Retriever - es8

go get github.com/cloudwego/eino-ext/components/retriever/es8@latest

import (
	"github.com/cloudwego/eino/components/embedding"
	"github.com/cloudwego/eino/schema"
	"github.com/elastic/go-elasticsearch/v8"
	"github.com/elastic/go-elasticsearch/v8/typedapi/types"

	"github.com/cloudwego/eino-ext/components/retriever/es8"
	"github.com/cloudwego/eino-ext/components/retriever/es8/search_mode"
)

const (
	indexName          = "eino_example"
	fieldContent       = "content"
	fieldContentVector = "content_vector"
	fieldExtraLocation = "location"
	docExtraLocation   = "location"
)

func main() {
	ctx := context.Background()

	// es supports multiple ways to connect
	username := os.Getenv("ES_USERNAME")
	password := os.Getenv("ES_PASSWORD")
	httpCACertPath := os.Getenv("ES_HTTP_CA_CERT_PATH")

	cert, err := os.ReadFile(httpCACertPath)
	if err != nil {
		log.Fatalf("read file failed, err=%v", err)
	}

	client, _ := elasticsearch.NewClient(elasticsearch.Config{
		Addresses: []string{"https://localhost:9200"},
		Username:  username,
		Password:  password,
		CACert:    cert,
	})

	// create retriever component
	retriever, _ := es8.NewRetriever(ctx, &es8.RetrieverConfig{
		Client: client,
		Index:  indexName,
		TopK:   5,
		SearchMode: search_mode.SearchModeApproximate(&search_mode.ApproximateConfig{
			QueryFieldName:  fieldContent,
			VectorFieldName: fieldContentVector,
			Hybrid:          true,
			// RRF only available with specific licenses
			// see: https://www.elastic.co/subscriptions
			RRF:             false,
			RRFRankConstant: nil,
			RRFWindowSize:   nil,
		}),
		ResultParser: func(ctx context.Context, hit types.Hit) (doc *schema.Document, err error) {
			doc = &schema.Document{
				ID:       *hit.Id_,
				Content:  "",
				MetaData: map[string]any{},
			}

			var src map[string]any
			if err = json.Unmarshal(hit.Source_, &src); err != nil {
				return nil, err
			}

			for field, val := range src {
				switch field {
				case fieldContent:
					doc.Content = val.(string)
				case fieldContentVector:
					var v []float64
					for _, item := range val.([]interface{}) {
						v = append(v, item.(float64))
					}
					doc.WithDenseVector(v)
				case fieldExtraLocation:
					doc.MetaData[docExtraLocation] = val.(string)
				}
			}

			if hit.Score_ != nil {
				doc.WithScore(float64(*hit.Score_))
			}

			return doc, nil
		},
		Embedding: emb, // your embedding component
	})

	// search without filter
	docs, _ := retriever.Retrieve(ctx, "tourist attraction")

	// search with filter
	docs, _ = retriever.Retrieve(ctx, "tourist attraction",
		es8.WithFilters([]types.Query{{
			Term: map[string]types.TermQuery{
				fieldExtraLocation: {
					CaseInsensitive: of(true),
					Value:           "China",
				},
			},
		}}),
	)
}

type RetrieverConfig struct {
    Client *elasticsearch.Client // Required: Elasticsearch client instance
    Index  string               // Required: Index name to retrieve documents from
    TopK   int                  // Required: Number of results to return
    
    // Required: Search mode configuration
    SearchMode search_mode.SearchMode
    
    // Required: Function to parse Elasticsearch hits into Documents
    ResultParser func(ctx context.Context, hit types.Hit) (*schema.Document, error)
    
    // Optional: Required only if query vectorization is needed
    Embedding embedding.Embedder
}