Add rake task that prints TOML storage configuration

Closes gitaly#173

Gemfile

@@ -353,3 +353,5 @@ gem 'sys-filesystem', '~> 1.1.6'
 
 # Gitaly GRPC client
 gem 'gitaly', '~> 0.5.0'
+
+gem 'toml-rb', '~> 0.3.15', require: false

Gemfile.lock

@@ -117,6 +117,7 @@ GEM
     chronic_duration (0.10.6)
       numerizer (~> 0.1.1)
     chunky_png (1.3.5)
+    citrus (3.0.2)
     cliver (0.3.2)
     coderay (1.1.1)
     coercible (1.0.0)
@@ -784,6 +785,8 @@ GEM
     tilt (2.0.6)
     timecop (0.8.1)
     timfel-krb5-auth (0.8.3)
+    toml-rb (0.3.15)
+      citrus (~> 3.0, > 3.0)
     tool (0.2.3)
     truncato (0.7.8)
       htmlentities (~> 4.3.1)
@@ -1014,6 +1017,7 @@ DEPENDENCIES
   test_after_commit (~> 1.1)
   thin (~> 1.7.0)
   timecop (~> 0.8.0)
+  toml-rb (~> 0.3.15)
   truncato (~> 0.7.8)
   u2f (~> 0.2.1)
   uglifier (~> 2.7.2)

lib/tasks/gitlab/gitaly.rake

@@ -19,5 +19,19 @@ namespace :gitlab do
         run_command!([command])
       end
     end
+
+    desc "GitLab | Print storage configuration in TOML format"
+    task storage_config: :environment do
+      require 'toml'
+
+      puts "# Gitaly storage configuration generated from #{Gitlab.config.source} on #{Time.current.to_s(:long)}"
+      puts "# This is in TOML format suitable for use in Gitaly's config.toml file."
+
+      config = Gitlab.config.repositories.storages.map do |key, val|
+        { name: key, path: val['path'] }
+      end
+
+      puts TOML.dump(storage: config)
+    end
   end
 end

spec/tasks/gitlab/gitaly_rake_spec.rb

@@ -75,4 +75,36 @@ describe 'gitlab:gitaly namespace rake task' do
       end
     end
   end
+
+  describe 'storage_config' do
+    it 'prints storage configuration in a TOML format' do
+      config = {
+        'default' => { 'path' => '/path/to/default' },
+        'nfs_01' => { 'path' => '/path/to/nfs_01' },
+      }
+      allow(Gitlab.config.repositories).to receive(:storages).and_return(config)
+
+      orig_stdout = $stdout
+      $stdout = StringIO.new
+
+      header = ''
+      Timecop.freeze do
+        header = <<~TOML
+          # Gitaly storage configuration generated from #{Gitlab.config.source} on #{Time.current.to_s(:long)}
+          # This is in TOML format suitable for use in Gitaly's config.toml file.
+        TOML
+        run_rake_task('gitlab:gitaly:storage_config')
+      end
+
+      output = $stdout.string
+      $stdout = orig_stdout
+
+      expect(output).to include(header)
+
+      parsed_output = TOML.parse(output)
+      config.each do |name, params|
+        expect(parsed_output['storage']).to include({ 'name' => name, 'path' => params['path'] })
+      end
+    end
+  end
 end