The Git Gem

Summary
v2.0.0 pre-release
Install
Major Objects
Errors Raised By This Gem
Specifying And Handling Timeouts
Examples
Ruby version support policy
License

Summary

The git gem provides an API that can be used to create, read, and manipulate Git repositories by wrapping system calls to the git command line. The API can be used for working with Git in complex interactions including branching and merging, object inspection and manipulation, history, patch generation and more.

Get started by obtaining a repository object by:

opening an existing working copy with Git.open
initializing a new repository with Git.init
cloning a repository with Git.clone

Methods that can be called on a repository object are documented in Git::Base

v2.0.0 pre-release

git 2.0.0 is available as a pre-release version for testing! Please give it a try.

JRuby on Windows is not yet supported by the 2.x release line. Users running JRuby on Windows should continue to use the 1.x release line.

The changes coming in this major release include:

Create a policy of supported Ruby versions to support only non-EOL Ruby versions
Create a policy of supported Git CLI versions (released 2020-12-25)
Update the required Ruby version to at least 3.0 (released 2020-07-27)
Update the required Git command line version to at least 2.28
Update how CLI commands are called to use the process_executer gem which is built on top of Kernel.spawn. See PR #684 for more details on the motivation for this implementation.

The tentative plan is to release 2.0.0 near the end of March 2024 depending on the feedback received during the pre-release period.

The master branch will be used for 2.x development. If needed, fixes for 1.x version will be done on the v1 branch.

Install

Install the gem and add to the application's Gemfile by executing:

bundle add git

If bundler is not being used to manage dependencies, install the gem by executing:

gem install git

Major Objects

Git::Base - The object returned from a Git.open or Git.clone. Most major actions are called from this object.

Git::Object - The base object for your tree, blob and commit objects, returned from @git.gtree or @git.object calls. the Git::AbstractObject will have most of the calls in common for all those objects.

Git::Diff - returns from a @git.diff command. It is an Enumerable that returns Git::Diff:DiffFile objects from which you can get per file patches and insertion/deletion statistics. You can also get total statistics from the Git::Diff object directly.

Git::Status - returns from a @git.status command. It is an Enumerable that returns Git:Status::StatusFile objects for each object in git, which includes files in the working directory, in the index and in the repository. Similar to running 'git status' on the command line to determine untracked and changed files.

Git::Branches - Enumerable object that holds Git::Branch objects. You can call .local or .remote on it to filter to just your local or remote branches.

Git::Remote- A reference to a remote repository that is tracked by this repository.

Git::Log - An Enumerable object that references all the Git::Object::Commit objects that encompass your log query, which can be constructed through methods on the Git::Log object, like:

@git.log(20).object("some_file").since("2 weeks ago").between('v2.6', 'v2.7').each { |commit| [block] }

Pass the --all option to git log as follows:

@git.log.all.each { |commit| [block] }

Git::Worktrees - Enumerable object that holds Git::Worktree objects.

Errors Raised By This Gem

The git gem will only raise an ArgumentError or an error that is a subclass of Git::Error. It does not explicitly raise any other types of errors.

It is recommended to rescue Git::Error to catch any runtime error raised by this gem unless you need more specific error handling.

begin
  # some git operation
rescue Git::Error => e
  puts "An error occurred: #{e.message}"
end

See Git::Error for more information.

Specifying And Handling Timeouts

The timeout feature was added in git gem version 2.0.0.

A timeout for git command line operations can be set either globally or for specific method calls that accept a :timeout parameter.

The timeout value must be a real, non-negative Numeric value that specifies a number of seconds a git command will be given to complete before being sent a KILL signal. This library may hang if the git command does not terminate after receiving the KILL signal.

When a command times out, it is killed by sending it the SIGKILL signal and a Git::TimeoutError is raised. This error derives from the Git::SignaledError and Git::Error.

If the timeout value is 0 or nil, no timeout will be enforced.

If a method accepts a :timeout parameter and a receives a non-nil value, the value of this parameter will override the global timeout value. In this context, a value of nil (which is usually the default) will use the global timeout value and a value of 0 will turn off timeout enforcement for that method call no matter what the global value is.

To set a global timeout, use the Git.config object:

Git.config.timeout = nil # a value of nil or 0 means no timeout is enforced
Git.config.timeout = 1.5 # can be any real, non-negative Numeric interpreted as number of seconds

The global timeout can be overridden for a specific method if the method accepts a :timeout parameter:

repo_url = 'https://github.com/ruby-git/ruby-git.git'
Git.clone(repo_url) # Use the global timeout value
Git.clone(repo_url, timeout: nil) # Also uses the global timeout value
Git.clone(repo_url, timeout: 0) # Do not enforce a timeout
Git.clone(repo_url, timeout: 10.5)  # Timeout after 10.5 seconds raising Git::SignaledError

If the command takes too long, a Git::TimeoutError will be raised:

begin
  Git.clone(repo_url, timeout: 10)
rescue Git::TimeoutError => e
  e.result.tap do |r|
    r.class #=> Git::CommandLineResult
    r.status #=> #<Process::Status: pid 62173 SIGKILL (signal 9)>
    r.status.timeout? #=> true
    r.git_cmd # The git command ran as an array of strings
    r.stdout # The command's output to stdout until it was terminated
    r.stderr # The command's output to stderr until it was terminated
  end
end

Examples

Here are a bunch of examples of how to use the Ruby/Git package.

