bunyan-stream-elasticsearch

bunyan-stream-elasticsearch

A Bunyan stream for saving logs into Elasticsearch 5.x with custom write function.

Install

npm install bunyan-stream-elasticsearch

Logstash Template

By default bunyan-stream-elasticsearch will create an index with a specific mapping template for your indexPattern. Template name will be 'template-logstash-' with default settings. If your index pattern is for example '[test-]YYYY.MM.DD[-pattern]', template name will be 'template-test--pattern'. Each time node app is starting, template is overwrite. You can disabled it via option template:false or overwrite it via template:{es template}.

Custom Write function

You can add or modify elasticsearch document providing a write(entry) callback option. This allow a fine tuning on how document will be defined. Do not forget to override default template if you add new fields.

Example

let bunyan = require('bunyan');
let bunyanStreamElasticsearch = require('bunyan-elasticsearch');

let writeEntryCallback = function(entry) {
   // modify entry values
   entry.myProperty = 'my value';
};

let esStream = new bunyanStreamElasticsearch({
  indexPattern: '[logstash-]YYYY.MM.DD',
  type: 'logs',
  host: 'localhost:9200',
  defaultTemplate:true,
  writeCallback : writeEntryCallback
});

// manage error case
esStream.on('error', function (err) {
  console.log('Buyan Stream Elasticsearch Error:', err.stack);
});

// Create the logger itself
let logger = bunyan.createLogger({
  name: "My Application",
  streams: [
    // default stream to console
    { stream: process.stdout },
    // and to Elasticsearch
    { stream: esStream }
  ],
  serializers: bunyan.stdSerializers
});

// start logging
logger.info('Starting application on port %d', app.get('port'));

Options

• client: Elasticsearch client. Defaults to new client created with current set of options as an argument
• type {string|function}: Elasticsearch type field. Default: 'logs'
• indexPattern {string}: Used to generate index if index option not set. Default: '[logstash-]YYYY.MM.DD'
• index {string|function}: Elasticsearch index. Defaults to index generated using index pattern
• template {json|boolean}: Elasticsearch Template to push to elasticseach at each start. if false no template will be pushed, if {...} will act as template remplacement.
• writeCallback {function} : Custom write callback to modify entry before pushing it to Elasticsearch.

Options type and index can be either a string or function. For these options, when the option is set to a function, the function is passed the log entry object as an argument