Source code for langchain_google_vertexai.utils
from datetime import datetime, timedelta
from typing import List, Optional
from langchain_core.messages import BaseMessage
from vertexai.preview import caching # type: ignore
from langchain_google_vertexai.chat_models import (
ChatVertexAI,
_parse_chat_history_gemini,
)
from langchain_google_vertexai.functions_utils import (
_format_to_gapic_tool,
_format_tool_config,
_ToolConfigDict,
_ToolsType,
)
[docs]def create_context_cache(
model: ChatVertexAI,
messages: List[BaseMessage],
expire_time: Optional[datetime] = None,
time_to_live: Optional[timedelta] = None,
tools: Optional[_ToolsType] = None,
tool_config: Optional[_ToolConfigDict] = None,
) -> str:
"""Creates a cache for content in some model.
Args:
model: ChatVertexAI model. Must be at least gemini-1.5 pro or flash.
messages: List of messages to cache.
expire_time: Timestamp of when this resource is considered expired.
At most one of expire_time and ttl can be set. If neither is set, default TTL
on the API side will be used (currently 1 hour).
time_to_live: The TTL for this resource. If provided, the expiration time is
computed: created_time + TTL.
At most one of expire_time and ttl can be set. If neither is set, default TTL
on the API side will be used (currently 1 hour).
tools: A list of tool definitions to bind to this chat model.
Can be a pydantic model, callable, or BaseTool. Pydantic
models, callables, and BaseTools will be automatically converted to
their schema dictionary representation.
tool_config: Optional. Immutable. Tool config. This config is shared for all
tools.
Raises:
ValueError: If model doesn't support context catching.
Returns:
String with the identificator of the created cache.
"""
if not model._is_gemini_advanced:
error_msg = f"Model {model.full_model_name} doesn't support context catching"
raise ValueError(error_msg)
system_instruction, contents = _parse_chat_history_gemini(messages, model.project)
if tool_config:
tool_config = _format_tool_config(tool_config)
if tools is not None:
tools = _format_to_gapic_tool(tools)
cached_content = caching.CachedContent.create(
model_name=model.full_model_name,
system_instruction=system_instruction,
contents=contents,
ttl=time_to_live,
expire_time=expire_time,
tool_config=tool_config,
tools=tools,
)
return cached_content.name