I've decided to have a play around with ruby so I've downloaded the windows one click installer. One of the options in the installer which isn't selected by default is to "Enable RubyGems" which automatically enables RubyGems by pre-appending 'rubygems' to the RUBYOPT environment variable.
Being completely new to Ruby I must admit that I have no idea what that means in terms of the impact it will have as I start developing programs in Ruby.
For one, I don't know what Ruby Gems are...but I also don't know how critical they are to ruby development. Should I just enable them by default or should I wait until I find that I definitely need them?
RubyGems or simply gems are Ruby packages or libraries that you can install and use in your Ruby programs. So you definitely will need them at some point in time and therefore you should enable them. When you will see that you need to install gem named "xxx" then you just need to run from command line:
gem install xxx
Related
In our Rails application we do require 'RRD' at some point, but that results in a cannot load such file -- RRD. So obviously I used homebrew to install rrdtool, but the error remains.
The docs at https://oss.oetiker.ch/rrdtool/prog/rrdruby.en.html provide two options:
Either:
$: << '/path/to/rrdtool/lib/ruby/1.8/i386-linux'
require "RRD"
In my /opt/homebrew/Cellar/rrdtool/1.8.0/lib directory there's no mention of ruby, which is because of the --disable-ruby-site-install flag in the formula, because when I skip that flag I do actually get something: /opt/homebrew/Cellar/rrdtool/1.8.0/lib/ruby/2.6.0/universal-darwin21. However replacing the path/to string with this path still gives the error.
Or:
If you use the --ruby-site-install configure option you can drop the $: line since the RRDtool module will be found automatically.
Which is a little confusing (and probably outdated) because here it seems that ruby site install is disabled by default and you have to enable it proactively, whereas in the formula it's actually actively disabled.
Either way: both options didn't do the trick for me and if there's a solution without homebrew that's also fine.
For good measure: I'm on macOS Monterey
TL;DR
For the most part, I'd say that using a non-standard gem without a Ruby version manager is your main issue. There are instructions on the rrdruby site for installing it, but they don't follow typical conventions, so your mileage will vary.
Some Practical Suggestions
The require keyword is for gems, not binaries. You need to have an rrdtool-related gem installed, available to your Ruby instance (usually through a Bundler Gemfile or gemspec, or via the RUBYOPTS environment variable or your in-process Ruby $LOAD_PATH), and then require the correct name of the gem in your code. For example, using the older rrd-ffi gem:
# use sudo if you're installing it to the system,
# but I would strongly recommend a ruby version
# manager instead
gem install rrd-ffi
# in your Ruby class/module file
require "rrd"
For the gem you seem to be using, you have to compile the gem first to make it usable, and then ensure it's available in your Ruby $LOAD_PATH (or other gem lookup mechanism) before trying to require it. The error message you're seeing is basically telling you that a gem with that name is not available as called within any of the standard lookup locations.
Again, I'd suggest reading the build documentation for your gem, and then seeing if you can install it as part of a Bundler bundle, RVM gemset, or other non-system approach if you can. Otherwise, follow the directions for the rrdruby tool, which is not available as a standard Rubygems.org gem, in order to make it available before trying to require it.
Beware of Outdated or Non-Standard Gems
Most of the RRD gems I found were quite old; most were 7-8 years old or older, so their compatibility with current Rubies is potentially suspect. The gem-builder you're using is newer, but doesn't seem to be designed as a standard gem, so you need to build it and install it in a suitable lookup path before it can be required. Installing gems as system gems is almost always a bad idea, so I'd strongly recommend building it from source and using a ruby version manager rather than following the rrdtool author's atypical suggestions. YMMV.
I have no knowledge in Ruby, but I need to run some tests in it. The code is in Ruby and Cucumber. I use intellij on Mac. When I first open intellij cucumber step definition where not recognised from feature file. In terminal I got:
Required ruby-2.1.2 is not installed.
To install do: 'rvm install "ruby-2.1.2"'
but
$ which ruby
/Users/myuser/.rvm/rubies/ruby-2.4.1/bin/ruby
so I run the install command as suggested and now I get
$ which ruby
/Users/myuser/.rvm/rubies/ruby-2.1.2/bin/ruby
Now my feature files connected to step definition as well. I will appreciate if anyone could explain me what happened. What prompted me to downgrade the version of Ruby and how it fixed cucumber.
