Cupcake

A Kotlin/Ktor backend that aggregates JavaZone conference and session data from Sleeping Pill and enriches speaker profiles with Norwegian postal code data from the Bring API. It serves as the API backend for frosting, enabling javaBin regions to discover potential speakers for local events.

Tech stack

• Language: Kotlin (JVM 22)
• Framework: Ktor
• Build: Gradle (Kotlin DSL)
• Caching: Caffeine (conference/session data) + Cache4k (postal codes)
• Auth: OIDC/JWT via configurable discovery endpoint
• Metrics: Micrometer + Prometheus

API endpoints

Method	Path	Description
GET	/api/conferences	Lists conferences (filtered by year, sorted by name descending)
GET	/api/conferences/{id}/sessions	Sessions for a conference, with speaker postal code/city/county data
GET	/api/me	Authenticated user info from OIDC token

Additional endpoints (/login, /refresh) are handled by the OIDC layer.

Build

./gradlew clean build

Code quality checks (Detekt, Kotlinter, JaCoCo coverage) run as part of check:

./gradlew check

The output artifact is build/libs/cupcake.jar (fat JAR with all dependencies bundled).

Local running

Set the following environment variables (a local.env file in the root is gitignored and works well with the IntelliJ IDEA EnvFile plugin):

Variable	Description
SP_BASE_URL	Sleeping Pill base URL (e.g. https://sleepingpill.javazone.no)
SP_USER	Sleeping Pill username
SP_PASSWORD	Sleeping Pill password
BRING_API_KEY	Bring API key
BRING_API_USER	Bring API user (email)
JWT_ENABLED	true to enforce JWT authentication, false to disable
OIDC_WELL_KNOWN_URL	Optional. OIDC discovery endpoint; defaults to the javaBin internal Cognito pool
LOG_LEVEL	Optional. Root log level; DEBUG by default, TRACE under ./gradlew run

Then run:

./gradlew run

The server starts on port 8080. With JWT_ENABLED=false, no auth is required and localhost is fine.

To test with login, set JWT_ENABLED=true here and in frosting's local.env. Both use the prod Cognito pool, whose client allows http://localhost:3000/ as a callback, so you sign in with your @java.no Google account as in prod. You need to be in the helter group.

Docker

The javaBin platform builds and pushes the deployed image (see CI/CD). To build locally:

docker build -t cupcake .

The image uses a multi-stage build (Eclipse Temurin 25 JDK build stage, JRE runtime stage) and runs on port 8080.

CI/CD

Trigger	Workflow	What it does
Push to main	deploy.yaml	The javaBin platform workflow runs ./gradlew build (which includes check: tests, kotlinter, detekt), then builds the image and deploys it. Nothing deploys if the build fails
Pull request	deploy.yaml	Platform build and Terraform plan, no deploy
Pull request	pr.yaml	Runs ./gradlew check (tests, linting, analysis)

Deploy

Example hostnames:

https://cupcake-backend.javazone.no  →  backend (this service)
https://cupcake.javazone.no          →  frontend (frosting)

Environment variables for deployment

JWT / OIDC (backend)

Variable	Value
JWT_ENABLED	true
OIDC_WELL_KNOWN_URL	OIDC discovery endpoint

Users must be members of the helter Cognito group (all approved javaBin heroes).

The platform injects OIDC_WELL_KNOWN_URL from the Cognito pool (auth.env in app.yaml).

OIDC (frontend)

The frontend uses the same Cognito pool; see the frosting README for its configuration.

Sleeping Pill

Variable	Description
SP_BASE_URL	Sleeping Pill base URL
SP_USER	Username
SP_PASSWORD	Password

Bring

Variable	Description
BRING_API_USER	Bring API user (email)
BRING_API_KEY	Bring API key