init db and docker

.gitignore

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+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+.venv/
+venv/
+*.egg-info/
+
+# Environment
+.env
+.env.local
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# Testing
+.pytest_cache/
+.coverage
+htmlcov/
+
+# Docker
+docker-compose.override.yml

Dockerfile

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+FROM python:3.12-slim
+
+WORKDIR /app
+
+# Install uv for fast package management
+RUN pip install uv
+
+# Copy dependency files
+COPY pyproject.toml .
+
+# Install dependencies
+RUN uv pip install --system -e .
+
+# Copy application code
+COPY app/ app/
+
+# Run with uvicorn
+CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8000"]

db/init.sql

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+-- URL Shortener Database Schema
+
+CREATE TABLE IF NOT EXISTS urls (
+    id BIGSERIAL PRIMARY KEY,
+    short_code VARCHAR(10) UNIQUE NOT NULL,
+    original_url TEXT NOT NULL,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    expires_at TIMESTAMP WITH TIME ZONE,
+    click_count BIGINT DEFAULT 0,
+
+    -- Metadata
+    user_agent TEXT,
+    ip_address INET
+);
+
+-- Index for fast lookups by short_code (most common query)
+CREATE INDEX idx_urls_short_code ON urls(short_code);
+
+-- Index for cleanup of expired URLs
+CREATE INDEX idx_urls_expires_at ON urls(expires_at) WHERE expires_at IS NOT NULL;
+
+-- Analytics table (for click tracking)
+CREATE TABLE IF NOT EXISTS clicks (
+    id BIGSERIAL PRIMARY KEY,
+    short_code VARCHAR(10) NOT NULL,
+    clicked_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    ip_address INET,
+    user_agent TEXT,
+    referer TEXT,
+    country_code VARCHAR(2)
+);
+
+-- Partition-friendly index (clicks will be high volume)
+CREATE INDEX idx_clicks_short_code ON clicks(short_code);
+CREATE INDEX idx_clicks_clicked_at ON clicks(clicked_at);
+
+-- Function to increment click count (atomic)
+CREATE OR REPLACE FUNCTION increment_click_count(code VARCHAR(10))
+RETURNS VOID AS $$
+BEGIN
+    UPDATE urls SET click_count = click_count + 1 WHERE short_code = code;
+END;
+$$ LANGUAGE plpgsql;

docker-compose.yml

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+services:
+  # PostgreSQL - Primary database
+  postgres:
+    image: postgres:16-alpine
+    environment:
+      POSTGRES_USER: urlshortner
+      POSTGRES_PASSWORD: localdev
+      POSTGRES_DB: urlshortner
+    ports:
+      - "5432:5432"
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
+      - ./db/init.sql:/docker-entrypoint-initdb.d/init.sql
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U urlshortner"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+
+  # Redis - Caching layer
+  redis:
+    image: redis:7-alpine
+    ports:
+      - "6379:6379"
+    volumes:
+      - redis_data:/data
+    healthcheck:
+      test: ["CMD", "redis-cli", "ping"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+
+  # API Server (can scale with --scale api=3)
+  api:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    environment:
+      DATABASE_URL: postgresql://urlshortner:localdev@postgres:5432/urlshortner
+      REDIS_URL: redis://redis:6379
+      MACHINE_ID: 1
+    depends_on:
+      postgres:
+        condition: service_healthy
+      redis:
+        condition: service_healthy
+    ports:
+      - "8000"  # Random port mapping for scaling
+
+  # Nginx - Load balancer
+  nginx:
+    image: nginx:alpine
+    ports:
+      - "80:80"
+    volumes:
+      - ./nginx/nginx.conf:/etc/nginx/nginx.conf:ro
+    depends_on:
+      - api
+
+volumes:
+  postgres_data:
+  redis_data:

pyproject.toml

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+[project]
+name = "url-shortner"
+version = "0.1.0"
+description = "Distributed URL shortening service for learning system design"
+requires-python = ">=3.11"
+dependencies = [
+    "fastapi>=0.109.0",
+    "uvicorn[standard]>=0.27.0",
+    "asyncpg>=0.29.0",
+    "redis>=5.0.0",
+    "pydantic>=2.5.0",
+]
+
+[project.optional-dependencies]
+dev = [
+    "pytest>=8.0.0",
+    "pytest-asyncio>=0.23.0",
+    "httpx>=0.26.0",
+    "ruff>=0.1.0",
+]
+
+[tool.ruff]
+line-length = 100
+target-version = "py311"
+
+[tool.ruff.lint]
+select = ["E", "F", "I", "UP"]
+
+[tool.pytest.ini_options]
+asyncio_mode = "auto"