How to copy Ruby gem from one server to another - ruby

Is there a way for a particular ruby gem (mysql gem) to be copied from one server to another (both are similar servers)?
In my case, the other server is a production server and gem install mysql is failing to compile there as rubymysqllib is missing and can't install build dependencies there.
Basically my question is: how can I copy a gem from one server to another server?

I couldn't figure out if it is a good practice but I did this way sometimes and worked.
To copy all gems I just copied and past the folder C:\Ruby187\lib\ruby\gems\ (adapt this in accordance with your case) from one machine to another.
To copy a single gem I went inside the gemsfolder and copied the files with same name (of the gem) inside of the respective folders.
C:\Ruby187\lib\ruby\gems\1.8\cache
C:\Ruby187\lib\ruby\gems\1.8\doc*
C:\Ruby187\lib\ruby\gems\1.8\gems*
C:\Ruby187\lib\ruby\gems\1.8\specifications
#*doc and gems are optional
Another way I found, but I never did is like this.
CAUTION
When you copy the gems like this you are not verifying the dependencies and it may cause bad behavior of your application.

Related

How to automatically download .gem files, including dependencies, and save .gem's to one folder?

I work behind a firewall and I need some gems to automate some processes at work.
Problem:
Rubygems cannot automatically download gem dependencies so I have to manually download each gem from rubygems.org and install using the local copies. As you can imagine, this could take a very long time to find each gem dependency and manually download.
Ideal Solution:
I would like to automatically download all of these gems on another computer not behind a firewall, package the entire collection into one folder (no need to install, just download .gem files), and make that folder available to myself to download at work. The file just needs to contain every .gem file including dependencies.
Notes:
location: A solution in Ruby would be ideal! Remember, I can use gems on the secondary computer to create the solution for the primary computer where I cannot download gems remotely.
attempts: I have poured over documentation at rubygems.org, google searched, and more, but cannot find a solution. I can't seem to access the downloaded .gem files, they are unpacked and installed before I have a chance to incercept the file and save them elsewhere.
Bundler has a great way to do this: bundle package.
http://bundler.io/v1.2/bundle_package.html
The package command will put all your gems in the bundle into ./vendor/cache. You can then do whatever you want with that directory, such as copying it to another machine, or checking it into version control, or torrenting it. etc.

Self contained ruby "binary"?

[Ruby Noob]
I have a small (command line) utility written in Ruby, which requires a few gems. Is there a way to create a self contained bundle of my program such that I can run it on another machine that has Ruby installed (but not necessarily the gems)?
FWIW, the target machine runs Linux/Ubuntu.
You can use the gem bundle http://gembundler.com/
With bundle you create a Gemfile in your project root - a text that contains all your dependencies, very similar to Maven concept
In order to fetch all your dependencies simply tun
bundle install
The only issue is that you need to have the bundle gem itself installed, so you are back with the chicken-or-Egg problem :-)
I've used:
http://www.erikveen.dds.nl/rubyscript2exe/
before, but it was a while ago. Seemed to work okay for simple programs.
You can download it here:
http://rubyforge.org/projects/rubyscript2exe/

Should Gemfile.lock be included in .gitignore?

