What is the major difference between running the rake command with and without bundle exec?
I have seen few posts stated that when you run the command with bundle exec then it will be run on scope of the gems version defined in the gem file. If that is the case, then it should be mandatory to run rake command with bundle exec?
bundle exec rake some:task runs the rake task within the context of your bundle.
You didn't explicitly mention Rails but i see you're post is tagged with Rails so a contrived example of this in action might be the following:
You have version 2.0 of the fictitious whateva-whateva gem installed on your system for some valid reason.
You decide you want to pull down an old Rails project from somewhere to check it out and run bundle install within the cloned project's root folder. That command will install all of the gems that the Rails app requires and one of them happens to be verison 1.0 of the fictitious whateva-whateva gem.
So the current state is this: your old rails app has a gem bundle that includes an older version of the whateva-whateva and your systemwide gems include a newer version of the whateva-whateva gem.
When you run rake tasks associated with your Rails app, which version do you want loaded? The older one of course.
In order to do this you can use bundle exec rake the:task and it runs the rake command within the context of your bundle -- the older version of the gem plus whatever other stuff was specified in the old rails app's Gemfile.
So yeah after all that, i think it's safe to say that BEST practice would be that you should always prepend bundle exec but to be honest I'm pretty lazy and rarely do it unless I see problems.
In other news, if you use Bundler's binstubs you don't need to add it. Here's a link to setting that up: https://thoughtbot.com/blog/use-bundlers-binstubs
BUNDLE_GEMFILE=/path/to/gemfile bundle exec can be used to precede any command (if BUNDLE_GEMFILE is not specified it searches up the file system and uses the first one it finds), not just rake.
Any command you run may invoke executable Ruby commands (such as rake) or require code from Ruby libraries (such as the Rake::Task class), and these things are typically provided by gems. gem env tells you where the gem-provided libraries and executables are. However if you use bundle exec it restricts the available gems to those specified in the Gemfile.lock file associated with the Gemfile your bundle exec context is using.
Using all the available gems on your machine (which can happen if you don't do bundle exec) can be undesirable for a couple reasons:
You may have incompatibilities in your full gem set.
It's harder to tell exactly what gems you're using, adding some unpredictability to your working environment.
Here's a quick way to see the difference.
gem install thin
Create a directory foo with two files: an empty Gemfile and a file foo.rb with the contents:
#! /usr/bin/ruby (or whatever the path to your system Ruby is)
require 'thin'
Make foo.rb executable.
Note that running thin and ./foo.rb from the command line both work, but preceding either with bundle exec will not work.
If you use bundle exec before any command in rails, It will search for the Gems Which are mentioned in our Gemfile, in application home folder.
Suppose, You have 2 applications, and using different ruby versions for each of them.
Without bundle exec the command might be failed to run, as it may take different version Gem to run that task. But If you start using bundle exec It will take the exact gem version to run the task/application.
I recommend you to use **bundle exec** before any command.
bundle-exec - Execute a command in the context of the bundle
This command executes the command, making all gems specified in the Gemfile(5) available to require in Ruby programs.
It's not for the only rake, instead applicable for rails, rspec, rackup command too.
Essentially, if you would have normally run something like rspec spec/my_spec.rb, and you want to use the gems specified in the Gemfile(5) and installed via bundle install(1), you should run bundle exec rspec spec/my_spec.rb.
Note that bundle exec does not require that an executable is available on your shell's $PATH.
For more detail, have a look to bundle exec doc.
Related
When I run a rails console using
rails console
everything is fine.
When I run a rails console using
bundle exec rails console
I get the following warning
Bundler is using a binstub that was created for a different gem.
This is deprecated, in future versions you may need to `bundle binstub my_gem` to work around a system/bundle conflict.
my_gem happens to be a gem that I've created that is completely unrelated and not used in the current project directory.
I've tried every solution in this question with no luck:
Bundler is using a binstub that was created for a different gem
I would appreciate any guidance on removing this warning or help understanding how binstubs work so that I can figure out what's going on.
Nowadays it's common for projects to have "specialized" versions of tools. E.g. in some projects the "rails" command may be expected to be run using "spring" (to start up faster).
So it's not uncommon to generate files in your project's 'bin' directory, and then use those versions when running commands, so e.g. instead of
bundle exec rails console
or
bundle exec spring rails console
you could simply expect the following to work correctly
bin/rails console
and not care whether the project needs spring or bundler or zeus or whatever.
So if you don't have 'bin/rails' in your project, you should generate one that suits the project, e.g. using
bin/rake rails:update:bin
If you don't already have bin/rake, you might have to use
bundle exec rake rails:update:bin
(so your bin/rake commands will also get a speedup from using spring)
Some people even put ./bin in their paths, so whenever they run rake (or whatever) they are actually running ./bin/rake if it exists.
