feat(server): add recipe-based model management (#2176)

examples/server/model_catalog.h

@@ -0,0 +1,56 @@
+#ifndef __SD_EXAMPLES_SERVER_MODEL_CATALOG_H__
+#define __SD_EXAMPLES_SERVER_MODEL_CATALOG_H__
+
+#include <chrono>
+#include <map>
+#include <mutex>
+#include <shared_mutex>
+#include <string>
+
+#include "runtime.h"
+
+struct ModelRoot {
+    std::filesystem::path path;
+    std::string id;
+    std::string label;
+    bool primary = false;
+};
+
+struct ModelFile {
+    std::string category;
+    std::string name;
+    std::string relative_path;
+    ModelRoot root;
+};
+
+std::string model_path_key(const std::filesystem::path& path);
+bool model_path_inside(const std::filesystem::path& root, const std::filesystem::path& path);
+ModelRoot make_model_root(const std::filesystem::path& path, bool primary);
+std::vector<ModelRoot> get_model_roots(const SDSvrParams& params);
+std::vector<std::filesystem::path> model_category_directories(const ModelRoot& root, const std::string& category);
+
+struct ServerModels {
+    std::shared_mutex runtime_mutex;
+    std::mutex catalog_mutex;
+    std::mutex status_mutex;
+    SDCtxPtr context;
+    SDContextParams base_context;
+    SDGenerationParams base_defaults;
+    std::map<std::string, json> recipes;
+    std::map<std::string, ModelFile> files;
+    std::chrono::steady_clock::time_point load_started_at;
+    json active_recipe  = nullptr;
+    json catalog_errors = json::array();
+    json status         = {{"state", "empty"}, {"recipe", nullptr}, {"models", json::object()}, {"error", nullptr}, {"load_elapsed_seconds", nullptr}};
+};
+
+void refresh_model_catalog(ServerRuntime& runtime);
+json model_status(ServerRuntime& runtime);
+void initialize_server_models(ServerRuntime& runtime);
+
+json resolve_recipe_features(const json& recipe);
+json model_generation_features(const ServerRuntime& runtime);
+
+void prepare_model_load(ServerRuntime& runtime, const json& body, SDContextParams& context, SDGenerationParams& defaults, json* loaded_recipe = nullptr);
+
+#endif