Pre-installation checks

doc/dbus_api.md

@@ -305,6 +305,20 @@ The main object of a service implements the following interface:
 - Finished: b (r)
   Whether the progress has finished.
 
+## Validation
+
+The main object of a service may implement the validation interface. It reports
+any issue that might block the installation.
+
+### org.opensuse.DInstaller.Validation1
+
+- Errors: array of strings (as)
+  List of validation errors.
+
+- Valid: boolean (b)
+  Whether there are validation errors. It is a way to check whether a service
+  is ready for installation without having to retrieve the list of errors.
+
 ## Manager
 
 ### Installation Phases
@@ -365,4 +379,4 @@ reason, the *manager* service will store the status of each service and the clie
 
 - BusyServices -> a(s) (r)
 
-  List of names of the currently busy services.
+  List of names of the currently busy services.

service/Gemfile.lock

@@ -77,6 +77,3 @@ DEPENDENCIES
   simplecov (~> 0.21.2)
   simplecov-lcov (~> 0.8.0)
   yard (~> 0.9.0)
-
-BUNDLED WITH
-   2.3.3

service/lib/dinstaller/dbus/clients/storage.rb

@@ -22,6 +22,7 @@
 require "dinstaller/dbus/clients/base"
 require "dinstaller/dbus/clients/with_service_status"
 require "dinstaller/dbus/clients/with_progress"
+require "dinstaller/dbus/clients/with_validation"
 
 module DInstaller
   module DBus
@@ -30,6 +31,7 @@ module Clients
       class Storage < Base
         include WithServiceStatus
         include WithProgress
+        include WithValidation
 
         PROPOSAL_IFACE = "org.opensuse.DInstaller.Storage.Proposal1"
         private_constant :PROPOSAL_IFACE

service/lib/dinstaller/dbus/clients/users.rb

@@ -21,13 +21,15 @@
 
 require "dinstaller/dbus/clients/base"
 require "dinstaller/dbus/clients/with_service_status"
+require "dinstaller/dbus/clients/with_validation"
 
 module DInstaller
   module DBus
     module Clients
       # D-Bus client for users configuration
       class Users < Base
         include WithServiceStatus
+        include WithValidation
 
         def initialize
           super

service/lib/dinstaller/dbus/clients/with_validation.rb

@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+# Copyright (c) [2022] SUSE LLC
+#
+# All Rights Reserved.
+#
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of version 2 of the GNU General Public License as published
+# by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+# more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, contact SUSE LLC.
+#
+# To contact SUSE LLC about this file by physical or electronic mail, you may
+# find current contact information at www.suse.com.
+
+require "dinstaller/validation_error"
+
+module DInstaller
+  module DBus
+    # Mixin to include in the clients of services that implement the Validation1 interface
+    module WithValidation
+      VALIDATION_IFACE = "org.opensuse.DInstaller.Validation1"
+      private_constant :VALIDATION_IFACE
+
+      # Returns the validation errors
+      #
+      # @return [Array<ValidationError>] Validation errors
+      def errors
+        dbus_object[VALIDATION_IFACE]["Errors"].map do |message|
+          DInstaller::ValidationError.new(message)
+        end
+      end
+
+      # Determines whether the service settings are valid or not
+      #
+      # @return [Boolean] true if the service has valid data; false otherwise
+      def valid?
+        dbus_object[VALIDATION_IFACE]["Valid"]
+      end
+    end
+  end
+end

service/lib/dinstaller/dbus/interfaces/validation.rb

@@ -0,0 +1,92 @@
+# frozen_string_literal: true
+
+# Copyright (c) [2022] SUSE LLC
+#
+# All Rights Reserved.
+#
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of version 2 of the GNU General Public License as published
+# by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+# more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, contact SUSE LLC.
+#
+# To contact SUSE LLC about this file by physical or electronic mail, you may
+# find current contact information at www.suse.com.
+
+require "dbus"
+
+module DInstaller
+  module DBus
+    module Interfaces
+      # Mixin to define the Validation D-Bus interface
+      #
+      # @example Update the validation on a D-Bus call
+      #   class Backend
+      #     def validate
+      #       ["Some error"]
+      #     end
+      #   end
+      #
+      #   class Demo < DInstaller::DBus::BaseObject
+      #     include DInstaller::DBus::Interfaces::Validation
+      #
+      #     dbus_interface "org.opensuse.DInstaller.Demo1" do
+      #       dbus_reader :errors, "as", dbus_name: "Errors"
+      #       dbus_method :Foo, "out result:u" do
+      #         # do some stuff
+      #         update_validation # run this method is the validation can change
+      #         0
+      #       end
+      #     end
+      #   end
+      #
+      # @note This mixin is expected to be included in a class that inherits from {DBus::BaseObject}
+      # and it requires a #backend method that returns an object that implements a #validate method.
+      module Validation
+        VALIDATION_INTERFACE = "org.opensuse.DInstaller.Validation1"
+
+        # D-Bus properties of the Validation1 interface
+        #
+        # @return [Hash]
+        def validation_properties
+          interfaces_and_properties[VALIDATION_INTERFACE]
+        end
+
+        # Updates the validation and raise the `PropertiesChanged` signal
+        def update_validation
+          @errors = nil
+          dbus_properties_changed(VALIDATION_INTERFACE, validation_properties, [])
+        end
+
+        # Returns the validation errors
+        #
+        # @return [Array<String>] Validation error messages
+        def errors
+          @errors ||= backend.validate.map(&:message)
+        end
+
+        # Determines whether the service settings are valid or not
+        #
+        # @return [Boolean] true if the service has valid data; false otherwise
+        def valid?
+          errors.empty?
+        end
+
+        def self.included(base)
+          base.class_eval do
+            dbus_interface VALIDATION_INTERFACE do
+              dbus_reader :errors, "as", dbus_name: "Errors"
+              dbus_reader :valid?, "b", dbus_name: "Valid"
+            end
+          end
+        end
+      end
+    end
+  end
+end

