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333 lines
10 KiB
Python
333 lines
10 KiB
Python
import logging
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from abc import ABC, abstractmethod
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from itertools import islice
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from typing import Any, Dict, Iterable, List, Optional
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from pydantic import BaseModel, Field
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from langchain.base_language import BaseLanguageModel
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from langchain.chains.llm import LLMChain
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from langchain.memory.chat_memory import BaseChatMemory
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from langchain.memory.prompt import (
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ENTITY_EXTRACTION_PROMPT,
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ENTITY_SUMMARIZATION_PROMPT,
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)
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from langchain.memory.utils import get_prompt_input_key
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from langchain.prompts.base import BasePromptTemplate
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from langchain.schema import BaseMessage, get_buffer_string
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logger = logging.getLogger(__name__)
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class BaseEntityStore(BaseModel, ABC):
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@abstractmethod
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def get(self, key: str, default: Optional[str] = None) -> Optional[str]:
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"""Get entity value from store."""
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pass
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@abstractmethod
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def set(self, key: str, value: Optional[str]) -> None:
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"""Set entity value in store."""
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pass
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@abstractmethod
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def delete(self, key: str) -> None:
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"""Delete entity value from store."""
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pass
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@abstractmethod
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def exists(self, key: str) -> bool:
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"""Check if entity exists in store."""
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pass
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@abstractmethod
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def clear(self) -> None:
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"""Delete all entities from store."""
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pass
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class InMemoryEntityStore(BaseEntityStore):
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"""Basic in-memory entity store."""
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store: Dict[str, Optional[str]] = {}
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def get(self, key: str, default: Optional[str] = None) -> Optional[str]:
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return self.store.get(key, default)
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def set(self, key: str, value: Optional[str]) -> None:
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self.store[key] = value
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def delete(self, key: str) -> None:
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del self.store[key]
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def exists(self, key: str) -> bool:
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return key in self.store
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def clear(self) -> None:
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return self.store.clear()
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class RedisEntityStore(BaseEntityStore):
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"""Redis-backed Entity store. Entities get a TTL of 1 day by default, and
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that TTL is extended by 3 days every time the entity is read back.
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"""
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redis_client: Any
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session_id: str = "default"
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key_prefix: str = "memory_store"
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ttl: Optional[int] = 60 * 60 * 24
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recall_ttl: Optional[int] = 60 * 60 * 24 * 3
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def __init__(
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self,
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session_id: str = "default",
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url: str = "redis://localhost:6379/0",
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key_prefix: str = "memory_store",
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ttl: Optional[int] = 60 * 60 * 24,
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recall_ttl: Optional[int] = 60 * 60 * 24 * 3,
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*args: Any,
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**kwargs: Any,
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):
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try:
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import redis
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except ImportError:
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raise ImportError(
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"Could not import redis python package. "
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"Please install it with `pip install redis`."
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)
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super().__init__(*args, **kwargs)
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try:
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self.redis_client = redis.Redis.from_url(url=url, decode_responses=True)
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except redis.exceptions.ConnectionError as error:
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logger.error(error)
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self.session_id = session_id
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self.key_prefix = key_prefix
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self.ttl = ttl
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self.recall_ttl = recall_ttl or ttl
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@property
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def full_key_prefix(self) -> str:
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return f"{self.key_prefix}:{self.session_id}"
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def get(self, key: str, default: Optional[str] = None) -> Optional[str]:
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res = (
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self.redis_client.getex(f"{self.full_key_prefix}:{key}", ex=self.recall_ttl)
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or default
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or ""
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)
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logger.debug(f"REDIS MEM get '{self.full_key_prefix}:{key}': '{res}'")
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return res
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def set(self, key: str, value: Optional[str]) -> None:
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if not value:
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return self.delete(key)
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self.redis_client.set(f"{self.full_key_prefix}:{key}", value, ex=self.ttl)
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logger.debug(
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f"REDIS MEM set '{self.full_key_prefix}:{key}': '{value}' EX {self.ttl}"
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)
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def delete(self, key: str) -> None:
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self.redis_client.delete(f"{self.full_key_prefix}:{key}")
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def exists(self, key: str) -> bool:
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return self.redis_client.exists(f"{self.full_key_prefix}:{key}") == 1
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def clear(self) -> None:
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# iterate a list in batches of size batch_size
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def batched(iterable: Iterable[Any], batch_size: int) -> Iterable[Any]:
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iterator = iter(iterable)
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while batch := list(islice(iterator, batch_size)):
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yield batch
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for keybatch in batched(
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self.redis_client.scan_iter(f"{self.full_key_prefix}:*"), 500
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):
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self.redis_client.delete(*keybatch)
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class SQLiteEntityStore(BaseEntityStore):
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"""SQLite-backed Entity store"""
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session_id: str = "default"
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table_name: str = "memory_store"
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def __init__(
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self,
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session_id: str = "default",
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db_file: str = "entities.db",
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table_name: str = "memory_store",
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*args: Any,
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**kwargs: Any,
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):
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try:
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import sqlite3
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except ImportError:
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raise ImportError(
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"Could not import sqlite3 python package. "
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"Please install it with `pip install sqlite3`."