Require the 'git' gem.

require 'git'

Git env config

Git.configure do |config|
  # If you want to use a custom git binary
  config.binary_path = '/git/bin/path'

  # If you need to use a custom SSH script
  config.git_ssh = '/path/to/ssh/script'
end

NOTE: Another way to specify where is the git binary is through the environment variable GIT_PATH

Here are the operations that need read permission only.

g = Git.open(working_dir, :log => Logger.new(STDOUT))

g.index
g.index.readable?
g.index.writable?
g.repo
g.dir

# log - returns a Git::Log object, which is an Enumerator of Git::Commit objects
# default configuration returns a max of 30 commits
g.log
g.log(200) # 200 most recent commits
g.log.since('2 weeks ago') # default count of commits since 2 weeks ago.
g.log(200).since('2 weeks ago') # commits since 2 weeks ago, limited to 200.
g.log.between('v2.5', 'v2.6')
g.log.each {|l| puts l.sha }
g.gblob('v2.5:Makefile').log.since('2 weeks ago')

g.object('HEAD^').to_s  # git show / git rev-parse
g.object('HEAD^').contents
g.object('v2.5:Makefile').size
g.object('v2.5:Makefile').sha

g.gtree(treeish)
g.gblob(treeish)
g.gcommit(treeish)


commit = g.gcommit('1cc8667014381')

commit.gtree
commit.parent.sha
commit.parents.size
commit.author.name
commit.author.email
commit.author.date.strftime("%m-%d-%y")
commit.committer.name
commit.date.strftime("%m-%d-%y")
commit.message

tree = g.gtree("HEAD^{tree}")

tree.blobs
tree.subtrees
tree.children # blobs and subtrees

g.revparse('v2.5:Makefile')

g.branches # returns Git::Branch objects
g.branches.local
g.current_branch
g.branches.remote
g.branches[:master].gcommit
g.branches['origin/master'].gcommit

g.grep('hello')  # implies HEAD
g.blob('v2.5:Makefile').grep('hello')
g.tag('v2.5').grep('hello', 'docs/')
g.describe()
g.describe('0djf2aa')
g.describe('HEAD', {:all => true, :tags => true})

g.diff(commit1, commit2).size
g.diff(commit1, commit2).stats
g.diff(commit1, commit2).name_status
g.gtree('v2.5').diff('v2.6').insertions
g.diff('gitsearch1', 'v2.5').path('lib/')
g.diff('gitsearch1', @git.gtree('v2.5'))
g.diff('gitsearch1', 'v2.5').path('docs/').patch
g.gtree('v2.5').diff('v2.6').patch

g.gtree('v2.5').diff('v2.6').each do |file_diff|
  puts file_diff.path
  puts file_diff.patch
  puts file_diff.blob(:src).contents
end

g.worktrees # returns Git::Worktree objects
g.worktrees.count
g.worktrees.each do |worktree|
  worktree.dir
  worktree.gcommit
  worktree.to_s
end

g.config('user.name')  # returns 'Scott Chacon'
g.config # returns whole config hash

# Configuration can be set when cloning using the :config option.
# This option can be an single configuration String or an Array
# if multiple config items need to be set.
#
g = Git.clone(
  git_uri, destination_path,
  :config => [
    'core.sshCommand=ssh -i /home/user/.ssh/id_rsa',
    'submodule.recurse=true'
  ]
)

g.tags # returns array of Git::Tag objects

g.show()
g.show('HEAD')
g.show('v2.8', 'README.md')

Git.ls_remote('https://github.com/ruby-git/ruby-git.git') # returns a hash containing the available references of the repo.
Git.ls_remote('/path/to/local/repo')
Git.ls_remote() # same as Git.ls_remote('.')

Git.default_branch('https://github.com/ruby-git/ruby-git') #=> 'master'

And here are the operations that will need to write to your git repository.

g = Git.init
  Git.init('project')
  Git.init('/home/schacon/proj',
  { :repository => '/opt/git/proj.git',
      :index => '/tmp/index'} )

# Clone from a git url
git_url = 'https://github.com/ruby-git/ruby-git.git'
# Clone into the ruby-git directory
g = Git.clone(git_url)

# Clone into /tmp/clone/ruby-git-clean
name = 'ruby-git-clean'
path = '/tmp/clone'
g = Git.clone(git_url, name, :path => path)
g.dir #=> /tmp/clone/ruby-git-clean

g.config('user.name', 'Scott Chacon')
g.config('user.email', 'email@email.com')

