import json
from typing import Any, Dict, List, Optional
from langchain_core.callbacks.manager import CallbackManagerForLLMRun
from langchain_core.language_models import BaseChatModel
from langchain_core.messages import (
AIMessage,
BaseMessage,
ChatMessage,
HumanMessage,
SystemMessage,
)
from langchain_core.outputs import ChatGeneration, ChatResult
from langchain_core.pydantic_v1 import Field, SecretStr, root_validator
from langchain_core.utils import (
convert_to_secret_str,
get_from_dict_or_env,
get_pydantic_field_names,
pre_init,
)
from langchain_core.utils.utils import build_extra_kwargs
SUPPORTED_ROLES: List[str] = [
"system",
"user",
"assistant",
]
[docs]class ChatSnowflakeCortexError(Exception):
"""Error with Snowpark client."""
def _convert_message_to_dict(message: BaseMessage) -> dict:
"""Convert a LangChain message to a dictionary.
Args:
message: The LangChain message.
Returns:
The dictionary.
"""
message_dict: Dict[str, Any] = {
"content": message.content,
}
# populate role and additional message data
if isinstance(message, ChatMessage) and message.role in SUPPORTED_ROLES:
message_dict["role"] = message.role
elif isinstance(message, SystemMessage):
message_dict["role"] = "system"
elif isinstance(message, HumanMessage):
message_dict["role"] = "user"
elif isinstance(message, AIMessage):
message_dict["role"] = "assistant"
else:
raise TypeError(f"Got unknown type {message}")
return message_dict
def _truncate_at_stop_tokens(
text: str,
stop: Optional[List[str]],
) -> str:
"""Truncates text at the earliest stop token found."""
if stop is None:
return text
for stop_token in stop:
stop_token_idx = text.find(stop_token)
if stop_token_idx != -1:
text = text[:stop_token_idx]
return text
[docs]class ChatSnowflakeCortex(BaseChatModel):
"""Snowflake Cortex based Chat model
To use you must have the ``snowflake-snowpark-python`` Python package installed and
either:
1. environment variables set with your snowflake credentials or
2. directly passed in as kwargs to the ChatSnowflakeCortex constructor.
Example:
.. code-block:: python
from langchain_community.chat_models import ChatSnowflakeCortex
chat = ChatSnowflakeCortex()
"""
_sp_session: Any = None
"""Snowpark session object."""
model: str = "snowflake-arctic"
"""Snowflake cortex hosted LLM model name, defaulted to `snowflake-arctic`.
Refer to docs for more options."""
cortex_function: str = "complete"
"""Cortex function to use, defaulted to `complete`.
Refer to docs for more options."""
temperature: float = 0.7
"""Model temperature. Value should be >= 0 and <= 1.0"""
max_tokens: Optional[int] = None
"""The maximum number of output tokens in the response."""
top_p: Optional[float] = None
"""top_p adjusts the number of choices for each predicted tokens based on
cumulative probabilities. Value should be ranging between 0.0 and 1.0.
"""
snowflake_username: Optional[str] = Field(default=None, alias="username")
"""Automatically inferred from env var `SNOWFLAKE_USERNAME` if not provided."""
snowflake_password: Optional[SecretStr] = Field(default=None, alias="password")
"""Automatically inferred from env var `SNOWFLAKE_PASSWORD` if not provided."""
snowflake_account: Optional[str] = Field(default=None, alias="account")
"""Automatically inferred from env var `SNOWFLAKE_ACCOUNT` if not provided."""
snowflake_database: Optional[str] = Field(default=None, alias="database")
"""Automatically inferred from env var `SNOWFLAKE_DATABASE` if not provided."""
snowflake_schema: Optional[str] = Field(default=None, alias="schema")
"""Automatically inferred from env var `SNOWFLAKE_SCHEMA` if not provided."""
snowflake_warehouse: Optional[str] = Field(default=None, alias="warehouse")
"""Automatically inferred from env var `SNOWFLAKE_WAREHOUSE` if not provided."""
snowflake_role: Optional[str] = Field(default=None, alias="role")
"""Automatically inferred from env var `SNOWFLAKE_ROLE` if not provided."""
