Well-Architected Framework（WAF 五大支柱）

// Reliability — Health Check + Circuit Breaker
builder.Services.AddHealthChecks()
    .AddDbContextCheck<AppDbContext>()
    .AddRedis(config["Redis:Connection"]!)
    .AddUrlGroup(new Uri("https://external-api.com/health"), "external-api");
 
// Circuit Breaker（使用 Polly）
builder.Services.AddHttpClient("ExternalApi")
    .AddTransientHttpErrorPolicy(p =>
        p.CircuitBreakerAsync(
            handledEventsAllowedBeforeBreaking: 3,   // 3 次失敗就斷路
            durationOfBreak: TimeSpan.FromSeconds(30) // 斷路 30 秒
        ))
    .AddTransientHttpErrorPolicy(p =>
        p.WaitAndRetryAsync(3, retryAttempt =>
            TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)) // 指數退避重試
        ));
 
// Security — 資料加密
builder.Services.AddDataProtection()
    .PersistKeysToAzureBlobStorage(blobUri)
    .ProtectKeysWithAzureKeyVault(keyUri, credential);
 
// Performance — Response Caching
builder.Services.AddResponseCaching();
app.UseResponseCaching();
 
[HttpGet("api/products")]
[ResponseCache(Duration = 60)] // 快取 60 秒
public async Task<ActionResult<IEnumerable<ProductDto>>> GetProducts()
{
    return Ok(await _productService.GetAllAsync());
}

// Operational Excellence — 結構化日誌
import winston from "winston";
 
const logger = winston.createLogger({
  format: winston.format.combine(
    winston.format.timestamp(),
    winston.format.json() // 結構化 JSON 格式
  ),
  transports: [
    new winston.transports.Console(),
    new winston.transports.File({ filename: "app.log" }),
  ],
});
 
// 每次請求記錄結構化日誌
app.use((req, res, next) => {
  const start = Date.now();
  res.on("finish", () => {
    logger.info("HTTP Request", {
      method: req.method,
      path: req.path,
      statusCode: res.statusCode,
      durationMs: Date.now() - start,
      userAgent: req.headers["user-agent"],
    });
  });
  next();
});
 
// Reliability — Graceful Shutdown
process.on("SIGTERM", async () => {
  logger.info("SIGTERM received, shutting down gracefully");
  server.close(() => {
    db.disconnect();
    process.exit(0);
  });
  // 強制超時
  setTimeout(() => process.exit(1), 10000);
});

# Performance Efficiency — 快取策略
from functools import lru_cache
import redis
 
redis_client = redis.Redis(host="localhost", port=6379)
 
# 應用層快取 — 減少資料庫查詢
async def get_product(product_id: int) -> dict:
    cache_key = f"product:{product_id}"
 
    # 先查 Redis
    cached = redis_client.get(cache_key)
    if cached:
        return json.loads(cached)
 
    # Cache Miss — 查資料庫
    product = await db.products.find_one({"id": product_id})
    if product:
        redis_client.setex(cache_key, 300, json.dumps(product))  # 快取 5 分鐘
 
    return product
 
# Reliability — 重試機制
from tenacity import retry, stop_after_attempt, wait_exponential
 
@retry(
    stop=stop_after_attempt(3),
    wait=wait_exponential(multiplier=1, min=1, max=10),
)
async def call_external_api(url: str) -> dict:
    async with httpx.AsyncClient() as client:
        response = await client.get(url, timeout=5.0)
        response.raise_for_status()
        return response.json()