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langchain/libs/experimental/langchain_experimental/graph_transformers/llm.py

692 lines
26 KiB
Python

import asyncio
import json
from typing import Any, Dict, List, Optional, Sequence, Tuple, Type, Union, cast
from langchain_community.graphs.graph_document import GraphDocument, Node, Relationship
from langchain_core.documents import Document
from langchain_core.language_models import BaseLanguageModel
from langchain_core.messages import SystemMessage
from langchain_core.output_parsers import JsonOutputParser
from langchain_core.prompts import (
ChatPromptTemplate,
HumanMessagePromptTemplate,
PromptTemplate,
)
from langchain_core.pydantic_v1 import BaseModel, Field, create_model
examples = [
{
"text": (
"Adam is a software engineer in Microsoft since 2009, "
"and last year he got an award as the Best Talent"
),
"head": "Adam",
"head_type": "Person",
"relation": "WORKS_FOR",
"tail": "Microsoft",
"tail_type": "Company",
},
{
"text": (
"Adam is a software engineer in Microsoft since 2009, "
"and last year he got an award as the Best Talent"
),
"head": "Adam",
"head_type": "Person",
"relation": "HAS_AWARD",
"tail": "Best Talent",
"tail_type": "Award",
},
{
"text": (
"Microsoft is a tech company that provide "
"several products such as Microsoft Word"
),
"head": "Microsoft Word",
"head_type": "Product",
"relation": "PRODUCED_BY",
"tail": "Microsoft",
"tail_type": "Company",
},
{
"text": "Microsoft Word is a lightweight app that accessible offline",
"head": "Microsoft Word",
"head_type": "Product",
"relation": "HAS_CHARACTERISTIC",
"tail": "lightweight app",
"tail_type": "Characteristic",
},
{
"text": "Microsoft Word is a lightweight app that accessible offline",
"head": "Microsoft Word",
"head_type": "Product",
"relation": "HAS_CHARACTERISTIC",
"tail": "accessible offline",
"tail_type": "Characteristic",
},
]
system_prompt = (
"# Knowledge Graph Instructions for GPT-4\n"
"## 1. Overview\n"
"You are a top-tier algorithm designed for extracting information in structured "
"formats to build a knowledge graph.\n"
"Try to capture as much information from the text as possible without "
"sacrifing accuracy. Do not add any information that is not explicitly "
"mentioned in the text\n"
"- **Nodes** represent entities and concepts.\n"
"- The aim is to achieve simplicity and clarity in the knowledge graph, making it\n"
"accessible for a vast audience.\n"
"## 2. Labeling Nodes\n"
"- **Consistency**: Ensure you use available types for node labels.\n"
"Ensure you use basic or elementary types for node labels.\n"
"- For example, when you identify an entity representing a person, "
"always label it as **'person'**. Avoid using more specific terms "
"like 'mathematician' or 'scientist'"
" - **Node IDs**: Never utilize integers as node IDs. Node IDs should be "
"names or human-readable identifiers found in the text.\n"
"- **Relationships** represent connections between entities or concepts.\n"
"Ensure consistency and generality in relationship types when constructing "
"knowledge graphs. Instead of using specific and momentary types "
"such as 'BECAME_PROFESSOR', use more general and timeless relationship types "
"like 'PROFESSOR'. Make sure to use general and timeless relationship types!\n"
"## 3. Coreference Resolution\n"
"- **Maintain Entity Consistency**: When extracting entities, it's vital to "
"ensure consistency.\n"
'If an entity, such as "John Doe", is mentioned multiple times in the text '
'but is referred to by different names or pronouns (e.g., "Joe", "he"),'
"always use the most complete identifier for that entity throughout the "
'knowledge graph. In this example, use "John Doe" as the entity ID.\n'
"Remember, the knowledge graph should be coherent and easily understandable, "
"so maintaining consistency in entity references is crucial.\n"
"## 4. Strict Compliance\n"
"Adhere to the rules strictly. Non-compliance will result in termination."