Troubleshooting
for project specific tasks, use bin/* files, creating them if needed (e.g. using special rake tasks like in Rails or using bundle binstub <gemname>) - usually those have Bundler specific lines that will make Bundler happy.
for non-project gems (like your gem), find out where it is (e.g. which mygem) and check out it's contents - it's probably using e.g. "bundler/setup" which is confusing Bundler (because bundler expects a local Gemfile file). Maybe your gem is using bundler (it shouldn't if it's a "global" kind of tool and not a "project" tool).
Also, if you're using them, check if tools like RVM and .rbenv are correctly adding their stuff to your bin files (they usually need to setup specific paths)
If you still have questions, it's best to post the contents of the bin file causing problems - it's meant to be a plain Ruby file, so if there's something wrong, it's usually because of the file contents (and not anything else).
More info: https://github.com/sstephenson/rbenv/wiki/Understanding-binstubs
It happened in a project of mine. Because I ran bundle install with another ruby version.
Make sure your rvm is the correctly ruby version.
I can run rails with bundle exec rails, can't I? What's the difference between this and bin/rails then? There's also bundler's binstubs feature, which makes things even more complex. Briefly, which way should I run executables of a rails app, and why?
https://github.com/sstephenson/rbenv/wiki/Understanding-binstubs
Preface, emphasises mine:
When you run rspec within your project’s directory, rbenv can ensure that it will get executed with the Ruby version configured for that project. However, nothing will ensure that the right version of RSpec gets activated; in fact, RubyGems will simply activate the latest RSpec version even if your project depends on an older version. In the context of a project, this is unwanted behavior.
This is why bundle exec is so essential. It ensures the right versions of dependencies get activated, ensuring a consistent ruby runtime environment. However, it's a pain to always have to write bundle exec.
To answer your question:
"I can run rails with bundle exec rails, can't I? What's the difference between this and bin/rails then?"
(from the same guide)
bundle exec is so often needed. It ensures the right versions of dependencies get activated, ensuring a consistent ruby runtime environment. However, bundle exec is a pain to always have to write.
This is where "bundlers binstubs feature" comes in:
Bundler can install binstubs for executables contained in your project's bundle:
bundle install --binstubs
RSpec can now be easily run with just bin/rspec
"which way should I run executables of a rails app, and why?"
You are encouraged to check these binstubs in the project's version control so your colleagues might benefit from them.
If I try to run tests I get
Gem::LoadError: You have already activated jruby-openssl 0.9.5, but your Gemfile requires jruby-openssl 0.8.5. Prepending bundle exec to your command may solve this.
I can do as indicated and prepend bundle exec to get around this.
This is happening because I have a newer version of the gem in another project.
However I am no longer using the other application with the newer version of the gem, so I was wondering:
How can I actually remove the newer version so I don't have to bundle exec before my rails commands?
You can delete a gem (or a specific version of a gem) by running
gem uninstall <gem_name>
If there's multiple versions then a prompt will ask which version to remove.
Use gem uninstall with the -v switch to specify a version to uninstall:
gem uninstall jruby-openssl -v 0.9.5
Depending on your OS and shell, you could create an alias or function for the command (I’m guessing this is using Rake).
For example I have this in my .bashrc
function bake {
bundle exec rake "$#"
}
So now I can type bake whatever and the command that is run is bundle exec rake whatever.
This usually happens when you are 'polluting' the global gemset using it for different projects.
A good way to isolate gemsets is to use rvm. Once installed, you can create a file per project named .ruby-version with a single line on it that identifies the gemset with the syntax <ruby version>#<your project>. From the console:
$> echo "2.1#myproject" > .ruby-version
$> cd .
This will create a gemset for your project and everytime you enter the root directory, the gemset will be specific to this project. Then you could have different gem versions for different projects and run rake (or any other command) just fine without messing dependencies.
I'm following this Rails tutorial section and this RVM doc page . My installation is all brand new (RVM 1.17.3), so, if I understand the tutorial and the RVM docs correctly:
RVM and Bundler should be integrated by default and I don't have to configure anything. (No need to run bundle --bunstubs?)
I don't need to type "bundle exec"
Did I read that right?
I don't see a bundler_stubs/ or bin/ directory in my application.
Is there a way for me to check that it's set up properly so I can be sure that bundle exec is not necessary?
edit:
Running which yields the following:
$ bundle show rspec
$ /home/{username}/.rvm/gems/ruby-1.9.3-p327#tutorial/gems/rspec-2.11.0
$ which rspec
$ /home/{username}/.rvm/gems/ruby-1.9.3-p327#tutorial/bin/rspec
Which seems to imply that I should keep using bundle exec because they are not the same?
