moodle/backup/controller/restore_controller.class.php
Cameron Ball 29df52af19 MDL-74548 backup: Refactor course copies
This patch modifies the way copy data is shared in order to mitigate potential race conditions
and ensure that the serialised controller stored in the DB is always in a valid state.

The restore controller is now considered the "source of truth" for all information about the
copy operation. Backup controllers can no longer contain information about course copies.

As copy creation is not atomic, it is still possible for copy controllers to become orphaned or
exist in an invalid state. To mitigate this the backup cleanup task has been modified to call
a new helper method copy_helper::cleanup_orphaned_copy_controllers.

Summary of changes in this patch:

    - Copy data must now be passed through the restore controller's constructor
    - base_controller::get_copy has been deprecated in favour of restore_controller::get_copy
    - base_controller::set_copy has been deprecated without replacement
    - core_backup\copy\copy has been deprecated, use copy_helper.class.php's copy_helper instead
    - backup_cleanup_task will now clean up orphaned controllers from copy operations that went awry

Thanks to Peter Burnett for assiting with testing this patch.
2022-06-29 09:13:29 +08:00

642 lines
25 KiB
PHP

<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle 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 Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* @package moodlecore
* @subpackage backup-controller
* @copyright 2010 onwards Eloy Lafuente (stronk7) {@link http://stronk7.com}
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
/**
* Class implementing the controller of any restore process
*
* This final class is in charge of controlling all the restore architecture, for any
* type of backup.
*
* TODO: Finish phpdocs
*/
class restore_controller extends base_controller {
protected $tempdir; // Directory under $CFG->backuptempdir awaiting restore
protected $restoreid; // Unique identificator for this restore
protected $courseid; // courseid where restore is going to happen
protected $type; // Type of backup (activity, section, course)
protected $format; // Format of backup (moodle, imscc)
protected $interactive; // yes/no
protected $mode; // Purpose of the backup (default settings)
protected $userid; // user id executing the restore
protected $operation; // Type of operation (backup/restore)
protected $target; // Restoring to new/existing/current_adding/_deleting
protected $samesite; // Are we restoring to the same site where the backup was generated
protected $status; // Current status of the controller (created, planned, configured...)
protected $precheck; // Results of the execution of restore prechecks
protected $info; // Information retrieved from backup contents
/** @var restore_plan */
protected $plan; // Restore execution plan
/**
* Immediate/delayed execution type.
* @var integer
*/
protected $execution;
protected $executiontime; // epoch time when we want the restore to be executed (requires cron to run)
protected $checksum; // Cache @checksumable results for lighter @is_checksum_correct() uses
/** @var int Number of restore_controllers that are currently executing */
protected static $executing = 0;
/**
* Holds the relevant destination information for course copy operations.
*
* @var \stdClass.
*/
protected $copy;
/**
* Constructor.
*
* If you specify a progress monitor, this will be used to report progress
* while loading the plan, as well as for future use. (You can change it
* for a different one later using set_progress.)
*
* @param string $tempdir Directory under $CFG->backuptempdir awaiting restore
* @param int $courseid Course id where restore is going to happen
* @param bool $interactive backup::INTERACTIVE_YES[true] or backup::INTERACTIVE_NO[false]
* @param int $mode backup::MODE_[ GENERAL | HUB | IMPORT | SAMESITE ]
* @param int $userid
* @param int $target backup::TARGET_[ NEW_COURSE | CURRENT_ADDING | CURRENT_DELETING | EXISTING_ADDING | EXISTING_DELETING ]
* @param \core\progress\base $progress Optional progress monitor
* @param \stdClass $copydata Course copy data, required when in MODE_COPY
* @param bool $releasesession Should release the session? backup::RELEASESESSION_YES or backup::RELEASESESSION_NO
*/
public function __construct($tempdir, $courseid, $interactive, $mode, $userid, $target,
\core\progress\base $progress = null, $releasesession = backup::RELEASESESSION_NO, ?\stdClass $copydata = null) {
if ($mode == backup::MODE_COPY && is_null($copydata)) {
throw new restore_controller_exception('cannot_instantiate_missing_copydata');
}
$this->copy = $copydata;
$this->tempdir = $tempdir;
$this->courseid = $courseid;
$this->interactive = $interactive;
$this->mode = $mode;
$this->userid = $userid;
$this->target = $target;
$this->releasesession = $releasesession;
// Apply some defaults