)
default_prompt = ChatPromptTemplate.from_messages(
[
(
"system",
system_prompt,
),
(
"human",
(
"Tip: Make sure to answer in the correct format and do "
"not include any explanations. "
"Use the given format to extract information from the "
"following input: {input}"
),
),
]
)
def _get_additional_info(input_type: str) -> str:
# Check if the input_type is one of the allowed values
if input_type not in ["node", "relationship", "property"]:
raise ValueError("input_type must be 'node', 'relationship', or 'property'")
# Perform actions based on the input_type
if input_type == "node":
return (
"Ensure you use basic or elementary types for node labels.\n"
"For example, when you identify an entity representing a person, "
"always label it as **'Person'**. Avoid using more specific terms "
"like 'Mathematician' or 'Scientist'"
)
elif input_type == "relationship":
return (
"Instead of using specific and momentary types such as "
"'BECAME_PROFESSOR', use more general and timeless relationship types like "
"'PROFESSOR'. However, do not sacrifice any accuracy for generality"
)
elif input_type == "property":
return ""
return ""
def optional_enum_field(
enum_values: Optional[List[str]] = None,
description: str = "",
input_type: str = "node",
**field_kwargs: Any,
) -> Any:
"""Utility function to conditionally create a field with an enum constraint."""
if enum_values:
return Field(
...,
enum=enum_values,
description=f"{description}. Available options are {enum_values}",
**field_kwargs,
)
else:
additional_info = _get_additional_info(input_type)
return Field(..., description=description + additional_info, **field_kwargs)
class _Graph(BaseModel):
nodes: Optional[List]
relationships: Optional[List]
class UnstructuredRelation(BaseModel):
head: str = Field(
description=(
"extracted head entity like Microsoft, Apple, John. "
"Must use human-readable unique identifier."
)
)
head_type: str = Field(
description="type of the extracted head entity like Person, Company, etc"
)
relation: str = Field(description="relation between the head and the tail entities")
tail: str = Field(
description=(
"extracted tail entity like Microsoft, Apple, John. "
"Must use human-readable unique identifier."
)
)
tail_type: str = Field(
description="type of the extracted tail entity like Person, Company, etc"
)
def create_unstructured_prompt(
node_labels: Optional[List[str]] = None, rel_types: Optional[List[str]] = None
) -> ChatPromptTemplate:
node_labels_str = str(node_labels) if node_labels else ""
rel_types_str = str(rel_types) if rel_types else ""
base_string_parts = [
"You are a top-tier algorithm designed for extracting information in "
"structured formats to build a knowledge graph. Your task is to identify "
"the entities and relations requested with the user prompt from a given "
"text. You must generate the output in a JSON format containing a list "
'with JSON objects. Each object should have the keys: "head", '
'"head_type", "relation", "tail", and "tail_type". The "head" '
"key must contain the text of the extracted entity with one of the types "
"from the provided list in the user prompt.",
f'The "head_type" key must contain the type of the extracted head entity, '
f"which must be one of the types from {node_labels_str}."
if node_labels
else "",
f'The "relation" key must contain the type of relation between the "head" '
f'and the "tail", which must be one of the relations from {rel_types_str}.'
if rel_types
else "",
f'The "tail" key must represent the text of an extracted entity which is '
f'the tail of the relation, and the "tail_type" key must contain the type '
f"of the tail entity from {node_labels_str}."
if node_labels
else "",
"Attempt to extract as many entities and relations as you can. Maintain "
"Entity Consistency: When extracting entities, it's vital to ensure "
'consistency. If an entity, such as "John Doe", is mentioned multiple '
"times in the text but is referred to by different names or pronouns "
'(e.g., "Joe", "he"), always use the most complete identifier for '
"that entity. The knowledge graph should be coherent and easily "
"understandable, so maintaining consistency in entity references is "
"crucial.",
"IMPORTANT NOTES:\n- Don't add any explanation and text.",
]
system_prompt = "\n".join(filter(None, base_string_parts))
system_message = SystemMessage(content=system_prompt)
parser = JsonOutputParser(pydantic_object=UnstructuredRelation)
human_prompt = PromptTemplate(
template="""Based on the following example, extract entities and
relations from the provided text.\n\n
Use the following entity types, don't use other entity that is not defined below:
# ENTITY TYPES:
{node_labels}
Use the following relation types, don't use other relation that is not defined below:
# RELATION TYPES:
{rel_types}
Below are a number of examples of text and their extracted entities and relationships.
