feat: introduce pydantic-settings for config definition and validation (#5202)

Co-authored-by: -LAN- <laipz8200@outlook.com>

api/configs/middleware/__init__.py

@@ -0,0 +1,43 @@
+from typing import Optional
+
+from pydantic import BaseModel, Field
+
+from configs.middleware.redis_configs import RedisConfigs
+
+
+class StorageConfigs(BaseModel):
+    STORAGE_TYPE: str = Field(
+        description='storage type,'
+                    ' default to `local`,'
+                    ' available values are `local`, `s3`, `azure-blob`, `aliyun-oss`, `google-storage`.',
+        default='local',
+    )
+
+    STORAGE_LOCAL_PATH: str = Field(
+        description='local storage path',
+        default='storage',
+    )
+
+
+class VectorStoreConfigs(BaseModel):
+    VECTOR_STORE: Optional[str] = Field(
+        description='vector store type',
+        default=None,
+    )
+
+
+class KeywordStoreConfigs(BaseModel):
+    KEYWORD_STORE: str = Field(
+        description='keyword store type',
+        default='jieba',
+    )
+
+
+class MiddlewareConfigs(
+    # place the configs in alphabet order
+    KeywordStoreConfigs,
+    RedisConfigs,
+    StorageConfigs,
+    VectorStoreConfigs,
+):
+    pass