Using Bumbler to reduce runtime dependencies
A few weeks ago, I found an interesting project called
Bumbler . If your project uses Bundler,
Bumbler shows you your project’s largest dependencies.
When you find yourself staring at the screen after running
bundle exec rails c, you may want to give this tool a try.
Using it is simple. Add gem 'bumbler' to your Gemfile under the development
group, run bundle, and you’re good to go.
When you run bundle exec bumbler you will see a progress bar and a detail of
the dependencies which took the longest to load.
Here’s an example of a project’s development dependencies:
➜ git:(master) ✗ bundle exec bumbler
[################################################# ]
(49/65) travis-lint...
Slow requires:
110.21 render_anywhere
147.33 nokogiri
173.83 haml
179.62 sass-rails
205.04 delayed_job_active_record
286.76 rails
289.36 mail
291.98 capistrano
326.05 delayed_job
414.27 pry
852.13 salesforce_bulk_api
As you can see, one of the gems takes almost 1 second to load on my system,
and removing it decreases the time it takes for bundle exec rails c to load
by 1 second. It’s not a lot, but consider every Rake task you run which depends
on the environment will take 1 less second to get started.
After we get rid of salesforce_bulk_api and render_anywhere and manually
call require on them when needed, the load time looks like this:
➜ git:(master) ✗ bundle exec bumbler
[################################################# ]
(47/65) fog-aws...
Slow requires:
167.50 sass-rails
188.87 nokogiri
218.49 haml
230.10 capistrano
253.77 delayed_job_active_record
284.26 mail
320.19 delayed_job
365.67 pry
464.09 rails
Your tests can also benefit from this, as you may find gems that you do not need to have in the test environment. Capistrano is one example, usually you want to have it load only in development, not in test nor production.
One caveat worth mentioning: you need to take a close look at your loaded gem’s
dependencies when removing them. For example, capistrano depends on
net-ssh and net-scp. If you remove capistrano from test or
production, you won’t be able to use Net::SSH or Net::SCP unless you
manually add the net-ssh and net-scp dependencies back in your Gemfile, as
you were relying on them implicitly via Capistrano.