有时，您需要跨多个服务追踪一个请求。 LangSmith 开箱即用地支持分布式追踪，通过上下文传播头（`langsmith-trace` 和可选的 `baggage` 用于元数据/标签）在跨服务的追踪中链接运行。 客户端-服务器设置示例：
Python 中的分布式追踪
# client.py
from langsmith.run_helpers import get_current_run_tree, traceable
import httpx
@traceable
async def my_client_function():
headers = {}
async with httpx.AsyncClient(base_url="...") as client:
if run_tree := get_current_run_tree():
# add langsmith-id to headers
headers.update(run_tree.to_headers())
return await client.post("/my-route", headers=headers)
`TracingMiddleware` 类是在 `langsmith==0.1.133` 中添加的。
from langsmith import traceable
from langsmith.middleware import TracingMiddleware
from fastapi import FastAPI, Request
app = FastAPI() # Or Flask, Django, or any other framework
app.add_middleware(TracingMiddleware)
@traceable
async def some_function():
...
@app.post("/my-route")
async def fake_route(request: Request):
return await some_function()
from starlette.applications import Starlette
from starlette.middleware import Middleware
from langsmith.middleware import TracingMiddleware
routes = ...
middleware = [
Middleware(TracingMiddleware),
]
app = Starlette(..., middleware=middleware)
# server.py
import langsmith as ls
from fastapi import FastAPI, Request
@ls.traceable
async def my_application():
...
app = FastAPI() # Or Flask, Django, or any other framework
@app.post("/my-route")
async def fake_route(request: Request):
# request.headers: {"langsmith-trace": "..."}
# as well as optional metadata/tags in `baggage`
with ls.tracing_context(parent=request.headers):
return await my_application()
# ... same as above
@app.post("/my-route")
async def fake_route(request: Request):
# request.headers: {"langsmith-trace": "..."}
my_application(langsmith_extra={"parent": request.headers})
TypeScript 中的分布式追踪
TypeScript 中的分布式追踪需要 `langsmith` 版本 `>=0.1.31`
// client.mts
import { getCurrentRunTree, traceable } from "langsmith/traceable";
const client = traceable(
async () => {
const runTree = getCurrentRunTree();
return await fetch("...", {
method: "POST",
headers: runTree.toHeaders(),
}).then((a) => a.text());
},
{ name: "client" }
);
await client();
// server.mts
import { RunTree } from "langsmith";
import { traceable, withRunTree } from "langsmith/traceable";
import express from "express";
import bodyParser from "body-parser";
const server = traceable(
(text: string) => `Hello from the server! Received "${text}"`,
{ name: "server" }
);
const app = express();
app.use(bodyParser.text());
app.post("/", async (req, res) => {
const runTree = RunTree.fromHeaders(req.headers);
const result = await withRunTree(runTree, () => server(req.body));
res.send(result);
});
