I'm developing a gem, and I need to load that gem's code into irb for testing purposes without building/publishing the gem and then installing it onto my system the traditional way via gem install <gem's name>.
To illustrate:
$ pwd
Users/me/development/gem_name/
$ irb
2.2.2 :001 > require 'gem_name'
=> true
The problem is that irb isn't loading the gem's code from my working dir because I added a method to the gem in the working dir and it's not available in the version of the gem that irb loaded above.
How can I load the version of the gem that is in the dir that I'm currently working in (i.e. the gem's dir)?
You could use require_relative to manually load the source code of your gem, for example require_relative './lib/gem_name/gem_name' assuming you have a file located at ./lib/gem_name/gem_name.rb that loads your gem. This guarantees that it is the version you have in your source code.
Related
I am trying to include the ruby-mysql gem in my ruby script. I have installed the gem using bundler but when I run bundle exec ./mysql_connector, I receive the error ./mysql_connector:4:in ``require': cannot load such file -- ruby-mysql (LoadError). Can you please help me troubleshoot what the problem is?
What I did
Installed rails in my home directory.
I do not have root access to the server so I have installed rails in my local directory by following the instructions here:
http://www.r-bloggers.com/installing-ruby-on-linux-as-a-user-other-than-root/
Created a directory for my application.
My application resides in my home directory in a folder called connector. It has a Gemfile that looks like this:
source 'https://rubygems.org'
gem 'ruby-mysql'
Call bundle install.
Using ruby-mysql 2.9.14
Using bundler 1.11.2
Bundle complete! 1 Gemfile dependency, 2 gems now installed.
Bundled gems are installed into ./vendor/bundle.
Add dependencies to my script. My script is in connector/mysql_connector and it reads:
#!/home/dcox/bin/ruby
require 'rubygems'
require 'bundler/setup'
require 'ruby-mysql'
Make script executable. I saw that you need to run bundle exec using an executable file, so I followed the instructions here to make my script executable: http://commandercoriander.net/blog/2013/02/16/making-a-ruby-script-executable/
Run the script. I execute using bundle exec mysql_connector and see:
/home/dcox/bin/mysql_connector:4:in `require': cannot load such file -- ruby-mysql (LoadError)
from /home/dcox/bin/mysql_connector:4:in `<main>'
Is it the $LOAD_PATH? After searching around for answers, I discovered a lot of SO answers as well as a blog post (https://codedecoder.wordpress.com/2013/09/23/require-and-load-in-ruby-loaderror-cannot-load-such-file/) that seem to suggest the problem is that the gem is not installed in a directory on the $LOAD_PATH. Here is what I see when I run $LOAD_PATH from IRB:
irb(main):002:0> $LOAD_PATH
=> ["/home/dcox/lib/ruby/site_ruby/2.1.0",
"/home/dcox/lib/ruby/site_ruby/2.1.0/x86_64-linux",
"/home/dcox/lib/ruby/site_ruby", "/home/dcox/lib/ruby/vendor_ruby/2.1.0",
"/home/dcox/lib/ruby/vendor_ruby/2.1.0/x86_64-linux",
"/home/dcox/lib/ruby/vendor_ruby", "/home/dcox/lib/ruby/2.1.0",
"/home/dcox/lib/ruby/2.1.0/x86_64-linux"]
Next I checked to see the location of ruby-mysql:
dcox#analytics1:~/connector$ bundle show ruby-mysql
/data/home/dcox/connector/vendor/bundle/ruby/2.1.0/gems/ruby-mysql-2.9.14
Obviously my connector/vendor/bundle path is not on the $LOAD_PATH. I could add it, but I have a feeling I am missing something simple here because bundler is supposed to work as long as you follow the instructions, right?
Any advice or help is very much appreciated! Thanks!!
If you just want to require this specific gem, require 'mysql' should work (e.g., https://github.com/tmtm/ruby-mysql/blob/master/test/test_mysql.rb#L10).
Your file should call Bundler.setup http://bundler.io/bundler_setup.html
Better yet, if you instead call Bundler.require(:default) it will setup and require all the gems in your Gemfile for you.
I use:
rvm 1.25.19 (stable)
ruby 1.9.3p545
I install gem rake command
gem install rake
I understand that $LOAD_PATH should contain the paths:
~/.rvm/rubies/ruby1.9/gems/rake/lib
~/.rvm/rubies/ruby1.9/gems/rake/bin
I execute command:
ruby -e 'puts $LOAD_PATH'
output:
/home/slip/.rvm/rubies/ruby-1.9.3-p545/lib/ruby/site_ruby/1.9.1
/home/slip/.rvm/rubies/ruby-1.9.3-p545/lib/ruby/site_ruby/1.9.1/x86_64-linux
/home/slip/.rvm/rubies/ruby-1.9.3-p545/lib/ruby/site_ruby
/home/slip/.rvm/rubies/ruby-1.9.3-p545/lib/ruby/vendor_ruby/1.9.1
/home/slip/.rvm/rubies/ruby-1.9.3-p545/lib/ruby/vendor_ruby/1.9.1/x86_64-linux
/home/slip/.rvm/rubies/ruby-1.9.3-p545/lib/ruby/vendor_ruby
/home/slip/.rvm/rubies/ruby-1.9.3-p545/lib/ruby/1.9.1
/home/slip/.rvm/rubies/ruby-1.9.3-p545/lib/ruby/1.9.1/x86_64-linux
why path to gem 'rake' don't add?
