Talk notes

Presented to the Boulder Ruby Group February 18, 2014

http://syntacticsugar.org/rubygems/

A bit of code

pry(main)> Dir.glob("**/*").
           delete_if {|f| f =~ /^.git/ or !File.file? f}.
           map {|f| File.open(f, 'r').readlines.length }.
           inject(&:+)
=> 64606

Takes a while to read…

A better place to start: http://guides.rubygems.org/

Gem installations taking too long?

In your ~/.gemrc - if you really can’t wait:

install: --no-rdoc --no-ri
update: --no-rdoc --no-ri

But don’t do this!

Gem #1: gem server

riddochc@cassia:~> gem server
Server started at http://0.0.0.0:8808

Point browser at http://localhost:8808/

#2: Making a local mirror.

Make a place for your gems, say:

mkdir -p /srv/www/htdocs/rubygems/gems/

Copy *.gem files there.

cp ~/.gem/cache/*.gem

Then, run generate_index

riddochc@cassia:~> gem generate_index -d /srv/www/htdocs/rubygems/
Generating Marshal quick index gemspecs for 100 gems
....................................................................................................
Complete
Generated Marshal quick index gemspecs: 0.375s
Generating specs index
Generated specs index: 0.022s
Generating latest specs index
Generated latest specs index: 0.014s
Generating prerelease specs index
Generated prerelease specs index: 0.000s
Compressing indicies
Compressed indicies: 0.017s

Configure rubygems to use your local mirror

riddochc@cassia:~> gem sources --add http://localhost/rubygems/

This modifies your ~/.gemrc

---
:backtrace: false
:bulk_threshold: 1000
:sources:
- https://rubygems.org/
- http://localhost/rubygems/
:update_sources: true
:verbose: true

Note… your project’s Gemfile takes precedence. Bundler overrdes a lot of this.

#3: Some Potentially useful tools on their own

Maybe you don’t need the minitar gem after all?

#4: Hooks!

A simple example from lib/rubygems/install_message.rb:

Gem.post_install do |installer|
  ui = Gem::DefaultUserInteraction.ui
  ui.say "Successfully installed #{installer.spec.full_name}"
end

#4.5: Plugins!

http://guides.rubygems.org/plugins/

#5: Arbitrary metadata in a gem specification

There’s now a metadata field in the specification, its value is a hash.

grep metadata ~/.gem/specifications/*

Lots of potential uses with this combined with the hooks!

#6: Why is loading gems so slow?

A default from bundler. This is how bundler’s own gemspec does it, and it’s not good.

spec.files = `git ls-files -z`.split("\x0")

Every time you require gem, git ls-files runs for that gem, and its own requires.

#7: Security

Rubygems break-in, January 2013

"Nobody Cares About Signed Gems"

http://www.rubygems-openpgp-ca.org/blog/nobody-cares-about-signed-gems.html

We can do better

PGP Keysigning event?

Tony Arcieri, RubyConf 2013:

"Being Boring: A Survival Guide to Ruby Cryptography"

http://tonyarcieri.com/lets-figure-out-a-way-to-start-signing-rubygems

#8: Saving typing

Jeweler, Hoe

gem-release plugin, adds subcommands to gem:

bootstrap, gemspec, release, tag, bump

#9: Bundler?

Ruby gems 2.2.0 release, Dec. 26, 2013:

In History.txt (and in release notes):

RubyGems can check for gem dependencies files (gem.deps.rb or Gemfile) when rubygems executables are started and uses the found dependencies. This means rake will work similar to bundle exec rake. To enable this set the RUBYGEMS_GEMDEPS environment variable to the location of your dependencies file. See Gem::use_gemdeps for further details.

gem install --file Gemfile

#10: You

You & Rubygems

Thanks

Chris Riddoch riddochc@gmail.com http://syntacticsugar.org/