Let's see how to compile ruby scripts into standalone binaries.

This method works with

• Rails apps (your executable file will be a portable webserver);
• Scripts with gems;
• Simple, single-source file scripts;
• Multiple source file scripts;

The final app will be a single executable file that can run on systems without a ruby interpreter installed.

---

UPDATE

I developed a gem to automate this process. Check it out: https://github.com/loureirorg/rb2exe (opens new window)

Usage

gem install rb2exe

echo "puts 'Hello world'" > test.rb

rb2exe test.rb
./test
    Hello world

---

How this works, step-by-step

First, let's create a Hello World app

mkdir hello
cd hello
echo "puts 'Hello world'" > test.rb
ruby test.rb
    Hello world

This method uses Ruby Traveler and pack everything into a self-extract file.

Ruby Traveler is just a static folder with a standalone "ruby" executable. The plan here is to add Ruby Traveler's folder and binaries to our project and compress everything into a single self-extractable zip file. This self-extractable file will extract the compressed data into a temporary folder and execute the main ruby script (ex. test.rb).

As this is based on Ruby Traveler (by Phusion), which seems to be a stalled project, we are locked to the only versions they support – the latest one is 2.2.2. 😦

TIP

If you want to use different Ruby versions, other than 2.2.2, I recommend adapting this script to zw693's Traveling Ruby, which supports ALL Ruby versions: https://github.com/zw963/traveling-ruby (opens new window)

---

Part I: Standalone Ruby

Your ruby version should be 2.2.2, 64 bits

echo $RUBY_VERSION
ruby-2.2.2

WARNING

If your version is different, please install the 2.2.2 (e.g. rvm use 2.2.2). This will NOT work with 2.2.0, 2.2.3, 2.1, etc.

Duplicate the project folder, naming it as "app"

# ~/hello/
cd ..
cp -r -pa hello app

cd hello

In the project folder, create a .package/payload/lib/ruby sub-folder

# ~/hello/
mkdir -p .package/payload/lib/ruby

Move the "app" folder to .package/payload/lib

# ~/hello/
mv ../app .package/payload/lib
tree -a
    .
    ├── .package
    │   └── payload
    │       └── lib
    │           ├── app
    │           │   └── test.rb
    │           └── ruby
    └── test.rb

Download ruby traveler 2.2.2 64 bits (5.6M), and unzip it on .package/payload/lib/ruby

# ~/hello/
cd .package/payload/lib/ruby

# ~/hello/.package/payload/lib/ruby/
wget http://d6r77u77i8pq3.cloudfront.net/releases/traveling-ruby-20150715-2.2.2-linux-x86_64.tar.gz
tar -xf traveling-ruby-20150715-2.2.2-linux-x86_64.tar.gz
rm traveling-ruby-20150715-2.2.2-linux-x86_64.tar.gz

Go back to .package/payload/

# ~/hello/.package/payload/lib/ruby/
cd ../..
pwd
    ~/hello/.package/payload

Create a wrapper script (name it as installer.sh)

# ~/hello/.package/payload/
nano installer.sh

#!/bin/bash
set -e

# Figure out where this script is located.
SELFDIR="`dirname \"$0\"`"
SELFDIR="`cd \"$SELFDIR\" && pwd`"

## GEMFILE
if [ -f "$SELFDIR/lib/vendor/Gemfile" ]
then
  # Tell Bundler where the Gemfile and gems are.
  export BUNDLE_GEMFILE="$SELFDIR/lib/vendor/Gemfile"
  unset BUNDLE_IGNORE_CONFIG

  # Run the actual app using the bundled Ruby interpreter, with Bundler activated.
  exec "$SELFDIR/lib/ruby/bin/ruby" -rbundler/setup "$SELFDIR/lib/app/test.rb"
else
  exec "$SELFDIR/lib/ruby/bin/ruby" "$SELFDIR/lib/app/test.rb"
fi

# ~/hello/.package/payload/
chmod +x installer.sh

Replace the exec lines with your actual command to start the application. Eg. for Rails apps, it should be: RAILS_ENV=production exec "$SELFDIR/lib/ruby/bin/ruby" -rbundler/setup "$SELFDIR/lib/app/bin/rails" server

TIP

The previous script is based on the "traveling ruby" tutorial. If you want to understand this process better, you can follow the official "traveling ruby" instructions.

---

Part II: Gemfile

If your project has a Gemfile, you need to follow these extra steps:

Create a tmp folder on .package/payload/lib

# ~/hello/.package/payload/
cd lib

# ~/hello/.package/payload/lib/
mkdir tmp
cd tmp

Copy the Gemfile to tmp

# ~/hello/.package/payload/lib/tmp/
cp ../app/Gemfile* .

Download gems into the lib/vendor folder

# ~/hello/.package/payload/lib/tmp/
BUNDLE_IGNORE_CONFIG=1 bundle install --path ../vendor --without development

Delete tmp folder

# ~/hello/.package/payload/lib/tmp/
cd ..
rm -Rf tmp

[Optional] Delete gem's cache in the vendor folder

# ~/hello/.package/payload/lib/
rm -f vendor/*/*/cache/*

Copy the Gemfile to the vendor folder

# ~/hello/.package/payload/lib/
cp app/Gemfile* vendor/

Create a bundler config

# ~/hello/.package/payload/lib/
mkdir vendor/.bundle/
cd vendor/.bundle/

# ~/hello/.package/payload/lib/vendor/.bundle/
nano config

BUNDLE_PATH: .
BUNDLE_WITHOUT: development
BUNDLE_DISABLE_SHARED_GEMS: '1'

---

Part III: Pack everything as a single self-extract file

This part is based on Jeff Parent's article (opens new window).

Create a script to decompress everything

# ~/hello/.package/
nano decompress.sh

The .package/decompress.sh:

#!/bin/bash
export TMPDIR=`mktemp -d /tmp/selfextract.XXXXXX`

ARCHIVE=`awk '/^__ARCHIVE_BELOW__/ {print NR + 1; exit 0; }' $0`

tail -n+$ARCHIVE $0 | tar -xz -C $TMPDIR

CDIR=`pwd`
cd $TMPDIR
./installer.sh

cd $CDIR
rm -rf $TMPDIR

exit 0

__ARCHIVE_BELOW__

Package builder

# ~/hello/.package/
nano build.sh

The .package/build.sh:

#!/bin/bash
cd payload
tar cf ../payload.tar ./*
cd ..

if [ -e "payload.tar" ]; then
    gzip payload.tar

    if [ -e "payload.tar.gz" ]; then
        cat decompress.sh payload.tar.gz > output.sh
    else
        echo "payload.tar.gz does not exist"
        exit 1
    fi
else
    echo "payload.tar does not exist"
    exit 1
fi

chmod +x output.sh
echo "Self-extract file created"
exit 0

# ~/hello/.package/
chmod +x decompress.sh
chmod +x build.sh
./build.sh
    Self-extract file created

And that's it. You can now rename and distribute the generated "output.sh" file 😃