strapi/docs/configuration/logging.md

title
Logging

Strapi comes with a simple and useful built-in logger. Its usage is purposely very similar to console.log(), but with a handful of extra features; namely support for multiple log levels with colorized, prefixed console output.

Configuration

Configuration:

• Key: logger
• Environment: development
• Location: ./config/environments/development/server.json
• Type: boolean

Example:

{
  "logger": true
}

Notes:

• Set to false to disable the lifecyle and request logs.

Usage

The logger is accessible through the strapi object directly with strapi.log.

You can work with this logger in the same way that you work with the default logger:

strapi.log.info('Logs work!');

Logging with Metadata

In addition to logging string messages, the logger will also optionally log additional JSON metadata objects. Adding metadata is simple:

strapi.log.info('Test log message', {
  anything: 'This is metadata'
});

String interpolation

The log method provides the same string interpolation methods like util.format.

This allows for the following log messages.

strapi.log.info('test message %s', 'my string');
// => info: test message my string

strapi.log.info('test message %d', 123);
// => info: test message 123

strapi.log.info('test message %j', {
  number: 123
}, {});
// => info: test message {"number":123}
// => meta = {}

strapi.log.info('test message %s, %s', 'first', 'second', {
  number: 123
});
// => info: test message first, second
// => meta = {number: 123}

strapi.log.info('test message', 'first', 'second', {
  number: 123
});
// => info: test message first second
// => meta = {number: 123}

strapi.log.info('test message %s, %s', 'first', 'second', {
  number: 123
}, function() {});
// => info: test message first, second
// => meta = {number: 123}
// => callback = function() {}

strapi.log.info('test message', 'first', 'second', {
  number: 123
}, function() {});
// => info: test message first second
// => meta = {number: 123}
// => callback = function() {}

Logging levels

Setting the level for your logging message can be accomplished by using the level specified methods defined.

strapi.log.debug('This is a debug log');
strapi.log.info('This is an info log');
strapi.log.warn('This is a warning log');
strapi.log.error('This is an error log');