I'm sort of new to bundler and the files it generates. I have a copy of a git repo from GitHub that is being contributed to by many people so I was surprised to find that bundler created a file that didn't exist in the repo and wasn't in the .gitignore list.
Since I have forked it, I know adding it to the repo won't break anything for the main repo, but if I do a pull request, will it cause a problem?
Should Gemfile.lock be included in the repository?
Update for 2022 from TrinitronX
Fast-forward to 2021 and now Bundler docs [web archive] now say to commit the Gemfile.lock inside a gem... ¯_(ツ)_/¯ I guess it makes sense for developers and ease of use when starting on a project. However, now CI jobs need to be sure to remove any stray Gemfile.lock files to test against other versions.
Legacy answer ~2010
Assuming you're not writing a rubygem, Gemfile.lock should be in your repository. It's used as a snapshot of all your required gems and their dependencies. This way bundler doesn't have to recalculate all the gem dependencies each time you deploy, etc.
From cowboycoded's comment below:
If you are working on a gem, then DO NOT check in your Gemfile.lock. If you are working on a Rails app, then DO check in your Gemfile.lock.
Here's a nice article explaining what the lock file is.
The real problem happens when you are working on an open-source Rails app that needs to have a configurable database adapter. I'm developing the Rails 3 branch of Fat Free CRM.
My preference is postgres, but we want the default database to be mysql2.
In this case, Gemfile.lock still needs be checked in with the default set of gems, but I need to ignore changes that I have made to it on my machine. To accomplish this, I run:
git update-index --assume-unchanged Gemfile.lock
and to reverse:
git update-index --no-assume-unchanged Gemfile.lock
It is also useful to include something like the following code in your Gemfile. This loads the appropriate database adapter gem, based on your database.yml.
# Loads the database adapter gem based on config/database.yml (Default: mysql2)
# -----------------------------------------------------------------------------
db_gems = {"mysql2" => ["mysql2", ">= 0.2.6"],
"postgresql" => ["pg", ">= 0.9.0"],
"sqlite3" => ["sqlite3"]}
adapter = if File.exists?(db_config = File.join(File.dirname(__FILE__),"config","database.yml"))
db = YAML.load_file(db_config)
# Fetch the first configured adapter from config/database.yml
(db["production"] || db["development"] || db["test"])["adapter"]
else
"mysql2"
end
gem *db_gems[adapter]
# -----------------------------------------------------------------------------
I can't say if this is an established best practice or not, but it works well for me.
My workmates and I have different Gemfile.lock, because we use different platforms, windows and mac, and our server is linux.
We decide to remove Gemfile.lock in repo and create Gemfile.lock.server in git repo, just like database.yml. Then before deploy it on server, we copy Gemfile.lock.server to Gemfile.lock on server using cap deploy hook
Agreeing with r-dub, keep it in source control, but to me, the real benefit is this:
collaboration in identical environments (disregarding the windohs and linux/mac stuff). Before Gemfile.lock, the next dude to install the project might see all kinds of confusing errors, blaming himself, but he was just that lucky guy getting the next version of super gem, breaking existing dependencies.
Worse, this happened on the servers, getting untested version unless being disciplined and install exact version. Gemfile.lock makes this explicit, and it will explicitly tell you that your versions are different.
Note: remember to group stuff, as :development and :test
Simple answer in the year 2021:
Gemfile.lock should be in the version control also for Rubygems. The accepted answer is now 11 years old.
Some reasoning here (cherry-picked from comments):
#josevalim https://github.com/heartcombo/devise/pull/3147#issuecomment-52193788
The Gemfile.lock should stay in the repository because contributors and developers should be able to fork the project and run it using versions that are guaranteed to work.
#rafaelfranca https://github.com/rails/rails/pull/18951#issuecomment-74888396
I don't think it is a good idea to ignore the lock file even for plugins.
This mean that a "git clone; bundle; rake test" sequence is not guarantee to be passing because one of yours dozens of dependencies were upgraded and made your code break. Also, as #chancancode said, it make a lot harder to bisect.
Also Rails has Gemfile.lock in git:
https://github.com/rails/rails/commit/0ad6d27643057f2eccfe8351409a75a6d1bbb9d0
The Bundler docs address this question as well:
ORIGINAL: http://gembundler.com/v1.3/rationale.html
EDIT: http://web.archive.org/web/20160309170442/http://bundler.io/v1.3/rationale.html
See the section called "Checking Your Code into Version Control":
After developing your application for a while, check in the
application together with the Gemfile and Gemfile.lock snapshot. Now,
your repository has a record of the exact versions of all of the gems
that you used the last time you know for sure that the application
worked. Keep in mind that while your Gemfile lists only three gems
(with varying degrees of version strictness), your application depends
on dozens of gems, once you take into consideration all of the
implicit requirements of the gems you depend on.
This is important: the Gemfile.lock makes your application a single
package of both your own code and the third-party code it ran the last
time 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.
The next time you run bundle install on the same machine, bundler will
see that it already has all of the dependencies you need, and skip the
installation process.
Do not check in the .bundle directory, or any of the files inside it.
Those files are specific to each particular machine, and are used to
persist installation options between runs of the bundle install
command.
If you have run bundle pack, the gems (although not the git gems)
required by your bundle will be downloaded into vendor/cache. Bundler
can run without connecting to the internet (or the RubyGems server) if
all the gems you need are present in that folder and checked in to
your source control. This is an optional step, and not recommended,
due to the increase in size of your source control repository.
No Gemfile.lock means:
new contributors cannot run tests because weird things fail, so they won't contribute or get failing PRs ... bad first experience.
you cannot go back to a x year old project and fix a bug without having to update/rewrite the project if you lost your local Gemfile.lock
-> Always check in Gemfile.lock, make travis delete it if you want to be extra thorough https://grosser.it/2015/08/14/check-in-your-gemfile-lock/
A little late to the party, but answers still took me time and foreign reads to understand this problem. So I want to summarize what I have find out about the Gemfile.lock.
When you are building a Rails App, you are using certain versions of gems in your local machine. If you want to avoid errors in the production mode and other branches, you have to use that one Gemfile.lock file everywhere and tell bundler to bundle for rebuilding gems every time it changes.
If Gemfile.lock has changed on your production machine and Git doesn't let you git pull, you should write git reset --hard to avoid that file change and write git pull again.
The other answers here are correct: Yes, your Ruby app (not your Ruby gem) should include Gemfile.lock in the repo. To expand on why it should do this, read on:
I was under the mistaken notion that each env (development, test, staging, prod...) each did a bundle install to build their own Gemfile.lock. My assumption was based on the fact that Gemfile.lock does not contain any grouping data, such as :test, :prod, etc. This assumption was wrong, as I found out in a painful local problem.
Upon closer investigation, I was confused why my Jenkins build showed fetching a particular gem (ffaker, FWIW) successfully, but when the app loaded and required ffaker, it said file not found. WTF?
A little more investigation and experimenting showed what the two files do:
First it uses Gemfile.lock to go fetch all the gems, even those that won't be used in this particular env. Then it uses Gemfile to choose which of those fetched gems to actually use in this env.
So, even though it fetched the gem in the first step based on Gemfile.lock, it did NOT include in my :test environment, based on the groups in Gemfile.
The fix (in my case) was to move gem 'ffaker' from the :development group to the main group, so all env's could use it. (Or, add it only to :development, :test, as appropriate)

