Docker Skill

VanDaemon uses a multi-container architecture with separate API and Web containers for local development, plus a combined single-container deployment for Fly.io. The API runs on .NET 10, the Web frontend uses nginx to serve Blazor WASM static files and proxy API/WebSocket requests. Data persists via Docker volumes for JSON file storage.

Quick Start

Start Development Environment

bash

# From solution root
docker compose up -d

# View logs
docker compose logs -f

# Rebuild after code changes
docker compose up --build

Access Points

Service	URL	Purpose
Web UI	http://localhost:8080	Blazor WASM frontend
API	http://localhost:5000	REST API + Swagger
Health	http://localhost:5000/health	Container health check
SignalR	ws://localhost:5000/hubs/telemetry	Real-time updates

Key Concepts

Concept	Usage	Example
Multi-stage builds	Minimize image size	`FROM sdk AS build` → `FROM aspnet AS final`
Health checks	Container orchestration	`HEALTHCHECK CMD curl /health`
Volume mounts	Persist JSON data	`api-data:/app/data`
Bridge network	Inter-container comms	`http://api:80` not `localhost:5000`
Supervisor	Multi-process container	Combined nginx + API for Fly.io

Common Patterns

Container Networking

When: Containers need to communicate

yaml

# docker-compose.yml
services:
  web:
    depends_on:
      api:
        condition: service_healthy
    # Use container name, not localhost
    environment:
      - API_BASE_URL=http://api:80

Volume Persistence

When: Data must survive container restarts