Pino is a very low overhead Node.js logger, which is inspired by Bunyan. It is designed to be as minimal as possible and to perform logging tasks with a very small performance overhead. Pino provides a simple to use API for structured logging and can be easily integrated with different transports for log processing.
Basic Logging
This feature allows you to perform basic logging tasks, such as logging informational messages.
const pino = require('pino');
const logger = pino();
logger.info('Hello, this is an info message!');Logging with Different Levels
Pino allows you to log messages with different severity levels, such as error, warn, and debug.
const logger = pino();
logger.error('This is an error message');
logger.warn('This is a warning message');
logger.debug('This is a debug message');Child Loggers
You can create child loggers from a parent logger, which can inherit the configuration of the parent and can also have additional properties.
const parentLogger = pino();
const childLogger = parentLogger.child({ a: 'property' });
childLogger.info('Hello from child logger');Custom Serializers
Pino allows you to define custom serializers for logging objects in a specific way.
const logger = pino({
serializers: {
req: (req) => ({ method: req.method, url: req.url })
}
});
logger.info({ req: requestObject }, 'Request log message');Pretty Printing
For development purposes, Pino can be combined with the 'pino-pretty' module to format logs in a more readable way.
const pino = require('pino');
const pretty = require('pino-pretty');
const logger = pino(pretty());
logger.info('This will be pretty printed');Winston is a multi-transport async logging library for Node.js. It is designed to be a simple and universal logging library with support for multiple transports. Compared to Pino, Winston is more feature-rich and configurable but can be heavier on performance.
Bunyan is a simple and fast JSON logging library for Node.js services. Like Pino, it is inspired by the Unix philosophy and focuses on structured logging. Bunyan is more similar to Pino in terms of philosophy, but Pino claims to be faster and more efficient.
Log4js is a logging framework for Node.js, which provides flexible configuration and supports multiple appenders. It is similar to the Log4j library for Java. Compared to Pino, Log4js offers more traditional logging features but may not be as performance-optimized.
Extremely fast node.js logger, inspired by Bunyan. It also includes a shell utility to pretty-print its log files.
npm install pino --save
'use strict'
var pino = require('pino')()
pino.info('hello world')
pino.error('this is at error level')
pino.info('the answer is %d', 42)
pino.info({ obj: 42 }, 'hello world')
pino.info({ obj: 42, b: 2 }, 'hello world')
pino.info({ obj: { aa: 'bbb' } }, 'another')
setImmediate(function () {
pino.info('after setImmediate')
})
pino.error(new Error('an error'))
var child = pino.child({ a: 'property' })
child.info('hello child!')
var childsChild = child.child({ another: 'property' })
childsChild.info('hello baby..')
This produces:
{"pid":94473,"hostname":"MacBook-Pro-3.home","level":30,"msg":"hello world","time":1459529098958,"v":1}
{"pid":94473,"hostname":"MacBook-Pro-3.home","level":50,"msg":"this is at error level","time":1459529098959,"v":1}
{"pid":94473,"hostname":"MacBook-Pro-3.home","level":30,"msg":"the answer is 42","time":1459529098960,"v":1}
{"pid":94473,"hostname":"MacBook-Pro-3.home","level":30,"msg":"hello world","time":1459529098960,"obj":42,"v":1}
{"pid":94473,"hostname":"MacBook-Pro-3.home","level":30,"msg":"hello world","time":1459529098960,"obj":42,"b":2,"v":1}
{"pid":94473,"hostname":"MacBook-Pro-3.home","level":30,"msg":"another","time":1459529098960,"obj":{"aa":"bbb"},"v":1}
{"pid":94473,"hostname":"MacBook-Pro-3.home","level":50,"msg":"an error","time":1459529098961,"type":"Error","stack":"Error: an error\n at Object.<anonymous> (/Users/davidclements/z/nearForm/pino/example.js:14:12)\n at Module._compile (module.js:435:26)\n at Object.Module._extensions..js (module.js:442:10)\n at Module.load (module.js:356:32)\n at Function.Module._load (module.js:311:12)\n at Function.Module.runMain (module.js:467:10)\n at startup (node.js:136:18)\n at node.js:963:3","v":1}
