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)
OIDC_WELL_KNOWN_URL	OIDC discovery endpoint (e.g. https://auth.example.com/realms/myrealm/.well-known/openid-configuration)
OIDC_EXPECTED_AZP	Expected OIDC client ID (defaults to cupcake-client)
JWT_ENABLED	true to enforce JWT authentication, false to disable

Then run:

./gradlew run

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

Docker

Multi-platform images (linux/amd64, linux/arm64) are published to ghcr.io/javabin/cupcake.

To build locally:

docker build -t cupcake .

The image uses a multi-stage build (Eclipse Temurin JDK 22 build stage, JRE runtime stage) and runs on port 8080.

CI/CD

Trigger	Workflow	What it does
Push to main	build.yaml	Runs check, builds and pushes multi-platform Docker image, tags as staging
Pull request	pr.yaml	Runs check (tests, linting, analysis)
Tag v*	release.yaml	Promotes staging image to release and version tag

Deploy

Example hostnames:

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

If deploying with Docker Compose or a shared Docker network, or inside kubernetes with access, use the service name as the CUPCAKE_BACKEND value.

Environment variables for deployment

JWT / OIDC (backend)

Variable	Value
JWT_ENABLED	true
OIDC_WELL_KNOWN_URL	OIDC discovery endpoint
OIDC_EXPECTED_AZP	Expected client ID (defaults to cupcake-client)

Users must have the pkom role assigned in the OIDC provider under the client specified by OIDC_EXPECTED_AZP.

OIDC (frontend — must match backend)

Variable	Description
NUXT_PUBLIC_OIDC_AUTHORITY	OIDC authority URL (e.g. https://auth.example.com/realms/myrealm)
NUXT_PUBLIC_OIDC_CLIENT_ID	OIDC client ID (defaults to cupcake-client)

See the frosting README for full frontend 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