# Clone can take a filter to tell the serve to send a partial clone
g = Git.clone(git_url, name, :path => path, :filter => 'tree:0')

# Clone can take an optional logger
logger = Logger.new
g = Git.clone(git_url, NAME, :log => logger)

g.add                                   # git add -- "."
g.add(:all=>true)                       # git add --all -- "."
g.add('file_path')                      # git add -- "file_path"
g.add(['file_path_1', 'file_path_2'])   # git add -- "file_path_1" "file_path_2"

g.remove()                                # git rm -f -- "."
g.remove('file.txt')                      # git rm -f -- "file.txt"
g.remove(['file.txt', 'file2.txt'])       # git rm -f -- "file.txt" "file2.txt"
g.remove('file.txt', :recursive => true)  # git rm -f -r -- "file.txt"
g.remove('file.txt', :cached => true)     # git rm -f --cached -- "file.txt"

g.commit('message')
g.commit_all('message')

# Sign a commit using the gpg key configured in the user.signingkey config setting
g.config('user.signingkey', '0A46826A')
g.commit('message', gpg_sign: true)

# Sign a commit using a specified gpg key
key_id = '0A46826A'
g.commit('message', gpg_sign: key_id)

# Skip signing a commit (overriding any global gpgsign setting)
g.commit('message', no_gpg_sign: true)

g = Git.clone(repo, 'myrepo')
g.chdir do
new_file('test-file', 'blahblahblah')
g.status.changed.each do |file|
  puts file.blob(:index).contents
end
end

g.reset # defaults to HEAD
g.reset_hard(Git::Commit)

g.branch('new_branch') # creates new or fetches existing
g.branch('new_branch').checkout
g.branch('new_branch').delete
g.branch('existing_branch').checkout
g.branch('master').contains?('existing_branch')

# delete remote branch
g.push('origin', 'remote_branch_name', force: true, delete: true)

g.checkout('new_branch')
g.checkout('new_branch', new_branch: true, start_point: 'master')
g.checkout(g.branch('new_branch'))

g.branch(name).merge(branch2)
g.branch(branch2).merge  # merges HEAD with branch2

g.branch(name).in_branch(message) { # add files }  # auto-commits
g.merge('new_branch')
g.merge('new_branch', 'merge commit message', no_ff: true)
g.merge('origin/remote_branch')
g.merge(g.branch('master'))
g.merge([branch1, branch2])

g.merge_base('branch1', 'branch2')

r = g.add_remote(name, uri)  # Git::Remote
r = g.add_remote(name, Git::Base)  # Git::Remote

g.remotes  # array of Git::Remotes
g.remote(name).fetch
g.remote(name).remove
g.remote(name).merge
g.remote(name).merge(branch)

g.fetch
g.fetch(g.remotes.first)
g.fetch('origin', {:ref => 'some/ref/head'} )
g.fetch(all: true, force: true, depth: 2)
g.fetch('origin', {:'update-head-ok' => true})

g.pull
g.pull(Git::Repo, Git::Branch) # fetch and a merge

g.add_tag('tag_name') # returns Git::Tag
g.add_tag('tag_name', 'object_reference')
g.add_tag('tag_name', 'object_reference', {:options => 'here'})
g.add_tag('tag_name', {:options => 'here'})

Options:
  :a | :annotate
  :d
  :f
  :m | :message
  :s

g.delete_tag('tag_name')

g.repack

g.push
g.push(g.remote('name'))

# delete remote branch
g.push('origin', 'remote_branch_name', force: true, delete: true)

# push all branches to remote at one time
g.push('origin', all: true)

g.worktree('/tmp/new_worktree').add
g.worktree('/tmp/new_worktree', 'branch1').add
g.worktree('/tmp/new_worktree').remove
g.worktrees.prune

Some examples of more low-level index and tree operations

g.with_temp_index do

  g.read_tree(tree3) # calls self.index.read_tree
  g.read_tree(tree1, :prefix => 'hi/')

  c = g.commit_tree('message')
  # or #
  t = g.write_tree
  c = g.commit_tree(t, :message => 'message', :parents => [sha1, sha2])

  g.branch('branch_name').update_ref(c)
  g.update_ref(branch, c)

  g.with_temp_working do # new blank working directory
    g.checkout
    g.checkout(another_index)
    g.commit # commits to temp_index
  end
end

g.set_index('/path/to/index')


g.with_index(path) do
  # calls set_index, then switches back after
end

g.with_working(dir) do
# calls set_working, then switches back after
end

g.with_temp_working(dir) do
  g.checkout_index(:prefix => dir, :path_limiter => path)
  # do file work
  g.commit # commits to index
end

Ruby version support policy

This gem will be expected to function correctly on:

All non-EOL versions of the MRI Ruby on Mac, Linux, and Windows
The latest version of JRuby on Linux and Windows
The latest version of Truffle Ruby on Linus

sudeeptarlekar/ruby-git