正式起服务打底

app/db.py

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+# app/db.py
+from contextlib import contextmanager
+from typing import Iterator
+
+import psycopg2
+from psycopg2.extras import RealDictCursor
+
+from .config import get_settings
+
+
+@contextmanager
+def get_connection(db_name: str) -> Iterator[psycopg2.extensions.connection]:
+    """
+    简单连接管理：每次请求开一个连接，用完就关。
+    当前访问量不高，这种写法足够。
+    """
+    settings = get_settings()
+    conn = psycopg2.connect(
+        host=settings.db_host,
+        port=settings.db_port,
+        user=settings.db_user,
+        password=settings.db_password,
+        dbname=db_name,
+    )
+    try:
+        # 设置 schema = XCX
+        with conn.cursor() as cur:
+            cur.execute("SET search_path TO %s;", (settings.db_schema,))
+        yield conn
+    finally:
+        conn.close()
+
+
+def check_health(db_name: str) -> bool:
+    """
+    DB 健康检查：SELECT 1
+    """
+    with get_connection(db_name) as conn:
+        with conn.cursor(cursor_factory=RealDictCursor) as cur:
+            cur.execute("SELECT 1 AS v;")
+            row = cur.fetchone()
+            return row["v"] == 1