fluent-logger
    TypeScript icon, indicating that this package has built-in type declarations

    3.4.1 • Public • Published

    fluent-logger for Node.js

    fluent-logger implementation for Node.js inspired by fluent-logger-python.

    NPM

    Build Status

    Install

    $ npm install fluent-logger
    

    Prerequistes

    Fluent daemon should listen on TCP port.

    Simple configuration is following:

    <source>
      @type forward
      port 24224
    </source>
     
    <match **.*>
      @type stdout
    </match>

    Usage

    Send an event record to Fluentd

    Singleton style

    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

    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

    .emit([label string], <record object>, [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

    logger.configure('tag_prefix', {
       host: 'localhost',
       port: 24224,
       timeout: 3.0,
       enableReconnect: false // defaults to true
    });

    Shared key authentication

    Logger configuration:

    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:

    <source>
      @type forward
      port 24224
      <security>
        self_hostname input.testing.local
        shared_key secure_communication_is_awesome
      </security>
    </source>
     
    <match dummy.*>
      @type stdout
    </match>

    See also Fluentd examples.

    TLS/SSL encryption

    Logger configuration:

    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:

    <source>
      @type forward
      port 24224
      <transport tls>
        ca_cert_path /path/to/ca_cert.pem
        ca_private_key_path /path/to/ca_key.pem
        ca_private_key_passphrase very_secret_passphrase
      </transport>
      <security>
        self_hostname input.testing.local
        shared_key secure_communication_is_awesome
      </security>
    </source>
     
    <match dummy.*>
      @type stdout
    </match>

    FYI: You can generate certificates using fluent-ca-generate command since Fluentd 1.1.0.

    See also How to enable TLS/SSL encryption.

    Mutual TLS Authentication

    Logger configuration:

    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:

    <source>
      @type forward
      port 24224
      <transport tls>
        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
      </transport>
      <security>
        self_hostname input.testing.local
        shared_key secure_communication_is_awesome
      </security>
    </source>
     
    <match dummy.*>
      @type stdout
    </match>

    EventTime support

    We can also specify EventTime as timestamp.

    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

    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.

    winston

    Before using winston support, you should install it IN YOUR APPLICATION.

    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.

    '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

    port

    The port to listen to. Default value = 24224.

    See socket.connect

    path

    The path to your Unix Domain Socket. If you set path then fluent-logger ignores host and port.

    See socket.connect

    timeout

    Set the socket to timetout after timeout milliseconds of inactivity on the socket.

    See socket.setTimeout

    reconnectInterval

    Set the reconnect interval in milliseconds. If error occurs then reconnect after this interval.

    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. 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

    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.

    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.

    About NodeJS versions

    This package is compatible with NodeJS versions >= 6.

    Install

    npm i fluent-logger

    DownloadsWeekly Downloads

    24,929

    Version

    3.4.1

    License

    Apache-2.0

    Unpacked Size

    95.2 kB

    Total Files

    20

    Last publish

    Collaborators

    • edsiper
    • okkez
    • repeatedly
    • yssk22