$this->type = '';
$this->format = backup::FORMAT_UNKNOWN;
$this->operation = backup::OPERATION_RESTORE;
$this->executiontime = 0;
$this->samesite = false;
$this->checksum = '';
$this->precheck = null;
// Apply current backup version and release if necessary
backup_controller_dbops::apply_version_and_release();
// Check courseid is correct
restore_check::check_courseid($this->courseid);
// Check user is correct
restore_check::check_user($this->userid);
// Calculate unique $restoreid
$this->calculate_restoreid();
// Default logger chain (based on interactive/execution)
$this->logger = backup_factory::get_logger_chain($this->interactive, $this->execution, $this->restoreid);
// Set execution based on backup mode.
if ($mode == backup::MODE_ASYNC || $mode == backup::MODE_COPY) {
$this->execution = backup::EXECUTION_DELAYED;
} else {
$this->execution = backup::EXECUTION_INMEDIATE;
}
// By default there is no progress reporter unless you specify one so it
// can be used during loading of the plan.
if ($progress) {
$this->progress = $progress;
} else {
$this->progress = new \core\progress\none();
}
$this->progress->start_progress('Constructing restore_controller');
// Instantiate the output_controller singleton and active it if interactive and immediate.
$oc = output_controller::get_instance();
if ($this->interactive == backup::INTERACTIVE_YES && $this->execution == backup::EXECUTION_INMEDIATE) {
$oc->set_active(true);
}
$this->log('instantiating restore controller', backup::LOG_INFO, $this->restoreid);
// Set initial status
$this->set_status(backup::STATUS_CREATED);
// Calculate original restore format
$this->format = backup_general_helper::detect_backup_format($tempdir);
// If format is not moodle2, set to conversion needed
if ($this->format !== backup::FORMAT_MOODLE) {
$this->set_status(backup::STATUS_REQUIRE_CONV);
// Else, format is moodle2, load plan, apply security and set status based on interactivity
} else {
// Load plan
$this->load_plan();
// Apply all default settings (based on type/format/mode).
$this->apply_defaults();
// Perform all initial security checks and apply (2nd param) them to settings automatically
restore_check::check_security($this, true);
if ($this->interactive == backup::INTERACTIVE_YES) {
$this->set_status(backup::STATUS_SETTING_UI);
} else {
$this->set_status(backup::STATUS_NEED_PRECHECK);
}
}
// Tell progress monitor that we finished loading.
$this->progress->end_progress();
}
/**
* Clean structures used by the restore_controller
*
* This method clean various structures used by the restore_controller,
* destroying them in an ordered way, so their memory will be gc properly
* by PHP (mainly circular references).
*
* Note that, while it's not mandatory to execute this method, it's highly
* recommended to do so, specially in scripts performing multiple operations
* (like the automated backups) or the system will run out of memory after
* a few dozens of backups)
*/
public function destroy() {
// Only need to destroy circulars under the plan. Delegate to it.
$this->plan->destroy();
// Loggers may have also chained references, destroy them. Also closing resources when needed.
$this->logger->destroy();
}
public function finish_ui() {
if ($this->status != backup::STATUS_SETTING_UI) {
throw new restore_controller_exception('cannot_finish_ui_if_not_setting_ui');
}
$this->set_status(backup::STATUS_NEED_PRECHECK);
}
public function process_ui_event() {
// Perform security checks throwing exceptions (2nd param) if something is wrong
restore_check::check_security($this, false);
}
public function set_status($status) {
// Note: never save_controller() with the object info after STATUS_EXECUTING or the whole controller,
// containing all the steps will be sent to DB. 100% (monster) useless.
$this->log('setting controller status to', backup::LOG_DEBUG, $status);
// TODO: Check it's a correct status.
$this->status = $status;
// Ensure that, once set to backup::STATUS_AWAITING | STATUS_NEED_PRECHECK, controller is stored in DB.
// Also save if executing so we can better track progress.
if ($status == backup::STATUS_AWAITING || $status == backup::STATUS_NEED_PRECHECK || $status == backup::STATUS_EXECUTING) {
$this->save_controller();
$tbc = self::load_controller($this->restoreid);
$this->logger = $tbc->logger; // wakeup loggers
$tbc->plan->destroy(); // Clean plan controller structures, keeping logger alive.
} else if ($status == backup::STATUS_FINISHED_OK) {
// If the operation has ended without error (backup::STATUS_FINISHED_OK)
// proceed by cleaning the object from database. MDL-29262.
$this->save_controller(false, true);
} else if ($status == backup::STATUS_FINISHED_ERR) {
// If the operation has ended with an error save the controller
// preserving the object in the database. We may want it for debugging.
$this->save_controller();
}
}
public function set_execution($execution, $executiontime = 0) {