@root_validator(pre=True)
def build_extra(cls, values: Dict[str, Any]) -> Dict[str, Any]:
"""Build extra kwargs from additional params that were passed in."""
all_required_field_names = get_pydantic_field_names(cls)
extra = values.get("model_kwargs", {})
values["model_kwargs"] = build_extra_kwargs(
extra, values, all_required_field_names
)
return values
@pre_init
def validate_environment(cls, values: Dict) -> Dict:
try:
from snowflake.snowpark import Session
except ImportError:
raise ImportError(
"`snowflake-snowpark-python` package not found, please install it with "
"`pip install snowflake-snowpark-python`"
)
values["snowflake_username"] = get_from_dict_or_env(
values, "snowflake_username", "SNOWFLAKE_USERNAME"
)
values["snowflake_password"] = convert_to_secret_str(
get_from_dict_or_env(values, "snowflake_password", "SNOWFLAKE_PASSWORD")
)
values["snowflake_account"] = get_from_dict_or_env(
values, "snowflake_account", "SNOWFLAKE_ACCOUNT"
)
values["snowflake_database"] = get_from_dict_or_env(
values, "snowflake_database", "SNOWFLAKE_DATABASE"
)
values["snowflake_schema"] = get_from_dict_or_env(
values, "snowflake_schema", "SNOWFLAKE_SCHEMA"
)
values["snowflake_warehouse"] = get_from_dict_or_env(
values, "snowflake_warehouse", "SNOWFLAKE_WAREHOUSE"
)
values["snowflake_role"] = get_from_dict_or_env(
values, "snowflake_role", "SNOWFLAKE_ROLE"
)
connection_params = {
"account": values["snowflake_account"],
"user": values["snowflake_username"],
"password": values["snowflake_password"].get_secret_value(),
"database": values["snowflake_database"],
"schema": values["snowflake_schema"],
"warehouse": values["snowflake_warehouse"],
"role": values["snowflake_role"],
}
try:
values["_sp_session"] = Session.builder.configs(connection_params).create()
except Exception as e:
raise ChatSnowflakeCortexError(f"Failed to create session: {e}")
return values
def __del__(self) -> None:
if getattr(self, "_sp_session", None) is not None:
self._sp_session.close()
@property
def _llm_type(self) -> str:
"""Get the type of language model used by this chat model."""
return f"snowflake-cortex-{self.model}"
def _generate(
self,
messages: List[BaseMessage],
stop: Optional[List[str]] = None,
run_manager: Optional[CallbackManagerForLLMRun] = None,
**kwargs: Any,
) -> ChatResult:
message_dicts = [_convert_message_to_dict(m) for m in messages]
message_str = str(message_dicts)
options = {"temperature": self.temperature}
if self.top_p is not None:
options["top_p"] = self.top_p
if self.max_tokens is not None:
options["max_tokens"] = self.max_tokens
options_str = str(options)
sql_stmt = f"""
select snowflake.cortex.{self.cortex_function}(
'{self.model}'
,{message_str},{options_str}) as llm_response;"""
try:
l_rows = self._sp_session.sql(sql_stmt).collect()
except Exception as e:
raise ChatSnowflakeCortexError(
f"Error while making request to Snowflake Cortex via Snowpark: {e}"
)
response = json.loads(l_rows[0]["LLM_RESPONSE"])
ai_message_content = response["choices"][0]["messages"]
content = _truncate_at_stop_tokens(ai_message_content, stop)
message = AIMessage(
content=content,
response_metadata=response["usage"],
)
generation = ChatGeneration(message=message)
return ChatResult(generations=[generation])
