Logging

Each plugin gets its own logger instance automatically. The logger uses SLF4J, so you can configure it with your preferred logging framework (Logback, Log4j, etc.).

Using the Logger

Access the logger in your plugin:

import org.slf4j.Logger;

@Override
public void start() {
    Logger logger = getLogger();
    
    logger.info("Plugin started!");
    logger.warn("This is a warning");
    logger.error("An error occurred", exception);
    logger.debug("Debug information");
}

Log Levels

The logger supports standard log levels:

getLogger().trace("Very detailed information");
getLogger().debug("Debug information");
getLogger().info("Informational message");
getLogger().warn("Warning message");
getLogger().error("Error message");
getLogger().error("Error with exception", exception);

Logger Naming

Each plugin's logger is automatically named after the plugin ID. This makes it easy to filter logs by plugin in your logging configuration.

For example, if your plugin ID is my-plugin, the logger name will be my-plugin.

Logging Best Practices

1. Use appropriate levels - Use info for important events, debug for detailed information, warn for warnings, and error for errors
2. Include context - Add relevant information to log messages
3. Log exceptions - Always include exceptions when logging errors
4. Avoid sensitive data - Don't log passwords, tokens, or other sensitive information
5. Use placeholders - Use SLF4J's placeholder syntax for better performance

Example: Good Logging

@Override
public void start() {
    PluginDescriptor meta = getMetaData();
    
    getLogger().info("Starting {} v{}", meta.getPluginId(), meta.getVersion());
    
    try {
        PluginConfig config = getDefaultConfig();
        String message = config.getString("message", "Default");
        getLogger().debug("Loaded configuration: message={}", message);
        
        // Plugin logic...
        
        getLogger().info("Plugin {} started successfully", meta.getPluginId());
    } catch (Exception e) {
        getLogger().error("Failed to start plugin {}", meta.getPluginId(), e);
        throw e;
    }
}

@Override
public void stop() {
    getLogger().info("Stopping plugin {}", getMetaData().getPluginId());
    // Cleanup logic...
    getLogger().info("Plugin stopped");
}

Configuring Logging

Since Jonion uses SLF4J, you can configure logging using any SLF4J-compatible logging framework:

• Logback - Add logback-classic dependency
• Log4j 2 - Add log4j-slf4j-impl dependency
• Java Util Logging - Use slf4j-jdk14 adapter

Configure your chosen framework's configuration file (e.g., logback.xml, log4j2.xml) to control log levels, formats, and outputs.