RVM by default installs gem https://github.com/mpapis/rubygems-bundler which detects if you are in context of Gemfile and automatically loads bundler if required, it is equivalent to manually typing bundle exec.
bundle exec is a bundle command to execute a script in the context of the current bundle (the one from your directory's Gemfile). rspec filename.rb is the script.
so bundle exec bundle exec rspec filename.rb executes the rake script with the command rspec filename.rb in the context of the current bundle.
As to the "why?" I'll quote from the bundler documentation:
In some cases, running executables without bundle exec may work,
if the executable happens to be installed in your system and does not pull in any gems that conflict with your bundle. However, this is unreliable and is the source of considerable pain. Even if it looks like it works, it may not work in the future or on another machine.
See http://gembundler.com/man/bundle-exec.1.html for more info.
What does bundle exec rake db:migrate mean? Or just bundle exec rake <command> in general?
I understand that bundle takes care of maintaining things in the Gemfile. I know what the word "exec" means. I understand that rake maintains all the different scripty things you can do, and I know that db:migrate is one of those. I just don't know what all these words are doing together. Why should bundle be used to execute rake to execute a database migrate?
bundle exec is a Bundler command to execute a script in the context of the current bundle (the one from your directory's Gemfile). rake db:migrate is the script where db is the namespace and migrate is the task name defined.
So bundle exec rake db:migrate executes the rake script with the command db:migrate in the context of the current bundle.
As to the "why?" I'll quote from the bundler page:
In some cases, running executables without bundle exec may work, if the executable happens to be installed in your system and does not pull in any gems that conflict with your bundle.
However, this is unreliable and is the source of considerable pain. Even if it looks like it works, it may not work in the future or on another machine.
You're running bundle exec on a program. The program's creators wrote it when certain versions of gems were available. The program Gemfile specifies the versions of the gems the creators decided to use. That is, the script was made to run correctly against these gem versions.
Your system-wide Gemfile may differ from this Gemfile. You may have newer or older gems with which this script doesn't play nice. This difference in versions can give you weird errors.
bundle exec helps you avoid these errors. It executes the script using the gems specified in the script's Gemfile rather than the systemwide Gemfile. It executes the certain gem versions with the magic of shell aliases.
See more on the man page.
Here's an example Gemfile:
source 'http://rubygems.org'
gem 'rails', '2.8.3'
Here, bundle exec would execute the script using rails version 2.8.3 and not some other version you may have installed system-wide.
This comes up a lot when your gemfile.lock has different versions of the gems installed on your machine. You may get a warning after running rake (or rspec or others) such as:
You have already activated rake 10.3.1, but your Gemfile requires rake 10.1.0. Prepending "bundle exec" to your command may solve this.
Prepending bundle exec tells the bundler to execute this command regardless of the version differential. There isn't always an issue, however, you might run into problems.
Fortunately, there is a gem that solves this: rubygems-bundler.
$ gem install rubygems-bundler
$ $ gem regenerate_binstubs
Then try your rake, rspec, or whatever again.
It should probably be mentioned, that there are ways to omit bundle exec (they are all stated in chapter 3.6.1 of Michael Hartls Ruby on Rails Tutorial book).
The simplest is to just use a sufficiently up-to-date version of RVM (>= 1.11.x).
If you're restricted to an earlier version of RVM, you can always use this method also mentioned by calasyr:
$ rvm get head && rvm reload
$ chmod +x $rvm_path/hooks/after_cd_bundler
$ bundle install --binstubs=./bundler_stubs
The bundler_stubs directory should then also be added to the .gitignore file.
A third option is to use the rubygems-bundler gem if you're not using RVM:
$ gem install rubygems-bundler
$ gem regenerate_binstubs
When you directly run the rake task or execute any binary file of a gem, there is no guarantee that the command will behave as expected. Because it might happen that you already have the same gem installed on your system which have a version say 1.0 but in your project you have higher version say 2.0. In this case you can not predict which one will be used.
To enforce the desired gem version you take the help of bundle exec command which would execute the binary in context of current bundle. That means when you use bundle exec, bundler checks the gem version configured for the current project and use that to perform the task.
I have also written a post about it which also shows how we can avoid using it using bin stubs.
I have not used bundle exec much, but am setting it up now.
I have had instances where the wrong rake was used and much time wasted tracking down the problem. This helps you avoid that.
Here's how to set up RVM so you can use bundle exec by default within a specific project directory:
https://thoughtbot.com/blog/use-bundlers-binstubs
It means use rake that bundler is aware of and is part of your Gemfile over any rake that bundler is not aware of and run the db:migrate task.