Getting started with gems and jeweler

With Jeweler I created a gem folder structure with ease.
However, I still have some questions:
Why are params like --gemcutter and --rubyforge still available for Jeweler. Aren't these replaced by RubyGems? Do I have to specify anything to create a gem for RubyGems?
In the Rakefile I have information about the gem, and when I run "rake install" it created a gemspec. Why is the same information in two places?
What is a manifest? Just read about it, haven't seen such file.
How do I make my gem callable from the shell once I have installed it, like rails. Cause right now it's just accessible through a Ruby script using require.
Should I use "jeweler release" or "gem push" to push my gem to RubyGems.org?
I have to specify "handle" when signing up in RubyGems. What is that?
Thanks.
jeweler was created before RubyGems became what it is, so it still reflects the split. I'm not sure when jeweler was last updated, either. (I think it also still recognizes building gems on Github, which is now disabled.)
I'm not sure I follow what you're saying. The specification in the Rakefile details what the spec that gets written should look like. The spec that gets written details what should be installed and how, I believe.
A manifest is a list of all the files that your gem should ship with. Not everyone uses one. See the hoe documentation for some pro-manifest discussion.
Many Ruby gems are only libraries. If you want yours to also have a program like jeweler or rake or rails that you can call, you have to write the callable program, put it in bin in your gem's layout and specify (in your gemspec) that it should be packaged and installed. See the Gem::Specification reference under files and executable.
Not sure. Consult both jeweler's docs and the docs for RubyGems.
You can give an email address or use a name (a 'handle', like I use Telemachus here), which is all they mean by 'handle'.
For the record, if you are just learning how to write gems, you do not need to upload your first attempts using RubyGems or anything like it. You can simply install the gem on your machine only.

Ruby gems in lib - spare tire principle

I'm working on a console ruby application (not rails!) I will be installing this application on several machines. I was wondering if there is a way i can build it so i dont have to install the gems i'm using for the app on each machine. I'd like to be able to just copy the directory to each machine and run it. Ideally, i'd like to put the gems in the lib folder or something and reference them from there, so i don't have to even install them on my dev machine. Is there a way to do this?
In .net, we call this the "spare tire" principle.
thanks,
Craig
How about using bundler?
Then you can include a Gemfile that specifies all the necssary gems and just run "bundle install" on each machine to pull them down.
If you really want to bundle them with the app run "bundle package" and the gems will be stored in vendor/cache.
You could take the same approach as rails allows and "vendor" your gems. This involves creating a new directory (rails uses vendor/gems) and unpack the gem into this directory, using gem unpack.
You then configure your load path to include all of the sub-folders below that.
Edit
You can configure your load path by doing something like this
Dir.glob(File.join("vendor", "gems", "*", "lib")).each do |lib|
$LOAD_PATH.unshift(File.expand_path(lib))
end

Resources