Feat/dify rag (#2528)

Co-authored-by: jyong <jyong@dify.ai>

api/core/rag/datasource/entity/embedding.py

@@ -0,0 +1,21 @@
+from abc import ABC, abstractmethod
+
+
+class Embeddings(ABC):
+    """Interface for embedding models."""
+
+    @abstractmethod
+    def embed_documents(self, texts: list[str]) -> list[list[float]]:
+        """Embed search docs."""
+
+    @abstractmethod
+    def embed_query(self, text: str) -> list[float]:
+        """Embed query text."""
+
+    async def aembed_documents(self, texts: list[str]) -> list[list[float]]:
+        """Asynchronous Embed search docs."""
+        raise NotImplementedError
+
+    async def aembed_query(self, text: str) -> list[float]:
+        """Asynchronous Embed query text."""
+        raise NotImplementedError