feat: upgrade langchain (#430)

Co-authored-by: jyong <718720800@qq.com>

api/core/embedding/cached_embedding.py

@@ -0,0 +1,72 @@
+import logging
+from typing import List
+
+from langchain.embeddings.base import Embeddings
+from sqlalchemy.exc import IntegrityError
+
+from extensions.ext_database import db
+from libs import helper
+from models.dataset import Embedding
+
+
+class CacheEmbedding(Embeddings):
+    def __init__(self, embeddings: Embeddings):
+        self._embeddings = embeddings
+
+    def embed_documents(self, texts: List[str]) -> List[List[float]]:
+        """Embed search docs."""
+        # use doc embedding cache or store if not exists
+        text_embeddings = []
+        embedding_queue_texts = []
+        for text in texts:
+            hash = helper.generate_text_hash(text)
+            embedding = db.session.query(Embedding).filter_by(hash=hash).first()
+            if embedding:
+                text_embeddings.append(embedding.get_embedding())
+            else:
+                embedding_queue_texts.append(text)
+
+        embedding_results = self._embeddings.embed_documents(embedding_queue_texts)
+
+        i = 0
+        for text in embedding_queue_texts:
+            hash = helper.generate_text_hash(text)
+
+            try:
+                embedding = Embedding(hash=hash)
+                embedding.set_embedding(embedding_results[i])
+                db.session.add(embedding)
+                db.session.commit()
+            except IntegrityError:
+                db.session.rollback()
+                continue
+            except:
+                logging.exception('Failed to add embedding to db')
+                continue
+
+            i += 1
+
+        text_embeddings.extend(embedding_results)
+        return text_embeddings
+
+    def embed_query(self, text: str) -> List[float]:
+        """Embed query text."""
+        # use doc embedding cache or store if not exists
+        hash = helper.generate_text_hash(text)
+        embedding = db.session.query(Embedding).filter_by(hash=hash).first()
+        if embedding:
+            return embedding.get_embedding()
+
+        embedding_results = self._embeddings.embed_query(text)
+
+        try:
+            embedding = Embedding(hash=hash)
+            embedding.set_embedding(embedding_results)
+            db.session.add(embedding)
+            db.session.commit()
+        except IntegrityError:
+            db.session.rollback()
+        except:
+            logging.exception('Failed to add embedding to db')
+
+        return embedding_results