Module Levels

This example demonstrates how to use module-specific log levels to control logging verbosity for different parts of your application. This is incredibly useful for debugging specific components without being overwhelmed by logs from the entire system.

Code Example

const std = @import("std");
const logly = @import("logly");

pub fn main() !void {
    var gpa = std.heap.DebugAllocator(.{}){};
    defer _ = gpa.deinit();
    const allocator = gpa.allocator();

    // Enable colors on Windows
     _ = logly.Terminal.enableAnsiColors();

    const logger = try logly.Logger.init(allocator);
    defer logger.deinit();

    // Set global level to INFO
    var config = logly.Config.default();
    config.level = .info;
    config.showModule = true;
    logger.configure(config);

    // Create scoped loggers for different modules
    const netLogger = logger.scoped("network");
    const dbLogger = logger.scoped("database");
    const uiLogger = logger.scoped("ui");

    // Default behavior (INFO and above)
    try logger.info("Application started", @src());
    try netLogger.info("Network initialized", @src()); // Shows [network]
    try netLogger.debug("Network debug message", @src()); // Hidden (global level is INFO)

    // Set specific level for network module (allow DEBUG)
    try logger.setModuleLevel("network", .debug);
    try logger.info("Changed network module level to DEBUG", @src());

    try netLogger.debug("Network debug message (now visible)", @src());
    try dbLogger.debug("Database debug message", @src()); // Still hidden

    // Set specific level for UI module (only ERROR)
    try logger.setModuleLevel("ui", .err);
    try logger.info("Changed UI module level to ERROR", @src());

    try uiLogger.warn("UI warning", @src()); // Hidden (using short alias)
    try uiLogger.err("UI error", @src()); // Visible

    // Verify database still follows global
    try dbLogger.info("Database info", @src()); // Visible
}

Expected Output

[INFO] Application started
[network] [INFO] Network initialized
[INFO] Changed network module level to DEBUG
[network] [DEBUG] Network debug message (now visible)
[INFO] Changed UI module level to ERROR
[ui] [ERROR] UI error
[database] [INFO] Database info