{examples}
For the following text, extract entities and relations as in the provided example.
{format_instructions}\nText: {input}""",
input_variables=["input"],
partial_variables={
"format_instructions": parser.get_format_instructions(),
"node_labels": node_labels,
"rel_types": rel_types,
"examples": examples,
},
)
human_message_prompt = HumanMessagePromptTemplate(prompt=human_prompt)
chat_prompt = ChatPromptTemplate.from_messages(
[system_message, human_message_prompt]
)
return chat_prompt
def create_simple_model(
node_labels: Optional[List[str]] = None,
rel_types: Optional[List[str]] = None,
node_properties: Union[bool, List[str]] = False,
) -> Type[_Graph]:
"""
Simple model allows to limit node and/or relationship types.
Doesn't have any node or relationship properties.
"""
node_fields: Dict[str, Tuple[Any, Any]] = {
"id": (
str,
Field(..., description="Name or human-readable unique identifier."),
),
"type": (
str,
optional_enum_field(
node_labels,
description="The type or label of the node.",
input_type="node",
),
),
}
if node_properties:
if isinstance(node_properties, list) and "id" in node_properties:
raise ValueError("The node property 'id' is reserved and cannot be used.")
# Map True to empty array
node_properties_mapped: List[str] = (
[] if node_properties is True else node_properties
)
class Property(BaseModel):
"""A single property consisting of key and value"""
key: str = optional_enum_field(
node_properties_mapped,
description="Property key.",
input_type="property",
)
value: str = Field(..., description="value")
node_fields["properties"] = (
Optional[List[Property]],
Field(None, description="List of node properties"),
)
SimpleNode = create_model("SimpleNode", **node_fields) # type: ignore
class SimpleRelationship(BaseModel):
"""Represents a directed relationship between two nodes in a graph."""
source_node_id: str = Field(
description="Name or human-readable unique identifier of source node"
)
source_node_type: str = optional_enum_field(
node_labels,
description="The type or label of the source node.",
input_type="node",
)
target_node_id: str = Field(
description="Name or human-readable unique identifier of target node"
)
target_node_type: str = optional_enum_field(
node_labels,
description="The type or label of the target node.",
input_type="node",
)
type: str = optional_enum_field(
rel_types,
description="The type of the relationship.",
input_type="relationship",
)
class DynamicGraph(_Graph):
"""Represents a graph document consisting of nodes and relationships."""
nodes: Optional[List[SimpleNode]] = Field(description="List of nodes") # type: ignore
relationships: Optional[List[SimpleRelationship]] = Field(
description="List of relationships"
)
return DynamicGraph
def map_to_base_node(node: Any) -> Node:
"""Map the SimpleNode to the base Node."""
properties = {}
if hasattr(node, "properties") and node.properties:
for p in node.properties:
properties[format_property_key(p.key)] = p.value
return Node(id=node.id, type=node.type, properties=properties)
def map_to_base_relationship(rel: Any) -> Relationship:
"""Map the SimpleRelationship to the base Relationship."""
