計算 Gemini 的符記

這個程式碼範例說明如何使用 Vertex AI Generative Models API 計算提示中的權杖數量，以及如何使用 Gemini 模型生成內容。

程式碼範例

Go

在試用這個範例之前，請先按照Go使用用戶端程式庫的 Vertex AI 快速入門中的操作說明進行設定。 詳情請參閱 Vertex AI Go API 參考說明文件。

如要向 Vertex AI 進行驗證，請設定應用程式預設憑證。 詳情請參閱「為本機開發環境設定驗證」。

import (
	"context"
	"fmt"
	"io"
	"mime"
	"path/filepath"

	"cloud.google.com/go/vertexai/genai"
)

// countTokensMultimodal finds the number of tokens for a multimodal prompt (video+text), and writes to w. Then,
// it calls the model with the multimodal prompt and writes token counts from the response metadata to w.
//
// video is a Google Cloud Storage path starting with "gs://"
func countTokensMultimodal(w io.Writer, projectID, location, modelName string) error {
	// location := "us-central1"
	// modelName := "gemini-2.0-flash-001"
	prompt := "Provide a description of the video."
	video := "gs://cloud-samples-data/generative-ai/video/pixel8.mp4"

	ctx := context.Background()

	client, err := genai.NewClient(ctx, projectID, location)
	if err != nil {
		return fmt.Errorf("unable to create client: %w", err)
	}
	defer client.Close()

	model := client.GenerativeModel(modelName)

	part1 := genai.Text(prompt)

	// Given a video file URL, prepare video file as genai.Part
	part2 := genai.FileData{
		MIMEType: mime.TypeByExtension(filepath.Ext(video)),
		FileURI:  video,
	}

	// Finds the total number of tokens for the 2 parts (text, video) of the multimodal prompt,
	// before actually calling the model for inference.
	resp, err := model.CountTokens(ctx, part1, part2)
	if err != nil {
		return err
	}

	fmt.Fprintf(w, "Number of tokens for the multimodal video prompt: %d\n", resp.TotalTokens)

	res, err := model.GenerateContent(ctx, part1, part2)
	if err != nil {
		return fmt.Errorf("unable to generate contents: %w", err)
	}

	// The token counts are also provided in the model response metadata, after inference.
	fmt.Fprintln(w, "\nModel response")
	md := res.UsageMetadata
	fmt.Fprintf(w, "Prompt Token Count: %d\n", md.PromptTokenCount)
	fmt.Fprintf(w, "Candidates Token Count: %d\n", md.CandidatesTokenCount)
	fmt.Fprintf(w, "Total Token Count: %d\n", md.TotalTokenCount)

	return nil
}

後續步驟

如要搜尋及篩選其他 Google Cloud 產品的程式碼範例，請參閱Google Cloud 範例瀏覽器。