import (
"context"
"encoding/json"
"fmt"
"io"
aiplatform "cloud.google.com/go/aiplatform/apiv1beta1"
aiplatformpb "cloud.google.com/go/aiplatform/apiv1beta1/aiplatformpb"
"google.golang.org/api/option"
"google.golang.org/protobuf/encoding/protojson"
"google.golang.org/protobuf/types/known/structpb"
)
// generateForTextAndImage shows how to use the multimodal model to generate embeddings for
// text and image inputs.
func generateForTextAndImage(w io.Writer, project, location string) error {
// location = "us-central1"
ctx := context.Background()
apiEndpoint := fmt.Sprintf("%s-aiplatform.googleapis.com:443", location)
client, err := aiplatform.NewPredictionClient(ctx, option.WithEndpoint(apiEndpoint))
if err != nil {
return fmt.Errorf("failed to construct API client: %w", err)
}
defer client.Close()
model := "multimodalembedding@001"
endpoint := fmt.Sprintf("projects/%s/locations/%s/publishers/google/models/%s", project, location, model)
// This is the input to the model's prediction call. For schema, see:
// https://cloud.google.com/vertex-ai/generative-ai/docs/model-reference/multimodal-embeddings-api#request_body
instance, err := structpb.NewValue(map[string]any{
"image": map[string]any{
// Image input can be provided either as a Google Cloud Storage URI or as
// base64-encoded bytes using the "bytesBase64Encoded" field.
"gcsUri": "gs://cloud-samples-data/vertex-ai/llm/prompts/landmark1.png",
},
"text": "Colosseum",
})
if err != nil {
return fmt.Errorf("failed to construct request payload: %w", err)
}
req := &aiplatformpb.PredictRequest{
Endpoint: endpoint,
// The model supports only 1 instance per request.
Instances: []*structpb.Value{instance},
}
resp, err := client.Predict(ctx, req)
if err != nil {
return fmt.Errorf("failed to generate embeddings: %w", err)
}
instanceEmbeddingsJson, err := protojson.Marshal(resp.GetPredictions()[0])
if err != nil {
return fmt.Errorf("failed to convert protobuf value to JSON: %w", err)
}
// For response schema, see:
// https://cloud.google.com/vertex-ai/generative-ai/docs/model-reference/multimodal-embeddings-api#response-body
var instanceEmbeddings struct {
ImageEmbeddings []float32 `json:"imageEmbedding"`
TextEmbeddings []float32 `json:"textEmbedding"`
}
if err := json.Unmarshal(instanceEmbeddingsJson, &instanceEmbeddings); err != nil {
return fmt.Errorf("failed to unmarshal JSON: %w", err)
}
imageEmbedding := instanceEmbeddings.ImageEmbeddings
textEmbedding := instanceEmbeddings.TextEmbeddings
fmt.Fprintf(w, "Text embedding (length=%d): %v\n", len(textEmbedding), textEmbedding)
fmt.Fprintf(w, "Image embedding (length=%d): %v\n", len(imageEmbedding), imageEmbedding)
// Example response:
// Text embedding (length=1408): [0.0023026613 0.027898183 -0.011858357 ... ]
// Image embedding (length=1408): [-0.012314269 0.07271844 0.00020170923 ... ]
return nil
}
