1. Initialization Module (lm::runtime)
include/lm/runtime/init.hpp
cpp

#pragma once
#include <string>
#include <nlohmann/json.hpp> // JSON library
#include <filesystem>

namespace lm::runtime {

class SystemState {
public:
    // Singleton access
    static SystemState& get_instance();
    
    // Initialize from JSON config
    void initialize(const std::filesystem::path& config_path);
    
    // Configuration accessors
    const nlohmann::json& config() const noexcept;
    std::string get_string(const std::string& key) const;
    int get_int(const std::string& key, int default_val = 0) const;
    
    // Subsystem states
    bool is_tokenizer_ready() const noexcept;
    bool is_model_loaded() const noexcept;

private:
    SystemState() = default; // Private constructor
    nlohmann::json config_;
    bool tokenizer_ready_ = false;
    bool model_loaded_ = false;
};

} // namespace lm::runtime

2. Shutdown Module (lm::runtime)
include/lm/runtime/shutdown.hpp
cpp

#pragma once
#include <nlohmann/json.hpp>
#include <filesystem>

namespace lm::runtime {

class ShutdownHandler {
public:
    // Serialize state to JSON
    static void save_state(
        const std::filesystem::path& output_path,
        bool include_model_weights = false
    );
    
    // Cleanup hooks
    static void register_cleanup(void (*func)());
    static void execute_cleanup();
};

} // namespace lm::runtime

3. Implementation Files
src/runtime/init.cpp
cpp

#include "lm/runtime/init.hpp"
#include <fstream>
#include <stdexcept>

using namespace lm::runtime;

void SystemState::initialize(const std::filesystem::path& config_path) {
    try {
        // Load JSON config
        std::ifstream f(config_path);
        config_ = nlohmann::json::parse(f);
        
        // Validate required fields
        if (!config_.contains("tokenizer") || !config_.contains("model")) {
            throw std::runtime_error("Invalid config: missing required sections");
        }
        
        // Initialize subsystems
        tokenizer_ready_ = initialize_tokenizer(config_["tokenizer"]);
        model_loaded_ = initialize_model(config_["model"]);
        
    } catch (const std::exception& e) {
        throw std::runtime_error("Initialization failed: " + std::string(e.what()));
    }
}

// ... (Other method implementations)

src/runtime/shutdown.cpp
cpp

#include "lm/runtime/shutdown.hpp"
#include <vector>
#include <mutex>

namespace {
    std::vector<void (*)()> cleanup_functions;
    std::mutex cleanup_mutex;
}

void ShutdownHandler::save_state(
    const std::filesystem::path& output_path,
    bool include_model_weights) 
{
    nlohmann::json state;
    
    // Capture framework state
    state["tokenizer"] = serialize_tokenizer_state();
    state["model"] = serialize_model_state(include_model_weights);
    state["threading"] = serialize_thread_pool_stats();
    
    // Write to file
    std::ofstream(output_path) << state.dump(2); // Pretty print
}

void ShutdownHandler::register_cleanup(void (*func)()) {
    std::lock_guard<std::mutex> lock(cleanup_mutex);
    cleanup_functions.push_back(func);
}

void ShutdownHandler::execute_cleanup() {
    std::lock_guard<std::mutex> lock(cleanup_mutex);
    for (auto it = cleanup_functions.rbegin(); it != cleanup_functions.rend(); ++it) {
        (*it)(); // Execute in reverse order
    }
}

4. Configuration JSON Schema
config_schema.json
json

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "required": ["tokenizer", "model"],
  "properties": {
    "tokenizer": {
      "type": "object",
      "properties": {
        "type": {"enum": ["bpe", "sentencepiece"]},
        "vocab_path": {"type": "string"},
        "dropout": {"type": "number", "minimum": 0, "maximum": 1}
      }
    },
    "model": {
      "type": "object",
      "properties": {
        "path": {"type": "string"},
        "max_seq_len": {"type": "integer", "minimum": 1}
      }
    },
    "threading": {
      "type": "object",
      "properties": {
        "worker_threads": {"type": "integer", "minimum": 1}
      }
    }
  }
}

5. Usage Example
Initialization
cpp

#include "lm/runtime/init.hpp"

int main() {
    try {
        auto& state = lm::runtime::SystemState::get_instance();
        state.initialize("config.json");
        
        if (!state.is_model_loaded()) {
            throw std::runtime_error("Model failed to load");
        }
    } catch (const std::exception& e) {
        std::cerr << "Fatal error: " << e.what() << std::endl;
        return 1;
    }
}

Shutdown
cpp

#include "lm/runtime/shutdown.hpp"

void cleanup_db_connections() {
    // Custom cleanup logic
}

int main() {
    lm::runtime::ShutdownHandler::register_cleanup(cleanup_db_connections);
    
    // ... run application ...
    
    lm::runtime::ShutdownHandler::save_state("shutdown_state.json");
    lm::runtime::ShutdownHandler::execute_cleanup();
}

6. CMake Integration
cmake

# Add to your CMakeLists.txt
find_package(nlohmann_json 3.9 REQUIRED)

add_library(lm_runtime
    src/runtime/init.cpp
    src/runtime/shutdown.cpp
)

target_link_libraries(lm_runtime
    PRIVATE nlohmann_json::nlohmann_json
)

Key Features

    Thread-Safe Cleanup: Reverse-order execution of registered handlers

    Config Validation: JSON schema verification during initialization

    State Capture: Full system snapshot on shutdown

    Singleton Pattern: Controlled access to system state

Error Handling
Error Case	Recovery Action
Invalid JSON	Throw std::runtime_error with path info
Missing Required Field	Fail fast during initialization
Shutdown Serialization Failure	Log warning, continue cleanup

This implementation provides a robust foundation for managing the framework lifecycle. Would you like to add any of the following?

    Configuration hot-reloading

    Encrypted config files

    Distributed state serialization