Chapter 76
Docker Compose
Docker Compose
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By now we have three pieces running - PostgreSQL, Grafana, and the Streamlit app. Starting each by hand works, but it adds up. You have to remember the network and type out long commands. Next time around, Docker complains that a container with that name already exists, and you have to go remove it.
Docker Compose describes all three services in one file and starts them together on a shared network. You run one command instead.
Project structure
The project layout:
code/
├── docker-compose.yaml
├── Dockerfile
├── .env
├── pyproject.toml
├── uv.lock
├── .python-version
├── app.py # Streamlit app
├── assistant.py # RAG pipeline + LLM
├── db_init.py # Database init
├── db_save.py # Save conversations
└── dashboard.py # Streamlit dashboardDockerfile
The Streamlit app needs its own container:
FROM python:3.12-slim
COPY --from=ghcr.io/astral-sh/uv:latest /uv /uvx /bin/
WORKDIR /app
ENV PATH="/app/.venv/bin:$PATH"
COPY pyproject.toml uv.lock .python-version ./
RUN uv sync --locked
COPY . .
CMD ["streamlit", "run", "app.py", "--server.port=8501", "--server.address=0.0.0.0"]Environment variables
The .env file stores configuration:
POSTGRES_DB=course_assistant
POSTGRES_USER=user
POSTGRES_PASSWORD=password
POSTGRES_HOST=postgres
OPENAI_API_KEY=your-key-hereDocker Compose
The Compose file defines all three services on the same network:
version: '3.8'
services:
postgres:
image: postgres:17
environment:
POSTGRES_DB: ${POSTGRES_DB}
POSTGRES_USER: ${POSTGRES_USER}
POSTGRES_PASSWORD: ${POSTGRES_PASSWORD}
ports:
- "5432:5432"
volumes:
- postgres_data:/var/lib/postgresql/data
grafana:
image: grafana/grafana
ports:
- "3000:3000"
volumes:
- grafana_data:/var/lib/grafana
environment:
- GF_SECURITY_ADMIN_PASSWORD=admin
depends_on:
- postgresThe Streamlit service is built from the Dockerfile:
streamlit:
build:
context: .
dockerfile: Dockerfile
environment:
- POSTGRES_HOST=postgres
- POSTGRES_DB=${POSTGRES_DB}
- POSTGRES_USER=${POSTGRES_USER}
- POSTGRES_PASSWORD=${POSTGRES_PASSWORD}
- OPENAI_API_KEY=${OPENAI_API_KEY}
ports:
- "8501:8501"
depends_on:
- postgres
volumes:
postgres_data:
grafana_data:Starting everything
Start all services:
docker-compose upInitialize the database:
uv run python db_init.pyAccess the app at http://localhost:8501 and Grafana at
http://localhost:3000 (login: admin / admin).
To stop:
docker-compose downThe data in PostgreSQL and Grafana persists across restarts thanks to Docker volumes.