Session management with Live API

在 Live API 中,工作階段是指持續連線,在同一連線中持續串流輸入和輸出 (進一步瞭解運作方式)。這種獨特的工作階段設計可降低延遲並支援獨特功能,但也可能帶來挑戰,例如工作階段時間限制和提早終止。本指南將說明如何克服使用 Live API 時可能發生的工作階段管理問題。

工作階段生命週期

如未壓縮,僅音訊的會話時間上限為 15 分鐘,音訊/視訊會話時間上限為 2 分鐘。如果超過這些限制,系統會終止工作階段 (並因此終止連線),但您可以使用內容視窗壓縮功能,將工作階段延長至無限的時間。

連線的生命週期也受到限制,大約為 10 分鐘。連線終止時,工作階段也會終止。在這種情況下,您可以使用工作階段恢復功能,將單一工作階段設定為在多個連線中保持有效。在連線結束前,您也會收到GoAway 訊息,方便您採取進一步行動。

脈絡窗口壓縮

如要啟用較長的工作階段,並避免連線突然中斷,您可以將 contextWindowCompression 欄位設為工作階段設定的一部分,啟用內容視窗壓縮功能。

ContextWindowCompressionConfig 中,您可以設定滑動視窗機制和觸發壓縮功能的符記數量

Python

from google.genai import types

config = types.LiveConnectConfig(
    response_modalities=["AUDIO"],
    context_window_compression=(
        # Configures compression with default parameters.
        types.ContextWindowCompressionConfig(
            sliding_window=types.SlidingWindow(),
        )
    ),
)

JavaScript

const config = {
  responseModalities: [Modality.AUDIO],
  contextWindowCompression: { slidingWindow: {} }
};

繼續工作階段

如要避免在伺服器定期重設 WebSocket 連線時終止工作階段,請在設定配置中設定 sessionResumption 欄位。

傳遞這項設定會導致伺服器傳送 SessionResumptionUpdate 訊息,可用於將上一個恢復權杖傳遞為後續連線的 SessionResumptionConfig.handle,藉此恢復工作階段。

Python

import asyncio
from google import genai
from google.genai import types

client = genai.Client()
model = "gemini-live-2.5-flash-preview"

async def main():
    print(f"Connecting to the service with handle {previous_session_handle}...")
    async with client.aio.live.connect(
        model=model,
        config=types.LiveConnectConfig(
            response_modalities=["AUDIO"],
            session_resumption=types.SessionResumptionConfig(
                # The handle of the session to resume is passed here,
                # or else None to start a new session.
                handle=previous_session_handle
            ),
        ),
    ) as session:
        while True:
            await session.send_client_content(
                turns=types.Content(
                    role="user", parts=[types.Part(text="Hello world!")]
                )
            )
            async for message in session.receive():
                # Periodically, the server will send update messages that may
                # contain a handle for the current state of the session.
                if message.session_resumption_update:
                    update = message.session_resumption_update
                    if update.resumable and update.new_handle:
                        # The handle should be retained and linked to the session.
                        return update.new_handle

                # For the purposes of this example, placeholder input is continually fed
                # to the model. In non-sample code, the model inputs would come from
                # the user.
                if message.server_content and message.server_content.turn_complete:
                    break

if __name__ == "__main__":
    asyncio.run(main())

JavaScript

import { GoogleGenAI, Modality } from '@google/genai';

const ai = new GoogleGenAI({});
const model = 'gemini-live-2.5-flash-preview';

async function live() {
  const responseQueue = [];

  async function waitMessage() {
    let done = false;
    let message = undefined;
    while (!done) {
      message = responseQueue.shift();
      if (message) {
        done = true;
      } else {
        await new Promise((resolve) => setTimeout(resolve, 100));
      }
    }
    return message;
  }

  async function handleTurn() {
    const turns = [];
    let done = false;
    while (!done) {
      const message = await waitMessage();
      turns.push(message);
      if (message.serverContent && message.serverContent.turnComplete) {
        done = true;
      }
    }
    return turns;
  }

console.debug('Connecting to the service with handle %s...', previousSessionHandle)
const session = await ai.live.connect({
  model: model,
  callbacks: {
    onopen: function () {
      console.debug('Opened');
    },
    onmessage: function (message) {
      responseQueue.push(message);
    },
    onerror: function (e) {
      console.debug('Error:', e.message);
    },
    onclose: function (e) {
      console.debug('Close:', e.reason);
    },
  },
  config: {
    responseModalities: [Modality.TEXT],
    sessionResumption: { handle: previousSessionHandle }
    // The handle of the session to resume is passed here, or else null to start a new session.
  }
});

const inputTurns = 'Hello how are you?';
session.sendClientContent({ turns: inputTurns });

const turns = await handleTurn();
for (const turn of turns) {
  if (turn.sessionResumptionUpdate) {
    if (turn.sessionResumptionUpdate.resumable && turn.sessionResumptionUpdate.newHandle) {
      let newHandle = turn.sessionResumptionUpdate.newHandle
      // ...Store newHandle and start new session with this handle here
    }
  }
}

  session.close();
}

async function main() {
  await live().catch((e) => console.error('got error', e));
}

main();

在工作階段中斷前接收訊息

伺服器會傳送「GoAway」GoAway訊息,表示目前的連線即將終止。這則訊息包含 timeLeft,可顯示剩餘時間,並讓您在連線因「已中止」而終止前採取進一步行動。

Python

async for response in session.receive():
    if response.go_away is not None:
        # The connection will soon be terminated
        print(response.go_away.time_left)

JavaScript

const turns = await handleTurn();

for (const turn of turns) {
  if (turn.goAway) {
    console.debug('Time left: %s\n', turn.goAway.timeLeft);
  }
}

產生完成後收到訊息

伺服器會傳送 generationComplete 訊息,表示模型已完成產生回應。

Python

async for response in session.receive():
    if response.server_content.generation_complete is True:
        # The generation is complete

JavaScript

const turns = await handleTurn();

for (const turn of turns) {
  if (turn.serverContent && turn.serverContent.generationComplete) {
    // The generation is complete
  }
}

後續步驟

如要進一步瞭解如何使用 Live API,請參閱完整的功能指南、工具使用頁面或 Live API 食譜