DB接続を環境変数からでも行えるように変更

app/db/session.py

@@ -77,6 +77,35 @@ def _parse_database_url(database_url: str) -> dict:
     return {key: val for key, val in connect_kwargs.items() if val not in {None, ""}}
 
 
+def _build_connect_kwargs_from_env() -> Optional[dict]:
+    host = _get_env("DB_HOST")
+    database = _get_env("DB_NAME") or _get_env("DB_DATABASE")
+    if not host or not database:
+        return None
+
+    connect_kwargs = {
+        "host": host,
+        "port": int(_get_env("DB_PORT", "3306")),  # TODO: DB_PORTのenv追加
+        "user": _get_env("DB_USER", ""),  # TODO: DB_USERのenv追加
+        "password": _get_env("DB_PASSWORD", ""),  # TODO: DB_PASSWORDのenv追加
+        "database": database,
+        "charset": _get_env("DB_CHARSET", "utf8mb4"),  # TODO: DB_CHARSETのenv追加
+        "autocommit": _str_to_bool(
+            _get_env("DB_AUTOCOMMIT", "true")
+        ),  # TODO: DB_AUTOCOMMITのenv追加
+    }
+
+    connect_timeout = _get_env("DB_CONNECT_TIMEOUT")
+    if connect_timeout:
+        connect_kwargs["connect_timeout"] = float(connect_timeout)
+
+    ssl_root_cert = _get_env("SSL_ROOT_CERT")
+    if ssl_root_cert:
+        connect_kwargs["ssl"] = {"ca": ssl_root_cert}
+
+    return {key: val for key, val in connect_kwargs.items() if val not in {None, ""}}
+
+
 class MySQLConnectionPool:
     """Simple thread-safe connection pool for PyMySQL."""
 
@@ -183,10 +212,15 @@ def _ensure_pool() -> MySQLConnectionPool:
             return _pool
 
         database_url = _get_env("DATABASE_URL")
-        if not database_url:
-            raise RuntimeError("DATABASE_URL is not set")
+        if database_url:
+            connect_kwargs = _parse_database_url(database_url)
+        else:
+            connect_kwargs = _build_connect_kwargs_from_env()
+            if connect_kwargs is None:
+                raise RuntimeError(
+                    "DATABASE_URL or DB_HOST and DB_NAME must be set in the environment"
+                )
 
-        connect_kwargs = _parse_database_url(database_url)
         min_size = int(_get_env("DB_POOL_MIN_SIZE", "1"))
         max_size = int(_get_env("DB_POOL_MAX_SIZE", "5"))