I'm pretty new to Ruby/Rails but I was taking a look at bundler and was wondering how it works exactly. Do you install a full set of gems like normal gem install XYZand then use the Gemfile to pull a certain subset of those gems for use with a specific application? Or do you not install gems normally anymore and just include them in the Gemfile and then do a bundle install to include them all in a bundle that is then used with your application?
Thank you so much for taking the time to answer this, I'm just a little confused on what bundler's functionality is exactly.
-- MAP
These two links explain everything about bundler.
How does bundler bundle
How does bundle require gems
Think of bundler as a package management tool.
From bundle help command:
bundle install # Install the current environment to the system
bundle package # Locks and then caches all of the gems into vendor/cache
So bundle install command will install all gems to the system that are listed in Gemfile as well as their dependencies. If the gem was not previously installed it will grab it from the gemcutter repo. bundle package will cache the .gem files into your apps vendor/cache directory.
No need to run gem install first.
Related
Generally, if I need a gem, I put it in the Gemfile and bundle install. However, I don't understand if there is a benefit to downloading the gems locally first with gem install _____. Is there any benefit to this? Does bundle install no longer have to connect to the net in that situation?
Bundler installs the gems located in your Gemfile locally the same as if you ran gem install for each of those gems.
Gem install needed for gems that can be used outside of bundler applications. For example request-log-analyzer need to be installed outside of any apps for be available in command line.
I myself use gem install _______ then i use bundle install --local which doesn't require internet connection if the gem is found locally but will return an error if the gem was not found locally...
I find this method faster in downloading and installing gems, plus if the gems are found locally then i have also the benefit of altering the gemfile and install the gems without having internet connection.
I used to have a new ruby installation for each new rails project, because it's impossible not to have conflicting gems with between two of them.
I have seen that 'bundle package' command could freeze a project specific set of gems in the 'vendr/cache' directory.
I though it wouldn't install them globally, just store them in that directory.
However, when i did it, 'bundle package' ended up installing (globally) the gems before storing them in 'vendor/cache' folder.
Did I do something wrong? Is it a bug?
From the Bundler docs:
The package command will copy the .gem files for your gems in the bundle into ./vendor/cache.
As far as I can tell, Bundler does not handle installing gems, it passes that off to the gem command. What Bundler does is to make sure that you have the right version of the gem activated. So even when you package the gems, when you later install them it'll take those gems and install them "globally".
So, to answer your question: No, you didn't do anything wrong and this is not a bug but the intended behaviour.
I am trying to run an app taken off Github.
I have run bundle install to install required gems from the Gemfile. However when running the app, an error message tells me the gems installed are the wrong version.
On inspecting the Gemfile.lock I note that the versions are older than the gems installed. (i.e. I have newer versions of gems installed and the application requires older gems.)
Is there a quick way to install all the gems as per the versions described in the Gemfile.lock file? Alternatively is there a method to ignore that file?
Gemfile:
source 'http://rubygems.org'
gem 'rails', "3.0.9"
gem "sass"
..
Gemfile.lock:
sass (3.1.1)
..
In the above example, even though sass is installed the app specially requires version 3.1.1.
With a valid Gemfile.lock file, bundle install alone should be sufficient, unless some particular gem version has been yanked. In that case you would need to look for an alternative gem version that is still currently available (usually bundle update name_of_yanked_gem would suffice).
About the sass 3.1.1, it is not so much that the application requires that particular version, but rather, that was likely the newest version available when the Gemfile.lock was last generated/updated given the overall version constraints as specified in Gemfile. As you have listed, there is no version range specified for sass itself, but other gems may impose further constraints if they have sass as a dependency.
Outright ignoring Gemfile.lock is not a good idea as under normal circumstances it will be specifying the gem versions that were last known to be still usable with the application.
try this ..
bundle install --deployment
With above deployment option, bundle then reads from Gemfile.lock.
What's more, the gems are installed to directory vendor/bundle, with the bundle directory being auto created.
Also, new directory .bundle is created directly under the rails root directory, and has a file named config, whose content is as follows ...
BUNDLE_FROZEN: '1'
BUNDLE_PATH: vendor/bundle
BUNDLE_DISABLE_SHARED_GEMS: '1'
Hope the above works for you.
Make sure you're running the web server with bundle execute rails server
And, how does the system install all the gems for the application without going through the bundle install process?
Note: This question is about the process of creating a new application. Not the same question as In Rails, why there is a new Gemfile.lock when no bundle or bundle install was run? (and a new Gemfile timestamp too) .
Gemfile.lock is a snapshot of the gems and their versions created when you run bundle install. As explained in the Checking Your Code into Version Control section of the Bundler rationale:
Gemfile.lock makes your application a single package of both your own
code and the third-party code it ran the last time so you know for sure
that everything worked. Specifying exact versions of the third-party
code you depend on in your Gemfile would not provide the same
guarantee, because gems usually declare a range of versions for their
dependencies.
Gems can be installed outside of bundler by RubyGems (e.g. gem install gem_name) but it's best to use RVM which allows you to install separate versions of Ruby and manage individual gemsets for each application as explained in the RVM best practices.
When you do rails new <app>, as part of setup it runs bundle install for you.
This might sound as a strange thing to do. Is there a bundler way to extract the bundled gems (from a Gemfile or from .bundle) and install them as system gems outside of the bundler context?
Something like bundle package, but instead of caching them in vendor/cache, installs them as system gems.
The new bundler does this by default
When you run bundle install your gems are installed to your BUNDLE_PATH (which defaults to ~/.bundle.
You can pass an argument specifying where you want to install your gems to; bundle install /usr/local/lib/bundle. From the user manual, "Further bundle commands or calls to Bundler.setup or Bundler.require will remember this location".
Of course, you'll need to use sudo to install to a system directory.
Is that what you're after?