DailyOM Logging Library

This library was generated with Nx.

The logging library provides a unified logging solution for Next.js and backend systems in the DailyOM Suite monorepo. It implements distributed tracing through trace and span IDs, allowing for correlation of logs across service boundaries

Features

• Trace Context Management: Automatic generation and propagation of trace and span IDs
• Hierarchical Spans: Create child spans for tracking operations within a request
• Configurable Output: Log to console, files, or both
• Daily Log Rotation: Automated log file rotation with size thresholds
• Context Preservation: Maintains trace context across asynchronous operations using AsyncLocalStorage

Usage

Basic Logging

import { TracedLogger } from '@dailyom-suite/logging';

// Create a logger instance
const logger = new TracedLogger({
  name: 'my-service',
  level: 'info',           // Optional: default is 'info'
  logToConsole: true,      // Optional: default is true
  logToFile: true,         // Optional: default is true
  fileName: 'app-name.log' // Optional: default uses name + timestamp
});

// Log messages with context
logger.info({ userId: '123' }, 'User logged in');
logger.error({ orderId: '456' }, 'Failed to process order');

Trace Context and Spans

// Create a traced operation
logger.withSpan('database-query', () => {
  // All logs in this function will share the same trace context
  logger.debug({ query: 'SELECT * FROM users' }, 'Executing query');
  // ...
  return result;
});

// For async operations
await logger.withSpanAsync('api-request', async () => {
  logger.info({ url: '/api/data' }, 'Making API request');
  const response = await fetch('/api/data');
  logger.info({ status: response.status }, 'Received API response');
  return response.json();
});

Manual Trace Context Manipulation

import { 
  createTraceContext, 
  createChildSpan, 
  traceContextStorage 
} from '@dailyom-suite/logging';

// Create a new trace context
const context = createTraceContext();

// Create a child span from parent context
const childContext = createChildSpan(context);

// Run code with a specific trace context
traceContextStorage.run(context, () => {
  // All logs in this scope will use this context
});

Configuration

The library looks for the following environment variables:

• LOG_DIR: Directory where log files will be stored (defaults to ./logs)

Log File Management

Log files follow this naming pattern:

{app-name}.{YYYY-MM-DD}.{HH-MM-SS}.log

Files rotate:

• Every day (24 hours)
• When they exceed 10MB in size

Building

Run nx build logging to build the library.

Running unit tests

Run nx test logging to execute the unit tests via Jest.

CI

PRs that contain changes to logging will run tests and builds to ensure project structure is adhered to