{"pid":94473,"hostname":"MacBook-Pro-3.home","level":30,"msg":"hello child!","time":1459529098962,"a":"property","v":1}
{"pid":94473,"hostname":"MacBook-Pro-3.home","level":30,"msg":"hello baby..","time":1459529098962,"another":"property","a":"property","v":1}
{"pid":94473,"hostname":"MacBook-Pro-3.home","level":30,"msg":"after setImmediate","time":1459529098963,"v":1}
As far as we know, it is one of the fastest loggers in town:
pino.info('hello world'):
benchBunyan*10000: 1355.229ms
benchWinston*10000: 2226.117ms
benchBole*10000: 291.727ms
benchDebug*10000: 445.291ms
benchLogLevel*10000: 322.181ms
benchPino*10000: 269.109ms
benchPinoExreme*10000: 102.239ms
pino.info({'hello': 'world'}):
benchBunyanObj*10000: 1464.568ms
benchWinstonObj*10000: 2177.602ms
benchBoleObj*10000: 322.105ms
benchLogLevelObject*10000: 1443.148ms
benchPinoObj*10000: 309.564ms
benchPinoUnsafeObj*10000: 301.308ms
benchPinoExtremeObj*10000: 130.343ms
benchPinoUnsafeExtremeObj*10000: 131.322ms
pino.info(aBigDeeplyNestedObject):
benchBunyanDeepObj*10000: 8749.174ms
benchWinstonDeepObj*10000: 17761.409ms
benchBoleDeepObj*10000: 5252.563ms
benchLogLevelDeepObj*10000: 43518.525ms
benchPinoDeepObj*10000: 5124.361ms
benchPinoUnsafeDeepObj*10000: 3539.253ms
benchPinoExtremeDeepObj*10000: 5138.457ms
benchPinoUnsafeExtremeDeepObj*10000: 3480.270ms
pino.info('hello %s %j %d', 'world', {obj: true}, 4, {another: 'obj'}):
benchDebugInterpolateExtra*10000: 640.001ms
benchBunyanInterpolateExtra*10000: 2888.825ms
benchWinstonInterpolateExtra*10000: 2616.285ms
benchBoleInterpolateExtra*10000: 1313.470ms
benchLogLevelInterpolateExtra*10000: 1487.610ms
benchPinoInterpolateExtra*10000: 486.367ms
benchPinoUnsafeInterpolateExtra*10000: 457.778ms
benchPinoExtremeInterpolateExtra*10000: 314.635ms
benchPinoUnsafeExtremeInterpolateExtra*10000: 294.915ms
In many cases, pino is over 6x faster than alternatives.
For a fair comparison, LogLevel was extended
to include a timestamp and bole had
fastTime mode switched on.
To use the command line tool, we can install pino globally:
npm install -g pino
Then we simply pipe a log file through pino:
cat log | pino
There are also two transformer flags..
-t that converts Epoch timestamps to ISO timestamps.
cat log | pino -t
and -l that flips the time and level on the standard output.
cat log | pino -l
pino -t will transform this:
{"pid":14139,"hostname":"MacBook-Pro-3.home","level":30,"msg":"hello world","time":1457537229339,"v":0}
Into this:
{"pid":14139,"hostname":"MacBook-Pro-3.home","level":30,"msg":"hello world","time":"2016-03-09T15:27:09.339Z","v":0}
pino -l will transform this:
[2016-03-09T15:27:09.339Z] INFO (14139 on MacBook-Pro-3.home): hello world
Into this:
INFO [2016-03-09T15:27:09.339Z] (14139 on MacBook-Pro-3.home): hello world
pino()logger.child()logger.levellogger.fatal()logger.error()logger.warn()logger.info()logger.debug()logger.trace()logger.flush()logger.levelVallogger.on('level-change', fn)logger.levels.values & pino.levels.valueslogger.levels.labels & pino.levels.labelspino.LOG_VERSION & logger.LOG_VERSIONpino.stdSerializers.reqpino.stdSerializers.respino.stdSerializers.errpino.pretty()Returns a new logger. Allowed options are:
safe: avoid error causes by circular references in the object tree,
default truename: the name of the logger, default undefinedserializers: an object containing functions for custom serialization of objects. These functions should return an JSONifiable object and they should never throwslowtime: Outputs ISO time stamps ('2016-03-09T15:18:53.889Z') instead of Epoch time stamps (1457536759176). WARNING: This option carries a 25% performance drop, we recommend using default Epoch timestamps and transforming logs after if required. The pino -t command will do this for you (see CLI). default false.extreme: Enables extreme mode, yields an additional 60% performance (from 250ms down to 100ms per 10000 ops). There are trade-off's should be understood before usage. See Extreme mode explained. default falselevel: one of 'fatal', 'error', 'warn', 'info', 'debug', 'trace'; also 'silent' is supported to disable logging.enabled: enables logging, defaults to true.stream is a Writable stream, defaults to process.stdout.
