Sync from upstream llama.cpp repository

tools/server/server-models.h

@@ -0,0 +1,203 @@
+#pragma once
+
+#include "common.h"
+#include "preset.h"
+#include "server-common.h"
+#include "server-http.h"
+
+#include <mutex>
+#include <condition_variable>
+#include <functional>
+#include <memory>
+#include <set>
+
+/**
+ * state diagram:
+ *
+ * UNLOADED ──► LOADING ──► LOADED
+ *  ▲            │            │
+ *  └───failed───┘            │
+ *  ▲                         │
+ *  └────────unloaded─────────┘
+ */
+enum server_model_status {
+    // TODO: also add downloading state when the logic is added
+    SERVER_MODEL_STATUS_UNLOADED,
+    SERVER_MODEL_STATUS_LOADING,
+    SERVER_MODEL_STATUS_LOADED
+};
+
+static server_model_status server_model_status_from_string(const std::string & status_str) {
+    if (status_str == "unloaded") {
+        return SERVER_MODEL_STATUS_UNLOADED;
+    }
+    if (status_str == "loading") {
+        return SERVER_MODEL_STATUS_LOADING;
+    }
+    if (status_str == "loaded") {
+        return SERVER_MODEL_STATUS_LOADED;
+    }
+    throw std::runtime_error("invalid server model status");
+}
+
+static std::string server_model_status_to_string(server_model_status status) {
+    switch (status) {
+        case SERVER_MODEL_STATUS_UNLOADED: return "unloaded";
+        case SERVER_MODEL_STATUS_LOADING:  return "loading";
+        case SERVER_MODEL_STATUS_LOADED:   return "loaded";
+        default:                           return "unknown";
+    }
+}
+
+struct server_model_meta {
+    common_preset preset;
+    std::string name;
+    int port = 0;
+    server_model_status status = SERVER_MODEL_STATUS_UNLOADED;
+    int64_t last_used = 0; // for LRU unloading
+    std::vector<std::string> args; // args passed to the model instance, will be populated by render_args()
+    int exit_code = 0; // exit code of the model instance process (only valid if status == FAILED)
+    int stop_timeout = 0; // seconds to wait before force-killing the model instance during shutdown
+
+    bool is_active() const {
+        return status == SERVER_MODEL_STATUS_LOADED || status == SERVER_MODEL_STATUS_LOADING;
+    }
+
+    bool is_failed() const {
+        return status == SERVER_MODEL_STATUS_UNLOADED && exit_code != 0;
+    }
+
+    void update_args(common_preset_context & ctx_presets, std::string bin_path);
+};
+
+struct subprocess_s;
+
+struct server_models {
+private:
+    struct instance_t {
+        std::shared_ptr<subprocess_s> subproc; // shared between main thread and monitoring thread
+        std::thread th;
+        server_model_meta meta;
+        FILE * stdin_file = nullptr;
+    };
+
+    std::mutex mutex;
+    std::condition_variable cv;
+    std::map<std::string, instance_t> mapping;
+
+    // for stopping models
+    std::condition_variable cv_stop;
+    std::set<std::string> stopping_models;
+
+    common_preset_context ctx_preset;
+
+    common_params base_params;
+    std::string bin_path;
+    std::vector<std::string> base_env;
+    common_preset base_preset; // base preset from llama-server CLI args
+
+    void update_meta(const std::string & name, const server_model_meta & meta);
+
+    // unload least recently used models if the limit is reached
+    void unload_lru();
+
+    // not thread-safe, caller must hold mutex
+    void add_model(server_model_meta && meta);
+
+public:
+    server_models(const common_params & params, int argc, char ** argv);
+
+    void load_models();
+
+    // check if a model instance exists (thread-safe)
+    bool has_model(const std::string & name);
+
+    // return a copy of model metadata (thread-safe)
+    std::optional<server_model_meta> get_meta(const std::string & name);
+
+    // return a copy of all model metadata (thread-safe)
+    std::vector<server_model_meta> get_all_meta();
+
+    // load and unload model instances
+    // these functions are thread-safe
+    void load(const std::string & name);
+    void unload(const std::string & name);
+    void unload_all();
+
+    // update the status of a model instance (thread-safe)
+    void update_status(const std::string & name, server_model_status status, int exit_code);
+
+    // wait until the model instance is fully loaded (thread-safe)
+    // return when the model is loaded or failed to load
+    void wait_until_loaded(const std::string & name);
+
+    // load the model if not loaded, otherwise do nothing (thread-safe)
+    // return false if model is already loaded; return true otherwise (meta may need to be refreshed)
+    bool ensure_model_loaded(const std::string & name);
+
+    // proxy an HTTP request to the model instance
+    server_http_res_ptr proxy_request(const server_http_req & req, const std::string & method, const std::string & name, bool update_last_used);
+
+    // notify the router server that a model instance is ready
+    // return the monitoring thread (to be joined by the caller)
+    static std::thread setup_child_server(const std::function<void(int)> & shutdown_handler);
+};
+
+struct server_models_routes {
+    common_params params;
+    json webui_settings = json::object();
+    server_models models;
+    server_models_routes(const common_params & params, int argc, char ** argv)
+            : params(params), models(params, argc, argv) {
+        if (!this->params.webui_config_json.empty()) {
+            try {
+                webui_settings = json::parse(this->params.webui_config_json);
+            } catch (const std::exception & e) {
+                LOG_ERR("%s: failed to parse webui config: %s\n", __func__, e.what());
+                throw;
+            }
+        }
+        init_routes();
+    }
+
+    void init_routes();
+    // handlers using lambda function, so that they can capture `this` without `std::bind`
+    server_http_context::handler_t get_router_props;
+    server_http_context::handler_t proxy_get;
+    server_http_context::handler_t proxy_post;
+    server_http_context::handler_t get_router_models;
+    server_http_context::handler_t post_router_models_load;
+    server_http_context::handler_t post_router_models_unload;
+};
+
+/**
+ * A simple HTTP proxy that forwards requests to another server
+ * and relays the responses back.
+ */
+struct server_http_proxy : server_http_res {
+    std::function<void()> cleanup = nullptr;
+public:
+    server_http_proxy(const std::string & method,
+                      const std::string & host,
+                      int port,
+                      const std::string & path,
+                      const std::map<std::string, std::string> & headers,
+                      const std::string & body,
+                      const std::function<bool()> should_stop,
+                      int32_t timeout_read,
+                      int32_t timeout_write
+                      );
+    ~server_http_proxy() {
+        if (cleanup) {
+            cleanup();
+        }
+    }
+private:
+    std::thread thread;
+    struct msg_t {
+        std::map<std::string, std::string> headers;
+        int status = 0;
+        std::string data;
+        std::string content_type;
+    };
+};