winston-logstash

A Logstash TCP transport for winston.

Usage

Winston 2.x

// See test cases from test-bench/winston-2x/test/smoke.js
const winston = require("winston");
const transports = require("winston-logstash");

const logger = new winston.Logger({
  transports: [
    new transports.Logstash({
      port: 28777,
      node_name: "my node name",
      host: "127.0.0.1",
    }),
  ],
});

logger.info("Hello world!");

Winston 3.x

// See test cases from test-bench/winston-3x/test/smoke.js
const winston = require("winston");
const LogstashTransport = require("winston-logstash/lib/winston-logstash-latest");

const logger = winston.createLogger({
  transports: [
    new LogstashTransport({
      port: 28777,
      node_name: "my node name",
      host: "127.0.0.1",
    }),
  ],
});

logger.info("Hello world!");

Logstash config

# See example from test-bench/logstash/logstash/pipeline/default.conf
input {
  # Sample input over TCP
  tcp { port => 28777 type=>"sample" }
}
output {
  stdout { debug => true }
}

filter {
  json {
    source => "message"
  }
}

FAQ

Error handling with the transport

While this is a relatively complex transport with an internal state and IO, I think the current solution is the yet best approach to network failure. Transport is transparent about the errors and lets the user decide what to do in the case of an error. Suppose the developer chooses not to address them, it fallback to a safe default, an exception that stops the process. I think this way; it's simple but not always easy.

You can check the test case from test-bench folder where is the test case per Winston's version. The simplest ways to write the error logic would be:

Winston 2.x

For Winston 2.x you have to add the error listener to the transport.

const logstashTransport =  new LogstashTransport({...});

logstashTransport.on('error', (error) => {
  // Make the decission in here
  throw new Error('Stop the press, logging not working');
});

Winston 3.x

For Winston 3.x you have to add the error listener to the logger. Remember that there might be also other errors which are not originated from LogstashTransport.

const logger = winston.createLogger({
      transports: [
        new LogstashTransport({
              ...
               max_connect_retries: -1
              ...
              })]});

logger.on('error', (error) => {
  // Make the decission in here
  throw new Error('Stop the press, logging not working');
});

What configuration options are available?

See documentation from docs/configuration

How to keep the connection open while Logstash is restarting?

It's possible to set max_connect_retries to -1 (infinite) so the client keeps trying to connect to the Logstash. So when Logstash is restarted the retry logic will reconnect when it comes back online.

    const logger = winston.createLogger({
      transports: [
        new LogstashTransport({
              ...
               max_connect_retries: -1
              ...
              })]});

Run Tests

  npm test

Run integration tests with Logstash

  cd test-bench/winston-3x
  docker-compose up -d
  npm test

Inspiration

winston-loggly

Author: Jaakko Suutarla

License: MIT

See LICENSE for the full license text.