使用 LangSmith REST API 进行追踪

强烈建议使用我们的 Python 或 TypeScript SDK 将追踪数据发送到 LangSmith。 我们已针对这些 SDK 进行了优化，例如批处理和后台处理，以确保发送追踪数据不会影响到您应用程序的性能。 但是，如果您无法使用我们的 SDK，也可以使用 LangSmith REST API 来发送追踪数据。如果在您的应用中同步发送追踪数据，可能会影响性能。 本指南将向您展示如何使用 LangSmith REST API 进行请求追踪。如需查看完整的端点列表和请求/响应模式，请查看我们的 API 文档 此处。

基础追踪​

记录运行最简单的方法是通过 POST 和 PATCH /runs 端点。这些路由期望提供关于树结构的最小上下文信息。

注意

当使用 LangSmith REST API 时，您需要将您的 API 密钥作为"x-api-key"提供在请求头中。

在简单示例中，您无需在请求体中设置 dotted_order 或 trace_id 字段。这些字段将由系统自动生成。 尽管这种方式更简单，但在 LangSmith 中它的速度较慢且速率限制较低。

以下示例展示了如何在 Python 中直接使用我们的 API。同样的原则也适用于其他语言。

import openai
import os
import requests
from datetime import datetime
from uuid import uuid4

# Send your API Key in the request headers
headers = {"x-api-key": os.environ["LANGSMITH_API_KEY"]}

def post_run(run_id, name, run_type, inputs, parent_id=None):
    """Function to post a new run to the API."""
    data = {
        "id": run_id.hex,
        "name": name,
        "run_type": run_type,
        "inputs": inputs,
        "start_time": datetime.utcnow().isoformat(),
    }
    if parent_id:
        data["parent_run_id"] = parent_id.hex
    requests.post(
        "https://api.smith.langchain.com/runs", # Update appropriately for self-hosted installations or the EU region
        json=data,
        headers=headers
    )

def patch_run(run_id, outputs):
    """Function to patch a run with outputs."""
    requests.patch(
        f"https://api.smith.langchain.com/runs/{run_id}",
        json={
            "outputs": outputs,
            "end_time": datetime.now(timezone.utc).isoformat(),
        },
        headers=headers,
    )


# This can be a user input to your app
question = "Can you summarize this morning's meetings?"

# This can be retrieved in a retrieval step
context = "During this morning's meeting, we solved all world conflict."
messages = [
    {"role": "system", "content": "You are a helpful assistant. Please respond to the user's request only based on the given context."},
    {"role": "user", "content": f"Question: {question}\\nContext: {context}"}
]

# Create parent run
parent_run_id = uuid4()
post_run(parent_run_id, "Chat Pipeline", "chain", {"question": question})

# Create child run
child_run_id = uuid4()
post_run(child_run_id, "OpenAI Call", "llm", {"messages": messages}, parent_run_id)

# Generate a completion
client = openai.Client()
chat_completion = client.chat.completions.create(model="gpt-4o-mini", messages=messages)

# End runs
patch_run(child_run_id, chat_completion.dict())
patch_run(parent_run_id, {"answer": chat_completion.choices[0].message.content})

有关更多信息，请参阅 运行（跨度）数据格式 文档。

批量数据摄入​

为了更快地摄入运行记录并获得更高的速率限制，您可以使用 POST /runs/multipart 链接 端点。 下面是一个示例。它需要 orjson（用于快速 JSON）和 requests_toolbelt 才能运行

import json
import os
import uuid
from datetime import datetime, timezone
from typing import Dict, List, Optional

import requests
from requests_toolbelt import MultipartEncoder


def create_dotted_order(
    start_time: Optional[datetime] = None, run_id: Optional[uuid.UUID] = None
) -> str:
    """Create a dotted order string for run ordering and hierarchy.

    The dotted order is used to establish the sequence and relationships between runs.
    It combines a timestamp with a unique identifier to ensure proper ordering and tracing.
    """
    st = start_time or datetime.now(timezone.utc)
    id_ = run_id or uuid.uuid4()
    return f"{st.strftime('%Y%m%dT%H%M%S%fZ')}{id_}"


def create_run_base(
    name: str, run_type: str, inputs: dict, start_time: datetime
) -> dict:
    """Create the base structure for a run."""
    run_id = uuid.uuid4()
    return {
        "id": str(run_id),
        "trace_id": str(run_id),
        "name": name,
        "start_time": start_time.isoformat(),
        "inputs": inputs,
        "run_type": run_type,
    }


def construct_run(
    name: str,
    run_type: str,
    inputs: dict,
    parent_dotted_order: Optional[str] = None,
) -> dict:
    """Construct a run dictionary with the given parameters.

