gelf pro

node-gelf - Graylog2 client library for Node.js. Pro - because of code-quality (at 2015). GELF - The Graylog Extended Log Format.

Installation

"dependencies": {
  "gelf-pro": "~1.3" // see the "releases" section
}

npm install gelf-pro (ALL node.js versions are supported [0.x to 20.x] 😃

Library depends on: lodash#~4.17

Initialization

var log = require('gelf-pro');

Adapters

> ⚠️ To provide predictable behaviour, all existing adapters do NOT re-use the socket connection.
There are multiple (1, 2) variants available which you can borrow from (and create a new adapter).
See related section.

• UDP (with deflation and chunking)
  • Input: GELF UDP
• TCP
  • Input: GELF TCP (with Null frame delimiter)
• TCP via TLS(SSL)
  • Input: GELF TCP (with Null frame delimiter and Enable TLS)

> Withing more or less stable network (which is most likely) I would recommend using the "udp" adapter.
I would also recommend it for an average to high-loaded project.
For sensitive information tcp-tls adapter is recommended.

Configuration

// simple
log.setConfig({adapterOptions: {host: 'my.glog-server.net'}});

// advanced
log.setConfig({
  fields: {facility: "example", owner: "Tom (a cat)"}, // optional; default fields for all messages
  filter: [], // optional; filters to discard a message
  transform: [], // optional; transformers for a message
  broadcast: [], // optional; listeners of a message
  levels: {}, // optional; default: see the levels section below
  aliases: {}, // optional; default: see the aliases section below
  adapterName: 'udp', // optional; currently supported "udp", "tcp" and "tcp-tls"; default: udp
  adapterOptions: { // this object is passed to the adapter.connect() method
    // common
    host: '127.0.0.1', // optional; default: 127.0.0.1
    port: 12201, // optional; default: 12201
    // ... and so on
    
    // tcp adapter example
    family: 4, // tcp only; optional; version of IP stack; default: 4
    timeout: 1000, // tcp only; optional; default: 10000 (10 sec)
    
    // udp adapter example
    protocol: 'udp4', // udp only; optional; udp adapter: udp4, udp6; default: udp4
    
    // tcp-tls adapter example
    key: fs.readFileSync('client-key.pem'), // tcp-tls only; optional; only if using the client certificate authentication
    cert: fs.readFileSync('client-cert.pem'), // tcp-tls only; optional; only if using the client certificate authentication
    ca: [fs.readFileSync('server-cert.pem')] // tcp-tls only; optional; only for the self-signed certificate
  }
});

> log.setConfig merges the data. Therefore, you can call it multiple times.

Basic functionality

var extra = {tom: 'cat', jerry: 'mouse', others: {spike: 1, tyke: 1}};

log.info("Hello world", extra, function (err, bytesSent) {});
log.info("Hello world", function (err, bytesSent) {});
log.info("Hello world", extra);
log.info("Hello world");

log.error('Oooops.', new Error('An error message'));
// ^-- extra becomes: {short_message: 'Oooops.', _error_message: 'An error message', _error_stack: Error's stack}

log.error(new Error('An error message'));
// ^-- extra becomes: {short_message: 'An error message', full_message: Error's stack}

log.message(new Error('An error message'), 3); // same as previous

Extra

In case extra is a plain object, the library converts it to a readable format. Other values are converted to string. The acceptable format of a key is: ^[\w-]$

log.info(
  'a new msg goes here',
  {me: {fname: 'k', lname: 'k', bdate: new Date(2000, 01, 01)}}
);
// ^-- extra becomes: {_me_fname: 'k', _me_lname: 'k', _me_bdate: 'Tue Feb 01 2000 00:00:00 GMT+0100 (CET)'}

Filtering

Sometimes we have to discard a message which is not suitable for the current environment. It is NOT possible to modify the data.

log.setConfig({
  filter: [
    function (message) { // rejects a "debug" message
      return (message.level < 7);
    }
  ]
});

Transforming

transforming happens after filtering. It is possible to modify the data.

log.setConfig({
  transform: [
    function (message) { // unwind an error
      if (_.isError(message.error)) {
        message.error = {message: message.error.message, stack: message.error.stack};
      }
      return message;
    }
  ]
});

Broadcasting

broadcasting happens after transforming. It is NOT possible to modify the data.

log.setConfig({
  broadcast: [
    function (message) { // broadcasting to console
      console[message.level > 3 ? 'log' : 'error'](message.short_message, message);
    }
  ]
});

Levels (1, 2, 3)

Default:
{emergency: 0, alert: 1, critical: 2, error: 3, warning: 4, notice: 5, info: 6, debug: 7}
Example: log.emergency(...), log.critical(...), etc.
Custom example: {alert: 0, notice: 1, ...}

Third party adapters

You can force using custom adapter by setting the adapter right after initialisation. The signature might be found here.

  var log = require('gelf-pro');
  var myFancyAdapter = require('...');
  log.adapter = myFancyAdapter;
  // (!) adapterName and adapterOptions will be ignored

Aliases

Default: {log: 'debug', warn: 'warning'}
Example: log.log(...) -> log.debug(...), log.warn(...) -> log.warning(...), etc.
Custom example: {red: 'alert', yellow: 'notice', ...}

Tests

Cli

npm install
npm test

Docker

[sudo] docker build --no-cache -t node-gelf-pro .
[sudo] docker run -ti --rm -v "${PWD}:/opt/app" -w "/opt/app" node-gelf-pro

Contributors

• corbinu
• joelharkes
• mkalam-alami

License

MIT