source = Node(id=rel.source_node_id, type=rel.source_node_type)
target = Node(id=rel.target_node_id, type=rel.target_node_type)
return Relationship(source=source, target=target, type=rel.type)
def _parse_and_clean_json(
argument_json: Dict[str, Any],
) -> Tuple[List[Node], List[Relationship]]:
nodes = []
for node in argument_json["nodes"]:
if not node.get("id"): # Id is mandatory, skip this node
continue
nodes.append(
Node(
id=node["id"],
type=node.get("type"),
)
)
relationships = []
for rel in argument_json["relationships"]:
# Mandatory props
if (
not rel.get("source_node_id")
or not rel.get("target_node_id")
or not rel.get("type")
):
continue
# Node type copying if needed from node list
if not rel.get("source_node_type"):
try:
rel["source_node_type"] = [
el.get("type")
for el in argument_json["nodes"]
if el["id"] == rel["source_node_id"]
][0]
except IndexError:
rel["source_node_type"] = None
if not rel.get("target_node_type"):
try:
rel["target_node_type"] = [
el.get("type")
for el in argument_json["nodes"]
if el["id"] == rel["target_node_id"]
][0]
except IndexError:
rel["target_node_type"] = None
source_node = Node(
id=rel["source_node_id"],
type=rel["source_node_type"],
)
target_node = Node(
id=rel["target_node_id"],
type=rel["target_node_type"],
)
relationships.append(
Relationship(
source=source_node,
target=target_node,
type=rel["type"],
)
)
return nodes, relationships
def _format_nodes(nodes: List[Node]) -> List[Node]:
return [
Node(
id=el.id.title() if isinstance(el.id, str) else el.id,
type=el.type.capitalize(),
properties=el.properties,
)
for el in nodes
]
def _format_relationships(rels: List[Relationship]) -> List[Relationship]:
return [
Relationship(
source=_format_nodes([el.source])[0],
target=_format_nodes([el.target])[0],
type=el.type.replace(" ", "_").upper(),
)
for el in rels
]
def format_property_key(s: str) -> str:
words = s.split()
if not words:
return s
first_word = words[0].lower()
capitalized_words = [word.capitalize() for word in words[1:]]
return "".join([first_word] + capitalized_words)
def _convert_to_graph_document(
raw_schema: Dict[Any, Any],
) -> Tuple[List[Node], List[Relationship]]:
# If there are validation errors
if not raw_schema["parsed"]:
try:
try: # OpenAI type response
argument_json = json.loads(
raw_schema["raw"].additional_kwargs["tool_calls"][0]["function"][
"arguments"
]
)
except Exception: # Google type response
argument_json = json.loads(
raw_schema["raw"].additional_kwargs["function_call"]["arguments"]
)
nodes, relationships = _parse_and_clean_json(argument_json)
except Exception: # If we can't parse JSON
return ([], [])
else: # If there are no validation errors use parsed pydantic object
parsed_schema: _Graph = raw_schema["parsed"]
nodes = (
[map_to_base_node(node) for node in parsed_schema.nodes]
if parsed_schema.nodes
else []
)
relationships = (
[map_to_base_relationship(rel) for rel in parsed_schema.relationships]
if parsed_schema.relationships
else []
)
# Title / Capitalize
return _format_nodes(nodes), _format_relationships(relationships)
class LLMGraphTransformer:
"""Transform documents into graph-based documents using a LLM.
It allows specifying constraints on the types of nodes and relationships to include
in the output graph. The class doesn't support neither extract and node or
relationship properties
Args:
llm (BaseLanguageModel): An instance of a language model supporting structured
output.
allowed_nodes (List[str], optional): Specifies which node types are
allowed in the graph. Defaults to an empty list, allowing all node types.
allowed_relationships (List[str], optional): Specifies which relationship types
are allowed in the graph. Defaults to an empty list, allowing all relationship
types.
prompt (Optional[ChatPromptTemplate], optional): The prompt to pass to
the LLM with additional instructions.
strict_mode (bool, optional): Determines whether the transformer should apply
filtering to strictly adhere to `allowed_nodes` and `allowed_relationships`.
Defaults to True.
Example:
.. code-block:: python
from langchain_experimental.graph_transformers import LLMGraphTransformer
from langchain_core.documents import Document
from langchain_openai import ChatOpenAI
llm=ChatOpenAI(temperature=0)
transformer = LLMGraphTransformer(
llm=llm,
allowed_nodes=["Person", "Organization"])
doc = Document(page_content="Elon Musk is suing OpenAI")
graph_documents = transformer.convert_to_graph_documents([doc])
"""
def __init__(
self,
llm: BaseLanguageModel,
allowed_nodes: List[str] = [],
allowed_relationships: List[str] = [],
prompt: Optional[ChatPromptTemplate] = None,
strict_mode: bool = True,
node_properties: Union[bool, List[str]] = False,
) -> None:
self.allowed_nodes = allowed_nodes
self.allowed_relationships = allowed_relationships
self.strict_mode = strict_mode
self._function_call = True
# Check if the LLM really supports structured output
try:
llm.with_structured_output(_Graph)
except NotImplementedError:
self._function_call = False
if not self._function_call:
if node_properties:
raise ValueError(
"The 'node_properties' parameter cannot be used "
"in combination with a LLM that doesn't support "
"native function calling."
