pino-http

What is pino-http?

pino-http is an HTTP logger middleware for Node.js that integrates with the Pino logging library. It provides high-performance logging for HTTP requests and responses, making it suitable for production environments where speed and efficiency are critical.

What are pino-http's main functionalities?

Basic HTTP Logging

This code sets up a basic HTTP server with pino-http middleware to log incoming requests and outgoing responses.

const http = require('http');
const pino = require('pino');
const pinoHttp = require('pino-http');

const logger = pino();
const httpLogger = pinoHttp({ logger });

const server = http.createServer((req, res) => {
  httpLogger(req, res);
  res.end('hello world');
});

server.listen(3000);

Custom Log Levels

This code demonstrates how to set custom log levels for the pino-http logger.

const http = require('http');
const pino = require('pino');
const pinoHttp = require('pino-http');

const logger = pino({ level: 'debug' });
const httpLogger = pinoHttp({ logger });

const server = http.createServer((req, res) => {
  httpLogger(req, res);
  res.end('hello world');
});

server.listen(3000);

Custom Log Formatting

This code shows how to customize the log output format using Pino's prettyPrint options.

const http = require('http');
const pino = require('pino');
const pinoHttp = require('pino-http');

const logger = pino({
  prettyPrint: {
    colorize: true,
    translateTime: 'SYS:standard',
    ignore: 'pid,hostname'
  }
});
const httpLogger = pinoHttp({ logger });

const server = http.createServer((req, res) => {
  httpLogger(req, res);
  res.end('hello world');
});

server.listen(3000);

Other packages similar to pino-http

morgan

Morgan is another HTTP request logger middleware for Node.js. It is simpler and more lightweight compared to pino-http, but it does not offer the same level of performance and flexibility in terms of log formatting and custom log levels.

winston

Winston is a versatile logging library for Node.js that can also be used for HTTP request logging. It provides more features and flexibility than pino-http, such as multiple transport layers and log levels, but it is generally slower in performance.

bunyan

Bunyan is another JSON logging library for Node.js that can be used for HTTP request logging. It offers similar features to pino-http, such as high performance and structured logging, but it is not as widely adopted or actively maintained as Pino.

README

pino-http  

High-speed HTTP logger for Node.js

To our knowledge, pino-http is the fastest HTTP logger in town.

• Installation
• Example
• Benchmarks
• API
• Team
• Acknowledgements
• License

Benchmarks

Benchmarks log each request/response pair while returning 'hello world', using autocannon with 100 connections and 10 pipelined requests.

• http-ndjson (equivalent info): 7730.73 req/sec
• http-ndjson (standard minimum info): 9522.37 req/sec
• pino-http: 21496 req/sec
• pino-http (extreme): 25770.91 req/sec
• no logger: 46139.64 req/sec

All benchmarks where taken on a Macbook Pro 2013 (2.6GHZ i7, 16GB of RAM).

Install

npm i pino-http --save

Example

'use strict'

var http = require('http')
var server = http.createServer(handle)

var logger = require('pino-http')()

function handle (req, res) {
  logger(req, res)
  req.log.info('something else')
  res.end('hello world')
}

server.listen(3000)

$ node example.js | pino-pretty
[2016-03-31T16:53:21.079Z] INFO (46316 on MBP-di-Matteo): something else
    req: {
      "id": 1,
      "method": "GET",
      "url": "/",
      "headers": {
        "host": "localhost:3000",
        "user-agent": "curl/7.43.0",
        "accept": "*/*"
      },
      "remoteAddress": "::1",
      "remotePort": 64386
    }
[2016-03-31T16:53:21.087Z] INFO (46316 on MBP-di-Matteo): request completed
    res: {
      "statusCode": 200,
      "header": "HTTP/1.1 200 OK\r\nX-Powered-By: restify\r\nContent-Type: text/html; charset=utf-8\r\nContent-Length: 11\r\nETag: W/\"b-XrY7u+Ae7tCTyyK7j1rNww\"\r\nDate: Thu, 31 Mar 2016 16:53:21 GMT\r\nConnection: keep-alive\r\n\r\n"
    }
    responseTime: 10
    req: {
      "id": 1,
      "method": "GET",
      "url": "/",
      "headers": {
        "host": "localhost:3000",
        "user-agent": "curl/7.43.0",
        "accept": "*/*"
      },
      "remoteAddress": "::1",
      "remotePort": 64386
    }

