# fluent-logger for Node.js fluent-logger implementation for Node.js inspired by [fluent-logger-python]. [![NPM](https://nodei.co/npm/fluent-logger.png?downloads=true&downloadRank=true)](https://nodei.co/npm/fluent-logger/) [![Build Status](https://secure.travis-ci.org/fluent/fluent-logger-node.png?branch=master,develop)](http://travis-ci.org/fluent/fluent-logger-node) ## Install $ npm install fluent-logger ## Prerequistes Fluent daemon should listen on TCP port. Simple configuration is following: ```aconf @type forward port 24224 @type stdout ``` ## Usage ### Send an event record to Fluentd Singleton style ```js var logger = require('fluent-logger') // The 2nd argument can be omitted. Here is a default value for options. logger.configure('tag_prefix', { host: 'localhost', port: 24224, timeout: 3.0, reconnectInterval: 600000 // 10 minutes }); // send an event record with 'tag.label' logger.emit('label', {record: 'this is a log'}); ``` Instance style ```js var logger = require('fluent-logger').createFluentSender('tag_prefix', { host: 'localhost', port: 24224, timeout: 3.0, reconnectInterval: 600000 // 10 minutes }); ``` The emit method has following signature ```js .emit([label string], , [timestamp number/date], [callback function]) ``` Where only the `record` argument is required. If the label is set it will be appended to the configured tag. ### Disable automatic reconnect Both Singleton and Instance style can disable automatic reconnect allowing the user to handle reconnect himself ```js logger.configure('tag_prefix', { host: 'localhost', port: 24224, timeout: 3.0, enableReconnect: false // defaults to true }); ``` ### Shared key authentication Logger configuration: ```js var logger = require('fluent-logger').createFluentSender('dummy', { host: 'localhost', port: 24224, timeout: 3.0, reconnectInterval: 600000, // 10 minutes security: { clientHostname: "client.localdomain", sharedKey: "secure_communication_is_awesome" } }); logger.emit('debug', { message: 'This is a message' }); ``` Server configuration: ```aconf @type forward port 24224 self_hostname input.testing.local shared_key secure_communication_is_awesome @type stdout ``` See also [Fluentd](https://github.com/fluent/fluentd) examples. ### TLS/SSL encryption Logger configuration: ```js var logger = require('fluent-logger').createFluentSender('dummy', { host: 'localhost', port: 24224, timeout: 3.0, reconnectInterval: 600000, // 10 minutes security: { clientHostname: "client.localdomain", sharedKey: "secure_communication_is_awesome" }, tls: true, tlsOptions: { ca: fs.readFileSync('/path/to/ca_cert.pem') } }); logger.emit('debug', { message: 'This is a message' }); ``` Server configuration: ```aconf @type forward port 24224 ca_cert_path /path/to/ca_cert.pem ca_private_key_path /path/to/ca_key.pem ca_private_key_passphrase very_secret_passphrase self_hostname input.testing.local shared_key secure_communication_is_awesome @type stdout ``` FYI: You can generate certificates using fluent-ca-generate command since Fluentd 1.1.0. See also [How to enable TLS/SSL encryption](https://docs.fluentd.org/input/forward#how-to-enable-tls-encryption). ### Mutual TLS Authentication Logger configuration: ```js var logger = require('fluent-logger').createFluentSender('dummy', { host: 'localhost', port: 24224, timeout: 3.0, reconnectInterval: 600000, // 10 minutes security: { clientHostname: "client.localdomain", sharedKey: "secure_communication_is_awesome" }, tls: true, tlsOptions: { ca: fs.readFileSync('/path/to/ca_cert.pem'), cert: fs.readFileSync('/path/to/client-cert.pem'), key: fs.readFileSync('/path/to/client-key.pem'), passphrase: 'very-secret' } }); logger.emit('debug', { message: 'This is a message' }); ``` Server configuration: ```aconf @type forward port 24224 ca_path /path/to/ca-cert.pem cert_path /path/to/server-cert.pem private_key_path /path/to/server-key.pem private_key_passphrase very_secret_passphrase client_cert_auth true self_hostname input.testing.local shared_key secure_communication_is_awesome @type stdout ``` ### EventTime support We can also specify [EventTime](https://github.com/fluent/fluentd/wiki/Forward-Protocol-Specification-v1#eventtime-ext-format) as timestamp. ```js var FluentLogger = require('fluent-logger'); var EventTime = FluentLogger.EventTime; var logger = FluentLogger.createFluentSender('tag_prefix', { var eventTime = new EventTime(1489547207, 745003500); // 2017-03-15 12:06:47 +0900 logger.emit('tag', { message: 'This is a message' }, eventTime); ``` ### Events * `connect` : Handle [net.Socket Event: connect](https://nodejs.org/api/net.html#net_event_connect) * `error` : Handle [net.Socket Event: error](https://nodejs.org/api/net.html#net_event_error_1) ```js var logger = require('fluent-logger').createFluentSender('tag_prefix', { host: 'localhost', port: 24224, timeout: 3.0, reconnectInterval: 600000 // 10 minutes }); logger.on('error', (error) => { console.log(error); }); logger.on('connect', () => { console.log('connected!'); }); ``` ## Logging Library Support ### log4js Use [log4js-fluent-appender](https://www.npmjs.com/package/log4js-fluent-appender). ### winston