I am trying to make an CLI tool with ruby.
My tool require some library in bundle (log4r, ...). So problem appear when i switch my ruby version (2.0.0 -> 2.1.2) or when switch gemset, some gem are not install in new ruby environment.
So how can i make my app work like vagrant, which work in every version of ruby i am using?
If you package your application as a Gem, you can include a Gemspec that describes your application. One of the things you can specify is its runtime dependencies; when the user runs gem install myapp, then the gem command will make sure it includes everything you specified (like log4r).
It will be harder to make this happen without Rubygems. You can package your application along with a defined version of Ruby and all its requirements - that's what Vagrant does - but that makes your application a larger download and means you have more to maintain. It's going to be hard work if you want to install your app system-wide and have it work with every single Ruby environment. It's far better to let the gem application install your app (whether systemwide, or via rbenv/rvm) and let that manage your dependencies for you. There's the default gems plugin for rbenv and rvm gemsets to help manage this.
Related
I'm learning ruby recently and I'm a front-end developer, I found the dependecies are installed to C:/Ruby31-x64/lib/ruby/gems/3.1.0 folder when I use bundle install. it seems dependencies are installed globally by default like the npm install -g. I know that Bundler also have a way to install the gems to the local folder, so I wonder is
it recommend to install the dependencies to the local folder like npm does?
Similar to Composer, Bundler takes care of maintaining your dependencies, but rather than installing everything in the project folder, it distributes your gems system-wide, which are then shared by all of your projects. Using the Gemfile in your project folder, it keeps track of which libraries each project needs. Bundler is the default package manager for Rails, so you should simply let it do its thing. It does it quite well.
Hope this helps.
Use a Version Manager for Ruby, and Bundler for Gem Version Management
There are occasionally reasons to install gems in from one another isolation, but most often you should use a Ruby version manager to manage your non-system Rubies and Bundler to handle multiple gem versions and locations. Avoid modifying your system Ruby or its gems whenever possible. Also, be aware that even using RVM gemsets (or similar features in other version managers) without tweaking some poorly documented features like rvm gemset globalcache enable can create a level of isolation that is likely unnecessary and can bloat disk usage dramatically.
If You Need Gem Isolation...
That said, if you want to ensure you are isolating your gems or localizing them to your application and aren't using direnv's Ruby layout to manage all the various environment variables involved, you can use Bundler's BUNDLE_PATH environment variable to "vendor" your gems into the local application directory (these days usually under vendor/bundle). For deployments or containerization, you can also invoke bundle-install with the --deployment or --standalone flags and a list of gem groups to install if you don't want to rely on the availability of Bundler itself after installing the gems.
This sort of thing might be useful for building containers or tarballs, but isn't really very useful for development. Don't do it unless you have a really strong reason.
I am writing a dev command-line tool gem (let's say called "tool") which I would like to use in any place in the system. I use RVM for different projects, but this tool should be available from the command-line inside those projects.
If I simply install the gem globally using "gem install" (let's say it installs to /usr/local/bin/tool), the executable is of course available inside of other projects, but since the gemset changed when executing "tool" it fails saying that it cannot find the "tool" gem (because "tool" was never installed to that gemset). I don't want to add the gem to all the Gemfiles of all the projects.
What's the best way of dealing with this? Perhaps there is a way to "lock" the gem_path/gem_home in the executable at the time of installation?
It turned out that https://github.com/sportngin/brew-gem does what I want, installing a Rubygems gem via brew and locking its GEM_HOME and GEM_PATH in a bin wrapper it generates, so that everything works even when executed in the context of a different RVM gemset.
I forked it into https://github.com/gtmax/brew-gem, adding support for installing a brew gem from a local.gem file or from a gem project on github.
When trying to install a ruby app via bundler, how does your system decide which version of Ruby to use?
Will I run into problems if i use a version of Ruby installed in a directory I do not have access to? If so, how do I ensure I use a version of Ruby installed in the correct directory.
For those voting to close, I am not looking for debugging help. I am looking for an understanding of how bundler decides which version of Ruby to use.
