February 2014



Live Project

Gem Version Build Status Code Climate

sugarcane screenshot

It's best to get beat with something sweet...

Sugarcane is an enhancement of the cane code quality tool. It makes various minor changes, but most importantly, it closes the gap between the text editor and cane.

You can find the original cane project at square/cane.


  • Go straight from violations to their lines in a text editor
  • Otherwise does what cane does
  • Editors supported: sublimetext (untested), vim, gedit, nano


  • K,W, UP - up
  • J,S, DOWN - down
  • Q,X - quit
  • O, Enter, Space - open file in text editor at the violation



$ brew install ncurses


$ sudo apt-get install ncurses-dev


$ gem install sugarcane

Installation (development)

$ git clone https://github.com/rlqualls/sugarcane
$ cd sugarcane
$ bundle
$ rake install

Usage Examples

To run the default checks on all .rb files in your project, navigate to the project root and run sugarcane.

$ sugarcane

If you just want to run all checks on a specific file:

$ sugarcane -f README.md

If you want to run checks on files matching a pattern:

$ sugarcane --abc-glob '{lib,spec}/**/*.rb' --abc-max 15

Sugarcane tries to find an editor in your PATH, choosing sublime then vim first if one is available. You can specify a different editor with --editor.

$ sugarcane --editor nano
$ sugarcane --editor=gedit

NOTE: Right now, navigating to a line number relies on the convention of +<num_lines> as an argument (sublimetext is included as an exception).

Not far from the Tree

For original cane functionality, add the --report option

$ sugarcane --report

Methods exceeded maximum allowed ABC complexity (2):

  lib/sugarcane.rb  SugarCane#sample    23
  lib/sugarcane.rb  SugarCane#sample_2  17

Lines violated style requirements (2):

  lib/sugarcane.rb:20   Line length >80
  lib/sugarcane.rb:42   Trailing whitespace

Class definitions require explanatory comments on preceding line (1):
  lib/sugarcane:3  SomeClass


$ sugarcane --help
Usage: sugarcane [options]

Default options are loaded from a .sugarcane file in the current directory.

-r, --require FILE               Load a Ruby file containing user-defined checks
-c, --check CLASS                Use the given user-defined check

    --abc-glob GLOB              Glob to run ABC metrics over (default: {app,lib}/**/*.rb)
    --abc-max VALUE              Ignore methods under this complexity (default: 15)
    --abc-exclude METHOD         Exclude method from analysis (eg. Foo::Bar#method)
    --no-abc                     Disable ABC checking

    --style-glob GLOB            Glob to run style checks over (default: {app,lib,spec}/**/*.rb)
    --style-measure VALUE        Max line length (default: 80)
    --style-exclude GLOB         Exclude file or glob from style checking
    --no-style                   Disable style checking

    --doc-glob GLOB              Glob to run doc checks over (default: {app,lib}/**/*.rb)
    --doc-exclude GLOB           Exclude file or glob from documentation checking
    --no-readme                  Disable readme checking
    --no-doc                     Disable documentation checking

    --lt FILE,THRESHOLD          Check the number in FILE is < to THRESHOLD (a number or another file name)
    --lte FILE,THRESHOLD         Check the number in FILE is <= to THRESHOLD (a number or another file name)
    --eq FILE,THRESHOLD          Check the number in FILE is == to THRESHOLD (a number or another file name)
    --gte FILE,THRESHOLD         Check the number in FILE is >= to THRESHOLD (a number or another file name)
    --gt FILE,THRESHOLD          Check the number in FILE is > to THRESHOLD (a number or another file name)

-f, --all FILE                   Apply all checks to given file
    --max-violations VALUE       Max allowed violations (default: 0)
    --editor PROGRAM             Text editor to use
    --json                       Output as JSON
    --report                     Original cane output
    --parallel                   Use all processors. Slower on small projects, faster on large.
    --color                      Colorize output

-v, --version                    Show version
-h, --help                       Show this message

Configuration Files

Set default options using a .cane or .sugarcane. This is easier than telling sugarcane what editor you want to use every time.

$ cat .sugarcane
--abc-glob **/*.rb
--editor gedit

It works exactly the same as specifying the options on the command-line. Command-line arguments will override arguments specified in the configuration file. Sugarcane will ignore a .cane file if it sees a .sugarcane file.

Integrating with Rake

Sugarcane retains the ability to create rake tasks. The tasks will look for configuration files the same way running sugarcane normally does. The build will fail if the task finds more than max_violations violations which is 0 by default. Keep this in mind if using sugarcane tasks in continuous integration.

  require 'sugarcane/rake_task'

  desc "Run sugarcane to check quality metrics"

  task :default => :quality

Instead of using a configuration file, you can specify options in a block. Rescuing LoadError is a good idea, since rake -T failing is totally frustrating.

  require 'sugarcane/rake_task'

  desc "Run sugarcane to check quality metrics"
  SugarCane::RakeTask.new(:quality) do |cane|
    cane.abc_max = 10
    cane.no_style = true
    cane.max_violations = 3
    cane.abc_exclude = %w(Foo::Bar#some_method)

  task :default => :quality
rescue LoadError
  warn "sugarcane not available, quality task not provided."

If you have multiple configuration files, you can specify which one to use with SugarCane::RakeTask#canefile=. For that, the name does not matter.

Implementing your own checks

Checks must implement:

  • A class level options method that returns a hash of available options. This will be included in help output if the check is added before --help. If your check does not require any configuration, return an empty hash.
  • A one argument constructor, into which will be passed the options specified for your check.
  • A violations method that returns an array of violations.

See existing checks for guidance. Create your check in a new file:

# unhappy.rb
class UnhappyCheck < Struct.new(:opts)
  def self.options
      unhappy_file: ["File to check", default: [nil]]

  def violations
      description: "Files are unhappy",
      file:        opts.fetch(:unhappy_file),
      label:       ":("

Include your check either using command-line options:

sugarcane -r unhappy.rb --check UnhappyCheck --unhappy-file myfile

Or in your rake task:

require 'unhappy'

SugarCane::RakeTask.new(:quality) do |c|
  c.use UnhappyCheck, unhappy_file: 'myfile'


Requires MRI 1.9, since it depends on the ripper library to calculate complexity metrics. This only applies to the Ruby used to run SugarCane, not the project it is being run against. In other words, you can run Cane against your 1.8 or JRuby project.


Make a new github issue.