Create a context cache

Create a context cache to reduce costs with repeated requests that contain the same token count input.

Code sample

C#

Before trying this sample, follow the C# setup instructions in the Vertex AI quickstart using client libraries. For more information, see the Vertex AI C# API reference documentation.

To authenticate to Vertex AI, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 


using Google.Cloud.AIPlatform.V1Beta1;
using Google.Protobuf.WellKnownTypes;
using System;
using System.Threading.Tasks;

public class CreateContextCache
{
    public async Task<CachedContentName> Create(string projectId)
    {
        var client = await new GenAiCacheServiceClientBuilder
        {
            Endpoint = "us-central1-aiplatform.googleapis.com"
        }.BuildAsync();

        var request = new CreateCachedContentRequest
        {
            Parent = $"projects/{projectId}/locations/us-central1",
            CachedContent = new CachedContent
            {
                Model = $"projects/{projectId}/locations/us-central1/publishers/google/models/gemini-1.5-pro-001",
                SystemInstruction = new Content
                {
                    Parts =
                    {
                        new Part { Text = "You are an expert researcher. You always stick to the facts in the sources provided and"
                            + " never make up new facts. Now look at these research papers, and answer the following questions." }
                    }
                },
                Contents =
                {
                    new Content
                    {
                        Role = "USER",
                        Parts =
                        {
                            new Part { FileData = new() { MimeType = "application/pdf", FileUri = "gs://cloud-samples-data/generative-ai/pdf/2312.11805v3.pdf" } },
                            new Part { FileData = new() { MimeType = "application/pdf", FileUri = "gs://cloud-samples-data/generative-ai/pdf/2403.05530.pdf" } }
                        }
                    }
                },
                Ttl = Duration.FromTimeSpan(TimeSpan.FromMinutes(60))
            }
        };

        var cachedContent = await client.CreateCachedContentAsync(request);
        Console.WriteLine($"Created cache: {cachedContent.CachedContentName}");
        return cachedContent.CachedContentName;
    }
}

Go

Before trying this sample, follow the Go setup instructions in the Vertex AI quickstart using client libraries. For more information, see the Vertex AI Go API reference documentation.

To authenticate to Vertex AI, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 

import (
	"context"
	"fmt"
	"io"
	"time"

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

// createContextCache shows how to create a cached content, and returns its name.
func createContextCache(w io.Writer, projectID, location, modelName string) (string, error) {
	// location := "us-central1"
	// modelName := "gemini-1.5-pro-001"
	ctx := context.Background()

	systemInstruction := `
    	You are an expert researcher. You always stick to the facts in the sources provided, and never make up new facts.
    	Now look at these research papers, and answer the following questions.
    `

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

	// These PDF are viewable at
	//   https://storage.googleapis.com/cloud-samples-data/generative-ai/pdf/2312.11805v3.pdf
	//   https://storage.googleapis.com/cloud-samples-data/generative-ai/pdf/2403.05530.pdf

	part1 := genai.FileData{
		MIMEType: "application/pdf",
		FileURI:  "gs://cloud-samples-data/generative-ai/pdf/2312.11805v3.pdf",
	}

	part2 := genai.FileData{
		MIMEType: "application/pdf",
		FileURI:  "gs://cloud-samples-data/generative-ai/pdf/2403.05530.pdf",
	}

	content := &genai.CachedContent{
		Model: modelName,
		SystemInstruction: &genai.Content{
			Parts: []genai.Part{genai.Text(systemInstruction)},
		},
		Expiration: genai.ExpireTimeOrTTL{TTL: 60 * time.Minute},
		Contents: []*genai.Content{
			{
				Role:  "user",
				Parts: []genai.Part{part1, part2},
			},
		},
	}

	result, err := client.CreateCachedContent(ctx, content)
	if err != nil {
		return "", fmt.Errorf("CreateCachedContent: %w", err)
	}
	fmt.Fprint(w, result.Name)
	return result.Name, nil
}

What's next

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