API

pinoHttp([opts], [stream])

opts: it has all the options as pino and

• logger: parent pino instance for a child logger instance, which will be used by pino-http. To refer to this child instance, use pinoHttp.logger
• genReqId: you can pass a function which gets used to generate a request id. The first argument is the request itself. As fallback pino-http is just using an integer. This default might not be the desired behavior if you're running multiple instances of the app
• useLevel: the logger level pino-http is using to log out the response. default: info
• customLogLevel: set to a function (res, err) => { /* returns level name string */ }. This function will be invoked to determine the level at which the log should be issued. This option is mutually exclusive with the useLevel option. The first argument is the HTTP response. The second argument is an error object if an error has occurred in the request.
• autoLogging: set to false, to disable the automatic "request completed" and "request errored" logging. Defaults to true. If set to an object, you can provide more options.
• autoLogging.ignorePaths: array that holds one or many paths that should not autolog on completion. Paths will be matched exactly to the url path req.url (using Node class URL.pathname). This is useful for ignoring e.g. health check paths that get called every X seconds, and would fill out the logs unnecessarily. If the path matches and succeeds (http 200), it will not log any text. If it fails, it will log the error (as with any other path).
• autoLogging.getPath: set to a function (req) => { /* returns path string */ }. This function will be invoked to return the current path as a string. This is useful for checking autoLogging.ignorePaths against a path other than the default req.url. e.g. An express server where req.originalUrl is preferred.
• stream: same as the second parameter
• customSuccessMessage: set to a function (res) => { /* returns message string */ } This function will be invoked at each successful response, setting "msg" property to returned string. If not set, default value will be used.
• customErrorMessage: set to a function (err, res) => { /* returns message string */ } This function will be invoked at each failed response, setting "msg" property to returned string. If not set, default value will be used.
• customAttributeKeys: allows the log object attributes added by pino-http to be given custom keys. Accepts an object of format { [original]: [override] }. Attributes available for override are req, res, err, and responseTime.
• wrapSerializers: when false, custom serializers will be passed the raw value directly. Defaults to true.
• customProps: set to a function (req,res) => { /* returns on object */ } or { /* returns on object */ } This function will be invoked for each request with req and res where we could pass additional properties that needs to be logged outside the req.

stream: the destination stream. Could be passed in as an option too.

Examples

Logger options

'use strict'

var http = require('http')
var server = http.createServer(handle)
var pino = require('pino')
var logger = require('pino-http')({
  // Reuse an existing logger instance
  logger: pino(),

  // Define a custom request id function
  genReqId: function (req) { return req.id },

  // Define custom serializers
  serializers: {
    err: pino.stdSerializers.err,
    req: pino.stdSerializers.req,
    res: pino.stdSerializers.res
  },

  // Set to `false` to prevent standard serializers from being wrapped.
  wrapSerializers: true,

  // Logger level is `info` by default
  useLevel: 'info',

  // Define a custom logger level
  customLogLevel: function (res, err) {
    if (res.statusCode >= 400 && res.statusCode < 500) {
      return 'warn'
    } else if (res.statusCode >= 500 || err) {
      return 'error'
    }
    return 'info'
  },

  // Define a custom success message
  customSuccessMessage: function (res) {
    if (res.statusCode === 404) {
      return 'resource not found'
    }
    return 'request completed'
  },

  // Define a custom error message
  customErrorMessage: function (error, res) {
    return 'request errored with status code: ' + res.statusCode
  },
  // Override attribute keys for the log object
  customAttributeKeys: {
    req: 'request',
    res: 'response',
    err: 'error',
    responseTime: 'timeTaken'
  },

  // Define additional custom request properties
  customProps: function (req,res) {
    return {
      customProp: req.customProp,
      // user request-scoped data is in res.locals for express applications
      customProp2: res.locals.myCustomData
    }
  }
})

function handle (req, res) {
  logger(req, res)
  req.log.info('something else')
  res.end('hello world')
}

server.listen(3000)

PinoHttp.logger (P.Logger)