$this->log('setting controller execution', backup::LOG_DEBUG);
// TODO: Check valid execution mode.
// TODO: Check time in future.
// TODO: Check time = 0 if immediate.
$this->execution = $execution;
$this->executiontime = $executiontime;
// Default logger chain (based on interactive/execution)
$this->logger = backup_factory::get_logger_chain($this->interactive, $this->execution, $this->restoreid);
}
// checksumable interface methods
public function calculate_checksum() {
// Reset current checksum to take it out from calculations!
$this->checksum = '';
// Init checksum
$tempchecksum = md5('tempdir-' . $this->tempdir .
'restoreid-' . $this->restoreid .
'courseid-' . $this->courseid .
'type-' . $this->type .
'format-' . $this->format .
'interactive-'. $this->interactive .
'mode-' . $this->mode .
'userid-' . $this->userid .
'target-' . $this->target .
'samesite-' . $this->samesite .
'operation-' . $this->operation .
'status-' . $this->status .
'precheck-' . backup_general_helper::array_checksum_recursive(array($this->precheck)) .
'execution-' . $this->execution .
'plan-' . backup_general_helper::array_checksum_recursive(array($this->plan)) .
'info-' . backup_general_helper::array_checksum_recursive(array($this->info)) .
'logger-' . backup_general_helper::array_checksum_recursive(array($this->logger)));
$this->log('calculating controller checksum', backup::LOG_DEBUG, $tempchecksum);
return $tempchecksum;
}
public function is_checksum_correct($checksum) {
return $this->checksum === $checksum;
}
public function get_tempdir() {
return $this->tempdir;
}
public function get_restoreid() {
return $this->restoreid;
}
public function get_type() {
return $this->type;
}
public function get_operation() {
return $this->operation;
}
public function get_courseid() {
return $this->courseid;
}
public function get_format() {
return $this->format;
}
public function get_interactive() {
return $this->interactive;
}
public function get_mode() {
return $this->mode;
}
public function get_userid() {
return $this->userid;
}
public function get_target() {
return $this->target;
}
public function is_samesite() {
return $this->samesite;
}
public function get_status() {
return $this->status;
}
public function get_execution() {
return $this->execution;
}
public function get_executiontime() {
return $this->executiontime;
}
/**
* Returns the restore plan
* @return restore_plan
*/
public function get_plan() {
return $this->plan;
}
/**
* Gets the value for the requested setting
*
* @param string $name
* @param bool $default
* @return mixed
*/
public function get_setting_value($name, $default = false) {
try {
return $this->get_plan()->get_setting($name)->get_value();
} catch (Exception $e) {
debugging('Failed to find the setting: '.$name, DEBUG_DEVELOPER);
return $default;
}
}
/**
* For debug only. Get a simple test display of all the settings.
*
* @return string
*/
public function debug_display_all_settings_values(): string {
return $this->get_plan()->debug_display_all_settings_values();
}
public function get_info() {
return $this->info;
}
public function execute_plan() {
// Basic/initial prevention against time/memory limits
core_php_time_limit::raise(1 * 60 * 60); // 1 hour for 1 course initially granted
raise_memory_limit(MEMORY_EXTRA);
// Release the session so other tabs in the same session are not blocked.
if ($this->get_releasesession() === backup::RELEASESESSION_YES) {
\core\session\manager::write_close();
}
// Do course cleanup precheck, if required. This was originally in restore_ui. Moved to handle async backup/restore.
if ($this->get_target() == backup::TARGET_CURRENT_DELETING || $this->get_target() == backup::TARGET_EXISTING_DELETING) {
$options = array();
$options['keep_roles_and_enrolments'] = $this->get_setting_value('keep_roles_and_enrolments');
$options['keep_groups_and_groupings'] = $this->get_setting_value('keep_groups_and_groupings');
$options['userid'] = $this->userid;
restore_dbops::delete_course_content($this->get_courseid(), $options);
}
// If this is not a course restore or single activity restore (e.g. duplicate), inform the plan we are not
// including all the activities for sure. This will affect any
// task/step executed conditionally to stop processing information
// for section and activity restore. MDL-28180.
if ($this->get_type() !== backup::TYPE_1COURSE && $this->get_type() !== backup::TYPE_1ACTIVITY) {
$this->log('notifying plan about excluded activities by type', backup::LOG_DEBUG);
$this->plan->set_excluding_activities();
}
self::$executing++;
try {
$this->plan->execute();
} catch (Exception $e) {
self::$executing--;
throw $e;
}
self::$executing--;
}
/**
* Checks whether restore is currently executing. Certain parts of code that
* is called during restore, but not directly part of the restore system, may
* need to behave differently during restore (e.g. do not bother resetting a
* cache because we know it will be reset at end of operation).
*
