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langchain/libs/community/langchain_community/document_compressors/flashrank_rerank.py
Harrison Chase 8516a03a02 langchain-community[major]: Upgrade community to pydantic 2 (#26011)
This PR upgrades langchain-community to pydantic 2.


* Most of this PR was auto-generated using code mods with gritql
(https://github.com/eyurtsev/migrate-pydantic/tree/main)
* Subsequently, some code was fixed manually due to accommodate
differences between pydantic 1 and 2

Breaking Changes:

- Use TEXTEMBED_API_KEY and TEXTEMBEB_API_URL for env variables for text
embed integrations:
cbea780492

Other changes:

- Added pydantic_settings as a required dependency for community. This
may be removed if we have enough time to convert the dependency into an
optional one.

---------

Co-authored-by: Eugene Yurtsev <eyurtsev@gmail.com>
Co-authored-by: Bagatur <baskaryan@gmail.com>
2024-09-05 14:07:10 -04:00

87 lines
2.8 KiB
Python

from __future__ import annotations
from typing import TYPE_CHECKING, Any, Dict, Optional, Sequence
from langchain_core.callbacks.manager import Callbacks
from langchain_core.documents import BaseDocumentCompressor, Document
from pydantic import ConfigDict, model_validator
if TYPE_CHECKING:
from flashrank import Ranker, RerankRequest
else:
# Avoid pydantic annotation issues when actually instantiating
# while keeping this import optional
try:
from flashrank import Ranker, RerankRequest
except ImportError:
pass
DEFAULT_MODEL_NAME = "ms-marco-MultiBERT-L-12"
class FlashrankRerank(BaseDocumentCompressor):
"""Document compressor using Flashrank interface."""
client: Ranker
"""Flashrank client to use for compressing documents"""
top_n: int = 3
"""Number of documents to return."""
score_threshold: float = 0.0
"""Minimum relevance threshold to return."""
model: Optional[str] = None
"""Model to use for reranking."""
prefix_metadata: str = ""
"""Prefix for flashrank_rerank metadata keys"""
model_config = ConfigDict(
arbitrary_types_allowed=True,
extra="forbid",
)
@model_validator(mode="before")
@classmethod
def validate_environment(cls, values: Dict) -> Any:
"""Validate that api key and python package exists in environment."""
if "client" in values:
return values
else:
try:
from flashrank import Ranker
except ImportError:
raise ImportError(
"Could not import flashrank python package. "
"Please install it with `pip install flashrank`."
)
values["model"] = values.get("model", DEFAULT_MODEL_NAME)
values["client"] = Ranker(model_name=values["model"])
return values
def compress_documents(
self,
documents: Sequence[Document],
query: str,
callbacks: Optional[Callbacks] = None,
) -> Sequence[Document]:
passages = [
{"id": i, "text": doc.page_content, "meta": doc.metadata}
for i, doc in enumerate(documents)
]
rerank_request = RerankRequest(query=query, passages=passages)
rerank_response = self.client.rerank(rerank_request)[: self.top_n]
final_results = []
for r in rerank_response:
if r["score"] >= self.score_threshold:
doc = Document(
page_content=r["text"],
metadata={
self.prefix_metadata + "id": r["id"],
self.prefix_metadata + "relevance_score": r["score"],
**r["meta"],
},
)
final_results.append(doc)
return final_results