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Logster is an embedded Ruby "exception reporting service" admins can view on live websites, at http://example.com/logs



Play with a live demo at logster.info/logs.


Add these lines to your application's Gemfile:

gem 'redis'
gem 'logster'

And then execute:

$ bundle

Make logster web available add the following to your routes.rb:

constraints lambda { |req| req.session["admin"] } do
  mount Logster::Web => "/logs"

By default, logster will only run in development and production environments.

To run logster in other environments, in config/application.rb

Logster.set_environments([:development, :staging, :production])

Tracking Error Rate

Logster allows you to register a callback when the rate of errors has exceeded a given limit.

Tracking buckets available are one minute and an hour.


Logster.register_rate_limit_per_minute(Logger::WARN, 60) do |rate|
  puts "O no! The error rate is now #{rate} errors/min"

Logster.register_rate_limit_per_hour([Logger::WARN, Logger::ERROR, Logger::FATAL], 60) do |rate|
  puts "O no! The error rate is now #{rate} errors/hour"


If you are seeing the error No such middleware to insert before: ActionDispatch::DebugExceptions after installing logster, then you are using a conflicting gem like better_errors.

To avoid this error, make sure logster is added behind those conflicting gems in your Gemfile.

Mount using warden (devise)

  admin_constraint = lambda do |request|
    request.env['warden'].authenticate? and request.env['warden'].user.admin?

  constraints admin_constraint do
    mount Logster::Web, at: "/logs"

Out of the box, logster will use the default redis connection, to customise, in config/application.rb

Logster.store = Logster::RedisStore.new(redis_connection)

Heroku Deployment

In case you may be using the rails_12factor gem in a production deployment on Heroku, the standard Rails.logger will not cooperate properly with Logster. Extend Rails.logger in your config/application.rb or config/initializers/logster.rb with:

if Rails.env.production?


Logster UI is built using Ember.js


  1. Fork it ( https://github.com/discourse/logster/fork )
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create a new Pull Request


  • 2016-03-22: Version 1.2.1

    • Feature: Add method to retrieve current rate from rate limiters.
    • Feature: Make RedisStore#rate_limits readable.
    • Feature: Make RedisRateLimiter#callback and RedisRateLimiter#duration readable.
  • 2016-03-18: Version 1.2.0

    • Fix: Move Redis configuration into RedisStore.
    • Feature: Allow RedisStore#redis_prefix to either be a String or a Proc.
  • 2016-02-11: Version 1.1.1

    • Feature: Error rate can now be tracked in one minute and one hour buckets.
  • 2015-11-27: Version 1.0.1

    • New assets and logster logo
    • Added favicon
    • Added title
    • Use rails logger instead of invoking store
  • 2015-08-18: Version 0.9.9

    • This marks the largest release of Logster to date, it has been in production use for quite a while, hence the version bump.
    • Feature: automatically group errors in production mode, can be manually controlled via Logster.config.allow_grouping
    • Feature: automatically track application version, can be manually controlled via Logster.config.application_version
    • Feature: Font Awesome icons used throughout
    • Feature: Ember upgrade to 1.13
    • Feature: you can now "solve" a class of errors, if error has an application_version and backtrace. Once an error is solved it will no longer be reported for the "solved" application_versions
    • Feature: allow users to delete a single error
    • UX: use table for env
    • Feature: display "protected" state of message in list
    • Feature: use local times as opposed to relative times in time column
    • UX: use Google Roboto font as opposed to system fonts
    • UX: remove pointless titles from log table
    • Feature: If Logster is in a background tab only poll once every 60 seconds (as opposed to 3)
    • Fix: protect/unprotect redirected to show page
  • 2015-06-16: Version 0.8.3

    • Chained loggers now respect chain ignore
    • Add hostname and process_id to env on all messages
  • 2015-06-10: Version 0.8.2

    • Add hostname and process_id to env on all messages
  • 2015-05-01: Version 0.8.1

    • Don't crash out logging routine if redis is down or stderr is closed
  • 2015-04-16: Version 0.8.0

    • Improve formatting of /show page
    • Big version bump cause it is quite stable
  • 2015-02-27: Version 0.1.7

    • Fix invalid request on ?test
  • 2014-08-05: Version 0.1.3

    • Automatically include ignore filter
  • 2014-08-13: Version 0.1.6

    • Simplify install process
    • Fix crash on 404 in /logs dir
  • 2014-08-10: Version 0.1.5

    • Fix crash in Rails 3
  • 2014-08-08: Version 0.1.4

    • Fix crash in ignore filter
  • 2014-07-17: Version 0.1.1

    • Refactored report method into base_store.rb - will be easier to make a new log store
    • Add link in UI to clear all (non-protected) logs
    • Add example of submitting logs from Sidekiq jobs
    • Show Protect/Share links on all tabs
    • Render hashes provided via Logster.add_to_env
  • 2014-07-04: Version 0.0.12

    • Feature: Able to share logs, at /logs/show/(hexdigits)
    • Add protecting logs, so they aren't deleted when old (for use with sharing)
    • Restructured Redis data model
  • 2014-05-24: Version 0.0.10

    • Correct context for error reporting
    • Clean up backtraces of reported exceptions
  • 2014-05-13: Version 0.0.9

    • Stray debugger message removed, add window.location logging to js
  • 2014-05-13: Version 0.0.8

    • Fix pacakging binstubs by mistake
  • 2014-05-13: Version 0.0.7

    • Add support for javascript exception logging
  • 2014-05-12: Version 0.0.6

    • Add referer to env
  • 2014-05-12: Version 0.0.5

    • Feature: We now log basic rack environment with the messages
    • Add your own with Logster.add_to_env(env, key, value)
  • 2014-05-07: Version 0.0.4

    • Feature: Ability to ignore patterns with Logster.store.ignore = [/regex/]
    • Feature: Store backtraces, allow people to view them in the GUI
  • 2014-05-07: Started changelog :)

    • Report params in env tab