@eqxjs/logger

A comprehensive logging library for NestJS applications that provides structured logging capabilities with masking, application insights integration, and summary logging features.

Installation

``bash
npm install @eqxjs/logger
`

Description

This module exports various components related to logging functionality including:

- Data Transfer Objects (DTOs) for logger options, extra options, masking options, and summary log types
- Enumerations for masking and log levels
- Helper services for logging, masking, and application insights
- Logger DTOs and interfaces for log dependency metadata
- Services for flushing summary logs, logging, and summarizing logs
- Singleton logger services and their helpers
- The main logger module

These components provide a comprehensive logging framework that can be used to log, mask, and summarize logs in an application.

Usage

$3

`typescript
import { Module } from '@nestjs/common';
import { LoggerModule } from '@eqxjs/logger';

@Module({
imports: [
LoggerModule.register({
app: {
name: 'MyApplication',
version: '1.0.0',
'component-name': 'MyComponent'
},
log: {
level: 'info',
detail: {
level: 'debug',
'enable-file-logging': true,
'log-file-properties': {
dirname: './logs',
filename: 'app-%DATE%.log',
'date-pattern': 'YYYY-MM-DD',
extension: '.log'
}
}
}
})
]
})
export class AppModule {}
`

$3

`typescript
import { Injectable } from '@nestjs/common';
import { CustomLoggerService } from '@eqxjs/logger';

@Injectable()
export class MyService {
constructor(private readonly logger: CustomLoggerService) {}

async someMethod() {
// Initialize logger
this.logger.init({
requestId: 'req-123',
userId: 'user-456'
});

// Log info with action data
this.logger.info(
{ action: 'USER_LOGIN', actionDescription: 'User login attempt', subAction: 'VALIDATE' },
{ username: 'john.doe', timestamp: new Date() }
);

// Log with masking sensitive data
this.logger.info(
{ action: 'PAYMENT_PROCESS', actionDescription: 'Processing payment', subAction: 'VALIDATE_CARD' },
{ cardNumber: '1234567890123456', amount: 100 },
[{ key: 'cardNumber', type: MaskingType.CREDIT_CARD }]
);

// Log errors
try {
// Some operation
} catch (error) {
this.logger.error(
{ action: 'DATABASE_OPERATION', actionDescription: 'Failed to save user', subAction: 'SAVE' },
{ userId: 'user-456' },
error.stack
);
}
}
}
`

API Reference

$3

#### LoggerModule
Main module class that provides configuration for the logging system.

Methods:
- static register(options: object): DynamicModule - Registers the logger module with the provided configuration options

#### CustomLoggerService
Primary service class responsible for logging various levels of messages with optional data masking and metadata management.

Properties:
- logDto: LogDto - The data transfer object for logging
- isSetSummaryLogParameters: boolean - Indicates if summary log parameters are set
- summaryLogParameters: SummaryParamsType - The parameters for summary logging
- additionalSummary: object - Additional summary information

Methods:
- init(data: LogDto) - Initializes the logger service with provided log data
- getSummaryLogAdditionalInfo() - Retrieves additional summary information
- setSummaryLogParameters(params: SummaryParamsType) - Sets summary log parameters
- getIsSetSummaryLogParameters(): boolean - Checks if summary log parameters are set
- getSummaryLogParameters(): SummaryParamsType - Retrieves summary log parameters
- setDependencyMetadata(metadata: LogDependencyMetadata) - Sets dependency metadata
- getLogDto(): LogDto - Retrieves the current log DTO
- update(key: string, value: any) - Updates log entry with specified key and value
- info(actionData: ILoggerActionData, data: any, options?: MaskingOptionDto[]) - Logs informational messages
- debug(actionData: ILoggerActionData, data: any, options?: MaskingOptionDto[]) - Logs debug messages
- error(actionData: ILoggerActionData, data: any, stack?: any, options?: MaskingOptionDto[]) - Logs error messages
- setSummaryLogErrorSource(param: ErrorSourceType) - Sets error source for summary log
- setSummaryLogAdditionalInfo(key: string, value: any) - Sets additional info for summary log
- setDetailLogAdditionalInfo(key: string, value: any) - Sets additional info for detailed log

#### CustomSummaryLoggerService
Service for handling summary logging functionality.

#### CustomSingletonLoggerService
Singleton pattern implementation of the logger service.

#### FlushSummaryLog
Service for flushing summary logs.

#### SingletonFlushSummaryLog
Singleton implementation for flushing summary logs.

#### LoggerHelperService
Helper service providing utility functions for logging operations.

#### SingletonLoggerHelperService
Singleton helper service for logging utilities.

#### MaskingService
Service for masking sensitive information in log data.

#### ApplicationInsightsService
Service for integrating with Microsoft Application Insights.

$3

#### LogDto
Main data transfer object for log entries.

#### LoggerOptionDto
Configuration options for the logger.

$3

#### ILoggerActionData
Interface defining the structure for logger action data:
- action: string - The action being performed
- actionDescription: string - Description of the action
- subAction?: string - Optional sub-action

#### LogDependencyMetadata
Interface for log dependency metadata.

#### ErrorSourceType
Interface for error source information.

$3

#### LogLevel
Enumeration of available log levels.

#### LogResultType
Enumeration of log result types.

#### LogSeverity
Enumeration of log severity levels.

#### MaskingType
Enumeration of masking types for sensitive data:
- CREDIT_CARD - For credit card number masking
- EMAIL - For email address masking
- PHONE - For phone number masking
- SSN - For social security number masking

$3

#### MaskingOptionDto
Type alias for masking configuration options.

#### LoggerExtraOptionDto
Type alias for additional logger options.

#### SummaryParamsType
Type alias for summary log parameters.

$3

#### createNestDosLogger()
Creates a NestJS logger using the Winston logging library.

Returns: winston.Logger - A configured Winston logger instance

$3

#### INTERNAL_LOGGER_OPTIONS
Internal configuration options for the logger.

#### INTERNAL_OS_NAME
Internal hostname of the operating system.

Features

$3

`typescript
// Mask credit card numbers
logger.info(
{ action: 'PAYMENT', actionDescription: 'Process payment' },
{ cardNumber: '1234567890123456' },
[{ key: 'cardNumber', type: MaskingType.CREDIT_CARD }]
);
`

$3

`typescript
logger.setSummaryLogParameters({
transactionId: 'txn-123',
userId: 'user-456'
});

logger.setSummaryLogAdditionalInfo('totalProcessingTime', 1500);
`

$3

`typescript
LoggerModule.register({
log: {
detail: {
'enable-file-logging': true,
'log-file-properties': {
dirname: './logs',
filename: 'app-%DATE%.log',
'date-pattern': 'YYYY-MM-DD',
extension: '.log'
}
}
}
});
`

$3

`typescript
{
app: {
name: string; // Application name
version: string; // Application version
'component-name': string; // Component name
},
log: {
level: string; // Log level (error, warn, info, debug)
detail?: {
level: string; // Detailed log level
'enable-file-logging': boolean; // Enable file logging
'log-file-properties': {
dirname: string; // Log file directory
filename: string; // Log filename pattern
'date-pattern': string; // Date pattern for rotation
extension: string; // File extension
}
}
}
}
``

License

ISC