implement generic provider for vendor-agnostic passthrough (#3175)

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

@@ -0,0 +1,85 @@
+package provider
+
+import (
+	"net/http"
+	"strconv"
+
+	"github.com/alibaba/higress/plugins/wasm-go/extensions/ai-proxy/util"
+	"github.com/higress-group/proxy-wasm-go-sdk/proxywasm"
+	"github.com/higress-group/proxy-wasm-go-sdk/proxywasm/types"
+	"github.com/higress-group/wasm-go/pkg/log"
+	"github.com/higress-group/wasm-go/pkg/wrapper"
+)
+
+// genericProviderInitializer 用于创建一个不做能力映射的通用 Provider。
+type genericProviderInitializer struct{}
+
+// ValidateConfig 通用 Provider 不需要额外的配置校验。
+func (m *genericProviderInitializer) ValidateConfig(config *ProviderConfig) error {
+	return nil
+}
+
+// DefaultCapabilities 返回空映射，表示不会做路径或能力重写。
+func (m *genericProviderInitializer) DefaultCapabilities() map[string]string {
+	return map[string]string{}
+}
+
+// CreateProvider 创建 generic provider，并沿用通用的上下文缓存能力。
+func (m *genericProviderInitializer) CreateProvider(config ProviderConfig) (Provider, error) {
+	config.setDefaultCapabilities(m.DefaultCapabilities())
+	return &genericProvider{
+		config: config,
+	}, nil
+}
+
+// genericProvider 只负责公共的头部、请求体处理逻辑，不绑定任何厂商。
+type genericProvider struct {
+	config ProviderConfig
+}
+
+func (m *genericProvider) GetProviderType() string {
+	return providerTypeGeneric
+}
+
+// OnRequestHeaders 复用通用的 handleRequestHeaders，并在配置首包超时时写入相关头部。
+func (m *genericProvider) OnRequestHeaders(ctx wrapper.HttpContext, apiName ApiName) error {
+	m.config.handleRequestHeaders(m, ctx, apiName)
+	if m.config.firstByteTimeout > 0 {
+		ctx.SetContext(ctxKeyIsStreaming, true)
+		m.applyFirstByteTimeout()
+	}
+	return nil
+}
+
+func (m *genericProvider) OnRequestBody(ctx wrapper.HttpContext, apiName ApiName, body []byte) (types.Action, error) {
+	return types.ActionContinue, nil
+}
+
+// TransformRequestHeaders 只处理鉴权与 Host 改写，不做路径重写。
+func (m *genericProvider) TransformRequestHeaders(ctx wrapper.HttpContext, apiName ApiName, headers http.Header) {
+	if len(m.config.apiTokens) > 0 {
+		if token := m.config.GetApiTokenInUse(ctx); token != "" {
+			util.OverwriteRequestAuthorizationHeader(headers, "Bearer "+token)
+		}
+	}
+	if m.config.genericHost != "" {
+		util.OverwriteRequestHostHeader(headers, m.config.genericHost)
+	}
+	headers.Del("Content-Length")
+}
+
+// applyFirstByteTimeout 在配置了 firstByteTimeout 时，为所有流式请求写入超时头。
+func (m *genericProvider) applyFirstByteTimeout() {
+	if m.config.firstByteTimeout == 0 {
+		return
+	}
+	err := proxywasm.ReplaceHttpRequestHeader(
+		"x-envoy-upstream-rq-first-byte-timeout-ms",
+		strconv.FormatUint(uint64(m.config.firstByteTimeout), 10),
+	)
+	if err != nil {
+		log.Errorf("generic provider: failed to set first byte timeout header: %v", err)
+		return
+	}
+	log.Debugf("[generic][firstByteTimeout] %d", m.config.firstByteTimeout)
+}

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

@@ -144,6 +144,7 @@ const (
 	providerTypeLongcat    = "longcat"
 	providerTypeFireworks  = "fireworks"
 	providerTypeVllm       = "vllm"
+	providerTypeGeneric    = "generic"
 
 	protocolOpenAI   = "openai"
 	protocolOriginal = "original"
@@ -227,6 +228,7 @@ var (
 		providerTypeLongcat:    &longcatProviderInitializer{},
 		providerTypeFireworks:  &fireworksProviderInitializer{},
 		providerTypeVllm:       &vllmProviderInitializer{},
+		providerTypeGeneric:    &genericProviderInitializer{},
 	}
 )
 
@@ -409,6 +411,9 @@ type ProviderConfig struct {
 	basePath string `required:"false" yaml:"basePath" json:"basePath"`
 	// @Title zh-CN basePathHandling用于指定basePath的处理方式，可选值：removePrefix、prepend
 	basePathHandling basePathHandling `required:"false" yaml:"basePathHandling" json:"basePathHandling"`
+	// @Title zh-CN generic Provider 对应的Host
+	// @Description zh-CN 仅适用于generic provider，用于覆盖请求转发的目标Host
+	genericHost string `required:"false" yaml:"genericHost" json:"genericHost"`
 	// @Title zh-CN 首包超时
 	// @Description zh-CN 流式请求中收到上游服务第一个响应包的超时时间，单位为毫秒。默认值为 0，表示不开启首包超时
 	firstByteTimeout uint32 `required:"false" yaml:"firstByteTimeout" json:"firstByteTimeout"`
@@ -619,6 +624,7 @@ func (c *ProviderConfig) FromJson(json gjson.Result) {
 	if c.basePath != "" && c.basePathHandling == "" {
 		c.basePathHandling = basePathHandlingRemovePrefix
 	}
+	c.genericHost = json.Get("genericHost").String()
 	c.vllmServerHost = json.Get("vllmServerHost").String()
 	c.vllmCustomUrl = json.Get("vllmCustomUrl").String()
 }