feat: Add an AI-Proxy Wasm plugin (#921)

Co-authored-by: 澄潭 <zty98751@alibaba-inc.com>

plugins/wasm-go/extensions/ai-proxy/provider/context.go

@@ -0,0 +1,100 @@
+package provider
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"net/url"
+
+	"github.com/alibaba/higress/plugins/wasm-go/pkg/wrapper"
+	"github.com/tidwall/gjson"
+)
+
+type ContextConfig struct {
+	// @Title zh-CN 文件URL
+	// @Description zh-CN 用于获取对话上下文的文件的URL。目前仅支持HTTP和HTTPS协议，纯文本格式文件
+	fileUrl string `required:"true" yaml:"url" json:"url"`
+	// @Title zh-CN 上游服务名称
+	// @Description zh-CN 文件服务所对应的网关内上游服务名称
+	serviceName string `required:"true" yaml:"serviceName" json:"serviceName"`
+	// @Title zh-CN 上游服务端口
+	// @Description zh-CN 文件服务所对应的网关内上游服务名称
+	servicePort int64 `required:"true" yaml:"serviceName" json:"serviceName"`
+
+	fileUrlObj *url.URL `yaml:"-"`
+}
+
+func (c *ContextConfig) FromJson(json gjson.Result) {
+	c.fileUrl = json.Get("fileUrl").String()
+	c.serviceName = json.Get("serviceName").String()
+	c.servicePort = json.Get("servicePort").Int()
+}
+
+func (c *ContextConfig) Validate() error {
+	if c.fileUrl == "" {
+		return errors.New("missing fileUrl in context config")
+	}
+	if fileUrlObj, err := url.Parse(c.fileUrl); err != nil {
+		return fmt.Errorf("invalid fileUrl in context config: %v", err)
+	} else {
+		c.fileUrlObj = fileUrlObj
+	}
+	if c.serviceName == "" {
+		return errors.New("missing serviceName in context config")
+	}
+	if c.servicePort == 0 {
+		return errors.New("missing servicePort in context config")
+	}
+	return nil
+}
+
+type contextCache struct {
+	client  wrapper.HttpClient
+	fileUrl *url.URL
+	timeout uint32
+
+	loaded  bool
+	content string
+}
+
+func (c *contextCache) GetContent(callback func(string, error), log wrapper.Log) error {
+	if callback == nil {
+		return errors.New("callback is nil")
+	}
+
+	if c.loaded {
+		log.Debugf("context file loaded from cache")
+		callback(c.content, nil)
+		return nil
+	}
+
+	log.Infof("loading context file from %s", c.fileUrl.String())
+	return c.client.Get(c.fileUrl.Path, nil, func(statusCode int, responseHeaders http.Header, responseBody []byte) {
+		if statusCode != http.StatusOK {
+			callback("", fmt.Errorf("failed to load context file, status: %d", statusCode))
+			return
+		}
+		c.content = string(responseBody)
+		c.loaded = true
+		log.Debugf("content: %s", c.content)
+		callback(c.content, nil)
+	}, c.timeout)
+}
+
+func createContextCache(providerConfig *ProviderConfig) *contextCache {
+	contextConfig := providerConfig.context
+	if contextConfig == nil {
+		return nil
+	}
+	fileUrlObj, _ := url.Parse(contextConfig.fileUrl)
+	cluster := plainCluster{
+		serviceName: contextConfig.serviceName,
+		servicePort: contextConfig.servicePort,
+		hostName:    fileUrlObj.Host,
+	}
+	return &contextCache{
+		client:  wrapper.NewClusterClient(cluster),
+		fileUrl: fileUrlObj,
+		timeout: providerConfig.timeout,
+	}
+}