feat: add baichuan llm support (#979)

Co-authored-by: Kent Dong <ch3cho@qq.com>

plugins/wasm-go/extensions/ai-proxy/README.md

@@ -64,6 +64,10 @@ Azure OpenAI 所对应的 `type` 为 `azure`。它特有的配置字段如下：
 
 通义千问所对应的 `type` 为 `qwen`。它并无特有的配置字段。
 
+#### 百川智能 (Baichuan AI)
+
+百川智能所对应的 `type` 为 `baichuan` 。它并无特有的配置字段。
+
 #### 零一万物（Yi）
 
 零一万物所对应的 `type` 为 `yi`。它并无特有的配置字段。

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

@@ -0,0 +1,87 @@
+package provider
+
+import (
+	"fmt"
+
+	"github.com/alibaba/higress/plugins/wasm-go/extensions/ai-proxy/util"
+	"github.com/alibaba/higress/plugins/wasm-go/pkg/wrapper"
+	"github.com/higress-group/proxy-wasm-go-sdk/proxywasm"
+	"github.com/higress-group/proxy-wasm-go-sdk/proxywasm/types"
+)
+
+// baichuanProvider is the provider for baichuan Ai service.
+
+const (
+	baichuanDomain             = "api.baichuan-ai.com"
+	baichuanChatCompletionPath = "/v1/chat/completions"
+)
+
+type baichuanProviderInitializer struct {
+}
+
+func (m *baichuanProviderInitializer) ValidateConfig(config ProviderConfig) error {
+	return nil
+}
+
+func (m *baichuanProviderInitializer) CreateProvider(config ProviderConfig) (Provider, error) {
+	return &baichuanProvider{
+		config:       config,
+		contextCache: createContextCache(&config),
+	}, nil
+}
+
+type baichuanProvider struct {
+	config       ProviderConfig
+	contextCache *contextCache
+}
+
+func (m *baichuanProvider) GetProviderType() string {
+	return providerTypeBaichuan
+}
+
+func (m *baichuanProvider) OnRequestHeaders(ctx wrapper.HttpContext, apiName ApiName, log wrapper.Log) (types.Action, error) {
+	if apiName != ApiNameChatCompletion {
+		return types.ActionContinue, errUnsupportedApiName
+	}
+	_ = util.OverwriteRequestPath(baichuanChatCompletionPath)
+	_ = util.OverwriteRequestHost(baichuanDomain)
+	_ = proxywasm.ReplaceHttpRequestHeader("Authorization", "Bearer "+m.config.GetRandomToken())
+
+	if m.contextCache == nil {
+		ctx.DontReadRequestBody()
+	} else {
+		_ = proxywasm.RemoveHttpRequestHeader("Content-Length")
+	}
+
+	return types.ActionContinue, nil
+}
+
+func (m *baichuanProvider) OnRequestBody(ctx wrapper.HttpContext, apiName ApiName, body []byte, log wrapper.Log) (types.Action, error) {
+	if apiName != ApiNameChatCompletion {
+		return types.ActionContinue, errUnsupportedApiName
+	}
+	if m.contextCache == nil {
+		return types.ActionContinue, nil
+	}
+	request := &chatCompletionRequest{}
+	if err := decodeChatCompletionRequest(body, request); err != nil {
+		return types.ActionContinue, err
+	}
+	err := m.contextCache.GetContent(func(content string, err error) {
+		defer func() {
+			_ = proxywasm.ResumeHttpRequest()
+		}()
+		if err != nil {
+			log.Errorf("failed to load context file: %v", err)
+			_ = util.SendResponse(500, util.MimeTypeTextPlain, fmt.Sprintf("failed to load context file: %v", err))
+		}
+		insertContextMessage(request, content)
+		if err := replaceJsonRequestBody(request, log); err != nil {
+			_ = util.SendResponse(500, util.MimeTypeTextPlain, fmt.Sprintf("failed to replace request body: %v", err))
+		}
+	}, log)
+	if err == nil {
+		return types.ActionPause, nil
+	}
+	return types.ActionContinue, err
+}

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

@@ -20,10 +20,11 @@ const (
 	providerTypeQwen     = "qwen"
 	providerTypeOpenAI   = "openai"
 	providerTypeGroq     = "groq"
+	providerTypeBaichuan = "baichuan"
 	providerTypeYi       = "yi"
 
-	protocolOpenAI   = "openai"
-	protocolOriginal = "original"
+	protocolOpenAI       = "openai"
+	protocolOriginal     = "original"
 
 	roleSystem = "system"
 
@@ -54,6 +55,7 @@ var (
 		providerTypeQwen:     &qwenProviderInitializer{},
 		providerTypeOpenAI:   &openaiProviderInitializer{},
 		providerTypeGroq:     &groqProviderInitializer{},
+		providerTypeBaichuan: &baichuanProviderInitializer{},
 		providerTypeYi:       &yiProviderInitializer{},
 	}
 )
@@ -84,7 +86,7 @@ type ResponseBodyHandler interface {
 
 type ProviderConfig struct {
 	// @Title zh-CN AI服务提供商
-	// @Description zh-CN AI服务提供商类型，目前支持的取值为："moonshot"、"qwen"、"openai"、"azure"
+	// @Description zh-CN AI服务提供商类型，目前支持的取值为："moonshot"、"qwen"、"openai"、"azure"、"baichuan"、"yi"
 	typ string `required:"true" yaml:"type" json:"type"`
 	// @Title zh-CN API Tokens
 	// @Description zh-CN 在请求AI服务时用于认证的API Token列表。不同的AI服务提供商可能有不同的名称。部分供应商只支持配置一个API Token（如Azure OpenAI）。