Implement commit transaction with pre-receive and post-receive hooks for web editor

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Gemfile

@@ -38,7 +38,7 @@ gem "browser", '~> 0.8.0'
 
 # Extracting information from a git repository
 # Provide access to Gitlab::Git library
-gem "gitlab_git", '~> 7.2.12'
+gem "gitlab_git", '~> 7.2.13'
 
 # Ruby/Rack Git Smart-HTTP Server Handler
 # GitLab fork with a lot of changes (improved thread-safety, better memory usage etc)

Gemfile.lock

@@ -271,7 +271,7 @@ GEM
       mime-types (~> 1.19)
     gitlab_emoji (0.1.0)
       gemojione (~> 2.0)
-    gitlab_git (7.2.12)
+    gitlab_git (7.2.13)
       activesupport (~> 4.0)
       charlock_holmes (~> 0.6)
       gitlab-linguist (~> 3.0)
@@ -783,7 +783,7 @@ DEPENDENCIES
   gitlab-grack (~> 2.0.2)
   gitlab-linguist (~> 3.0.1)
   gitlab_emoji (~> 0.1)
-  gitlab_git (~> 7.2.12)
+  gitlab_git (~> 7.2.13)
   gitlab_meta (= 7.0)
   gitlab_omniauth-ldap (= 1.2.1)
   gollum-lib (~> 4.0.2)
@@ -875,4 +875,4 @@ DEPENDENCIES
   wikicloth (= 0.8.1)
 
 BUNDLED WITH
-   1.10.4
+   1.10.6

app/models/repository.rb

@@ -373,7 +373,7 @@ class Repository
     options[:author] = committer
     options[:commit] = {
       message: message,
-      branch: ref
+      branch: ref,
     }
 
     options[:file] = {

app/services/commit_service.rb

+require 'securerandom'
+
+class CommitService
+  def self.transaction(project, current_user, ref)
+    repository = project.repository
+    path_to_repo = repository.path_to_repo
+
+    # Create temporary ref
+    random_string = SecureRandom.hex
+    tmp_ref = "refs/tmp/#{random_string}/head"
+    target = repository.find_branch(ref).target
+    repository.rugged.references.create(tmp_ref, target)
+
+    # Make commit in tmp ref
+    sha = yield(tmp_ref)
+
+    unless sha
+      raise 'Failed to create commit'
+    end
+
+    # Run GitLab pre-receive hook
+    status = PreCommitService.new(project, current_user).execute(sha, ref)
+
+    if status
+      # Update head
+      repository.rugged.references.update(Gitlab::Git::BRANCH_REF_PREFIX + ref, sha)
+
+      # Run GitLab post receive hook
+      PostCommitService.new(project, current_user).execute(sha, ref)
+    else
+      # Remove tmp ref and return error to user
+      repository.rugged.references.delete(tmp_ref)
+
+      raise 'Commit was rejected by pre-reveive hook'
+    end
+  end
+end

app/services/files/base_service.rb

@@ -22,7 +22,6 @@ module Files
       end
 
       if sha = commit
-        after_commit(sha, @target_branch)
         success
       else
         error("Something went wrong. Your changes were not committed")
@@ -33,10 +32,6 @@ module Files
 
     private
 
-    def after_commit(sha, branch)
-      PostCommitService.new(project, current_user).execute(sha, branch)
-    end
-
     def current_branch
       @current_branch ||= params[:current_branch]
     end

app/services/files/create_service.rb

@@ -3,7 +3,9 @@ require_relative "base_service"
 module Files
   class CreateService < Files::BaseService
     def commit
-      repository.commit_file(current_user, @file_path, @file_content, @commit_message, @target_branch)
+      CommitService.transaction(project, current_user, @target_branch)  do |tmp_ref|
+        repository.commit_file(current_user, @file_path, @file_content, @commit_message, tmp_ref)
+      end
     end
 
     def validate

app/services/files/delete_service.rb

@@ -3,7 +3,9 @@ require_relative "base_service"
 module Files
   class DeleteService < Files::BaseService
     def commit
-      repository.remove_file(current_user, @file_path, @commit_message, @target_branch)
+      CommitService.transaction(project, current_user, @target_branch)  do |tmp_ref|
+        repository.remove_file(current_user, @file_path, @commit_message, tmp_ref)
+      end
     end
   end
 end

app/services/files/update_service.rb

@@ -3,7 +3,9 @@ require_relative "base_service"
 module Files
   class UpdateService < Files::BaseService
     def commit
-      repository.commit_file(current_user, @file_path, @file_content, @commit_message, @target_branch)
+      CommitService.transaction(project, current_user, @target_branch)  do |tmp_ref|
+        repository.commit_file(current_user, @file_path, @file_content, @commit_message, tmp_ref)
+      end
     end
   end
 end

app/services/pre_commit_service.rb

+class PreCommitService < BaseService
+  include Gitlab::Popen
+
+  attr_reader :changes, :repo_path
+
+  def execute(sha, branch)
+    commit = repository.commit(sha)
+    full_ref = Gitlab::Git::BRANCH_REF_PREFIX + branch
+    old_sha = commit.parent_id || Gitlab::Git::BLANK_SHA
+    @changes = "#{old_sha} #{sha} #{full_ref}"
+    @repo_path = repository.path_to_repo
+
+    pre_receive
+  end
+
+  private
+
+  def pre_receive
+    hook = hook_file('pre-receive', repo_path)
+    return true if hook.nil?
+    call_receive_hook(hook)
+  end
+
+  def call_receive_hook(hook)
+    # function  will return true if succesful
+    exit_status = false
+
+    vars = {
+      'GL_ID' => Gitlab::ShellEnv.gl_id(current_user),
+      'PWD' => repo_path
+    }
+
+    options = {
+      chdir: repo_path
+    }
+
+    # we combine both stdout and stderr as we don't know what stream
+    # will be used by the custom hook
+    Open3.popen2e(vars, hook, options) do |stdin, stdout_stderr, wait_thr|
+      exit_status = true
+      stdin.sync = true
+
+      # in git, pre- and post- receive hooks may just exit without
+      # reading stdin. We catch the exception to avoid a broken pipe
+      # warning
+      begin
+        # inject all the changes as stdin to the hook
+        changes.lines do |line|
+          stdin.puts line
+        end
+      rescue Errno::EPIPE
+      end
+
+      # need to close stdin before reading stdout
+      stdin.close
+
+      # only output stdut_stderr if scripts doesn't return 0
+      unless wait_thr.value == 0
+        exit_status = false
+      end
+    end
+
+    exit_status
+  end
+
+  def hook_file(hook_type, repo_path)
+    hook_path = File.join(repo_path.strip, 'hooks')
+    hook_file = "#{hook_path}/#{hook_type}"
+    hook_file if File.exist?(hook_file)
+  end
+end