@sap-ux/logger

What is @sap-ux/logger?

@sap-ux/logger is an npm package designed to provide logging functionalities for SAP UX applications. It allows developers to log messages with different severity levels, format log messages, and manage log outputs efficiently.

What are @sap-ux/logger's main functionalities?

Basic Logging

This feature allows you to log messages with different severity levels such as info, warn, and error.

const { Logger } = require('@sap-ux/logger');
const logger = new Logger('myApp');
logger.info('This is an info message');
logger.warn('This is a warning message');
logger.error('This is an error message');

Custom Log Levels

This feature allows you to set custom log levels, enabling more granular control over what gets logged.

const { Logger, LogLevel } = require('@sap-ux/logger');
const logger = new Logger('myApp', { level: LogLevel.DEBUG });
logger.debug('This is a debug message');

Log Formatting

This feature allows you to format log messages, including options for timestamps and log levels.

const { Logger, LogFormatter } = require('@sap-ux/logger');
const formatter = new LogFormatter({ timestamp: true, level: true });
const logger = new Logger('myApp', { formatter });
logger.info('This is a formatted info message');

Log Output Management

This feature allows you to manage log outputs, such as writing logs to a file.

const { Logger, LogOutput } = require('@sap-ux/logger');
const output = new LogOutput({ filePath: 'logs/app.log' });
const logger = new Logger('myApp', { output });
logger.info('This message will be written to a file');

Other packages similar to @sap-ux/logger

winston

Winston is a versatile logging library for Node.js that supports multiple transports (e.g., console, file, HTTP) and log levels. It is highly configurable and widely used in the Node.js community. Compared to @sap-ux/logger, Winston offers more flexibility and a broader range of features.

bunyan

Bunyan is a simple and fast JSON logging library for Node.js services. It provides a structured logging approach and supports various log levels and outputs. Bunyan is known for its performance and ease of use. Compared to @sap-ux/logger, Bunyan focuses more on JSON-based structured logging.

pino

Pino is a low-overhead, high-performance logging library for Node.js. It is designed to be extremely fast and efficient, making it suitable for high-throughput applications. Pino offers a similar set of features to @sap-ux/logger but emphasizes performance and speed.

README

@sap-ux/logger

This is a simple logging library. It uses Winston underneath to do the heavy-lifting. The API is agnostic to any particular logging library. Don't depend on any Winston-specific implemenation as the underlying library may change in the future.

Quick Usage

Add the package @sap-ux/logger to your project using your preferred package manager.

In Typescript/ES6, import the logger and instantiate it. By default the log level is info and the logs are sent to the console.

import { ToolsLogger } from '@sap-ux/logger';
...

const logger = new ToolsLogger();
...
logger.info('This is an information message');
...
logger.warn('This is a warning');
...
logger.error('This is an error!');
// Can also log objects
logger.debug({a: 42, b: 'some value'});

Logger Options

Option	Default Value	Description
logLevel	LogLevel.Info	Log only if equal to or more severe than this level (supported levels)
transports	ConsoleTransport	An array of transports

Log Levels

Log levels are exposed an as enumeration. The following levels are available, in decreasing order of severity:

• Error
• Warn
• Info
• Verbose
• Debug
• Silly

Transports

These are the targets of the log messages. You can have multiple targets for a single logger. The targets can be added and removed dynamically, if required.

The following transports are currently supported:

ConsoleTransport

This is used to write to the console.

FileTransport

This is used to write to files. Logs are appended to files. Currently there's no support to rotate logs.

VSCodeTransport

This is used to write to an output channel in VS Code.

NullTransport

This is the equivalent of writing to /dev/null. If an API needs a logger and you really don't want to capture logs, you can use NullTransport to use completely ignore the logs.

Logger API

Logging methods

error(), warn(), info() and debug() methods can be used to either print log a string or an object.

Transport management

You can add(), remove() transport dynamically. transports() returns a list of the current transports of the logger.

Examples

The unit test file can be used as an example to explore the logger's API: ./test/unit/wiston-logger/logger.test.ts

Please refer to the debugging section in the project root README for help debugging the test.

Not supported

The following options are not supported yet. There are no definite plans to add them in the future. They will be considered on a need-basis.

• Custom formatters
  • VSCodeTransport logs timestamped lines
  • FileTransport logs in JSON
  • ConsoleTransport logs colored and timestamped lines (piping will remove color encoding though)
• File rotation - the file transport appends to an existing file or creates a new one if missing