如何流式传输图的状态更新¶

先决条件

流式处理

本指南介绍了如何为您的图使用 stream_mode="updates"，这将流式传输在每个节点执行后对图状态做出的更新。这与使用 stream_mode="values" 不同：后者在每个超级步骤中流式传输整个状态值，而前者仅流式传输在该超级步骤中对状态做出更新的每个节点的更新。

设置¶

首先，让我们设置客户端和线程：

PythonJavaScriptCURL

from langgraph_sdk import get_client

client = get_client(url=<DEPLOYMENT_URL>)
# 使用名为 "agent" 的图
assistant_id = "agent"
# 创建线程
thread = await client.threads.create()
print(thread)

import { Client } from "@langchain/langgraph-sdk";

const client = new Client({ apiUrl: <DEPLOYMENT_URL> });
// 使用名为 "agent" 的图
const assistantID = "agent";
// 创建线程
const thread = await client.threads.create();
console.log(thread);

curl --request POST \
  --url <DEPLOYMENT_URL>/threads \
  --header 'Content-Type: application/json' \
  --data '{}'

输出：

{
  'thread_id': '979e3c89-a702-4882-87c2-7a59a250ce16',
  'created_at': '2024-06-21T15:22:07.453100+00:00',
  'updated_at': '2cq2024-06-21T15:22:07.453100+00:00',
  'metadata': {},
  'status': 'idle',
  'config': {},
  'values': None 
}

更新模式下的流图¶

现在我们可以按更新流式传输，这将输出每个节点执行后对状态所做的更新：

PythonJavascriptCURL

input = {
    "messages": [
        {
            "role": "user",
            "content": "what's the weather in la"
        }
    ]
}
async for chunk in client.runs.stream(
    thread["thread_id"],
    assistant_id,
    input=input,
    stream_mode="updates",
):
    print(f"接收新事件类型: {chunk.event}...")
    print(chunk.data)
    print("\n\n")

const input = {
  messages: [
    {
      role: "human",
      content: "What's the weather in la"
    }
  ]
};

const streamResponse = client.runs.stream(
  thread["thread_id"],
  assistantID,
  {
    input,
    streamMode: "updates"
  }
);

for await (const chunk of streamResponse) {
  console.log(`接收新事件类型: ${chunk.event}...`);
  console.log(chunk.data);
  console.log("\n\n");
}

curl --request POST \
 --url <DEPLOYMENT_URL>/threads/<THREAD_ID>/runs/stream \
 --header 'Content-Type: application/json' \
 --data "{
   \"assistant_id\": \"agent\",
   \"input\": {\"messages\": [{\"role\": \"human\", \"content\": \"What's the weather in la\"}]},
   \"stream_mode\": [
     \"updates\"
   ]
 }" | \
 sed 's/\r$//' | \
 awk '
 /^event:/ {
     if (data_content != "") {
         print data_content "\n"
     }
     sub(/^event: /, "接收事件类型: ", $0)
     printf "%s...\n", $0
     data_content = ""
 }
 /^data:/ {
     sub(/^data: /, "", $0)
     data_content = $0
 }
 END {
     if (data_content != "") {
         print data_content "\n"
     }
 }
 '

输出：

接收新事件类型: metadata...
{"run_id": "cfc96c16-ed9a-44bd-b5bb-c30e3c0725f0"}



接收新事件类型: updates...
{
  "agent": {
    "messages": [
      {
        "type": "ai",
        "tool_calls": [
          {
            "name": "tavily_search_results_json",
            "args": {
              "query": "weather in los angeles"
            },
            "id": "toolu_0148tMmDK51iLQfG1yaNwRHM"
          }
        ],
        ...
      }
    ]
  }
}



接收新事件类型: updates...
{
  "action": {
    "messages": [
      {
        "content": [
          {
            "url": "https://www.weatherapi.com/",
            "content": "{\"location\": {\"name\": \"Los Angeles\", \"region\": \"California\", \"country\": \"United States of America\", \"lat\": cq.05, \"lon\": -118.24, \"tz_id\": \"America/Los_Angeles\", \"localtime_epoch\": 1716062239, \"localtime\": \"2024-05-18 12:57\"}, \"current\": {\"last_updated_epoch\": 1716061500, \"last_updated\": \"2024-05-18 12:45\", \"temp_c\": 18.9, \"temp_f\": 66.0, \"is_day\": 1, \"condition\": {\"text\": \"Overcast\", \"icon\": \"//cdn.weatherapi.com/weather/64x64/day/122.png\", \"code\": 1009}, \"wind_mph\": 2.2, \"wind_kph\": 3.6, \"wind_degree\": 10, \"wind_dir\": \"N\", \"pressure_mb\": 1017.0, \"pressure_in\": 30.02, \"precip_mm\": 0.0, \"precip_in\": 0.0, \"humidity\": 65, \"cloud\": 100, \"feelslike_c\": 18.9, \"feelslike_f\": 66.0, \"vis_km\": 16.0, \"vis_miles\": 9.0, \"uv\": 6.0, \"gust_mph\": 7.5, \"gust_kph\": 12.0}}"
          }
        ],
        "type": "tool",
        "name": "tavily_search_results_json",
        "tool_call_id": "toolu_0148tMmDK51iLQfG1yaNwRHM",
        ...
      }
    ]
  }
}



接收新事件类型: updates...
{
  "agent": {
    "messages": [
      {
        "content": "The weather in Los Angeles is currently overcast with a temperature of around 66°F (18.9°C). There are light winds from the north at around 2-3 mph. The humidity is 65% and visibility is good at 9 miles. Overall, mild spring weather conditions in LA.",
        "type": "ai",
        ...
      }
    ]
  }
}



接收新事件类型: end...
None

如何流式传输图的状态更新¶

设置¶

更新模式下的流图¶

Comments