I'm a newbie, but I have a question regarding managing different versions of a gem, in my case, zurb-foundation. A new version just came out and I did a gem update and it made my older versions of the framework no longer compile.
My project contains a config.rb file that starts with
require 'zurb-foundation'
How does Ruby know to use the latest version of this? Is there a symlink somewhere pointing to the latest version? If so, I was thinking I could just re-write this symlink depending on which project I'm currently working in.
If you have multiple projects that use different versions of a gem you probably want to have a look at Bundler.
http://gembundler.com/
Bundler makes managing Ruby gems a breeze. This is highly recommended!
You should use RVM to manage multiple versions of ruby and gems.
Visit followings links to have an idea of rvm and to install.
https://rvm.io/
https://rvm.io/rvm/install/
Related
I've recently replaced an aging Mac with a new one, and so I am setting up my new environment. I installed ruby using rbenv, and have installed many gems already, but one, won't seem to install due to this error:
rdoc's executable "rdoc" conflicts with /Users/username/.rbenv/versions/2.1.2/bin/rdoc
Overwrite the executable? [yN] N
It's refinerycms of which I've built a production site on and am fairly familiar with. I thought I'd start looking at rbenv first and then look into the actual gem (not much here https://rubygems.org/gems/refinerycms that was of any help, but I'll reach out to their awesome devs next)...I was trying to see what version the refinerycms gem was using.
I appreciate any help!
Thank you, everyone,
Dinos
Try prepending yes |. This is unlikely to solve the problem but you might also wanna take a look at this issue on github where people are trying to solve the same problem:
Conflict when installing gems that have default versions
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I am new to Ruby and trying to wrap my head around following concepts: bundler vs RVM vs gems vs RubyGems vs gemsets vs system rub and I'm confused.
Can someone please describe a 'best practice' of how I should manage all this on a fresh install of the latest version of Ubuntu? What should I install, and how should I use it all?
I'm guessing that doing a sudo apt-get install ruby is not be recommended, but I am not sure. I tried it on my system in addition to 'all the other Ruby stuff'. It's just adding to my confusion. I am not talking about Rails but just regular Ruby gems (e.g. Vagrant, Chef, scripts).
As per the previous answer, this is quite a lot to cover, so consider this a short introduction.
gems are the way Ruby libraries are packaged. They are to Ruby what jars are to Java. Inside a gem file, you find Ruby code (.rb files), but also tests, and a special file giving information on the gem itself, such as its name, dependencies and version (gemspec). Any Ruby project can define the gems it needs via a Gemfile that just need to declare dependencies. Rubygems is the name of the package manager - the tool used to install the packages (while the gems are the packages themselves). Rubygems is now part of Ruby.
Bundler is what makes managing gems bearable. Based on your Gemfile, a simple call to bundler using bundle install will download and install all the required gems. Using standard gem command, you would have to install each of them manually, using gem install <gem_name>. Bundler is not part of Ruby (it is itself packaged as a gem), but it a "de facto standard" for most applications (you will not find many people not using it, and no good reasons not to use it, actually).
RVM is a tool allowing you to install multiple versions of Ruby on a machine, switching between them when needed. This can be used to install both a Ruby 1.8 and 1.9, or even a "MRI" (Matz's Ruby, the default implementation) and alternatives (such as JRuby or Rubinius). Note that RVM is not alone in this field, see for instance rbenv.
A gemset in RVM is a set of gems specific to a given context, typically a project. This is useful if you are for example developing different applications, each with its own sets of gems, and want to keep them separate.
system Ruby is, when using RVM, the Ruby version installed on the machine (ie, not via RVM).
If you are just starting, gems and bundler are of interest to you. You can let RVM and gemsets aside for now.
You're asking for more information in one question than is in-scope for Stack Overflow. To cover it all would take a book.
On Ubuntu it's easy to install and remove gems to the "system" version of Ruby, so get used to installing and removing regular gems via sudo. (On Mac OS I'd give different advice because Apple bundles Ruby for their own use and it's not a great idea to mess with it.) Then, when you have an idea how the whole gem idea works, and you know you want multiple Ruby versions on your system, try "rbenv" or "RVM" and install a version or two in your sandbox.
Linux makes it easy to add/remove Ruby via a distribution, but we're limited to the versions the distro maintainers have packaged, so I usually install from source. But, that's a pain when managing several versions of Ruby for development, test and production systems, which is why rbenv and RVM were invented -- they handle the dirty detail allowing us to concentrate on programming.
I've used both rbenv and RVM, and have been using rbenv for the last six months or so, with good results. It's less complicated than RVM which I like. In either case they make it easy to have different versions installed, with separate sets of Gems. You can have different Ruby versions open in different terminal windows if you want, making it easy to test for compatibility.
Rule one when debugging is to make changes one at a time, which is true for learning to program or learning a new language. Don't be distracted, just keep it simple.
