[AUR-420] Provide document store base interface and an in-memory version (#21)

Document store handles storing and indexing Documents. It supports the following interfaces:

- add: add 1 or more documents into document store
- get: get a list of documents
- get_all: get all documents in a document store
- delete: delete 1 or more document
- save: persist a document store into disk
- load: load a document store from disk

knowledgehub/docstores/__init__.py

@@ -0,0 +1,4 @@
+from .base import BaseDocumentStore
+from .simple import InMemoryDocumentStore
+
+__all__ = ["BaseDocumentStore", "InMemoryDocumentStore"]

knowledgehub/docstores/base.py

@@ -0,0 +1,54 @@
+from abc import ABC, abstractmethod
+from pathlib import Path
+from typing import List, Optional, Union
+
+from ..documents.base import Document
+
+
+class BaseDocumentStore(ABC):
+    """A document store is in charged of storing and managing documents"""
+
+    @abstractmethod
+    def __init__(self, *args, **kwargs):
+        ...
+
+    @abstractmethod
+    def add(
+        self,
+        docs: Union[Document, List[Document]],
+        ids: Optional[Union[List[str], str]] = None,
+        exist_ok: bool = False,
+    ):
+        """Add document into document store
+
+        Args:
+            docs: Document or list of documents
+            ids: List of ids of the documents. Optional, if not set will use doc.doc_id
+            exist_ok: If True, will not raise error if document already exist
+        """
+        ...
+
+    @abstractmethod
+    def get(self, ids: Union[List[str], str]) -> List[Document]:
+        """Get document by id"""
+        ...
+
+    @abstractmethod
+    def get_all(self) -> dict:
+        """Get all documents"""
+        ...
+
+    @abstractmethod
+    def delete(self, ids: Union[List[str], str]):
+        """Delete document by id"""
+        ...
+
+    @abstractmethod
+    def save(self, path: Union[str, Path]):
+        """Save document to path"""
+        ...
+
+    @abstractmethod
+    def load(self, path: Union[str, Path]):
+        """Load document store from path"""
+        ...

knowledgehub/docstores/simple.py

@@ -0,0 +1,68 @@
+import json
+from pathlib import Path
+from typing import List, Optional, Union
+
+from ..documents.base import Document
+from .base import BaseDocumentStore
+
+
+class InMemoryDocumentStore(BaseDocumentStore):
+    """Simple memory document store that store document in a dictionary"""
+
+    def __init__(self):
+        self.store = {}
+
+    def add(
+        self,
+        docs: Union[Document, List[Document]],
+        ids: Optional[Union[List[str], str]] = None,
+        exist_ok: bool = False,
+    ):
+        """Add document into document store
+
+        Args:
+            docs: Union[Document, List[Document]],
+            ids: Optional[Union[List[str], str]] = None,
+        """
+        doc_ids = ids if ids else [doc.doc_id for doc in docs]
+        if not isinstance(doc_ids, list):
+            doc_ids = [doc_ids]
+
+        if not isinstance(docs, list):
+            docs = [docs]
+
+        for doc_id, doc in zip(doc_ids, docs):
+            if doc_id in self.store and not exist_ok:
+                raise ValueError(f"Document with id {doc_id} already exist")
+            self.store[doc_id] = doc
+
+    def get(self, ids: Union[List[str], str]) -> List[Document]:
+        """Get document by id"""
+        if not isinstance(ids, list):
+            ids = [ids]
+
+        return [self.store[doc_id] for doc_id in ids]
+
+    def get_all(self) -> dict:
+        """Get all documents"""
+        return self.store
+
+    def delete(self, ids: Union[List[str], str]):
+        """Delete document by id"""
+        if not isinstance(ids, list):
+            ids = [ids]
+
+        for doc_id in ids:
+            del self.store[doc_id]
+
+    def save(self, path: Union[str, Path]):
+        """Save document to path"""
+        store = {key: value.to_dict() for key, value in self.store.items()}
+        with open(path, "w") as f:
+            json.dump(store, f)
+
+    def load(self, path: Union[str, Path]):
+        """Load document store from path"""
+        with open(path) as f:
+            store = json.load(f)
+        self.store = {key: Document.from_dict(value) for key, value in store.items()}

knowledgehub/embeddings/base.py

@@ -1,7 +1,7 @@
 from abc import abstractmethod
 from typing import List, Type
 
-from langchain.embeddings.base import Embeddings as LCEmbeddings
+from langchain.schema.embeddings import Embeddings as LCEmbeddings
 from theflow import Param
 
 from ..components import BaseComponent