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how does bundler
work, anyway?
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how does bundler
work, anyway?
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a brief (?) history of
dependency management
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André Arko
@indirect
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let’s share
ruby code
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Gemfile
gem “foo”
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Terminal
$ bundle install
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Terminal
$ bundle exec foo
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done!
pretty cool, right?
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but…
what just
happened?
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iiiiit’s
History ⚔ Time
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1994 2000 2003 2009
dependency timeline
require setup.rb RubyGems Bundler
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require
it loads the codes
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def require(filename)
eval File.read(filename)
end
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i’m sure it’s fine
run code twice?
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$LOADED_FEATURES = []
def require(filename)
if $LOADED_FEATURES.include?(filename)
return true
end
eval File.read(filename)
$LOADED_FEATURES << filename
end
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probably fine too
only absolute paths?
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$LOAD_PATH = []
def require(filename)
full_path = $LOAD_PATH.first do |path|
File.exist?(File.join(path, filename))
end
eval File.read(full_path)
end
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load paths are
⛄ pretty ❄ cool
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but now we need…
setup.rb
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how do setup.rb?
ruby setup.rb setup
ruby setup.rb config
ruby setup.rb install
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use ruby libraries
1. Find a cool library
2. Download the library
3. Untar the library
4. Run `ruby setup.rb all`
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no versions
no uninstall
but it’s fine, I’m sure
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maybe a little bit
incredibly tedious
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what if you could…
gem install
gem uninstall
gem list rails
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bonus round!
gem install rails -v 4.1
gem install rails -v 4.2
gem install rails -v 5.0
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gem "rack", "1.0"
require "rack"
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$ rackup _1.2.2_ -p 3000
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so many gems!
100,000 gems
1,000,000 versions
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but gem apps don’t
play well with others
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welcome to the team
here’s your machine
we expect setting up
to take a week
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# config/application.rb
[…]
config.gem “rack”
config.gem “rails”
config.gem “what?”
[…]
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“why is this broken in production?”
“dunno, it works on every developer machine”
3 days of debugging later…
“oh, look, one production server has frobnitz
1.1.3, but the others have 1.1.4”
“welp. that explains those exceptions ”
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version conflicts
gem install rails
rails s
cd ../other-project
rails s
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activation errors
how common can
they be, really?
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$ rails s
Gem::LoadError: can't activate
rack (~> 1.0.0., runtime) for
["actionpack-2.3.5"], already
activated rack-1.1.0 for
["thin-1.2.7"]
activation errors
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the moral
runtime resolution
install-time resolution
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wait…
how do we resolve
at install-time?
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addressable (2.3.7)
arel (6.0.0)
bcrypt (3.1.10)
binding_of_caller (0.7.2)
debug_inspector (>= 0.0.1)
builder (3.2.2)
byebug (3.5.1)
columnize (~> 0.8)
debugger-linecache (~> 1.2)
slop (~> 3.6)
celluloid (0.16.0)
Gemfile.lock
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bundle install
my old friend
1. Read the Gemfile (and lock, if it's there)
2. Ask RubyGems.org for a list of every gem we need
2. Find gems allowed by the Gemfile that work together
3. Write down those versions in the lock for future installs
4. Install gems until every locked gem is installed
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bundle exec
everyone’s nemesis
1. Read the Gemfile (and lock, if it's there)
2a. Use locked gems if possible OR
2b. Find versions that work to put in the lock
3. Remove any existing gems the $LOAD_PATH
4. Add each gem in the lock to the $LOAD_PATH
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pro tip
no more bundle exec!
$ bundle binstubs rspec-core
$ bin/rspec
repeat as needed for other gems
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was that the end?
in a word, no.
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or if you’re too busy,
fund this work.
http://rubytogether.org/join