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)
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super().__init__(*args, **kwargs)
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self.conn = sqlite3.connect(db_file)
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self.session_id = session_id
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self.table_name = table_name
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self._create_table_if_not_exists()
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@property
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def full_table_name(self) -> str:
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return f"{self.table_name}_{self.session_id}"
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def _create_table_if_not_exists(self) -> None:
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create_table_query = f"""
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CREATE TABLE IF NOT EXISTS {self.full_table_name} (
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key TEXT PRIMARY KEY,
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value TEXT
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)
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"""
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with self.conn:
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self.conn.execute(create_table_query)
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def get(self, key: str, default: Optional[str] = None) -> Optional[str]:
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query = f"""
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SELECT value
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FROM {self.full_table_name}
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WHERE key = ?
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"""
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cursor = self.conn.execute(query, (key,))
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result = cursor.fetchone()
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if result is not None:
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value = result[0]
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return value
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return default
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def set(self, key: str, value: Optional[str]) -> None:
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if not value:
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return self.delete(key)
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query = f"""
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INSERT OR REPLACE INTO {self.full_table_name} (key, value)
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VALUES (?, ?)
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"""
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with self.conn:
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self.conn.execute(query, (key, value))
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def delete(self, key: str) -> None:
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query = f"""
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DELETE FROM {self.full_table_name}
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WHERE key = ?
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"""
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with self.conn:
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self.conn.execute(query, (key,))
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def exists(self, key: str) -> bool:
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query = f"""
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SELECT 1
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FROM {self.full_table_name}
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WHERE key = ?
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LIMIT 1
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"""
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cursor = self.conn.execute(query, (key,))
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result = cursor.fetchone()
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return result is not None
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def clear(self) -> None:
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query = f"""
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DELETE FROM {self.full_table_name}
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"""
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with self.conn:
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self.conn.execute(query)
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class ConversationEntityMemory(BaseChatMemory):
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"""Entity extractor & summarizer to memory."""
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human_prefix: str = "Human"
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ai_prefix: str = "AI"
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llm: BaseLanguageModel
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entity_extraction_prompt: BasePromptTemplate = ENTITY_EXTRACTION_PROMPT
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entity_summarization_prompt: BasePromptTemplate = ENTITY_SUMMARIZATION_PROMPT
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entity_cache: List[str] = []
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k: int = 3
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chat_history_key: str = "history"
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entity_store: BaseEntityStore = Field(default_factory=InMemoryEntityStore)
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@property
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def buffer(self) -> List[BaseMessage]:
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return self.chat_memory.messages
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@property
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def memory_variables(self) -> List[str]:
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"""Will always return list of memory variables.
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:meta private:
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"""
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return ["entities", self.chat_history_key]
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def load_memory_variables(self, inputs: Dict[str, Any]) -> Dict[str, Any]:
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"""Return history buffer."""
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chain = LLMChain(llm=self.llm, prompt=self.entity_extraction_prompt)
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if self.input_key is None:
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prompt_input_key = get_prompt_input_key(inputs, self.memory_variables)
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else:
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prompt_input_key = self.input_key
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buffer_string = get_buffer_string(
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self.buffer[-self.k * 2 :],
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human_prefix=self.human_prefix,
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ai_prefix=self.ai_prefix,
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)
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output = chain.predict(
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history=buffer_string,
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input=inputs[prompt_input_key],
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)
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if output.strip() == "NONE":
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entities = []
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else:
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entities = [w.strip() for w in output.split(",")]
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entity_summaries = {}
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for entity in entities:
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entity_summaries[entity] = self.entity_store.get(entity, "")
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self.entity_cache = entities
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if self.return_messages:
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buffer: Any = self.buffer[-self.k * 2 :]
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else:
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buffer = buffer_string
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return {
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self.chat_history_key: buffer,
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"entities": entity_summaries,
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}
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def save_context(self, inputs: Dict[str, Any], outputs: Dict[str, str]) -> None:
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"""Save context from this conversation to buffer."""
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super().save_context(inputs, outputs)
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if self.input_key is None:
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prompt_input_key = get_prompt_input_key(inputs, self.memory_variables)
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else:
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prompt_input_key = self.input_key
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buffer_string = get_buffer_string(
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self.buffer[-self.k * 2 :],
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human_prefix=self.human_prefix,
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ai_prefix=self.ai_prefix,
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)
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input_data = inputs[prompt_input_key]
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chain = LLMChain(llm=self.llm, prompt=self.entity_summarization_prompt)
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for entity in self.entity_cache:
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existing_summary = self.entity_store.get(entity, "")
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output = chain.predict(
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summary=existing_summary,
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entity=entity,
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history=buffer_string,
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input=input_data,
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)
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self.entity_store.set(entity, output.strip())
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def clear(self) -> None:
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"""Clear memory contents."""
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self.chat_memory.clear()
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self.entity_cache.clear()
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self.entity_store.clear()
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