The pinoHttp instance has a property logger, which references to an actual logger instance, used by pinoHttp. This instance will be a child of an instance, passed as opts.logger, or a fresh one, if no opts.logger is passed. It can be used, for example, for doing most of the things, possible to do with any pino instance, for example changing logging level in runtime, like so:

var pinoHttp = require('pinoHttp')();
pinoHttp.logger.level = 'silent';

pinoHttp.startTime (Symbol)

The pinoHttp function has a property called startTime which contains a symbol that is used to attach and reference a start time on the HTTP res object. If the function returned from pinoHttp is not the first function to be called in an HTTP servers request listener function then the responseTime key in the log output will be offset by any processing that happens before a response is logged. This can be corrected by manually attaching the start time to the res object with the pinoHttp.startTime symbol, like so:

var http = require('http')
var logger = require('pino-http')()
var someImportantThingThatHasToBeFirst = require('some-important-thing')
http.createServer((req, res) => {
  res[logger.startTime] = Date.now()
  someImportantThingThatHasToBeFirst(req, res)
  logger(req, res)
  res.end('hello world')
}).listen(3000)

Default serializers

pinoHttp.stdSerializers.req

Generates a JSONifiable object from the HTTP request object passed to the createServer callback of Node's HTTP server.

It returns an object in the form:

{
  pid: 93535,
  hostname: 'your host',
  level: 30,
  msg: 'my request',
  time: '2016-03-07T12:21:48.766Z',
  v: 0,
  req: {
    id: 42,
    method: 'GET',
    url: '/',
    headers: {
      host: 'localhost:50201',
      connection: 'close'
    },
    remoteAddress: '::ffff:127.0.0.1',
    remotePort: 50202
  }
}

pinoHttp.stdSerializers.res

Generates a JSONifiable object from the HTTP response object passed to the createServer callback of Node's HTTP server.

It returns an object in the form:

{
  pid: 93581,
  hostname: 'myhost',
  level: 30,
  msg: 'my response',
  time: '2016-03-07T12:23:18.041Z',
  v: 0,
  res: {
    statusCode: 200,
    header: 'HTTP/1.1 200 OK\r\nDate: Mon, 07 Mar 2016 12:23:18 GMT\r\nConnection: close\r\nContent-Length: 5\r\n\r\n'
  }
}

Custom serializers

Each of the standard serializers can be extended by supplying a corresponding custom serializer. For example, let's assume the request object has custom properties attached to it, and that all of the custom properties are prefixed by foo. In order to show these properties, along with the standard serialized properties, in the resulting logs, we can supply a serializer like:

var logger = require('pino-http')({
  serializers: {
    req (req) {
      Object.keys(req.raw).forEach((k) => {
        if (k.startsWith('foo')) {
          req[k] = req.raw[k]
        }
      })
      return req
    }
  }
})

If you prefer to work with the raw value directly, or you want to honor the custom serializers already defined by opts.logger, you can pass in opts.wrapSerializers as false:

var logger = require('pino-http')({
  wrapSerializers: false,
  serializers: {
    req (req) {
      // `req` is the raw `IncomingMessage` object, not the already serialized request from `pino.stdSerializers.req`.
      return {
        message: req.foo
      };
    }
  }
})

Logging request body

Logging of requests' bodies is disabled by default since it can cause security risks such as having private user information (password, other GDPR-protected data, etc.) logged (and persisted in most setups). However if enabled, sensitive information can be redacted as per redaction documentation.

Furthermore, logging more bytes does slow down throughput. This video by pino maintainers Matteo Collina & David Mark Clements goes into this in more detail.

After considering these factors, logging of the request body can be achieved as follows:

const http = require('http')
const logger = require('pino-http')({
  serializers: {
    req(req) {
      req.body = req.raw.body;
      return req;
    },
  },
});

Custom serializers + custom log attribute keys

If custom attribute keys for req, res, or err log keys have been provided, serializers will be applied with the following order of precedence:

serializer matching custom key > serializer matching default key > default pino serializer

Team

Matteo Collina

https://github.com/mcollina

https://www.npmjs.com/~matteo.collina

https://twitter.com/matteocollina

David Mark Clements

https://github.com/davidmarkclements

https://www.npmjs.com/~davidmarkclements

https://twitter.com/davidmarkclem

Acknowledgements

This project was kindly sponsored by nearForm.

Logo and identity designed by Beibhinn Murphy O'Brien: https://www.behance.net/BeibhinnMurphyOBrien.

License

MIT