main:添加核心文件并初始化项目

新增内容：
- 创建基础项目结构。
- 添加 `.gitignore` 和 `.dockerignore` 文件。
- 编写 `pyproject.toml` 和依赖文件。
- 添加算法模块及示例算法。
- 实现核心功能模块（日志、错误处理、指标）。
- 添加开发和运行所需的相关脚本文件及文档。

src/functional_scaffold/main.py

@@ -0,0 +1,138 @@
+"""FastAPI 应用入口"""
+
+from fastapi import FastAPI, Request
+from fastapi.middleware.cors import CORSMiddleware
+from fastapi.responses import Response
+from prometheus_client import generate_latest, CONTENT_TYPE_LATEST
+import logging
+import time
+
+from .api import router
+from .config import settings
+from .core.logging import setup_logging
+from .core.metrics import metrics_registry, request_counter, request_latency, in_progress_requests
+
+# 设置日志
+setup_logging(level=settings.log_level, format_type=settings.log_format)
+logger = logging.getLogger(__name__)
+
+# 创建 FastAPI 应用
+app = FastAPI(
+    title=settings.app_name,
+    description="算法工程化 Serverless 脚手架 - 提供标准化的算法服务接口",
+    version=settings.app_version,
+    docs_url="/docs",
+    redoc_url="/redoc",
+    openapi_url="/openapi.json",
+)
+
+# CORS 中间件
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+
+# 请求日志中间件
+@app.middleware("http")
+async def log_requests(request: Request, call_next):
+    """记录所有HTTP请求"""
+    logger.info(f"Request: {request.method} {request.url.path}")
+    response = await call_next(request)
+    logger.info(f"Response: {response.status_code}")
+    return response
+
+
+# 指标跟踪中间件
+@app.middleware("http")
+async def track_metrics(request: Request, call_next):
+    """记录所有HTTP请求的指标"""
+    if not settings.metrics_enabled:
+        return await call_next(request)
+
+    # 跳过 /metrics 端点本身，避免循环记录
+    if request.url.path == "/metrics":
+        return await call_next(request)
+
+    in_progress_requests.inc()
+    start_time = time.time()
+    status = "success"
+
+    try:
+        response = await call_next(request)
+        # 根据 HTTP 状态码判断成功或失败
+        if response.status_code >= 400:
+            status = "error"
+        return response
+    except Exception as e:
+        status = "error"
+        raise e
+    finally:
+        elapsed = time.time() - start_time
+        request_counter.labels(
+            method=request.method,
+            endpoint=request.url.path,
+            status=status
+        ).inc()
+        request_latency.labels(
+            method=request.method,
+            endpoint=request.url.path
+        ).observe(elapsed)
+        in_progress_requests.dec()
+
+
+# 注册路由
+app.include_router(router, tags=["Algorithm"])
+
+
+# Prometheus 指标端点
+@app.get(
+    "/metrics",
+    tags=["Monitoring"],
+    summary="Prometheus 指标",
+    description="导出 Prometheus 格式的监控指标",
+)
+async def metrics():
+    """
+    Prometheus 指标端点
+
+    返回应用的监控指标，供 Prometheus 抓取
+    """
+    if not settings.metrics_enabled:
+        return Response(content="Metrics disabled", status_code=404)
+
+    return Response(
+        content=generate_latest(metrics_registry),
+        media_type=CONTENT_TYPE_LATEST,
+    )
+
+
+# 启动事件
+@app.on_event("startup")
+async def startup_event():
+    """应用启动时执行"""
+    logger.info(f"Starting {settings.app_name} v{settings.app_version}")
+    logger.info(f"Environment: {settings.app_env}")
+    logger.info(f"Metrics enabled: {settings.metrics_enabled}")
+
+
+# 关闭事件
+@app.on_event("shutdown")
+async def shutdown_event():
+    """应用关闭时执行"""
+    logger.info(f"Shutting down {settings.app_name}")
+
+
+if __name__ == "__main__":
+    import uvicorn
+
+    uvicorn.run(
+        "functional_scaffold.main:app",
+        host=settings.host,
+        port=settings.port,
+        reload=settings.app_env == "development",
+        log_level=settings.log_level.lower(),
+    )