "authDomain": "auth.frond.cntnus.app",
    "authDisabled": false,
    "features": { "publishing": true, "collaboration": false }
  }
}

Runtime config.json

Rendered per environment by the CDK and uploaded next to the app bundle:

{
  "version": 1,
  "environment": "dev",
  "productName": "Frond",
  "auth": { "region": "us-east-1", "userPoolId": "…", "userPoolClientId": "…",
            "issuer": "https://auth.dev.frond.cntnus.app",
            "redirectUri": "https://dev.frond.cntnus.app/callback",
            "scopes": ["openid", "email", "profile"] },
  "api": { "baseUrl": "https://api.dev.frond.cntnus.app" },
  "storage": { "region": "us-east-1", "bucket": "…" },
  "links": { "app": "https://dev.frond.cntnus.app", "www": "…", "docs": "…", "api": "…" },
  "features": { "publishing": true, "collaboration": false }
}

The app loads it at startup (window.__FROND_CONFIG__ takes precedence, for embedding). The same file drives the marketing site’s links — so one build artifact deploys to all three environments; only the injected JSON differs.

Rebranding / domain change checklist

1. Update infra/config/environments.json (new domains).
2. Redeploy each environment (CDK recreates certificates and DNS records in the env’s hosted zone; NS delegation for the new zone is a one-time manual step in the parent zone — see Deployment).
3. Re-point the Cognito hosted-UI callback URLs (CDK regenerates them from appDomain).
4. That’s it — no application code changes.

Secret management

There are deliberately no secrets in the repo. The only sensitive deploy-time inputs are the GitHub CodeStar connection ARN (passed via CDK context / env var) and optional alert email addresses (CDK context). If secrets are ever needed, they go to Secrets Manager / SSM Parameter Store and are read by the Lambda via IAM, never via environment values checked in.