Before using [winston](https://github.com/winstonjs/winston) support, you should install it IN YOUR APPLICATION. ```js var winston = require('winston'); var config = { host: 'localhost', port: 24224, timeout: 3.0, requireAckResponse: true // Add this option to wait response from Fluentd certainly }; var fluentTransport = require('fluent-logger').support.winstonTransport(); var fluent = new fluentTransport('mytag', config); var logger = winston.createLogger({ transports: [fluent, new (winston.transports.Console)()] }); logger.on('flush', () => { console.log("flush"); }) logger.on('finish', () => { console.log("finish"); fluent.sender.end("end", {}, () => {}) }); logger.log('info', 'this log record is sent to fluent daemon'); logger.info('this log record is sent to fluent daemon'); logger.info('end of log message'); logger.end(); ``` **NOTE** If you use `winston@2`, you can use `fluent-logger@2.7.0` or earlier. If you use `winston@3`, you can use `fluent-logger@2.8` or later. ### stream Several libraries use stream as output. ```js 'use strict'; const Console = require('console').Console; var sender = require('fluent-logger').createFluentSender('tag_prefix', { host: 'localhost', port: 24224, timeout: 3.0, reconnectInterval: 600000 // 10 minutes }); var logger = new Console(sender.toStream('stdout'), sender.toStream('stderr')); logger.log('this log record is sent to fluent daemon'); setTimeout(()=> sender.end(), 5000); ``` ## Options **tag_prefix** The tag prefix string. You can specify `null` when you use `FluentSender` directly. In this case, you must specify `label` when you call `emit`. **host** The hostname. Default value = 'localhost'. See [socket.connect][1] **port** The port to listen to. Default value = 24224. See [socket.connect][1] **path** The path to your Unix Domain Socket. If you set `path` then fluent-logger ignores `host` and `port`. See [socket.connect][1] **timeout** Set the socket to timetout after `timeout` milliseconds of inactivity on the socket. See [socket.setTimeout][2] **reconnectInterval** Set the reconnect interval in milliseconds. If error occurs then reconnect after this interval. [1]: https://nodejs.org/api/net.html#net_socket_connect_path_connectlistener [2]: https://nodejs.org/api/net.html#net_socket_settimeout_timeout_callback **requireAckResponse** Change the protocol to at-least-once. The logger waits the ack from destination. **ackResponseTimeout** This option is used when requireAckResponse is true. The default is 190. This default value is based on popular `tcp_syn_retries`. **eventMode** Set [Event Modes](https://github.com/fluent/fluentd/wiki/Forward-Protocol-Specification-v1#event-modes). This logger supports `Message`, `PackedForward` and `CompressedPackedForward`. Default is `Message`. NOTE: We will change default to `PackedForward` and drop `Message` in next major release. **flushInterval** Set flush interval in milliseconds. This option has no effect in `Message` mode. The logger stores emitted events in buffer and flush events for each interval. Default `100`. **messageQueueSizeLimit** Maximum number of messages that can be in queue at the same time. If a new message is received and it overflows the queue then the oldest message will be removed before adding the new item. This option has effect only in `Message` mode. No limit by default. **security.clientHostname** Set hostname of this logger. Use this value for hostname based authentication. **security.sharedKey** Shared key between client and server. **security.username** Set username for user based authentication. Default values is empty string. **security.password** Set password for user based authentication. Default values is empty string. **sendQueueSizeLimit** Queue size limit in bytes. This option has no effect in `Message` mode. Default is `8 MiB`. **tls** Enable TLS for socket. **tlsOptions** Options to pass to tls.connect when tls is true. For more details, see following documents * [tls.connect()](https://nodejs.org/api/tls.html#tls_tls_connect_options_callback) * [tls.createSecureContext()](https://nodejs.org/api/tls.html#tls_tls_createsecurecontext_options) **internalLogger** Set internal logger object for FluentLogger. Use `console` by default. This logger requires `info` and `error` method. ## Examples ### Winston Integration An example of integrating with Winston can be found at [`./example/winston`](./example/winston). You will need Docker Compose to run it. After navigating to `./example/winston`, run `docker-compose up` and then `node index.js`. You should see the Docker logs having an `"it works"` message being output to FluentD. ## License Apache License, Version 2.0. [fluent-logger-python]: https://github.com/fluent/fluent-logger-python ## About NodeJS versions This package is compatible with NodeJS versions >= 6.

	Stars	Issues	Version	Updated	Created
fluent-logger	258	22	3.4.1	4 years ago	13 years ago
log4js			6.9.1	a year ago	13 years ago
logging			3.3.0	3 years ago	13 years ago
morgan	7,828	25	1.10.0	4 years ago	10 years ago
pino	13,346	93	9.1.0	4 days ago	8 years ago

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