@midwayjs/logger

@midwayjs/logger is a log module for midway project.

Required

Node.js >= v20 since v4.0.0

Install

$ npm install @midwayjs/logger --save

Create Logger

import { loggers } from '@midwayjs/logger';

const logger = loggers.createLogger('logger', {
  // some logger options
})

Create With Transport

Create logger with console and file transports instance.

import { loggers, ConsoleTransport, FileTransport } from '@midwayjs/logger';

const logger = loggers.createLogger('logger', {
  transports: {
    console: new ConsoleTransport(),
    file: new FileTransport({
      dir: '...',
      fileLogName: 'app.log',
    }),
  }
})

Create console logger.

const logger = loggers.createLogger('consoleLogger', {
  transports: {
    console: new ConsoleTransport(),
  }
})

Create logger with options mode.

const logger = loggers.createLogger('consoleLogger', {
  transports: {
    console: {
      autoColors: true,
    },
    file: {
      dir: '...',
      fileLogName: 'app.log',
    }
  }
})

Logger Output Method

logger.debug('debug info');
logger.info('启动耗时 %d ms', Date.now() - start);
logger.warn('warning!');
logger.error(new Error('my error'));
logger.write('abcde');

Logger Level

log level is divided into the following categories, and the log level decreases sequentially (the larger the number, the lower the level):

const levels = {
  none: 0,
  error: 1,
  trace: 2,
  warn: 3,
  info: 4,
  verbose: 5,
  debug: 6,
  silly: 7,
  all: 8,
}

Set level for all transports

const logger = loggers.createLogger('logger', {
  // ...
  level: 'warn',
});

// not output
logger.debug('debug info');

// not output
logger.info('debug info');

Format and ContextFormat

Add logger format and context format.

const logger = loggers.createLogger('logger', {
  // ...
  format: info => {
    return `${info.timestamp} ${info.message}`;
  },
  contextFormat: info => {
    return `${info.timestamp} [${info.ctx.traceId}] ${info.message}`;
  }
});

info is a default metadata, include some properties.

Tranports

The actual behavior of the log output we call the transport.The log library has four built-in default Transports.

• ConsoleTransport Output message to stdout and stderr with color.
• FileTransport Output message to file and rotate by self.
• ErrorTransport Inherit FileTransport and only output error message.
• JSONTransport Inherit FileTransport and output json format.

The above Transports are all registered by default and can be configured by the name when registering.

const logger = loggers.createLogger('consoleLogger', {
  transports: {
    console: {/*...options*/},
    file: {/*...options*/},
    error: {/*...options*/},
    json: {/*...options*/},
  }
});

Implement a new Transport

Inherit Transport abstract class and implement log and close method.

import { Transport, ITransport } from '@midwayjs/logger';

export interface CustomTransportOptions {
  // ...
}

export class CustomTransport extends Transport<CustomTransportOptions> implements ITransport {
  log(level: LoggerLevel | false, meta: LogMeta, ...args) {
    // save file or post to remote server
  }
  
  close() {}
}

Register class to TransportManager before used.

import { TransportManager } from '@midwayjs/logger';

TransportManager.set('custom', CustomTransport);

And you can configure it in your code.

const logger = loggers.createLogger('consoleLogger', {
  transports: {
    custom: {/*...options*/}
  }
});

Default Logger Options

find more options in interface.

License

MIT