Make sure you have ruby 2.1.2 set in File -> Settings -> Languages & Frameworks -> Ruby SDK and Gems
What I suspect is happening is you have run rvm use 2.1.2 in the terminal but when your IDE runs something it is using the ruby version set in the settings.
You probably have a .ruby_version file in the project root directory. This will enforce a specific version of Ruby. So the person who put it there is who to ask why the version was restricted like that. There may have been a good reason, such as that's what is being used by all your users.
It has nothing to do with Cucumber. rvm has some kind of operating system hook, I think, that runs whenever you cd into a directory. It looks for its special control fiels such as .ruby_version and .rvmrc file. This page describes this in more detail: https://rvm.io/workflow/projects.
I am in the early stages of learning Ruby and want to learn how to debug a gem, but am having trouble finding learning resources around this. A simple example would go a long way for me.
Is debugger the preferred debugger? Where do I require it? How do I set breakpoints with it?
Note: I am making an educated guess that the debugging process may be different depending on the gem that needs debugging, so for reference I am particularly interested in debugging certain issues with Compass.
OK, figured this out on my own. Here were the steps I took..
I am running Ruby 1.9.3 (determined by running ruby -v), so after testing ruby-debug and ruby-debug19, I determined these debuggers were no longer maintained, or at least didn't work properly with my install of ruby1.9.3-p125. This lead me to debugger.
The install instructions that worked were:
$ gem install debugger -- --with-ruby-include=PATH_TO_HEADERS
The PATH_TO_HEADERS on my machine, was simply the source location of ruby:
/Users/myusername/.rvm/src/ruby-1.9.3-p125/
Since I was particularly determined to debug the Compass compiler, I did the following:
Cloned the source: $ git clone git://github.com/chriseppstein/compass.git
Checked existing compass version first $ compass -v which was 13.0
Edited VERSION.yml and increased the patch number (to 13.1) so it didn't conflict with my existing install.
Edited the .rb of the file I wanted to debug, which was lib/compass/compiler.rb and added this line at the top: require 'debugger'; debugger
Built the gem: gem build compass.gemspec
Installed the newly compiled gem: sudo gem install compass-0.13.2.058ead2.gem
Compiled an existing compass based project that I was experiencing problems with, and started debugging.
When I was done debugging, I uninstalled the debugging version with sudo gem uninstall compass and chose the number corresponding to Compass 13.2.
Note about step 7: Since debugger has the same debugging commands as ruby-debug/ruby-debug19, I was able to follow existing tutorials around debugging steps..
Such as this RailsCast:
http://railscasts.com/episodes/54-debugging-with-ruby-debug
And this blog (and linked cheat sheet):
http://pivotallabs.com/users/chad/blog/articles/366-ruby-debug-in-30-seconds-we-don-t-need-no-stinkin-gui-
If you have other debugger tutorials, pointers, tips, etc, please post them.
I want my app to not be able to use any installed gems. Is there a ruby 1.9 startup parameter or way of doing this programmatically?
ruby --disable-gems
is the MRI (1.9) commandline parameter. "It prevents the addition of gem installation directories to the default load path". (The Ruby Programming Language, p. 391)
Edit 25-10-2012: Ruby core had the same idea as #rogerdpack in the comments and added the more verbose ruby --help parameter. Ruby revision!
Looking at the rubygems configuration file, I would attempt to hack out gempath or gemhome to see if you can override (instead of just append to) defaults.
If, for example, setting gempath to be empty, or to point to /dev/null, prevents using system gems, then that would be the way to go.
The main advantage to this, as I see it, is that your anti-rubygems config file can be passed to ruby 1.9 as a startup parameter (so not coded in), well documented, and checked into your repository.
All of this is, of course, disregarding that rubygems is part of ruby 1.9's standard library - so ruby may choke and die if it can't have access to its gems, depending on how much of ruby's base install requires gem functionality. YMMV.
I was wondering if there was a solution to automatically - from my ruby source code - ask Gem to install various librairies my code my require to work?
From what i read on the internet, it seems we are obliged to either use an install script that directly runs "gem install ..." commands or do it manually or some people have posted a ruby script that simply iterate over a list of dependencies and use the system command to install them.
Any other better options?
Thanks for your time.
You could use internal RubyGems commands, but that's a pain and error-prone process, especially for dependencies.
I would setup a Gemfile and use Bundler instead. http://github.com/carlhuda/bundler