Installing a gem in Ruby doesn’t automatically add that gem’s files to the load path. When you require a file, first the existing load path is searched and if no matching file is found then Rubygems searches the installed gems for the file. If such a gem is found, then it is activated, which is when the gem’s lib directory is added to the load path.
Here’s an example using the Haml gem:
puts "Before:"
puts $LOAD_PATH
puts
require 'haml'
puts "After:"
puts $LOAD_PATH
This produces:
Before:
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/site_ruby/1.9.1
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/site_ruby/1.9.1/x86_64-darwin10.8.0
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/site_ruby
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/vendor_ruby/1.9.1
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/vendor_ruby/1.9.1/x86_64-darwin10.8.0
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/vendor_ruby
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1/x86_64-darwin10.8.0
After:
/Users/matt/.rvm/gems/ruby-1.9.3-p448/gems/tilt-1.4.1/lib
/Users/matt/.rvm/gems/ruby-1.9.3-p448/gems/haml-4.0.5/lib
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/site_ruby/1.9.1
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/site_ruby/1.9.1/x86_64-darwin10.8.0
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/site_ruby
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/vendor_ruby/1.9.1
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/vendor_ruby/1.9.1/x86_64-darwin10.8.0
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/vendor_ruby
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1/x86_64-darwin10.8.0
See how the lib directories for Tilt (which is a dependency of Haml) and Haml have been added to the start of the load path.
In the case of some gems, such as Rake, this is complicated by the fact they are part of the standard library and so are already on the load path. If you changed the example above to use require 'rake' then you wouldn’t see any change in the load path. In this situation you can specify you want to use the gem version with the gem method. This activates the gem in question, placing its lib directory at the start of the load path so when you later call require you will load the correct version.
For example, this script
require 'rake'
puts Rake::VERSION
produces 0.9.2.2 with Ruby 1.9.3, as that is the version of Rake included in the standard library. However this script:
gem 'rake'
require 'rake'
puts Rake::VERSION
produces 10.1.1, since that is the current highest version of the Rake gem installed on my system. You can also specify a particular gem version by providing a second argument to gem (this is the same syntax as used in Gemfiles). Note that the gem method doesn’t require any files, you have to do that as a separate step.
awesome_print looks like a pretty nice gem, so I wanted to try it out.
I went to one of my projects and did:
gem install awesome_print
and it says one gem installed, documentation installed, etc.
Then, while I am in that project, I went to my Rails console to try it out, but when I did a require "awesome_print" as their help file says, I get a "cannot load such file".
Has anyone got this to work?
gem install will put the gem code on your computer, but unless the gem's source code files are on your load path, require won't be able to find them. bundle exec looks at the nearest Gemfile.lock and adds the source code for all the gems listed there to your load path. Rails initialization includes getting Bundler to do this for you.
One solution is to add awesome_print to your Gemfile. However, this will cause your application to have awesome_print as a dependency. Alternatively you can manually add the awesome_print library to your load path after starting up the Rails console and then requiring it:
$ rails c
> $LOAD_PATH << path/to/awesome_print-x.x.x/lib
> require 'awesome_print'
> ap {foo: {bar: {baz: :qux}}}
If you're using RVM, the path is likely to be something like:
~/.rvm/rubies/ruby-x.x.x-pxxx#your_gemset_name/gems/awesome_print-x.x.x/lib
Add it to your Gemfile like this:
gem 'awesome_print', :require => 'ap'
I add it to the development group, since that's the only time I need it. The gem doesn't have any other gem dependencies, so I routinely add it to my Gemfile.
Also, add these two lines to your ~/.irbrc file to set ap to be your default pager:
require "awesome_print"
AwesomePrint.irb!
Note that if you use this, however, any projects where awesome_print is not installed in its Gemfile will raise this error when you run rails c:
cannot load such file -- awesome_print
Depending on whatever else you may have in your ~/.irbrc file, this can cause other side effects, such as messing up your prompt. To avoid these, simply add the two lines to the very end of that file.
install it :
$ gem install awesome_print
include it in you GemFile, if you want :
gem 'awesome_print', :require => 'ap'
add this line to the file ~/.irbrc :
require 'awesome_print'
AwesomePrint.irb!
restart your shell!
just a note: I did this and it didnt work right away, probably need to restart the computer... or I just needed to close all shell tabs and open the terminal again!
