Don't use transactions and exceptions

Instead return error objects.

2 files changed, 167 insertions, 0 deletions

diff --git a/app/models/concerns/stepable.rb b/app/models/concerns/stepable.rb
new file mode 100644
index 00000000000..d00a049a004
--- /dev/null
+++ b/app/models/concerns/stepable.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+module Stepable
+  extend ActiveSupport::Concern
+
+  def steps
+    self.class._all_steps
+  end
+
+  def execute_steps
+    initial_result = {}
+
+    steps.inject(initial_result) do |previous_result, callback|
+      result = method(callback).call
+
+      if result[:status] == :error
+        result[:failed_step] = callback
+
+        break result
+      end
+
+      previous_result.merge(result)
+    end
+  end
+
+  class_methods do
+    def _all_steps
+      @_all_steps ||= []
+    end
+
+    def steps(*methods)
+      _all_steps.concat methods
+    end
+  end
+end
diff --git a/app/services/self_monitoring/project/create_service.rb b/app/services/self_monitoring/project/create_service.rb
new file mode 100644
index 00000000000..e5ef8c15456
--- /dev/null
+++ b/app/services/self_monitoring/project/create_service.rb
@@ -0,0 +1,132 @@
+# frozen_string_literal: true
+
+module SelfMonitoring
+  module Project
+    class CreateService < ::BaseService
+      include Stepable
+
+      DEFAULT_VISIBILITY_LEVEL = Gitlab::VisibilityLevel::INTERNAL
+      DEFAULT_NAME = 'GitLab Instance Administration'
+      DEFAULT_DESCRIPTION = <<~HEREDOC
+        This project is automatically generated and will be used to help monitor this GitLab instance.
+      HEREDOC
+
+      steps :validate_admins,
+        :create_project,
+        :add_project_members,
+        :add_prometheus_manual_configuration
+
+      def initialize
+        super(nil)
+      end
+
+      def execute
+        execute_steps
+      end
+
+      private
+
+      def validate_admins
+        unless instance_admins.any?
+          log_error('No active admin user found')
+          return error('No active admin user found')
+        end
+
+        success
+      end
+
+      def create_project
+        admin_user = project_owner
+        @project = ::Projects::CreateService.new(admin_user, create_project_params).execute
+
+        if project.persisted?
+          success(project: project)
+        else
+          log_error("Could not create self-monitoring project. Errors: #{project.errors.full_messages}")
+          error('Could not create project')
+        end
+      end
+
+      def add_project_members
+        members = project.add_users(project_maintainers, Gitlab::Access::MAINTAINER)
+        errors = members.flat_map { |member| member.errors.full_messages }
+
+        if errors.any?
+          log_error("Could not add admins as members to self-monitoring project. Errors: #{errors}")
+          error('Could not add admins as members')
+        else
+          success
+        end
+      end
+
+      def add_prometheus_manual_configuration
+        return success unless prometheus_enabled?
+        return success unless prometheus_listen_address.present?
+
+        # TODO: Currently, adding the internal prometheus server as a manual configuration
+        # is only possible if the setting to allow webhooks and services to connect
+        # to local network is on.
+        # https://gitlab.com/gitlab-org/gitlab-ce/issues/44496 will add
+        # a whitelist that will allow connections to certain ips on the local network.
+
+        service = project.find_or_initialize_service('prometheus')
+
+        unless service.update(prometheus_service_attributes)
+          log_error("Could not save prometheus manual configuration for self-monitoring project. Errors: #{service.errors.full_messages}")
+          return error('Could not save prometheus manual configuration')
+        end
+
+        success
+      end
+
+      def prometheus_enabled?
+        Gitlab.config.prometheus.enable
+      rescue Settingslogic::MissingSetting
+        false
+      end
+
+      def prometheus_listen_address
+        Gitlab.config.prometheus.listen_address
+      rescue Settingslogic::MissingSetting
+      end
+
+      def instance_admins
+        @instance_admins ||= User.admins.active
+      end
+
+      def project_owner
+        instance_admins.first
+      end
+
+      def project_maintainers
+        # Exclude the first so that the project_owner is not added again as a member.
+        instance_admins - [project_owner]
+      end
+
+      def create_project_params
+        {
+          initialize_with_readme: true,
+          visibility_level: DEFAULT_VISIBILITY_LEVEL,
+          name: DEFAULT_NAME,
+          description: DEFAULT_DESCRIPTION
+        }
+      end
+
+      def internal_prometheus_listen_address_uri
+        if prometheus_listen_address.starts_with?('http')
+          prometheus_listen_address
+        else
+          'http://' + prometheus_listen_address
+        end
+      end
+
+      def prometheus_service_attributes
+        {
+          api_url: internal_prometheus_listen_address_uri,
+          manual_configuration: true,
+          active: true
+        }
+      end
+    end
+  end
+end