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Scatter "log!" calls in your Rails app to make debugging and timing easy
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Logbang provides log!, which is Rails.logger.debug on steroids.

Logbang allows you to scatter log! calls throughout your Rails application (views, controller, helpers) and appends the message to the logs in a pretty, coloured format.

It also keeps track of the timing information, and generates a timing table at the end of the request showing the time between calls, and unique tokens you can use to jump directly to the relevant position in the logs.

It is useful for any kind of debugging where navigating full stack traces is hard, or where you are hunting performance issues and want to selectively drill down into pieces of your code, rather than profile the entire execution.

It's also great for wrapping around a piece of functionality to be able to pinpoint which SQL queries are related.


Add this line to your application's Gemfile:

gem 'logbang'

And then execute:

$ bundle

Or install it yourself as:

$ gem install logbang


Simply call log! (with a message or without) anywhere that is called in the context of +ActionController::Base+ (controller, views, helpers).

It will create log entries that look like this:

 = Marked: container-start - 4380ee5

They'll be bright yellow, so you can't miss them!

At the end of a successful request, a table with timing information will be output :

 = 56e83ce @     0ms (+    0ms)  /app/views/agreements/index.html.erb
 = 8933225 @   391ms (+  391ms)    helper-start
 = 8dc03cc @   444ms (+   53ms)    helper-end
 = 4380ee5 @   625ms (+  180ms)  container-start
 = bcec099 @   694ms (+   69ms)  container-end

Note that the random ID in the first column of the table match up with the individual log lines so as that you can easily find them. They change every request so the chances of having multiple matches is reduced.

The second column shows the time since the first call to log!, and the third column is the delta from the previous log entry. Both these values are incredibly helpful when you're hunting of debugging performance issues, or testing optimisations.

Where possible, logbang will indent subsequent calls to log when it can work out that they are nested. Currently this is fairly naive, and can only make the match when the files are the direct caller (eg. a view calling a helper, or a helper calling another helper).


  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Added some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request
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