    This function creates a run with a unique ID and dotted order, establishing its place
    in the trace hierarchy if it's a child run.
    """
    start_time = datetime.now(timezone.utc)
    run = create_run_base(name, run_type, inputs, start_time)

    current_dotted_order = create_dotted_order(start_time, uuid.UUID(run["id"]))
    if parent_dotted_order:
        current_dotted_order = f"{parent_dotted_order}.{current_dotted_order}"
        run["trace_id"] = parent_dotted_order.split(".")[0].split("Z")[1]
        run["parent_run_id"] = parent_dotted_order.split(".")[-1].split("Z")[1]
    run["dotted_order"] = current_dotted_order

    return run


def serialize_run(operation: str, run_data: dict) -> List[tuple]:
    """Serialize a run for the multipart request.

    This function separates the run data into parts for efficient transmission and storage.
    The main run data and optional fields (inputs, outputs, events) are serialized separately.
    """
    run_id = run_data.get("id", str(uuid.uuid4()))

    # Separate optional fields
    inputs = run_data.pop("inputs", None)
    outputs = run_data.pop("outputs", None)
    events = run_data.pop("events", None)

    parts = []

    # Serialize main run data
    run_data_json = json.dumps(run_data).encode("utf-8")
    parts.append(
        (
            f"{operation}.{run_id}",
            (
                None,
                run_data_json,
                "application/json",
                {"Content-Length": str(len(run_data_json))},
            ),
        )
    )

    # Serialize optional fields
    for key, value in [("inputs", inputs), ("outputs", outputs), ("events", events)]:
        if value:
            serialized_value = json.dumps(value).encode("utf-8")
            parts.append(
                (
                    f"{operation}.{run_id}.{key}",
                    (
                        None,
                        serialized_value,
                        "application/json",
                        {"Content-Length": str(len(serialized_value))},
                    ),
                )
            )

    return parts


def batch_ingest_runs(
    api_url: str,
    api_key: str,
    posts: Optional[List[dict]] = None,
    patches: Optional[List[dict]] = None,
) -> None:
    """Ingest multiple runs in a single batch request.

    This function handles both creating new runs (posts) and updating existing runs (patches).
    It's more efficient for ingesting multiple runs compared to individual API calls.
    """
    boundary = uuid.uuid4().hex
    all_parts = []

    for operation, runs in zip(("post", "patch"), (posts, patches)):
        if runs:
            all_parts.extend(
                [part for run in runs for part in serialize_run(operation, run)]
            )

    encoder = MultipartEncoder(fields=all_parts, boundary=boundary)
    headers = {"Content-Type": encoder.content_type, "x-api-key": api_key}

    try:
        response = requests.post(
            f"{api_url}/runs/multipart", data=encoder, headers=headers
        )
        response.raise_for_status()
        print("Successfully ingested runs.")
    except requests.RequestException as e:
        print(f"Error ingesting runs: {e}")
        # In a production environment, you might want to log this error or handle it more robustly


# Configure API URL and key
# For production use, consider using a configuration file or environment variables
api_url = "https://api.smith.langchain.com"
api_key = os.environ.get("LANGSMITH_API_KEY")
if not api_key:
    raise ValueError("LANGSMITH_API_KEY environment variable is not set")

# Create a parent run
parent_run = construct_run(
    name="Parent Run",
    run_type="chain",
    inputs={"main_question": "Tell me about France"},
)

# Create a child run, linked to the parent
child_run = construct_run(
    name="Child Run",
    run_type="llm",
    inputs={"question": "What is the capital of France?"},
    parent_dotted_order=parent_run["dotted_order"],
)

# First, post the runs to create them
posts = [parent_run, child_run]
batch_ingest_runs(api_url, api_key, posts=posts)

# Then, update the runs with their end times and any outputs
child_run_update = {
    **child_run,
    "end_time": datetime.now(timezone.utc).isoformat(),
    "outputs": {"answer": "Paris is the capital of France."},
}
parent_run_update = {
    **parent_run,
    "end_time": datetime.now(timezone.utc).isoformat(),
    "outputs": {"summary": "Discussion about France, including its capital."},
}
patches = [parent_run_update, child_run_update]
batch_ingest_runs(api_url, api_key, patches=patches)

# Note: This example requires the `requests` and `requests_toolbelt` libraries.
# You can install them using pip:
# pip install requests requests_toolbelt