Improve CI builds seeder

db/fixtures/development/14_builds.rb

-Gitlab::Seeder.quiet do
-  build_artifacts_path = Rails.root + 'spec/fixtures/ci_build_artifacts.tar.gz'
-  build_artifacts_cache_file = build_artifacts_path.to_s.gsub('ci_', '')
+class Gitlab::Seeder::Builds
+  BUILD_STATUSES = %w(running pending success failed canceled)
 
-  Project.all.sample(5).each do |project|
-    commits = project.repository.commits('master', nil, 5)
-    commits_sha = commits.map { |commit| commit.raw.id }
-    ci_commits = commits_sha.map do |sha|
-      project.ensure_ci_commit(sha)
-    end
+  def initialize(project)
+    @project = project
+  end
 
+  def seed!
     ci_commits.each do |ci_commit|
-      attributes = { type: 'Ci::Build', name: 'test build', commands: "$ build command",
-                     stage: 'test', stage_idx: 1, ref: 'master',
-                     user_id: project.team.users.sample, gl_project_id: project.id,
-                     status: %w(running pending success failed canceled).sample,
-                     commit_id: ci_commit.id, created_at: Time.now, updated_at: Time.now }
+      build = Ci::Build.new(build_attributes_for(ci_commit))
 
-      build = Ci::Build.new(attributes)
-      build.artifacts_metadata = `tar tzf #{build_artifacts_path}`.split(/\n/)
-
-      FileUtils.copy(build_artifacts_path, build_artifacts_cache_file)
-      build.artifacts_file = artifacts_file = File.open(build_artifacts_cache_file, 'r')
+      FileUtils.copy(artifacts_path, artifacts_cache_file_path)
+      File.open(artifacts_cache_file_path, 'r') do |file|
+        build.artifacts_file = file
+        build.artifacts_metadata = artifacts_metadata
+      end
 
       begin
         build.save!
         print '.'
       rescue ActiveRecord::RecordInvalid
-        puts build.error.messages.inspect
         print 'F'
-      ensure
-        artifacts_file.close
       end
     end
   end
+
+  def ci_commits
+    commits = @project.repository.commits('master', nil, 5)
+    commits_sha = commits.map { |commit| commit.raw.id }
+    commits_sha.map do |sha|
+      @project.ensure_ci_commit(sha)
+    end
+  rescue
+    []
+  end
+
+  def build_attributes_for(ci_commit)
+    { name: 'test build', commands: "$ build command",
+      stage: 'test', stage_idx: 1, ref: 'master',
+      user_id: build_user, gl_project_id: @project.id,
+      status: build_status, commit_id: ci_commit.id,
+      created_at: Time.now, updated_at: Time.now }
+  end
+
+  def build_user
+    @project.team.users.sample
+  end
+
+  def build_status
+    BUILD_STATUSES.sample
+  end
+
+  def artifacts_path
+    Rails.root + 'spec/fixtures/ci_build_artifacts.tar.gz'
+  end
+
+  def artifacts_cache_file_path
+    artifacts_path.to_s.gsub('ci_', "p#{@project.id}_")
+  end
+
+  def artifacts_metadata
+    return @artifacts_metadata if @artifacts_metadata
+    logs, _exit_status = Gitlab::Popen.popen(%W(tar tzf #{artifacts_path}))
+    @artifacts_metadata = logs.split(/\n/)
+  end
+end
+
+Gitlab::Seeder.quiet do
+  Project.all.sample(10).each do |project|
+    project_builds = Gitlab::Seeder::Builds.new(project)
+    project_builds.seed!
+  end
 end