Write Librato metrics to your logs with a convenient interface



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librato-logreporter provides an easy interface to write metrics ultimately bound for Librato Metrics to your logs or another IO stream. It is fully format-compliant with l2met. If you are running on Heroku it will allow you to easily insert metrics which can be retrieved via a log drain.

NOTE: Current versions of this library use the logging conventions established in l2met 2.0 and greater. For use with older versions of l2met, use v0.1 of this gem.

This library is ideally suited for custom or short-lived processes where the overhead of in-process collection will be costly and external metric collectors are unavailable.

If you are considering using librato-logreporter for a rails or rack-based web app, first explore librato-rails and/or librato-rack. In most cases one of these libraries will be a better solution for your web applications.

Currently Ruby 1.9.2+ is required.

Quick Start

Install librato-logreporter in your application:

require 'librato/logreporter'

You can now track custom metrics by adding simple one-liners to your code:

# keep counts of key events
Librato.increment 'jobs.worked'

# benchmark sections of code to verify performance
Librato.timing 'my.complicated.work' do
  # do work

# track averages across processes/jobs/requests
Librato.measure 'payload.size', payload.length_in_bytes

Installation & Configuration

Install the gem:

$ gem install librato-logreporter

Or add to your Gemfile if using bundler:

gem "librato-logreporter"

Then require it:

require 'librato-reporter'

If you don't have a Librato Metrics account already, sign up. In order to send measurements to Librato you will need to provide your account credentials to the processor for output from librato-reporter.

Environment variables

There are a few optional environment variables you may find useful:

  • LIBRATO_SOURCE - the default source to use for submitted metrics. If not set your metrics will be submitted without a source.
  • LIBRATO_PREFIX - a prefix which will be prepended to all metric names
Running on Heroku

You should specify a custom source for your app to track properly. You can set the source in your environment:

heroku config:add LIBRATO_SOURCE=myappname

NOTE: if Heroku idles your process no measurements will be sent until it receives a request and is restarted. If you see intermittent gaps in your measurements during periods of low traffic this is the most likely cause.

Silencing Output

If you would like to turn off logging to StdOut, for example, in your local environment, you can add the following after require 'librato-reporter' to send output to /dev/null:

Librato.log_reporter.log = File.open(File::NULL, "w")
Harvesting your metrics from your logs

There are few options for this which we will document further going forward. For the moment, come ask us about it.

Custom Measurements

Tracking anything that interests you is easy with Librato. There are four primary helpers available:


Use for tracking a running total of something across jobs or requests, examples:

# increment the 'jobs.completed' metric by one
Librato.increment 'jobs.completed'

# increment by five
Librato.increment 'items.purchased', :by => 5

# increment with a custom source
Librato.increment 'user.purchases', :source => user.id

Other things you might track this way: user activity, requests of a certain type or to a certain route, total jobs queued or processed, emails sent or received


Use when you want to track an average value per-measurement period. Examples:

Librato.measure 'payload.size', 212

# report from a custom source
Librato.measure 'jobs.by.user', 3, :source => job.requestor.id


Like Librato.measure this is per-period, but specialized for timing information:

Librato.timing 'twitter.lookup.time', 21.2

The block form auto-submits the time it took for its contents to execute as the measurement value:

Librato.timing 'twitter.lookup.time' do
  @twitter = Twitter.lookup(user)


There is also a grouping helper, to make managing nested metrics easier. So this:

Librato.measure 'memcached.gets', 20
Librato.measure 'memcached.sets', 2
Librato.measure 'memcached.hits', 18

Can also be written as:

Librato.group 'memcached' do |g|
  g.measure 'gets', 20
  g.measure 'sets', 2
  g.measure 'hits', 18

Symbols can be used interchangeably with strings for metric names.


  • Check out the latest master to make sure the feature hasn't been implemented or the bug hasn't been fixed yet.
  • Check out the issue tracker to make sure someone already hasn't requested it and/or contributed it.
  • Fork the project and submit a pull request from a feature or bugfix branch.
  • Please include tests. This is important so we don't break your changes unintentionally in a future version.
  • Please don't modify the gemspec, Rakefile, version, or changelog. If you do change these files, please isolate a separate commit so we can cherry-pick around it.


Copyright (c) 2013 Librato Inc. See LICENSE for details.