Install the gem on your machine
gem install awesome_print
Get the path to which it has installed
gem which awesome_print
Add the following configuration to your ~/.irbrc and ~/.pryrc. This will load Awesome Print whenever you fire an IRB or a pry session.
*Remember $LOAD_PATH will hold whatever you got from typing gem which awesome_print
# ~/.irbc and ~/.pryrc
$LOAD_PATH << "~/.asdf/installs/ruby/2.6.3/lib/ruby/gems/2.6.0/gems/awesome_print-1.8.0/lib/"
require "awesome_print"
AwesomePrint.irb!
If you are looking to install it without having it in your Gemfile, this is how to do it:
$ gem install awesome_print
I was running into an issue where it was installing successfully but it not in the right directory.
In that case just put this in your .bashrc, this will set the load path:
export PATH="/home/user/.gem/ruby/2.3.0/bin:$PATH"
PATH="`ruby -e 'puts Gem.user_dir'`/bin:$PATH"
replace 2.3.0 with the version of ruby you are working with.
replace user with your username or if you are using vagrant then replace with vagrant
reload your .bashrc or exit the Terminal to reload changes, then install the gem again.
In my case, I struggled with PATHs and such, while missing something obvious!
# which ruby
/usr/bin/ruby
# ruby -v
ruby 2.3.7p456 (2018-03-28 revision 63024) [universal.x86_64-darwin17]
# locate bin/ruby
/usr/bin/ruby
/usr/local/Cellar/ruby/2.7.2/bin/ruby
/usr/local/opt/ruby/bin/ruby
# /usr/local/opt/ruby/bin/ruby -v
ruby 2.7.2p137 (2020-10-01 revision 5445e04352) [x86_64-darwin17]
#
Aha! Version crud. I was running an old ruby. Thanks, Apple!
# sudo mv /usr/bin/ruby /usr/bin/ruby_2.3.7
# sudo ln /usr/local/opt/ruby/bin/ruby /usr/bin/ruby
Solved the problem!
There is probably something I could have told brew to do to fix things, but I was impatient. :-)
I'm trying to use rake in my ruby script...(Ruby 1.8.6, JRuby 1.6.5)
Downloaded rake using gem install --remote rake, looks ok on install...
Fetching: rake-0.9.2.2.gem (100%)
Successfully installed rake-0.9.2.2
1 gem installed
I've got a simple ruby script which works fine, but when I import rake to using any of the following requires, it starts complaining....
require 'rake'
LoadError: no such file to load -- rake
or
require '/lib/rake'
LoadError: no such file to load -- lib/rake
After some searching, I found that adding require 'rubygems' just before rakefixes the issue....
require 'rubygems'
require 'rake'
Even though it's working, I've got some questions...
The gem spec on rake shows the require_path as lib, so why
doesn't require '/lib/rake' work? Am I misunderstanding the significance of require_path?
Why is it necessary to place require 'rubygems' before require
'rake'
Yes, you are misunderstanding the significance. The require_paths in the specification is an array of subdirectories of that gem's installation directory that should be searched for files belonging to the gem.
To find out where rake really is, try this:
$ gem which rake
You'll see that it is actually installed somewhere completely unrelated to /lib; on my system, it's under /var/lib/gems. Ruby gems, in general, live in their own directory structure; the only file in the standard Ruby include path ($:) is rubygems itself, which you used to have to explicitly require in order to make any actual gems visible. (Since Ruby 1.9, that has not been necessary.)
Gems are more complex than just libraries to load; you can have multiple versions of the same gem installed, and specify which one you want at a time, and do other things that wouldn't work if the gems were just dumped into the standard Ruby include path.
The require_path in the gemspec tells ruby where the files of this gem are located within the gem. It makes you able to type require 'rake', and ruby then knows it needs to look for /lib/rake within the gem installation folder.
In Ruby 1.8, rubygems (the mechanism responsible for making gems available to your app) is not loaded by default, and the default ruby isn't aware of any gem on your system. You need to load rubygems before being able to require any other gem. This is not the case anymore with Ruby 1.9.
Code inspection in the IntelliJ IDEA editor reports a LoadError "no such file to load" on the code
require 'state_machine'
The gem is installed locally. From the command line:
~$ echo $RUBYOPT
rubygems
~$ irb
irb(main):001:0> require 'state_machine'
=> true
So Ruby and Rubygems are playing nicely together. The IDEA Ruby plugin's project settings even lists the gem, so why can't the editor see it?
Ruby version 1.8.7, IntelliJ IDEA 10.5.4.
This gem must be specified in the Gemfile, refer to help.