Example:
'use strict'
var pino = require('pino')
var logger = pino({
name: 'myapp',
safe: true,
serializers: {
req: pino.stdSerializers.req,
res: pino.stdSerializers.res
}
})
Creates a child logger, setting all key-value pairs in bindings as
properties in the log lines. All serializers will be applied to the
given pair.
Example:
logger.child({ a: 'property' }).info('hello child!')
// generates
// {"pid":46497,"hostname":"MacBook-Pro-di-Matteo.local","level":30,"msg":"hello child!","time":1458124707120,"v":0,"a":"property"}
Child loggers use the same output stream as the parent and inherit the current log level of the parent at the time they are spawned.
From v2.x.x the log level of a child is mutable (whereas in
v1.x.x it was immutable), and can be set independently of the parent.
If a level property is present in the object passed to child it will
override the child logger level.
For example
var logger = pino()
logger.level = 'error'
logger.info('nope') //does not log
var child = logger.child({foo: 'bar'})
child.info('nope again') //does not log
child.level = 'info'
child.info('hooray') //will log
logger.info('nope nope nope') //will not log, level is still set to error
logger.child({ foo: 'bar', level: 'debug' }).debug('debug!')
Child loggers inherit the serializers from the parent logger but it is possible to override them.
For example
var pino = require('./pino')
var customSerializers = {
test: function () {
return 'this is my serializer'
}
}
var child = pino().child({serializers: customSerializers})
child.info({test: 'should not show up'})
Will produce the following output:
{"pid":7971,"hostname":"mycomputer.local","level":30,"time":1469488147985,"test":"this is my serializer","v":1}
Also from version 2.x.x we can spawn child loggers from child loggers, for instance
var logger = pino()
var child = logger.child({father: true})
var childChild = child.child({baby: true})
Child logger creation is fast:
benchBunyanCreation*10000: 1291.332ms
benchBoleCreation*10000: 1630.542ms
benchPinoCreation*10000: 352.330ms
benchPinoExtremeCreation*10000: 102.282ms
Logging through a child logger has little performance penalty:
benchBunyanChild*10000: 1343.933ms
benchBoleChild*10000: 1605.969ms
benchPinoChild*10000: 334.573ms
benchPinoExtremeChild*10000: 152.792ms
Spawning children from children has negligible overhead:
benchBunyanChildChild*10000: 1397.202ms
benchPinoChildChild*10000: 338.930ms
benchPinoExtremeChildChild*10000: 150.143ms
Set this property to the desired logging level.
In order of priority, available levels are:
Example: logger.level = 'info'
The logging level is a minimum level. For instance if logger.level is 'info' then all 'fatal', 'error', 'warn', and 'info' logs will be enabled.
You can pass 'silent' to disable logging.
Log at 'fatal' level the given msg. If the first argument is an
object, all its properties will be included in the JSON line.
If more args follows msg, these will be used to format msg using
util.format
Log at 'error' level the given msg. If the first argument is an
object, all its properties will be included in the JSON line.
If more args follows msg, these will be used to format msg using
util.format
Log at 'warn' level the given msg. If the first argument is an
object, all its properties will be included in the JSON line.
If more args follows msg, these will be used to format msg using
util.format
Log at 'info' level the given msg. If the first argument is an
object, all its properties will be included in the JSON line.
If more args follows msg, these will be used to format msg using
util.format
Log at 'debug' level the given msg. If the first argument is an
object, all its properties will be included in the JSON line.
If more args follows msg, these will be used to format msg using
util.format
Log at 'trace' level the given msg. If the first argument is an
object, all its properties will be included in the JSON line.
If more args follows msg, these will be used to format msg using
util.format
Flushes the content of the buffer in extreme mode. It has no effect if extreme mode is not enabled.
Returns the integer value for the logger instance's logging level.
Registers a listener function that is triggered when the level is changed.
The listener is passed four arguments: levelLabel, levelValue, previousLevelLabel, previousLevelValue.
Note: When browserified, this functionality will only be available if the events module has been required else where (e.g. if you're using streams in the browser). This allows for a trade-off between bundle size and functionality.
var listener = function (lvl, val, prevLvl, prevVal) {
console.log(lvl, val, prevLvl, prevVal)
}
logger.on('level-change', listener)
logger.level = 'trace' // trigger console message
logger.removeListener('level-change', listener)
logger.level = 'info' // no message, since listener was removed
Returns the mappings of level names to their respective internal number representation. For example:
pino.levels.values.error === 50 // true
Returns the mappings of level internal level numbers to their string representations. For example:
pino.levels.labels[50] === 'error' // true
Read only. Holds the current log format version (as output in the v property of each log record).
