feat: support deepseek ai model (#989)

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

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

@@ -77,6 +77,10 @@ Azure OpenAI 所对应的 `type` 为 `azure`。它特有的配置字段如下：
 
 零一万物所对应的 `type` 为 `yi`。它并无特有的配置字段。
 
+#### DeepSeek（DeepSeek）
+
+DeepSeek所对应的 `type` 为 `deepseek`。它并无特有的配置字段。
+
 #### Groq
 
 Groq 所对应的 `type` 为 `groq`。它并无特有的配置字段。

plugins/wasm-go/extensions/ai-proxy/provider/deepseek.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"
+)
+
+// deepseekProvider is the provider for deepseek Ai service.
+
+const (
+	deepseekDomain             = "api.deepseek.com"
+	deepseekChatCompletionPath = "/v1/chat/completions"
+)
+
+type deepseekProviderInitializer struct {
+}
+
+func (m *deepseekProviderInitializer) ValidateConfig(config ProviderConfig) error {
+	return nil
+}
+
+func (m *deepseekProviderInitializer) CreateProvider(config ProviderConfig) (Provider, error) {
+	return &deepseekProvider{
+		config:       config,
+		contextCache: createContextCache(&config),
+	}, nil
+}
+
+type deepseekProvider struct {
+	config       ProviderConfig
+	contextCache *contextCache
+}
+
+func (m *deepseekProvider) GetProviderType() string {
+	return providerTypeDeepSeek
+}
+
+func (m *deepseekProvider) OnRequestHeaders(ctx wrapper.HttpContext, apiName ApiName, log wrapper.Log) (types.Action, error) {
+	if apiName != ApiNameChatCompletion {
+		return types.ActionContinue, errUnsupportedApiName
+	}
+	_ = util.OverwriteRequestPath(deepseekChatCompletionPath)
+	_ = util.OverwriteRequestHost(deepseekDomain)
+	_ = proxywasm.ReplaceHttpRequestHeader("Authorization", "Bearer "+m.config.GetRandomToken())
+
+	if m.contextCache == nil {
+		ctx.DontReadRequestBody()
+	} else {
+		_ = proxywasm.RemoveHttpRequestHeader("Content-Length")
+	}
+
+	return types.ActionContinue, nil
+}
+
+func (m *deepseekProvider) 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

@@ -22,6 +22,7 @@ const (
 	providerTypeGroq     = "groq"
 	providerTypeBaichuan = "baichuan"
 	providerTypeYi       = "yi"
+	providerTypeDeepSeek = "deepseek"
 
 	protocolOpenAI   = "openai"
 	protocolOriginal = "original"
@@ -58,6 +59,7 @@ var (
 		providerTypeGroq:     &groqProviderInitializer{},
 		providerTypeBaichuan: &baichuanProviderInitializer{},
 		providerTypeYi:       &yiProviderInitializer{},
+		providerTypeDeepSeek: &deepseekProviderInitializer{},
 	}
 )