service/lib/dinstaller/dbus/manager.rb

@@ -59,6 +59,7 @@ def initialize(backend, logger)
       dbus_interface MANAGER_INTERFACE do
         dbus_method(:Probe, "") { config_phase }
         dbus_method(:Commit, "") { install_phase }
+        dbus_method(:CanInstall, "out result:b") { can_install? }
         dbus_reader :installation_phases, "aa{sv}"
         dbus_reader :current_installation_phase, "u"
         dbus_reader :busy_services, "as"
@@ -73,11 +74,20 @@ def config_phase
 
       # Runs the install phase
       def install_phase
+        raise ::DBus::Error, "Installation settings are invalid" unless backend.valid?
+
         safe_run do
           busy_while { backend.install_phase }
         end
       end
 
+      # Determines whether the installation can start
+      #
+      # @return [Boolean]
+      def can_install?
+        backend.valid?
+      end
+
       # Description of all possible installation phase values
       #
       # @return [Array<Hash>]

service/lib/dinstaller/dbus/storage/manager.rb

@@ -24,6 +24,7 @@
 require "dinstaller/dbus/with_service_status"
 require "dinstaller/dbus/interfaces/progress"
 require "dinstaller/dbus/interfaces/service_status"
+require "dinstaller/dbus/interfaces/validation"
 
 module DInstaller
   module DBus
@@ -33,6 +34,7 @@ class Manager < BaseObject
         include WithServiceStatus
         include Interfaces::Progress
         include Interfaces::ServiceStatus
+        include Interfaces::Validation
 
         PATH = "/org/opensuse/DInstaller/Storage1"
         private_constant :PATH
@@ -44,6 +46,7 @@ class Manager < BaseObject
         def initialize(backend, logger)
           super(PATH, logger: logger)
           @backend = backend
+          register_proposal_callbacks
           register_progress_callbacks
           register_service_status_callbacks
         end
@@ -73,6 +76,10 @@ def finish
 
         # @return [DInstaller::Software::Manager]
         attr_reader :backend
+
+        def register_proposal_callbacks
+          backend.proposal.on_calculate { update_validation }
+        end
       end
     end
   end

service/lib/dinstaller/dbus/storage/proposal.rb

@@ -94,9 +94,7 @@ def available_devices
         #
         # @return [Array<String>]
         def candidate_devices
-          return [] unless backend.settings
-
-          backend.settings.candidate_devices
+          backend.candidate_devices
         end
 
         # Whether the proposal creates logical volumes

service/lib/dinstaller/dbus/users.rb

@@ -24,13 +24,15 @@
 require "dinstaller/dbus/base_object"
 require "dinstaller/dbus/with_service_status"
 require "dinstaller/dbus/interfaces/service_status"
+require "dinstaller/dbus/interfaces/validation"
 
 module DInstaller
   module DBus
     # YaST D-Bus object (/org/opensuse/DInstaller/Users1)
     class Users < BaseObject
       include WithServiceStatus
       include Interfaces::ServiceStatus
+      include Interfaces::Validation
 
       PATH = "/org/opensuse/DInstaller/Users1"
       private_constant :PATH
@@ -64,6 +66,7 @@ def initialize(backend, logger)
           backend.assign_root_password(value, encrypted)
 
           dbus_properties_changed(USERS_INTERFACE, { "RootPasswordSet" => !value.empty? }, [])
+          update_validation
           0
         end
 
@@ -73,6 +76,7 @@ def initialize(backend, logger)
 
           dbus_properties_changed(USERS_INTERFACE, { "RootPasswordSet" => backend.root_password? },
             [])
+          update_validation
           0
         end
 
@@ -81,6 +85,7 @@ def initialize(backend, logger)
           backend.root_ssh_key = (value)
 
           dbus_properties_changed(USERS_INTERFACE, { "RootSSHKey" => value }, [])
+          update_validation
           0
         end
 
@@ -90,6 +95,7 @@ def initialize(backend, logger)
           backend.assign_first_user(full_name, user_name, password, auto_login, data)
 
           dbus_properties_changed(USERS_INTERFACE, { "FirstUser" => first_user }, [])
+          update_validation
           0
         end
 
@@ -98,6 +104,7 @@ def initialize(backend, logger)
           backend.remove_first_user
 
           dbus_properties_changed(USERS_INTERFACE, { "FirstUser" => first_user }, [])
+          update_validation
           0
         end
 

service/lib/dinstaller/manager.rb

@@ -187,6 +187,13 @@ def on_services_status_change(&block)
       service_status_recorder.on_service_status_change(&block)
     end
 
+    # Determines whether the configuration is valid and the system is ready for installation
+    #
+    # @return [Boolean]
+    def valid?
+      [storage, users].all?(&:valid?)
+    end
+
   private
 
     attr_reader :config

service/lib/dinstaller/storage/manager.rb

@@ -96,6 +96,13 @@ def proposal
         @proposal ||= Proposal.new(logger, config)
       end
 
+      # Validates the storage configuration
+      #
+      # @return [Array<ValidationError>] List of validation errors
+      def validate
+        proposal.validate
+      end
+
     private
 
       PROPOSAL_ID = "storage_proposal"