Rename projects with reserved path names

We cant have project with name 'project' or 'tree' anymore.
This merge request containts a migration that will find and rename all
projects using reserved names by adding N digit to the end of the name.
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/models/project.rb

@@ -921,7 +921,7 @@ class Project < ActiveRecord::Base
       Rails.logger.error "Project #{old_path_with_namespace} cannot be renamed because container registry tags are present"
 
       # we currently doesn't support renaming repository if it contains tags in container registry
-      raise Exception.new('Project cannot be renamed, because tags are present in its container registry')
+      raise StandardError.new('Project cannot be renamed, because tags are present in its container registry')
     end
 
     if gitlab_shell.mv_repository(repository_storage_path, old_path_with_namespace, new_path_with_namespace)
@@ -948,7 +948,7 @@ class Project < ActiveRecord::Base
 
       # if we cannot move namespace directory we should rollback
       # db changes in order to prevent out of sync between db and fs
-      raise Exception.new('repository cannot be renamed')
+      raise StandardError.new('repository cannot be renamed')
     end
 
     Gitlab::AppLogger.info "Project was renamed: #{old_path_with_namespace} -> #{new_path_with_namespace}"

changelogs/unreleased/dz-rename-reserved-project-names.yml

+---
+title: Rename projects wth reserved names
+merge_request: 8234
+author:

db/post_migrate/20161221153951_rename_reserved_project_names.rb

+class RenameReservedProjectNames < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+  include Gitlab::ShellAdapter
+
+  DOWNTIME = false
+
+  class Project < ActiveRecord::Base; end
+
+  def up
+    threads = reserved_projects.each_slice(100).map do |slice|
+      Thread.new do
+        rename_projects(slice)
+      end
+    end
+
+    threads.each(&:join)
+  end
+
+  def down
+    # nothing to do here
+  end
+
+  private
+
+  def reserved_projects
+    select_all("SELECT p.id, p.path, p.repository_storage, n.path AS namespace_path, n.id AS namespace_id FROM projects p
+               INNER JOIN namespaces n ON n.id = p.namespace_id
+               WHERE p.path IN (
+               '.well-known', 'all', 'assets', 'files', 'groups', 'hooks', 'issues',
+               'merge_requests', 'new', 'profile', 'projects', 'public', 'repository',
+               'robots.txt', 's', 'snippets', 'teams', 'u', 'unsubscribes', 'users',
+               'tree', 'commits', 'wikis', 'new', 'edit', 'create', 'update', 'logs_tree',
+               'preview', 'blob', 'blame', 'raw', 'files', 'create_dir', 'find_file')")
+  end
+
+  def route_exists?(full_path)
+    select_all("SELECT id, path FROM routes WHERE path = '#{quote_string(full_path)}'").present?
+  end
+
+  # Adds number to the end of the path that is not taken by other route
+  def rename_path(namespace_path, path_was)
+    counter = 0
+    path = "#{path_was}#{counter}"
+
+    while route_exists?("#{namespace_path}/#{path}")
+      counter += 1
+      path = "#{path_was}#{counter}"
+    end
+
+    path
+  end
+
+  def rename_projects(projects)
+    projects.each do |row|
+      id = row['id']
+      path_was = row['path']
+      namespace_path = row['namespace_path']
+      path = rename_path(namespace_path, path_was)
+      project = Project.find_by(id: id)
+
+      begin
+        # Because project path update is quite complex operation we can't safely
+        # copy-paste all code from GitLab. As exception we use Rails code here
+        if project &&
+          project.respond_to?(:update_attributes) &&
+          project.update_attributes(path: path) &&
+          project.respond_to?(:rename_repo)
+
+          project.rename_repo
+        end
+      rescue => e
+        Rails.logger.error "Exception when rename project #{id}: #{e.message}"
+      end
+    end
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20161221140236) do
+ActiveRecord::Schema.define(version: 20161221153951) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"

spec/migrations/rename_reserved_project_names_spec.rb

+# encoding: utf-8
+
+require 'spec_helper'
+require Rails.root.join('db', 'post_migrate', '20161221153951_rename_reserved_project_names.rb')
+
+describe RenameReservedProjectNames do
+  let(:migration) { described_class.new }
+  let!(:project) { create(:project) }
+
+  before do
+    project.path = 'projects'
+    project.save!(validate: false)
+    allow(Thread).to receive(:new).and_yield
+  end
+
+  describe '#up' do
+    context 'when project repository exists' do
+      before { project.create_repository }
+
+      context 'when no exception is raised' do
+        it 'renames project with reserved names' do
+          migration.up
+
+          expect(project.reload.path).to eq('projects0')
+        end
+      end
+
+      context 'when exception is raised during rename' do
+        before do
+          allow(project).to receive(:rename_repo).and_raise(StandardError)
+        end
+
+        it 'captures exception from project rename' do
+          expect { migration.up }.not_to raise_error
+        end
+      end
+    end
+
+    context 'when project repository does not exist' do
+      it 'does not raise error' do
+        expect { migration.up }.not_to raise_error
+      end
+    end
+  end
+end