If your app has a Gemfile (most will) you can specify ruby version on Gemfile.
See this question Set ruby version in Gemfile
I am new to Ruby but I really enjoyed it.
I used Aptana Studio 3 as an IDE, but I feel it lacks support (even though I installed the undle). When I created a Ruby project, there were no files inside it.
I added a test.rb file and started playing with it.
Now I hav a simple project in which I needed to install some gems. To do so I opened the CMD, navigated to my project's folder and issued the command "gem install xxxx". On my test.rb I include the gems using require 'xxxx'.
What is the best practice to add gems?
If I ever wanted to deploy this application, I would need to add the gems to my production server. Is there any way I can list the required gems so that the server intalls it automatically when I run deploy the application?
thanks!
Put them in a Gemfile, it is used to manage the gem required by an application.
http://bundler.io/v1.3/gemfile.html
It might depend on where you are deploying to but I like to use Capistrano for deployment. Capistrano will install the gems for you by running bundler which reads your Gemfile.
Also checkout bundler. It will read your Gemfile (create one if you don't have one). To install your gems it is as simple as:
$ bundle install
I am not sure what the differences are between these two tools. There seems to be a big overlap, but I have been using RVM and facing some miss-compatibility issues.
What does Bundler do that RVM does not?
They serve different purposes. RVM creates a sandbox to manage your Ruby installations. As a part of that, it also lets you define gemsets.
Bundler doesn't manage your Rubies, it works with the currently selected Ruby.
So, I think you should consider RVM as the configuration manager for your development environment, and Bundler the gem manager for an application.
EDIT: Additional thoughts -
Whether we use RVM or not, typically we'd have to load all the gems we're going to use for an app by hand, using gem install blah, for every gem we want to use.
I end up managing my gems across multiple Rubies by hand. Once they're installed I can create gemsets using RVM, but RVM won't automatically retrieve a particular version of a gem if it's not installed, or go get it again if it was removed. Because RVM is more concerned with your Ruby environment, it mostly leaves the versioning of gems to gem and to us.
Bundler, on the other hand, does care about those missing parts in RVM. When you create the Gemfile for bundler, it will retrieve the necessary gems and specific versions if specified. So, the task of installing a Ruby app on a different machine becomes much simpler. Push the files to the other machine, then run bundle install and it'll do the rest.
It works nicely with Rails and is a sensible solution for my production files. It will be much simpler than how I have to handle Perl distributions in order to run Perl apps on the same hosts.
RVM is more like a containment unit. While Bundler is like a manifest (dependency manager) of what the application will require or use in it's lifecycle (among other things).
If you are working in Rails, you will not be able to escape Bundler. But I use it all the time just so I know what Gems I'll need, and so will others who later come into the project.
RVM helps me separate out my Rubies and then further into Rubies/projects. This way I don't have a slew of Gems and different versions all in one pile.
Not exactly the most action packed answer, but hope it helps a little.
To directly answer your question...
What does Bundler do that RVM does
not?
Bunlder will install all gems that are needed by a project (that uses bundler, and have all needed gems specified in a Gemfile). RVM does not do this.
Using the Gemfile you can specify what gem groups (ie: development, testing)...
There are many 'small' things like these that bundler does but RVM does not. In general as the good people above explained, RVM has a different set of goals from that of bundler. RVMs about managing ruby runtimes while bundler is about managing dependent gems for a application.
Bundler is a tool for managing dependencies in your code -- i.e., all the gems it requires. It will make sure that all the gems you specify in your Gemfile, and any dependencies, are installed on your system. It doesn't really care which version of ruby you are using, it just installs the gems for you under whichever interpreter is in use.
RVM is a tool for running multiple rubies, and in theory, multiple gemsets as well. It doesn't handle dependencies for you at all -- it's still up to you to install the gems.
My experience (and I'm new to RVM), is that you don't want to bother with RVM unless you have a need for running multiple rubies, or need gems installed for different projects that somehow conflict with each other. Even if you are using RVM, it makes sense to use Bundler to manage gem dependencies so that your Gemfile can be tracked in whatever code repository you are using.