)
try:
import json_repair
self.json_repair = json_repair
except ImportError:
raise ImportError(
"Could not import json_repair python package. "
"Please install it with `pip install json-repair`."
)
prompt = prompt or create_unstructured_prompt(
allowed_nodes, allowed_relationships
)
self.chain = prompt | llm
else:
# Define chain
schema = create_simple_model(
allowed_nodes, allowed_relationships, node_properties
)
structured_llm = llm.with_structured_output(schema, include_raw=True)
prompt = prompt or default_prompt
self.chain = prompt | structured_llm
def process_response(self, document: Document) -> GraphDocument:
"""
Processes a single document, transforming it into a graph document using
an LLM based on the model's schema and constraints.
"""
text = document.page_content
raw_schema = self.chain.invoke({"input": text})
if self._function_call:
raw_schema = cast(Dict[Any, Any], raw_schema)
nodes, relationships = _convert_to_graph_document(raw_schema)
else:
nodes_set = set()
relationships = []
parsed_json = self.json_repair.loads(raw_schema.content)
for rel in parsed_json:
# Nodes need to be deduplicated using a set
nodes_set.add((rel["head"], rel["head_type"]))
nodes_set.add((rel["tail"], rel["tail_type"]))
source_node = Node(id=rel["head"], type=rel["head_type"])
target_node = Node(id=rel["tail"], type=rel["tail_type"])
relationships.append(
Relationship(
source=source_node, target=target_node, type=rel["relation"]
)
)
# Create nodes list
nodes = [Node(id=el[0], type=el[1]) for el in list(nodes_set)]
# Strict mode filtering
if self.strict_mode and (self.allowed_nodes or self.allowed_relationships):
if self.allowed_nodes:
lower_allowed_nodes = [el.lower() for el in self.allowed_nodes]
nodes = [
node for node in nodes if node.type.lower() in lower_allowed_nodes
]
relationships = [
rel
for rel in relationships
if rel.source.type.lower() in lower_allowed_nodes
and rel.target.type.lower() in lower_allowed_nodes
]
if self.allowed_relationships:
relationships = [
rel
for rel in relationships
if rel.type.lower()
in [el.lower() for el in self.allowed_relationships]
]
return GraphDocument(nodes=nodes, relationships=relationships, source=document)
def convert_to_graph_documents(
self, documents: Sequence[Document]
) -> List[GraphDocument]:
"""Convert a sequence of documents into graph documents.
Args:
documents (Sequence[Document]): The original documents.
**kwargs: Additional keyword arguments.
Returns:
Sequence[GraphDocument]: The transformed documents as graphs.
"""
return [self.process_response(document) for document in documents]
async def aprocess_response(self, document: Document) -> GraphDocument:
"""
Asynchronously processes a single document, transforming it into a
graph document.
"""
text = document.page_content
raw_schema = await self.chain.ainvoke({"input": text})
raw_schema = cast(Dict[Any, Any], raw_schema)
nodes, relationships = _convert_to_graph_document(raw_schema)
if self.strict_mode and (self.allowed_nodes or self.allowed_relationships):
if self.allowed_nodes:
lower_allowed_nodes = [el.lower() for el in self.allowed_nodes]
nodes = [
node for node in nodes if node.type.lower() in lower_allowed_nodes
]
relationships = [
rel
for rel in relationships
if rel.source.type.lower() in lower_allowed_nodes
and rel.target.type.lower() in lower_allowed_nodes
]
if self.allowed_relationships:
relationships = [
rel
for rel in relationships
if rel.type.lower()
in [el.lower() for el in self.allowed_relationships]
]
return GraphDocument(nodes=nodes, relationships=relationships, source=document)
async def aconvert_to_graph_documents(
self, documents: Sequence[Document]
) -> List[GraphDocument]:
"""
Asynchronously convert a sequence of documents into graph documents.
"""
tasks = [
asyncio.create_task(self.aprocess_response(document))
for document in documents
]
results = await asyncio.gather(*tasks)
return results