Checksum calculation is handled by Gitaly when feature is enabled

lib/gitlab/git/checksum.rb

@@ -7,13 +7,14 @@ module Gitlab
 
       Failure = Class.new(StandardError)
 
-      attr_reader :path, :relative_path, :storage, :storage_path
+      attr_reader :path, :relative_path, :storage, :storage_path, :gl_repository
 
-      def initialize(storage, relative_path)
+      def initialize(storage, relative_path, gl_repository)
         @storage       = storage
         @storage_path  = Gitlab.config.repositories.storages[storage].legacy_disk_path
         @relative_path = "#{relative_path}.git"
         @path          = File.join(storage_path, @relative_path)
+        @gl_repository = gl_repository
       end
 
       def calculate
@@ -21,8 +22,14 @@ module Gitlab
           failure!(Gitlab::Git::Repository::NoRepository, 'No repository for such path')
         end
 
+        raw_repository.gitaly_migrate(:calculate_checksum) do |is_enabled|
+          if is_enabled
+            calculate_checksum_gitaly
+          else
             calculate_checksum_by_shelling_out
           end
+        end
+      end
 
       private
 
@@ -30,6 +37,10 @@ module Gitlab
         raw_repository.exists?
       end
 
+      def calculate_checksum_gitaly
+        gitaly_repository_client.calculate_checksum
+      end
+
       def calculate_checksum_by_shelling_out
         args = %W(--git-dir=#{path} show-ref --heads --tags)
         output, status = run_git(args)
@@ -69,7 +80,11 @@ module Gitlab
       end
 
       def raw_repository
-        Gitlab::Git::Repository.new(storage, relative_path, nil)
+        @raw_repository ||= Gitlab::Git::Repository.new(storage, relative_path, gl_repository)
+      end
+
+      def gitaly_repository_client
+        raw_repository.gitaly_repository_client
       end
 
       def run_git(args)

spec/lib/gitlab/git/checksum_spec.rb

@@ -2,9 +2,11 @@ require 'spec_helper'
 
 describe Gitlab::Git::Checksum, seed_helper: true do
   let(:storage) { 'default' }
+  let(:gl_repository) { 'project-123' }
 
+  shared_examples 'calculating checksum' do
     it 'raises Gitlab::Git::Repository::NoRepository when there is no repo' do
-    checksum = described_class.new(storage, 'nonexistent-repo')
+      checksum = described_class.new(storage, 'nonexistent-repo', gl_repository)
 
       expect { checksum.calculate }.to raise_error Gitlab::Git::Repository::NoRepository
     end
@@ -17,22 +19,31 @@ describe Gitlab::Git::Checksum, seed_helper: true do
              out:   '/dev/null',
              err:   '/dev/null')
 
-    checksum = described_class.new(storage, 'empty-repo')
+      checksum = described_class.new(storage, 'empty-repo', gl_repository)
 
       expect(checksum.calculate).to eq '0000000000000000000000000000000000000000'
     end
 
-  it 'raises Gitlab::Git::Repository::Failure when shelling out to git return non-zero status' do
-    checksum = described_class.new(storage, 'gitlab-git-test')
+    it 'calculates the checksum when there is a repo' do
+      checksum = described_class.new(storage, 'gitlab-git-test', gl_repository)
 
-    allow(checksum).to receive(:popen).and_return(['output', nil])
+      expect(checksum.calculate).to eq '54f21be4c32c02f6788d72207fa03ad3bce725e4'
+    end
+  end
 
-    expect { checksum.calculate }.to raise_error Gitlab::Git::Checksum::Failure
+  context 'when calculate_checksum Gitaly feature is enabled' do
+    it_behaves_like 'calculating checksum'
   end
 
-  it 'calculates the checksum when there is a repo' do
-    checksum = described_class.new(storage, 'gitlab-git-test')
+  context 'when calculate_checksum Gitaly feature is disabled', :disable_gitaly do
+    it_behaves_like 'calculating checksum'
 
-    expect(checksum.calculate).to eq '54f21be4c32c02f6788d72207fa03ad3bce725e4'
+    it "raises a Gitlab::Git::Repository::Failure error if the `popen` call to git returns a non-zero exit code" do
+      checksum = described_class.new(storage, 'gitlab-git-test', gl_repository)
+
+      allow(checksum).to receive(:popen).and_return(['output', nil])
+
+      expect { checksum.calculate }.to raise_error Gitlab::Git::Checksum::Failure
+    end
   end
 end