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: {
method: 'GET',
url: '/',
headers: {
host: 'localhost:50201',
connection: 'close'
},
remoteAddress: '::ffff:127.0.0.1',
remotePort: 50202
}
}
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'
}
}
Serializes an Error object if passed in as an property.
{
"pid": 40510,
"hostname": "MBP-di-Matteo",
"level": 50,
"msg": "an error",
"time": 1459433282301,
"v": 1,
"type": "Error",
"stack": "Error: an error\n at Object.<anonymous> (/Users/matteo/Repositories/pino/example.js:16:7)\n at Module._compile (module.js:435:26)\n at Object.Module._extensions..js (module.js:442:10)\n at Module.load (module.js:356:32)\n at Function.Module._load (module.js:313:12)\n at Function.Module.runMain (module.js:467:10)\n at startup (node.js:136:18)\n at node.js:963:3"
}
Returns a transform stream that formats JSON output into pretty print output as per the cli tool.
Options:
timeTransOnly, if set to true, it will only covert the unix timestamp to
ISO 8601 date format, and reserialize the JSON (equivalent to pino -t).You can use the pretty transformer internally, like so:
'use strict'
var pino = require('pino')
var pretty = pino.pretty()
pretty.pipe(process.stdout)
var log = pino({
name: 'app',
safe: true
}, pretty)
log.child({ widget: 'foo' }).info('hello')
log.child({ widget: 'bar' }).warn('hello 2')
In essence, Extreme mode enables extreme performance by buffering log messages and writing them in larger chunks.
This has a couple of important caveats:
logger.info) and writes to a log file (or log stream)process.stdout or process.stderr, there is a slight possibility of lost logs or even partially written logs if the OS buffers don't have enough space, or something else is being written to the stream (or maybe some other reason we've not thought of)So in summary, only use extreme mode if you're doing an extreme amount of logging, and you're happy in some scenarios to lose the most recent logs.
We've got you covered:
npm install --save express-pino-logger
var app = require('express')()
var pino = require('express-pino-logger')()
app.use(pino)
app.get('/', function (req, res) {
req.log.info('something')
res.send('hello world')
})
app.listen(3000)
See the express-pino-logger readme for more info.
We've got you covered:
npm install --save hapi-pino
'use strict'
const Hapi = require('hapi')
const server = new Hapi.Server()
server.connection({ port: 3000 })
server.route({
method: 'GET',
path: '/',
handler: function (request, reply) {
request.logger.info('In handler %s', request.path)
return reply('hello world')
}
})
server.register(require('hapi-pino'), (err) => {
if (err) {
console.error(err)
process.exit(1)
}
server.logger().info('another way for accessing it')
// Start the server
server.start((err) => {
if (err) {
console.error(err)
process.exit(1)
}
})
})
See the hapi-pino readme for more info.
We've got you covered:
npm install --save restify-pino-logger
var server = require('restify').createServer({name: 'server'})
var pino = require('restify-pino-logger')()
server.use(pino)
server.get('/', function (req, res) {
req.log.info('something')
res.send('hello world')
})
server.listen(3000)
See the restify-pino-logger readme for more info.
We've got you covered:
npm install --save koa-pino-logger@1
var app = require('koa')()
var pino = require('koa-pino-logger')()
app.use(pino)
app.use(function * () {
this.log.info('something else')
this.body = 'hello world'
})
app.listen(3000)
See the koa-pino-logger v1 readme for more info.
npm install --save koa-pino-logger@2
var Koa = require('koa')
var app = new Koa()
var pino = require('koa-pino-logger')()
app.use(pino)
app.use((ctx) => {
ctx.log.info('something else')
ctx.body = 'hello world'
})
app.listen(3000)
See the koa-pino-logger v2 readme for more info.
Use a separate tool for log rotation.
We recommend logrotate
Consider we output our logs to /var/log/myapp.log like so:
> node server.js > /var/log/myapp.log
We would rotate our log files with logrotate, by adding the following to /etc/logrotate.d/myapp:
/var/log/myapp.log {
su root
daily
rotate 7
delaycompress
compress
notifempty
missingok
copytruncate
}
Create a separate process and pipe to it.
