b2c-logging

# Logging Skill

This skill guides you through implementing logging in B2C Commerce using the Logger and Log classes.

## Overview

B2C Commerce provides a logging framework with:

| Feature | Description |
|---------|-------------|
| **Log Levels** | debug, info, warn, error, fatal |
| **Categories** | Organize logs by functional area |
| **Custom Files** | Write to dedicated log files |
| **NDC** | Nested Diagnostic Context for tracing |
| **BM Configuration** | Enable/disable levels per category |

## Log Levels

| Level | Method | Description | Default State |
|-------|--------|-------------|---------------|
| `debug` | `debug()` | Detailed debugging information | Disabled (never on production) |
| `info` | `info()` | General information | Disabled by default |
| `warn` | `warn()` | Warning conditions | Always enabled |
| `error` | `error()` | Error conditions | Always enabled |
| `fatal` | `fatal()` | Critical failures | Always enabled, can send email |

## Basic Logging

### Using Logger (Static Methods)

The `Logger` class provides static methods for quick logging:

```javascript
var Logger = require('dw/system/Logger');

// Simple messages
Logger.debug('Debug message');
Logger.info('Info message');
Logger.warn('Warning message');
Logger.error('Error message');

// Messages with parameters (Java MessageFormat syntax)
Logger.info('Processing order {0} for customer {1}', orderNo, customerEmail);
Logger.error('Failed to process {0}: {1}', productId, errorMessage);
```

### Using Log (Instance Methods)

The `Log` class provides instance-based logging with categories:

```javascript
var Logger = require('dw/system/Logger');

// Get logger for a category
var log = Logger.getLogger('checkout');

log.debug('Cart contents: {0}', JSON.stringify(cart));
log.info('Checkout started for basket {0}', basketId);
log.warn('Inventory low for product {0}', productId);
log.error('Payment failed: {0}', errorMessage);
log.fatal('Critical checkout failure: {0}', errorMessage);
```