Skip to content


Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?

Latest commit


Git stats


Failed to load latest commit information.
Latest commit message
Commit time


Build Status Gem Version

Static analysis tool for checking your Ruby code for Sandi Metz' four rules.

  • 100 lines per class
  • 5 lines per method
  • 4 params per method call (and don't even try cheating with hash params)
  • 1 instance variable per controller action

CLI mode

gem install sandi_meter

sandi_meter --help
    -d, --details                    CLI mode. Show details (path, line number)
    -g, --graph                      HTML mode. Create folder, log data and output stats to HTML file.
        --json                       Output as JSON
    -l, --log                        Show syntax error and indentation log output
    -o, --output-path PATH           Path for storing generated output files (default: ./sandi_meter/)
    -p, --path PATH                  Path to folder or file to analyze
    -q, --quiet                      Do not open HTML report for graph option in browser.
    -t, --thresholds THRESHOLD       Thresholds for each rule (default: "90,90,90,90" or in config.yml)
    -r, --rules                      Show rules
    -v, --version                    Gem version
    -h, --help                       Help

cd ~/your/ruby/or/rails/project
sandi_meter -d

1. 85% of classes are under 100 lines.
2. 45% of methods are under 5 lines.
3. 99% of method calls accepted are less than 4 parameters.
4. 66% of controllers have one instance variable per action.

Classes with 100+ lines
  Class name                 | Size  | Path
  SandiMeter::Analyzer       | 219   | ./lib/sandi_meter/analyzer.rb:7
  SandiMeter::Calculator     | 172   | ./lib/sandi_meter/calculator.rb:2
  SandiMeter::HtmlGenerator  | 135   | ./lib/sandi_meter/html_generator.rb:5
  Valera                     | 109   | ./spec/test_classes/12.rb:1

Misindented classes
  Class name        | Path
  MyApp::TestClass  | ./spec/test_classes/1.rb:2
  OneLinerClass     | ./spec/test_classes/5.rb:1

Methods with 5+ lines
  Class name                          | Method name                   | Size  | Path
  SandiMeter::Analyzer                | initialize                    | 10    | ./lib/sandi_meter/analyzer.rb:10
  SandiMeter::Analyzer                | analyze                       | 13    | ./lib/sandi_meter/analyzer.rb:22

Misindented methods
  Class name        | Method name  | Path
  MyApp::TestClass  | blah         | ./spec/test_classes/1.rb:3

Method calls with 4+ arguments
  # of arguments  | Path
  5               | ./lib/sandi_meter/html_generator.rb:55
  5               | ./lib/sandi_meter/html_generator.rb:71

Controllers with 1+ instance variables
  Controller name         | Action name  | Instance variables
  AnotherUsersController  | index        | @users, @excess_variable

HTML mode

Try using gem with -g (--graph) option, so it will create a folder with beautiful html output and log file with results of any scan.

SandiMeter HTML mode pie charts SandiMeter HTML mode details

Add ignore files and folders in sandi_meter/.sandi_meter file.

Ruby script mode

require 'sandi_meter/file_scanner'
require 'pp'

scanner =
data = scanner.scan(PATH_TO_PROJECT)
pp data
# {:first_rule=>
#   {:small_classes_amount=>916,
#    :total_classes_amount=>937,
#    :misindented_classes_amount=>1},
#  :second_rule=>
#   {:small_methods_amount=>1144,
#    :total_methods_amount=>1833,
#    :misindented_methods_amount=>0},
#  :third_rule=>{:proper_method_calls=>5857, :total_method_calls=>5894},
#  :fourth_rule=>{:proper_controllers_amount=>17, :total_controllers_amount=>94}}