Add cohere embedding for ai-cache (#1572)

plugins/wasm-go/extensions/ai-cache/embedding/cohere.go

@@ -0,0 +1,158 @@
+package embedding
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"strconv"
+
+	"github.com/alibaba/higress/plugins/wasm-go/pkg/wrapper"
+	"github.com/tidwall/gjson"
+)
+
+const (
+	COHERE_DOMAIN             = "api.cohere.com"
+	COHERE_PORT               = 443
+	COHERE_DEFAULT_MODEL_NAME = "embed-english-v2.0"
+	COHERE_ENDPOINT           = "/v2/embed"
+)
+
+type cohereProviderInitializer struct {
+}
+
+var cohereConfig cohereProviderConfig
+
+type cohereProviderConfig struct {
+	// @Title zh-CN 文本特征提取服务 API Key
+	// @Description zh-CN 文本特征提取服务 API Key
+	apiKey string
+}
+
+func (c *cohereProviderInitializer) InitConfig(json gjson.Result) {
+	cohereConfig.apiKey = json.Get("apiKey").String()
+}
+func (c *cohereProviderInitializer) ValidateConfig() error {
+	if cohereConfig.apiKey == "" {
+		return errors.New("[Cohere] apiKey is required")
+	}
+	return nil
+}
+
+func (t *cohereProviderInitializer) CreateProvider(c ProviderConfig) (Provider, error) {
+	if c.servicePort == 0 {
+		c.servicePort = COHERE_PORT
+	}
+	if c.serviceHost == "" {
+		c.serviceHost = COHERE_DOMAIN
+	}
+	return &CohereProvider{
+		config: c,
+		client: wrapper.NewClusterClient(wrapper.FQDNCluster{
+			FQDN: c.serviceName,
+			Host: c.serviceHost,
+			Port: int64(c.servicePort),
+		}),
+	}, nil
+}
+
+type cohereResponse struct {
+	Embeddings cohereEmbeddings `json:"embeddings"`
+}
+
+type cohereEmbeddings struct {
+	FloatTypeEebedding [][]float64 `json:"float"`
+}
+
+type cohereEmbeddingRequest struct {
+	Texts          []string `json:"texts"`
+	Model          string   `json:"model"`
+	InputType      string   `json:"input_type"`
+	EmbeddingTypes []string `json:"embedding_types"`
+}
+
+type CohereProvider struct {
+	config ProviderConfig
+	client wrapper.HttpClient
+}
+
+func (t *CohereProvider) GetProviderType() string {
+	return PROVIDER_TYPE_COHERE
+}
+func (t *CohereProvider) constructParameters(texts []string, log wrapper.Log) (string, [][2]string, []byte, error) {
+	model := t.config.model
+
+	if model == "" {
+		model = COHERE_DEFAULT_MODEL_NAME
+	}
+	data := cohereEmbeddingRequest{
+		Texts:          texts,
+		Model:          model,
+		InputType:      "search_document",
+		EmbeddingTypes: []string{"float"},
+	}
+
+	requestBody, err := json.Marshal(data)
+	if err != nil {
+		log.Errorf("failed to marshal request data: %v", err)
+		return "", nil, nil, err
+	}
+
+	headers := [][2]string{
+		{"Authorization", fmt.Sprintf("BEARER %s", cohereConfig.apiKey)},
+		{"Content-Type", "application/json"},
+	}
+
+	return COHERE_ENDPOINT, headers, requestBody, nil
+}
+
+func (t *CohereProvider) parseTextEmbedding(responseBody []byte) (*cohereResponse, error) {
+	var resp cohereResponse
+	err := json.Unmarshal(responseBody, &resp)
+	if err != nil {
+		return nil, err
+	}
+	return &resp, nil
+}
+
+func (t *CohereProvider) GetEmbedding(
+	queryString string,
+	ctx wrapper.HttpContext,
+	log wrapper.Log,
+	callback func(emb []float64, err error)) error {
+	embUrl, embHeaders, embRequestBody, err := t.constructParameters([]string{queryString}, log)
+	if err != nil {
+		log.Errorf("failed to construct parameters: %v", err)
+		return err
+	}
+
+	var resp *cohereResponse
+	err = t.client.Post(embUrl, embHeaders, embRequestBody,
+		func(statusCode int, responseHeaders http.Header, responseBody []byte) {
+
+			if statusCode != http.StatusOK {
+				err = errors.New("failed to get embedding due to status code: " + strconv.Itoa(statusCode))
+				callback(nil, err)
+				return
+			}
+
+			log.Debugf("get embedding response: %d, %s", statusCode, responseBody)
+
+			resp, err = t.parseTextEmbedding(responseBody)
+			if err != nil {
+				err = fmt.Errorf("failed to parse response: %v", err)
+				callback(nil, err)
+				return
+			}
+
+			if len(resp.Embeddings.FloatTypeEebedding) == 0 {
+				err = errors.New("no embedding found in response")
+				callback(nil, err)
+				return
+			}
+
+			callback(resp.Embeddings.FloatTypeEebedding[0], nil)
+
+		}, t.config.timeout)
+	return err
+}