Q: Your development and automated integration test pipelines rely on Docker Compose. Developers frequently experience race conditions where API microservices crash during startup with `connection refused` because the PostgreSQL database container is accepting TCP sockets but has not finished initializing its data directory and schema. Furthermore, unconstrained containers consume 100% host CPU, crashing local test runners. You must modernize the `compose.yaml` file to use Compose v2 healthcheck dependencies, secrets, and CPU/memory constraints.

Docker Compose v2 (written in Go, invoked as `docker compose`) fully replaces legacy Python-based Compose v1 (`docker-compose`). It introduces native support for service health dependencies, Compose profiles, and environment file interpolation.

# Compose v1 (Deprecated Anti-pattern):
# depends_on: ["db"] -> Only waits for db container to START, not to be READY!

# Compose v2 (Modern Standard):
# depends_on:
#   db:
#     condition: service_healthy

Define an explicit `healthcheck` block on the PostgreSQL database service using `pg_isready` with appropriate `interval`, `timeout`, and `retries` parameters.

services:
  postgres:
    image: postgres:16-alpine
    environment:
      POSTGRES_DB: app_db
      POSTGRES_USER: app_user
      POSTGRES_PASSWORD_FILE: /run/secrets/db_password
    secrets:
      - db_password
    volumes:
      - postgres_data:/var/lib/postgresql/data
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U app_user -d app_db"]
      interval: 5s
      timeout: 3s
      retries: 5
      start_period: 10s
    deploy:
      resources:
        limits:
          cpus: '1.0'
          memory: 1024M

Configure dependent API services to wait until the database reports healthy before launching, eliminating connection retry loops and race condition startup crashes.

  api-service:
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - "8080:8080"
    environment:
      DB_HOST: postgres
    depends_on:
      postgres:
        condition: service_healthy
      redis:
        condition: service_started
    secrets:
      - db_password
    deploy:
      resources:
        limits:
          cpus: '0.5'
          memory: 512M

secrets:
  db_password:
    file: ./secrets/db_password.txt

volumes:
  postgres_data:

Execute `docker compose up` and observe Compose waiting for the database healthcheck to turn green before initiating the API service container.

# Run compose with detailed status
docker compose up -d

# Inspect service health statuses
docker compose ps
# Displays: 'postgres (healthy)', 'api-service (running)'