Docker Compose

calit ships a docker-compose.yml with two services: db (Postgres 18) and app (the calit server). The app is stateless — all shared state lives in Postgres — so the same file works for a single node or a scaled-out cluster.

The compose file

services:
  db:
    image: postgres:18
    environment:
      POSTGRES_DB: ${DB_NAME:-calit}
      POSTGRES_USER: ${DB_USER:-calit}
      POSTGRES_PASSWORD: ${DB_PASSWORD:?set DB_PASSWORD in .env}
    volumes:
      # postgres:18 default PGDATA is /var/lib/postgresql/18/docker — mount the parent so data persists
      - calit-db:/var/lib/postgresql
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U ${DB_USER:-calit} -d ${DB_NAME:-calit}"]
      interval: 5s
      timeout: 5s
      retries: 10
    restart: unless-stopped
  app:
    image: ghcr.io/asm0dey/calit:latest
    depends_on:
      db:
        condition: service_healthy
    env_file:
      - path: .env
        required: false
    environment:
      DB_URL: jdbc:postgresql://db:5432/${DB_NAME:-calit}
      DB_USER: ${DB_USER:-calit}
      DB_PASSWORD: ${DB_PASSWORD:?set DB_PASSWORD in .env}
    ports:
      - "${APP_PORT:-8080}:8080"
    restart: unless-stopped
volumes:
  calit-db:

You don’t need to clone the repository — save the file above as docker-compose.yml, grab .env.example next to it, and you’re ready.

Key details

What	Why it matters
image: ghcr.io/asm0dey/calit:latest	Pulls the published multi-arch image from GitHub Container Registry — no local build. A smaller native variant and a build-from-source option are below.
depends_on: condition: service_healthy	The app starts only after Postgres passes its pg_isready healthcheck, so Flyway migrations never race a cold DB.
env_file: .env	All secrets are loaded from .env. Marked required: false so docker compose config works on a fresh checkout without an .env file present.
DB_URL (derived)	jdbc:postgresql://db:5432/${DB_NAME:-calit} is injected automatically — your .env only needs to carry DB_PASSWORD.
${APP_PORT:-8080}:8080	The container always listens on 8080. Set APP_PORT in .env to expose a different host port.
Volume mount: /var/lib/postgresql	Postgres 18 changed its default PGDATA to /var/lib/postgresql/18/docker. Mounting the parent directory (/var/lib/postgresql) ensures data persists across container restarts regardless of the exact subdirectory used.

Native image (lower footprint)

Every published tag also has a GraalVM native counterpart with a -native suffix (:latest-native, :edge-native, :1.11.0-native, …). It runs the same application compiled ahead-of-time on a minimal Alpaquita musl base — no JRE.

	:latest (JVM)	:latest-native
Image size	~205 MB	~115 MB
Memory (idle)	~300 MB	~60 MB
Startup	~2.4 s	~0.4 s

Use it by appending -native to the tag:

  app:
    image: ghcr.io/asm0dey/calit:latest-native

The native image is functionally identical and multi-arch (amd64 + arm64). Its smaller memory footprint suits small VPS hosts. The JVM image remains the default; pick whichever fits your deployment.

Build from source

Prefer to build the image yourself (e.g. running a fork or an unreleased commit)? Clone the repository and swap the app service’s image: line for build: .:

  app:
    build: .

Then start with docker compose up --build -d. This is what the docker-compose.yml in the repository does by default (Liberica JDK 26 build). For just running calit, the prebuilt image above is faster and needs no build toolchain.

Scaling

calit is stateless — scale the app service horizontally behind your own load balancer:

docker compose up -d --scale app=3

Postgres is the single shared state store; no additional coordination is needed between replicas.

Starting up

1. Copy .env.example to .env and fill in your values — see the Configuration page for every variable.
2. Start the stack:

docker compose up -d

Compose pulls ghcr.io/asm0dey/calit:latest on first run. On first boot, Flyway applies all database migrations automatically. Navigate to your APP_BASE_URL — if no users exist yet, you will be redirected to /setup to create the first admin account.