Callbacks

Callbacks allow you to hook into the logging process and execute custom code whenever a log message is processed. This is useful for integrating with external monitoring systems, sending alerts, or updating metrics.

Setting a Callback

You can set a global callback function that receives the Record object.

fn logCallback(record: *const logly.Record) !void {
    // Check if the log level is ERROR or higher
    if (record.level.priority() >= logly.Level.err.priority()) {
        // Send alert to external system
        sendAlert(record.message);
    }
}

// Register the callback
logger.setLogCallback(&logCallback);

The Record Object

The Record object contains all information about the log event:

• level: The log level
• message: The log message
• timestamp: The timestamp
• module: The module name
• function: The function name
• file: The filename
• line: The line number
• context: The bound context values

Custom Color Callbacks

You can also customize the colors used for each log level by setting a color callback.

fn colorCallback(level: logly.Level, message: []const u8) []const u8 {
    // Return ANSI color codes based on level
    return switch (level) {
        .err => "\x1b[31m", // Red
        .info => "\x1b[32m", // Green
        else => "\x1b[0m",  // Reset
    };
}

logger.setColorCallback(&colorCallback);