Logging library

Table of Contents

• Introduction
• Key Features
• Basic Usage
• Main Components
• Configuration

Introduction

The D7 SDK Logging library provides a flexible and efficient logging system for applications. It allows developers to add detailed logging capabilities with minimal overhead, supporting multiple log levels, destinations, and formatting options.

Key Features

• Multiple log levels (TRACE, DEBUG, INFO, WARNING, ERROR, CRITICAL)
• Customizable log formatting
• File and console output
• Runtime log level configuration
• Module-based logging control

Basic Usage

Here's a simple example of using the logging library:

#include <log/log.h>
#include <iostream>
 
using namespace vsdk::diag;
 
int main() {
    // Create basic log configuration
    nlohmann::json config = {
        {"enabled", true},
        {"pattern", "[%H:%M:%S.%e] [%^%l%$] %v"},
        {"level", "info"},
        {"console_output", true},
        {"enabled_modules", {"system"}}
    };
 
    // Initialize logging, this step is not required if you use the default configuration (/appdata/config/vsdk.json)
    log::instance()->load_config_json(config);
    
    // Log messages at different levels
    LOG_INFO(module::system, "Application started");
    LOG_DEBUG(module::network, "Debug information"); // This will not be logged because it's not in the enabled modules
    
    // Add some values
    int count = 42;
    LOG_INFO(module::system, "Processing {} items", count);
 
    // Error handling
    try {
        // Some operation
    } catch (const std::exception& e) {
        LOG_ERROR(module::system, "Error occurred: {}", e.what());
    }
    return 0;
}

Main Components

• vsdk::diag::log - Core logging class (singleton instance accessed via vsdk::diag::log::instance())
• module - Enumeration of available logging modules
• LOG_TRACE, LOG_DEBUG, LOG_INFO, LOG_WARN, LOG_ERROR, LOG_CRITICAL - Logging macros

Configuration

The logging system can be configured through a JSON file or directly via the API. Configuration options include:

{
    "enabled": true, // Master enable/disable switch
    "pattern": "[%H:%M:%S.%e] [%^%l%$] [%s:%# %!] %v", // Log format pattern
    "level": "trace", // Global minimum log level
    "console_output": false, // Enable/disable console output
    "log_file": "/appdata/logs/vsdk.log", // Path to the log file
    "enabled_modules": [ // List of enabled modules
    "analog",
    "digital_in",
    "digital_out",
    "pwm_in",
    "pwm_out",
    "system",
    "network"]
}