Version: 0.9.65.dev.260503

后端：
1. 阶段 1.5/1.6
收口 llm-service / rag-service，统一模型出口与检索基础设施入口，清退 backend/infra/llm 与 backend/infra/rag 旧实现；
2. 同步更新相关调用链与微服务迁移计划文档

backend/services/rag/factory.go

@@ -0,0 +1,142 @@
+package rag
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"os"
+	"strings"
+
+	ragchunk "github.com/LoveLosita/smartflow/backend/services/rag/chunk"
+	ragconfig "github.com/LoveLosita/smartflow/backend/services/rag/config"
+	"github.com/LoveLosita/smartflow/backend/services/rag/core"
+	ragembed "github.com/LoveLosita/smartflow/backend/services/rag/embed"
+	ragrerank "github.com/LoveLosita/smartflow/backend/services/rag/rerank"
+	ragstore "github.com/LoveLosita/smartflow/backend/services/rag/store"
+)
+
+// FactoryDeps 描述 Runtime 工厂所需的可选依赖。
+//
+// 说明：
+// 1. Logger 仅作为“当前项目尚无统一日志系统”时的默认落点；
+// 2. Observer 是正式的统一观测插槽，后续可替换为项目级 logger/metrics/tracing 适配器；
+// 3. 业务侧仍然只拿 Runtime，不直接碰底层装配细节。
+type FactoryDeps struct {
+	Logger   *log.Logger
+	Observer Observer
+}
+
+// NewRuntimeFromConfig 按配置统一组装 RAG Runtime。
+//
+// 设计说明：
+// 1. 所有底层实现选择都收口到这里，业务侧不再自行 new store/embedder/reranker；
+// 2. 即使后续引入更多 provider，也应优先扩展本工厂，而不是把选择逻辑扩散到业务模块；
+// 3. 观测能力也在此统一注入，避免 runtime/store/pipeline 各自偷偷打印日志。
+func NewRuntimeFromConfig(ctx context.Context, cfg ragconfig.Config, deps FactoryDeps) (Runtime, error) {
+	logger, observer := normalizeFactoryDeps(deps)
+
+	embedder, err := buildEmbedder(ctx, cfg)
+	if err != nil {
+		return nil, err
+	}
+
+	store, err := buildStore(cfg, logger, observer)
+	if err != nil {
+		return nil, err
+	}
+
+	reranker, err := buildReranker(cfg, observer)
+	if err != nil {
+		return nil, err
+	}
+
+	pipeline := core.NewPipeline(ragchunk.NewTextChunker(), embedder, store, reranker)
+	pipeline.SetLogger(logger)
+	pipeline.SetObserver(observer)
+	return newRuntime(cfg, pipeline, observer), nil
+}
+
+func normalizeFactoryDeps(deps FactoryDeps) (*log.Logger, Observer) {
+	logger := deps.Logger
+	if logger == nil {
+		logger = log.Default()
+	}
+	observer := deps.Observer
+	if observer == nil {
+		observer = NewLoggerObserver(logger)
+	}
+	return logger, observer
+}
+
+func buildEmbedder(ctx context.Context, cfg ragconfig.Config) (core.Embedder, error) {
+	switch strings.ToLower(strings.TrimSpace(cfg.EmbedProvider)) {
+	case "", "mock":
+		return ragembed.NewMockEmbedder(cfg.EmbedDimension), nil
+	case "eino":
+		// 1. RAG embedding 与普通 LLM 链路保持同一套密钥来源，统一直接读取 ARK_API_KEY；
+		// 2. 这样可以避免再维护一层 “env 名称配置 -> 再读环境变量” 的间接映射，减少配置分叉；
+		// 3. 若后续真的需要多套 embedding 凭据，再显式设计独立字段，而不是继续隐式透传 env 名称。
+		apiKey := strings.TrimSpace(os.Getenv("ARK_API_KEY"))
+		if apiKey == "" {
+			return nil, fmt.Errorf("rag embed api key is empty: env=%s", "ARK_API_KEY")
+		}
+		return ragembed.NewEinoEmbedder(ctx, ragembed.EinoConfig{
+			APIKey:    apiKey,
+			BaseURL:   cfg.EmbedBaseURL,
+			Model:     cfg.EmbedModel,
+			TimeoutMS: cfg.EmbedTimeoutMS,
+			Dimension: cfg.EmbedDimension,
+		})
+	default:
+		return nil, fmt.Errorf("unsupported rag embed provider: %s", cfg.EmbedProvider)
+	}
+}
+
+func buildStore(cfg ragconfig.Config, logger *log.Logger, observer Observer) (core.VectorStore, error) {
+	switch strings.ToLower(strings.TrimSpace(cfg.Store)) {
+	case "", "inmemory":
+		return ragstore.NewInMemoryVectorStore(), nil
+	case "milvus":
+		return ragstore.NewMilvusStore(ragstore.MilvusConfig{
+			Address:          cfg.MilvusAddress,
+			Token:            cfg.MilvusToken,
+			DBName:           cfg.MilvusDBName,
+			CollectionName:   cfg.MilvusCollectionName,
+			RequestTimeoutMS: cfg.MilvusRequestTimeoutMS,
+			Dimension:        cfg.EmbedDimension,
+			MetricType:       cfg.MilvusMetricType,
+			Logger:           logger,
+			Observer:         observer,
+		})
+	default:
+		return nil, fmt.Errorf("unsupported rag store: %s", cfg.Store)
+	}
+}
+
+func buildReranker(cfg ragconfig.Config, observer Observer) (core.Reranker, error) {
+	if !cfg.RerankerEnabled {
+		return ragrerank.NewNoopReranker(), nil
+	}
+
+	switch strings.ToLower(strings.TrimSpace(cfg.RerankerProvider)) {
+	case "", "noop":
+		return ragrerank.NewNoopReranker(), nil
+	case "eino":
+		if observer != nil {
+			observer.Observe(context.Background(), ObserveEvent{
+				Level:     ObserveLevelWarn,
+				Component: "factory",
+				Operation: "reranker_fallback",
+				Fields: map[string]any{
+					"provider":        "eino",
+					"status":          "fallback",
+					"fallback_target": "noop",
+					"reason":          "reranker_not_implemented",
+				},
+			})
+		}
+		return ragrerank.NewNoopReranker(), nil
+	default:
+		return nil, fmt.Errorf("unsupported rag reranker provider: %s", cfg.RerankerProvider)
+	}
+}