# EPPP Docker Compose baseline — [E00-S02-T01/T02]
#
# `docker compose up -d` starts both the database (PostgreSQL) and the
# application (@personal-blog/server). Rollback: `docker compose down`.
#
# PostgreSQL health gate (T02): the `db` service carries a `pg_isready`
# healthcheck and the `app` service depends on it with
# `condition: service_healthy`, so the application does not start until the
# database is accepting connections.
#
# Explicitly out of scope for T01/T02 (land in later E00-S02 tasks):
#   - application health endpoint (T03)
#   - DB volume persistence (T04)
#
# All values have defaults so `docker compose up -d` works from a clean clone
# without a .env file (a committed .env.example template lands in E00-S04).

services:
  db:
    # PostgreSQL 18 on Debian bookworm — the documented runtime target
    # (Technology-Stack §5.2/§5.4/§6.2, golden tuple §7; no Alpine drift).
    image: postgres:18-bookworm
    environment:
      POSTGRES_DB: ${POSTGRES_DB:-eppp}
      POSTGRES_USER: ${POSTGRES_USER:-eppp}
      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD:-eppp}
    ports:
      - "${POSTGRES_PORT:-5432}:5432"
    # Health gate for the app service (T02): probe the same credentials the db
    # service was created with. `$$` defers interpolation to the container, so
    # POSTGRES_USER/POSTGRES_DB overrides apply to the probe too.
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U $${POSTGRES_USER} -d $${POSTGRES_DB}"]
      interval: 5s
      timeout: 5s
      retries: 5
      start_period: 5s

  app:
    build:
      context: .
      dockerfile: apps/server/Dockerfile
    environment:
      DATABASE_URL: postgres://eppp:eppp@db:5432/eppp
    ports:
      - "${APP_PORT:-3000}:3000"
    # T02: start only once the database reports healthy (service_healthy), so
    # the application waits for PostgreSQL before starting.
    depends_on:
      db:
        condition: service_healthy