Files
letta-server/letta/adapters/simple_llm_stream_adapter.py

180 lines
8.1 KiB
Python

from typing import AsyncGenerator, List
from letta.adapters.letta_llm_stream_adapter import LettaLLMStreamAdapter
from letta.helpers.datetime_helpers import get_utc_timestamp_ns
from letta.interfaces.anthropic_streaming_interface import SimpleAnthropicStreamingInterface
from letta.interfaces.openai_streaming_interface import SimpleOpenAIStreamingInterface
from letta.schemas.enums import ProviderType
from letta.schemas.letta_message import LettaMessage
from letta.schemas.letta_message_content import SummarizedReasoningContent, TextContent
from letta.schemas.provider_trace import ProviderTraceCreate
from letta.schemas.usage import LettaUsageStatistics
from letta.schemas.user import User
from letta.settings import settings
from letta.utils import safe_create_task
class SimpleLLMStreamAdapter(LettaLLMStreamAdapter):
"""
Adapter for handling streaming LLM requests with immediate token yielding.
This adapter supports real-time streaming of tokens from the LLM, providing
minimal time-to-first-token (TTFT) latency. It uses specialized streaming
interfaces for different providers (OpenAI, Anthropic) to handle their
specific streaming formats.
"""
async def invoke_llm(
self,
request_data: dict,
messages: list,
tools: list,
use_assistant_message: bool, # NOTE: not used
requires_approval_tools: list[str] = [],
step_id: str | None = None,
actor: User | None = None,
) -> AsyncGenerator[LettaMessage, None]:
"""
Execute a streaming LLM request and yield tokens/chunks as they arrive.
This adapter:
1. Makes a streaming request to the LLM
2. Yields chunks immediately for minimal TTFT
3. Accumulates response data through the streaming interface
4. Updates all instance variables after streaming completes
"""
# Store request data
self.request_data = request_data
# Instantiate streaming interface
if self.llm_config.model_endpoint_type in [ProviderType.anthropic, ProviderType.bedrock]:
# NOTE: different
self.interface = SimpleAnthropicStreamingInterface(
requires_approval_tools=requires_approval_tools,
)
elif self.llm_config.model_endpoint_type == ProviderType.openai:
# Decide interface based on payload shape
use_responses = "input" in request_data and "messages" not in request_data
# No support for Responses API proxy
is_proxy = self.llm_config.provider_name == "lmstudio_openai"
if use_responses and not is_proxy:
self.interface = SimpleOpenAIResponsesStreamingInterface(
is_openai_proxy=False,
messages=messages,
tools=tools,
requires_approval_tools=requires_approval_tools,
)
else:
self.interface = SimpleOpenAIStreamingInterface(
is_openai_proxy=self.llm_config.provider_name == "lmstudio_openai",
messages=messages,
tools=tools,
requires_approval_tools=requires_approval_tools,
model=self.llm_config.model,
)
else:
raise ValueError(f"Streaming not supported for provider {self.llm_config.model_endpoint_type}")
# Extract optional parameters
# ttft_span = kwargs.get('ttft_span', None)
# Start the streaming request
stream = await self.llm_client.stream_async(request_data, self.llm_config)
# Process the stream and yield chunks immediately for TTFT
async for chunk in self.interface.process(stream): # TODO: add ttft span
# Yield each chunk immediately as it arrives
yield chunk
# After streaming completes, extract the accumulated data
self.llm_request_finish_timestamp_ns = get_utc_timestamp_ns()
# Extract tool call from the interface
try:
self.tool_call = self.interface.get_tool_call_object()
except ValueError as e:
# No tool call, handle upstream
self.tool_call = None
# Extract reasoning content from the interface
# TODO this should probably just be called "content"?
# self.reasoning_content = self.interface.get_reasoning_content()
# Extract non-reasoning content (eg text)
self.content: List[TextContent | SummarizedReasoningContent] = self.interface.get_content()
# Extract usage statistics
# Some providers don't provide usage in streaming, use fallback if needed
if hasattr(self.interface, "input_tokens") and hasattr(self.interface, "output_tokens"):
# Handle cases where tokens might not be set (e.g., LMStudio)
input_tokens = self.interface.input_tokens
output_tokens = self.interface.output_tokens
# Fallback to estimated values if not provided
if not input_tokens and hasattr(self.interface, "fallback_input_tokens"):
input_tokens = self.interface.fallback_input_tokens
if not output_tokens and hasattr(self.interface, "fallback_output_tokens"):
output_tokens = self.interface.fallback_output_tokens
self.usage = LettaUsageStatistics(
step_count=1,
completion_tokens=output_tokens or 0,
prompt_tokens=input_tokens or 0,
total_tokens=(input_tokens or 0) + (output_tokens or 0),
)
else:
# Default usage statistics if not available
self.usage = LettaUsageStatistics(step_count=1, completion_tokens=0, prompt_tokens=0, total_tokens=0)
# Store any additional data from the interface
self.message_id = self.interface.letta_message_id
# Log request and response data
self.log_provider_trace(step_id=step_id, actor=actor)
def log_provider_trace(self, step_id: str | None, actor: User | None) -> None:
"""
Log provider trace data for telemetry purposes in a fire-and-forget manner.
Creates an async task to log the request/response data without blocking
the main execution flow. For streaming adapters, this includes the final
tool call and reasoning content collected during streaming.
Args:
step_id: The step ID associated with this request for logging purposes
actor: The user associated with this request for logging purposes
"""
if step_id is None or actor is None or not settings.track_provider_trace:
return
safe_create_task(
self.telemetry_manager.create_provider_trace_async(
actor=actor,
provider_trace_create=ProviderTraceCreate(
request_json=self.request_data,
response_json={
"content": {
"tool_call": self.tool_call.model_dump_json() if self.tool_call else None,
# "reasoning": [content.model_dump_json() for content in self.reasoning_content],
# NOTE: different
# TODO potentially split this into both content and reasoning?
"content": [content.model_dump_json() for content in self.content],
},
"id": self.interface.message_id,
"model": self.interface.model,
"role": "assistant",
# "stop_reason": "",
# "stop_sequence": None,
"type": "message",
"usage": {
"input_tokens": self.usage.prompt_tokens,
"output_tokens": self.usage.completion_tokens,
},
},
step_id=step_id, # Use original step_id for telemetry
organization_id=actor.organization_id,
),
),
label="create_provider_trace",
)