Logger Plugin

Building your own logger plugin

Create your own logger to interact with your favorite logging platform or filter logs to what you want exactly.

You can see the code for this here

Configuring the plugin

Via config.yml:

logger:
    path: './logger/pino-logger'

Via deepstream constructor:

import { Deepstream } from '@deepstream/server'

export const deepstream = new Deepstream({
    logger: {
        path: './logger/pino-logger',
        options: {}
    }
})

deepstream.start()

Via deepstream setter:

import { Deepstream } from '@deepstream/server'
import PinoLogger from './pino-logger'

const deepstream = new Deepstream({})

deepstream.set('logger', new PinoLogger({}, deepstream.getServices()))

deepstream.start()

Example Documented Plugin

import { DeepstreamPlugin, DeepstreamServices, DeepstreamLogger, LOG_LEVEL, NamespacedLogger, EVENT } from '@deepstream/types'
import * as pino from 'pino'
import { Dictionary } from 'ts-essentials'

interface PinoLoggerOptions {
}

const DSToPino: Dictionary<string> = {
    [LOG_LEVEL.DEBUG]: 'debug',
    [LOG_LEVEL.FATAL]: 'fatal',
    [LOG_LEVEL.ERROR]: 'error',
    [LOG_LEVEL.WARN]: 'warn',
    [LOG_LEVEL.INFO]: 'info',
}

export default class PinoLogger extends DeepstreamPlugin implements DeepstreamLogger {
    public description = 'Pino Logger'
    // @ts-ignore
    private logger: any = pino()

    constructor (private pluginOptions: PinoLoggerOptions, private services: Readonly<DeepstreamServices>) {
        super()
    }

    /**
     * Return true if logging is enabled. This is used in deepstream to stop generating useless complex strings
     * that we know will never be logged.
     */
    public shouldLog(logLevel: LOG_LEVEL): boolean {
        return this.logger.islevelenabled(DSToPino[logLevel])
    }

    /**
     * Set the log level desired by deepstream. Since deepstream uses LOG_LEVEL this needs to be mapped
     * to whatever your libary uses (this is usually just conversion stored in a static map)
     */
    public setLogLevel(logLevel: LOG_LEVEL): void {
        this.logger.level = DSToPino[logLevel]
    }
    
    /**
     * Log as info
     */
    public info(event: string, message?: string, metaData?: any): void {
        this.logger.info(`${event}, ${message}`)
    }

    /**
     * Log as debug
     */
    public debug(event: string, message?: string, metaData?: any): void {
        this.logger.debug(`${event}, ${message}`)
    }

    /**
     * Log as warn
     */
    public warn(event: string, message?: string, metaData?: any): void {
        this.logger.warn(`${event}, ${message}`)
    }

    /**
     * Log as error
     */
    public error(event: string, message?: string, metaData?: any): void {
        this.logger.error(`${event}, ${message}`)
    }

    /**
     * Log as error
     */
    public fatal(event: string, message?: string, metaData?: any): void {
        this.logger.fatal(`${event}, ${message}`)
        this.services.notifyFatalException()
    }

    /**
     * Create a namespaced logger, used by plugins. This could either be a new instance of a logger
     * or just a thin wrapper to add the namespace at the beginning of the log method.
     */
    public getNameSpace (namespace: string): NamespacedLogger {
        return {
          shouldLog: this.shouldLog.bind(this),
          fatal: this.log.bind(this, LOG_LEVEL.FATAL, namespace),
          error: this.log.bind(this, LOG_LEVEL.ERROR, namespace),
          warn: this.log.bind(this, LOG_LEVEL.WARN, namespace),
          info: this.log.bind(this, LOG_LEVEL.INFO, namespace),
          debug: this.log.bind(this, LOG_LEVEL.DEBUG, namespace),
        }
    }

    private log (logLevel: LOG_LEVEL, namespace: string, event: EVENT, logMessage: string) {
        this.logger[logLevel](`${namespace} ${event} ${logMessage}`)
    }
}