I'm using RVM to manage my local Ruby installations, and Bundler for application dependency management.
Some people recommend using a separate RVM gemset for each application, while some seem to think that's not necessary.
So what are the advantages of using a separate RVM gemset for each application, when I'm using Bundler anyway? What are the risks of not doing so?
i use gemsets in addition to bundler because of the following:
easy to just drop everything once a while (i like messing around with my installed gems)
no need to call bundle exec (this is obsolete with binstubs)
faster loading, because less gem-specs need to be parsed
easy to distribute (copy it to your mates)
there are probably more reasons to use them, but i generally like the idea of sandboxes!
I've found that it's useful to have rvm if you're using rails 2. RVM is great if you need to work on an app that has old code. Rails 2 doesn't use a Gemfile, so bundle exec doesn't work. RVM makes it easy to keep the gem versions correct for that project, and they you can switch back to newer versions of rails and use the Gemfile to specify versions. If you have multiple apps that use different gem versions, but the same version of ruby, it's convenient to share most of the gems, and specify them in the Gemfile where they differ.
I think it's kind of case dependent. If you find that there are tons of version issues between two apps, and constantly modifying Gemfiles to keep them straight is annoying, then use separate gemsets. If there is enough in common, it might make sense to just use the same gemset
RVM gemsets allow you to separate gems without loading bundler - which is faster, it will be simpler to load the gems.
You should be using gemsets to just separate projects from your helper gems (like gist).
But if you decide that gemsets are of no help for you you can tell RVM to ignore gemsets totally:
echo "export rvm_ignore_gemsets_flag=1" >> ~/.rvmrc
Might I also refer you to the 'globalcache' documentation in the form of an rvm-test located at fast/globalcache_comment_test.sh in conjunction with your projects' Gemfile.
This will also cut down on the network traffic to rubygems.org. Initial loadout of global, not withstanding.
So, I've created a separate rvm gemset for each of my rails projects. They both use the same version of ruby 1.9.3.
This causes bundle install to completely install a fresh set of gems for both projects. It doesn't matter if the other project has the exact same version of the gem installed in the other gemset. I'm guessing this is the expected behavior to me but it seems like an inefficient use of hard drive space and bandwidth.
I know that I could manually move some of those gems to a global gemset, but that seems tedious to me and also prone to breaking if my dependencies change for a particular project.
Is there a better way to organize things, or have rvm auto detect when a gem version is already installed and just use that copy?
Or is there a better alternative to RVM that I should be using.
This is by design. Gemsets allow you to completely isolate the libraries used so you don't have any accidental interaction between projects. If you don't need the isolate you can just use an interpreter without a gemset:
rvm use 1.9.3
If there are a few gems you use across all projects, just switch to the global gemset for the interpreter:
rvm use 1.9.3#global
gem install the common gems and then they won't be re-installed per-project anymore when you are in a gemset.
While gemsets definitely aren't efficient in terms of bandwidth or HD space, they are extremely handy because you can easily blow away all dependencies for a project and re-bundle from scratch any time you want to. They also completely eliminate accidentally changing versions of your dependencies. If you don't like gemsets, correctly specifying versions in your Gemfile can get you pretty far on this without them.
As far as alternatives, rbenv is the main one I'd check out.
I'm really just a beginner to ruby, so hopefully this is an easy one. I've got to the point where I'm starting to look into some of the gems that the community have put together. I decided to check out something that would help my application consume rss feeds. So, headed over to rubygems (which is where i thought people go to get these kinds of things) and searched for rss. I found this one;
http://rubygems.org/gems/simple-rss
instructions were to just install the gem with
gem install simple-rss
So far, so good. When i came to actually use the gem, the documentation I received from doing the above was a bit naff, so i searched a bit further and found the git repo;
https://github.com/cardmagic/simple-rss
The documentation there (their code examples) complain about missing methods etc. and after a bit of digging I came to the conclusion that I must have downloaded an older version of the gem than the git trunk.
So, my question is, should I be using rubygems to get the latest gems, and if not, what other resources are out there to help find the latest builds of the comminities gems?
As far as finding a good gem for a task — use Ruby Toolbox, since it also shows you how actively maintained a gem is. Here's, for example, a section on feed parsing.
If you want to get the latest gem code that hasn't been released yet, you could download the code directly from github and build the gem yourself. However, it's easier to use bundler for that. It allows you to create a Gemfile for your project looking something like the following.
gem 'simple_rss', :git => "git://github.com/cardmagic/simple-rss.git"
Then run bundle command to download and build these gems from their corresponding sources.
In general, bundler is a great solution for managing gem dependencies for any ruby project. It provides ways to quickly reference any released gems, automatically builds gems directly from a git source, git refs, or paths on your filesystem, and has other convenient features.
By far the best place for all things Ruby & Ruby on Rails for the devs is the Ruby Toolbox