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

Interface

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

Installation

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"
end

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])

Configuration

Logster can be configured using Logster.config:

• Logster.config.application_version: set to a unique identifier denoting version of your app. The "solve" function takes this version into account when suppressing errors.
• Logster.config.enable_js_error_reporting : enable js error reporting from clients
• Logster.config.rate_limit_error_reporting : controls automatic 1 minute rate limiting for JS error reporting.
• Logster.config.web_title : <title> tag for logster error page.

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.

Example:

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

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"
end

Note

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 or web-console.

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

If you're using Logster with a non-rails app, you'll need to be careful that the env hashes of messages that Logster receives don't contain strings with invalid encoding because at some point Logster calls #to_json on the message env and the method will fail with JSON::GeneratorError.

The reason this doesn't happen in rails apps is because ActiveSupport has a monkey patch for #to_json.

Mount using warden (devise)

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

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

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?
    Rails.logger.extend(ActiveSupport::Logger.broadcast(Logster.logger))
end

Thanks

Logster UI is built using Ember.js

Contributing

1. Fork it ( https://github.com/discourse/logster/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Run cd client-app && npm install
4. Run bundle exec rake client_dev to start Sinatra server (port 9292) and Ember server (port 4200). Use Ember server for hot reload for client code.
5. Once you're done making changes, run ./build_client_app.sh to make and copy a production build to the assets folder.
6. Commit your changes (git commit -am 'Add some feature')
7. Push to the branch (git push origin my-new-feature)
8. Create a new Pull Request