Fix/llm bugs empty extraction (#1533)

* Add llm singleton and check for empty extraction

* Semver

* Tests and spellcheck

* Move the singletons to a proper place

* Leftover print

* Ruff

.semversioner/next-release/patch-20241218221915558063.json

@@ -0,0 +1,4 @@
+{
+  "type": "patch",
+  "description": "Manage llm instances inside a cached singleton. Check for empty dfs after entity/relationship extraction"
+}

graphrag/index/flows/extract_graph.py

@@ -52,6 +52,18 @@ async def extract_graph(
         num_threads=extraction_num_threads,
     )
 
+    if not _validate_data(entity_dfs):
+        error_msg = "Entity Extraction failed. No entities detected during extraction."
+        callbacks.error(error_msg)
+        raise ValueError(error_msg)
+
+    if not _validate_data(relationship_dfs):
+        error_msg = (
+            "Entity Extraction failed. No relationships detected during extraction."
+        )
+        callbacks.error(error_msg)
+        raise ValueError(error_msg)
+
     merged_entities = _merge_entities(entity_dfs)
     merged_relationships = _merge_relationships(relationship_dfs)
 
@@ -145,3 +157,10 @@ def _compute_degree(graph: nx.Graph) -> pd.DataFrame:
         {"name": node, "degree": int(degree)}
         for node, degree in graph.degree  # type: ignore
     ])
+
+
+def _validate_data(df_list: list[pd.DataFrame]) -> bool:
+    """Validate that the dataframe list is valid. At least one dataframe must contain data."""
+    return any(
+        len(df) > 0 for df in df_list
+    )  # Check for len, not .empty, as the dfs have schemas in some cases

graphrag/index/llm/load_llm.py

@@ -24,6 +24,7 @@ from pydantic import TypeAdapter
 import graphrag.config.defaults as defs
 from graphrag.config.enums import LLMType
 from graphrag.config.models.llm_parameters import LLMParameters
+from graphrag.index.llm.manager import ChatLLMSingleton, EmbeddingsLLMSingleton
 
 from .mock_llm import MockChatLLM
 
@@ -110,6 +111,10 @@ def load_llm(
     chat_only=False,
 ) -> ChatLLM:
     """Load the LLM for the entity extraction chain."""
+    singleton_llm = ChatLLMSingleton().get_llm(name)
+    if singleton_llm is not None:
+        return singleton_llm
+
     on_error = _create_error_handler(callbacks)
     llm_type = config.type
 
@@ -119,7 +124,9 @@ def load_llm(
             raise ValueError(msg)
 
         loader = loaders[llm_type]
-        return loader["load"](on_error, create_cache(cache, name), config)
+        llm_instance = loader["load"](on_error, create_cache(cache, name), config)
+        ChatLLMSingleton().set_llm(name, llm_instance)
+        return llm_instance
 
     msg = f"Unknown LLM type {llm_type}"
     raise ValueError(msg)
@@ -134,15 +141,21 @@ def load_llm_embeddings(
     chat_only=False,
 ) -> EmbeddingsLLM:
     """Load the LLM for the entity extraction chain."""
+    singleton_llm = EmbeddingsLLMSingleton().get_llm(name)
+    if singleton_llm is not None:
+        return singleton_llm
+
     on_error = _create_error_handler(callbacks)
     llm_type = llm_config.type
     if llm_type in loaders:
         if chat_only and not loaders[llm_type]["chat"]:
             msg = f"LLM type {llm_type} does not support chat"
             raise ValueError(msg)
-        return loaders[llm_type]["load"](
+        llm_instance = loaders[llm_type]["load"](
             on_error, create_cache(cache, name), llm_config or {}
         )
+        EmbeddingsLLMSingleton().set_llm(name, llm_instance)
+        return llm_instance
 
     msg = f"Unknown LLM type {llm_type}"
     raise ValueError(msg)
@@ -198,6 +211,7 @@ def _create_openai_config(config: LLMParameters, azure: bool) -> OpenAIConfig:
         n=config.n,
         temperature=config.temperature,
     )
+
     if azure:
         if config.api_base is None:
             msg = "Azure OpenAI Chat LLM requires an API base"

graphrag/index/llm/manager.py

@@ -0,0 +1,40 @@
+# Copyright (c) 2024 Microsoft Corporation.
+# Licensed under the MIT License
+
+"""LLM Manager singleton."""
+
+from functools import cache
+
+from fnllm import ChatLLM, EmbeddingsLLM
+
+
+@cache
+class ChatLLMSingleton:
+    """A singleton class for the chat LLM instances."""
+
+    def __init__(self):
+        self.llm_dict = {}
+
+    def set_llm(self, name, llm):
+        """Add an LLM to the dictionary."""
+        self.llm_dict[name] = llm
+
+    def get_llm(self, name) -> ChatLLM | None:
+        """Get an LLM from the dictionary."""
+        return self.llm_dict.get(name)
+
+
+@cache
+class EmbeddingsLLMSingleton:
+    """A singleton class for the embeddings LLM instances."""
+
+    def __init__(self):
+        self.llm_dict = {}
+
+    def set_llm(self, name, llm):
+        """Add an LLM to the dictionary."""
+        self.llm_dict[name] = llm
+
+    def get_llm(self, name) -> EmbeddingsLLM | None:
+        """Get an LLM from the dictionary."""
+        return self.llm_dict.get(name)