For example:
var split = require('split2')
var pump = require('pump')
var through = require('through2')
var myTransport = through.obj(function (chunk, enc, cb) {
// do whatever you want here!
console.log(chunk)
cb()
})
pump(process.stdin, split2(JSON.parse), myTransport)
node my-app-which-logs-stuff-to-stdout.js | node my-transport-process.js
Using transports in the same process causes unnecessary load and slows down Node's single threaded event loop.
If you write a transport, let us know and we will add a link here!
pino-elasticsearch uploads the log lines in bulk to Elasticsearch, to be displayed in Kibana.
It is extremely simple to use and setup
$ node yourapp.js | pino-elasticsearch
Assuming Elasticsearch is running on localhost.
If you wish to connect to an external elasticsearch instance (recommended for production):
network.host in your elasticsearch.yml configuration file. See elasticsearch Network Settings documentation for more details.$ node yourapp.js | pino-elasticsearch --host 192.168.1.42
Assuming Elasticsearch is running on 192.168.1.42.
Then, head to your
Kibana instance, and create an index pattern on 'pino',
the default for pino-elasticsearch.
pino-socket is a transport that will forward logs to a IPv4
UDP or TCP socket. As an example, use socat to fake a listener:
$ socat -v udp4-recvfrom:6000,fork exec:'/bin/cat'
And then run an application that uses pino for logging:
$ node yourapp.js | pino-socket -p 6000
You should see the logs from your application on both consoles.
pino-syslog is a transport, really a "transform," that converts
pino's logs to RFC3164 compatible log messages. pino-syslog does not
forward the logs anywhere, it merely re-writes the messages to stdout. But
in combination with pino-socket, you can relay logs to a syslog server:
$ node yourapp.js | pino-syslog | pino-socket -a syslog.example.com
Example output for the "hello world" log:
<134>Apr 1 16:44:58 MacBook-Pro-3 none[94473]: {"pid":94473,"hostname":"MacBook-Pro-3","level":30,"msg":"hello world","time":1459529098958,"v":1}
You can also use pino-socket to upload logs to [Logstash][logstash] via:
$ node yourapp.js | pino-socket -a 127.0.0.1 -p 5000 -m tcp
Assuming your logstash is running on the same host and configured as follows:
input {
tcp {
port => 5000
}
}
filter {
json {
source => "message"
}
}
output {
elasticsearch {
hosts => "127.0.0.1:9200"
}
}
See https://www.elastic.co/guide/en/kibana/current/setup.html to learn how to setup Kibana.
If you are a Docker fan, you can use https://github.com/deviantony/docker-elk to setup an ELK stack.
There's some fine points to be aware of, which are a result of worthwhile trade-offs:
The logger functions (e.g. pino.info) can take a maximum of 11 arguments.
If you need more than that to write a log entry, you're probably doing it wrong.
It's possible for naming conflicts to arise between child loggers and children of child loggers.
This isn't as bad as it sounds, even if you do use the same keys between parent and child loggers Pino resolves the conflict in the sanest way.
For example, consider the following:
var pino = require('pino')
var fs = require('fs')
pino(fs.createWriteStream('./my-log'))
.child({a: 'property'})
.child({a: 'prop'})
.info('howdy')
$ cat my-log
{"pid":95469,"hostname":"MacBook-Pro-3.home","level":30,"msg":"howdy","time":1459534114473,"a":"property","a":"prop","v":1}
Notice how there's two key's named a in the JSON output. The sub-childs properties
appear after the parent child properties. This means if we run our logs through pino -t (or convert them to objects in any other way) we'll end up with one a property whose value corresponds to the lowest child in the hierarchy:
$ cat my-log | pino -t
{"pid":95469,"hostname":"MacBook-Pro-3.home","level":30,"msg":"howdy","time":"2016-04-01T18:08:34.473Z","a":"prop","v":1}
This equates to the same log output that Bunyan supplies.
One of Pino's performance tricks is to avoid building objects and stringifying them, so we're building strings instead. This is why duplicate keys between parents and children will end up in log output.
https://www.npmjs.com/~matteo.collina
https://twitter.com/matteocollina
https://github.com/davidmarkclements
https://www.npmjs.com/~davidmarkclements
https://twitter.com/davidmarkclem
https://gitter.im/mcollina/pino
This project was kindly sponsored by nearForm.
Logo and identity designed by Beibhinn Murphy O'Brien: https://www.behance.net/BeibhinnMurphyOBrien.
Licensed under MIT.
FAQs
super fast, all natural json logger
The npm package pino receives a total of 6,765,178 weekly downloads. As such, pino popularity was classified as popular.
We found that pino demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 4 open source maintainers collaborating on the project.
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