Querly - Pattern Based Checking Tool for Ruby
Querly is a query language and tool to find out method calls from Ruby programs. Define rules to check your program with patterns to find out bad pieces. Querly finds out matching pieces from your program.
Your project may have many local rules:
- Should not use
Customer#update_mailand use 30x faster
#update_mailis left just for existing code, but new code should not use it)
- Should not use
- Should not use
Net::HTTPfor Web API calls, but use
These local rule violations will be found during code review. Reviewers will ask commiter to revise; commiter will fix; fine. Really? It is boring and time-consuming. We need some automation!
However, that rules cannot be the standard. They make sense only in your project. Okay, start writing a plug-in for RuboCop? (or other checking tools)
Instead of writing RuboCop plug-in, just define a Querly rule in a few lines of YAML.
rules: - id: my_project.use_faster_email_update pattern: update_mail message: When updating Customer#email, newly written code should use 30x faster Customer.update_all_email justification: - When you are editing old code (it should be refactored...) - You are sure updating only small number of customers, and performance does not matter - id: my_project.root_url_without_locale pattern: "root_url(!locale: _)" message: Links to top page should be with locale parameter - id: my_project.net_http pattern: Net::HTTP message: Use HTTPClient to make HTTP request
Write down your local rules, and let Querly check conformance with them. Focus on spec, design, UX, and other important things during code review!
Install via RubyGems.
$ gem install querly
Or you can put it in your Gemfile.
Copy the following YAML and paste as
querly.yml in your project's repo.
rules: - id: sample.debug_print pattern: - self.p - self.pp message: Delete debug print
querly in the repo.
$ querly check .
If your code contains
pp calls, querly will print warning messages.
./app/models/account.rb:44:10 p(account.id) Delete debug print ./app/controllers/accounts_controller.rb:17:2 pp params: params Delete debug print
See the following manual for configuration and query language reference.
querly console command to test patterns interactively.
import section in config file now allows accepts
import: - require: querly/rules/sample - require: your_library/querly/rules
Querly ships with
querly/rules/sample rule set. Check
rules/sample.yml for detail.
Publishing Gems with Querly Rules
Querly.load_rule API to allow publishing your rules as part of Ruby library.
Put rules YAML file in your gem, and add Ruby script in some directory like
Querly.load_rules File.join(__dir__, relative_path_to_yaml_file)
Querly's analysis is syntactic
The analysis is currently purely syntactic:
x = false record.save(validate: x)
will yield different results. This can be improved by doing very primitive data flow analysis, and I'm planning to do that.
Too many false positives!
The analysis itself does not have very good precision. There will be many false positives, and querly warning free code does not make much sense.
- TODO: support to ignore warnings through magic comments in code
Querly is not to ensure there is nothing wrong in the code, but just tells you code fragments you should review with special care. I believe it still improves your software development productivity.
The following is the list of updates which would make sense.
- Support for importing rule sets, and provide some good default rules
- Support for ignoring warnings
- Improve analysis precision by intra procedural data flow analysis
After checking out the repo, run
bin/setup to install dependencies. Then, run
rake test to run the tests. You can also run
bin/console for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run
bundle exec rake install. To release a new version, update the version number in
version.rb, and then run
bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the
.gem file to rubygems.org.
Bug reports and pull requests are welcome on GitHub at https://github.com/soutaro/querly.