MIDDLEWARE.md

Middleware

Middleware for Koa ^2.0

Logger Middleware

Using Dr Queue as middleware is an option if you already have a webserver and want to connect the Redis transport to your Redis connections (or if you just want to send formatted log files to text files without Redis), that option is available too.

The included logger middleware is easy to replace with your own. The logger Middleware returns a Koa middleware function and looks like this.

export function loggerMiddleware(Logger) {
  const errorIgnoreLevels = Logger.getInoreLevels()
  return async (ctx, next, ...args) => {
    const start = new Date()
    await next()
    const ms = new Date() - start
    const bypassError = !!(errorIgnoreLevels.find((status) => ctx.status === status))
    const hasError = ctx.status >= 400 && !bypassError
    const message = `${ctx.request.origin} ${chalk['magentaBright'](ctx.method)} ${chalk['blueBright'](ctx.status)} ${chalk['yellowBright'](ctx.request.url)}`
    const payload = { ip: ctx.request.ip, query: {...ctx.query}, body: {...ctx.request.body}, userAgent: ctx.request.header['user-agent'], ms}
    if (hasError)
      Logger.error(message, payload)
    else
      Logger.log(message, payload)
  }
}

Example:

import {Logger as LoggerUtil} from 'dr_queue'
import Koa from 'koa'
import Router from 'koa-router'
import bodyParser from 'koa-bodyparser'

const config = require('config')
const Logger = require('../out/logger').default
const Koa = require('koa')
const Router = require('koa-router')
const bodyParser = require('koa-bodyparser')
const moment = require('moment')

const config = {
  hostIp : '127.0.0.1',
  appName: 'queue',
  timezone: 'America/Los_Angeles',
  hostname: 'localhost',
  errorIgnoreLevels: [401, 403],
  transports:[{
    filename: './info.log',
    format: 'txt'
    },{
      filename: './error.log',
      format: 'txt'
    }]
}

const dbs = {
  client: redisClient, // for the queue`
  publisher: redisPublisher, // for the stream`
}

const LoggerUtil = LoggerUtil.init(config)
const Logger = LoggerUtil.init(config, dbs)

const app = new Koa()
app.use(bodyParser())
  .use(LoggerUtil.middleware(Logger))
  .use(router.allowedMethods())
  .use(router.routes())
  app.listen(port, () => Logger.log(`✅ The server is running at ${protocol}://${hostIp}:${port}/`), {meta: 'test'})
return app

Or, you can set your connections later if necessary:

export const Logger = LoggerUtil.init(config)
Logger.setRedisConnections({ publisher: dbs.redisPublisher, client: dbs.redisClient })

To add middleware you just add this line to your Koa middleware like this,

const app = new Koa()
app.use(LoggerUtil.init(config))

Or, just pass the instance

export const Logger = LoggerUtil.init(config)
const app = new Koa()
app.use(Logger)

If you need to do any filtering on your logger, or add or remove request properties like passwords or other sensitive information, you can write a middleware function similar to this one for koa.

export function loggerMiddleware(Logger, filters) {
  const errorIgnoreLevels = Logger.getInoreLevels()
  const omitFields = Logger.getOmitFields()
  return async (ctx, next, ...args) => {
    const start = new Date()
    await next()
    const ms = new Date() - start
    const bypassError = !!(errorIgnoreLevels.find((status) => ctx.status === status))
    const hasError = ctx.status >= 400 && !bypassError
    const body = omit(ctx.request.body || {}, ...omitFields)
    const message = `${ctx.request.origin} ${chalk['magentaBright'](ctx.method)} ${chalk['blueBright'](ctx.status)} ${chalk['yellowBright'](ctx.request.url)}`
    const payload = { url: ctx.request.url, ip: ctx.request.ip, query: {...ctx.query}, body, userAgent: ctx.request.header['user-agent'], ms, createdAt: start}
    if (hasError)
      Logger.error(message, payload)
    else
      Logger.log(message, payload)
  }
}

Then setup your logging configuration to support the Redis clients and Redis publishers. (See Logging)