* @return bool True if any restore is currently executing
*/
public static function is_executing() {
return self::$executing > 0;
}
/**
* Execute the restore prechecks to detect any problem before proceed with restore
*
* This function checks various parts of the restore (versions, users, roles...)
* returning true if everything was ok or false if any warning/error was detected.
* Any warning/error is returned by the get_precheck_results() method.
* Note: if any problem is found it will, automatically, drop all the restore temp
* tables as far as the next step is to inform about the warning/errors. If no problem
* is found, then default behaviour is to keep the temp tables so, in the same request
* restore will be executed, saving a lot of checks to be executed again.
* Note: If for any reason (UI to show after prechecks...) you want to force temp tables
* to be dropped always, you can pass true to the $droptemptablesafter parameter
*/
public function execute_precheck($droptemptablesafter = false) {
if (is_array($this->precheck)) {
throw new restore_controller_exception('precheck_alredy_executed', $this->status);
}
if ($this->status != backup::STATUS_NEED_PRECHECK) {
throw new restore_controller_exception('cannot_precheck_wrong_status', $this->status);
}
// Basic/initial prevention against time/memory limits
core_php_time_limit::raise(1 * 60 * 60); // 1 hour for 1 course initially granted
raise_memory_limit(MEMORY_EXTRA);
$this->precheck = restore_prechecks_helper::execute_prechecks($this, $droptemptablesafter);
if (!array_key_exists('errors', $this->precheck)) { // No errors, can be executed
$this->set_status(backup::STATUS_AWAITING);
}
if (empty($this->precheck)) { // No errors nor warnings, return true
return true;
}
return false;
}
public function get_results() {
return $this->plan->get_results();
}
/**
* Returns true if the prechecks have been executed
* @return bool
*/
public function precheck_executed() {
return (is_array($this->precheck));
}
public function get_precheck_results() {
if (!is_array($this->precheck)) {
throw new restore_controller_exception('precheck_not_executed');
}
return $this->precheck;
}
/**
* Save controller information
*
* @param bool $includeobj to decide if the object itself must be updated (true) or no (false)
* @param bool $cleanobj to decide if the object itself must be cleaned (true) or no (false)
*/
public function save_controller($includeobj = true, $cleanobj = false) {
// Going to save controller to persistent storage, calculate checksum for later checks and save it
// TODO: flag the controller as NA. Any operation on it should be forbidden util loaded back
$this->log('saving controller to db', backup::LOG_DEBUG);
if ($includeobj ) { // Only calculate checksum if we are going to include the object.
$this->checksum = $this->calculate_checksum();
}
restore_controller_dbops::save_controller($this, $this->checksum, $includeobj, $cleanobj);
}
public static function load_controller($restoreid) {
// Load controller from persistent storage
// TODO: flag the controller as available. Operations on it can continue
$controller = restore_controller_dbops::load_controller($restoreid);
$controller->log('loading controller from db', backup::LOG_DEBUG);
return $controller;
}
/**
* class method to provide pseudo random unique "correct" tempdir names
*/
public static function get_tempdir_name($courseid = 0, $userid = 0) {
// Current epoch time + courseid + userid + random bits
return md5(time() . '-' . $courseid . '-'. $userid . '-'. random_string(20));
}
/**
* Converts from current format to backup::MOODLE format
*/
public function convert() {
global $CFG;
require_once($CFG->dirroot . '/backup/util/helper/convert_helper.class.php');
// Basic/initial prevention against time/memory limits
core_php_time_limit::raise(1 * 60 * 60); // 1 hour for 1 course initially granted
raise_memory_limit(MEMORY_EXTRA);
$this->progress->start_progress('Backup format conversion');
if ($this->status != backup::STATUS_REQUIRE_CONV) {
throw new restore_controller_exception('cannot_convert_not_required_status');
}
$this->log('backup format conversion required', backup::LOG_INFO);
// Run conversion to the proper format
if (!convert_helper::to_moodle2_format($this->get_tempdir(), $this->format, $this->get_logger())) {
// todo - unable to find the conversion path, what to do now?
// throwing the exception as a temporary solution
throw new restore_controller_exception('unable_to_find_conversion_path');
}
$this->log('backup format conversion successful', backup::LOG_INFO);
// If no exceptions were thrown, then we are in the proper format
$this->format = backup::FORMAT_MOODLE;
// Load plan, apply security and set status based on interactivity
$this->load_plan();
// Perform all initial security checks and apply (2nd param) them to settings automatically
restore_check::check_security($this, true);
if ($this->interactive == backup::INTERACTIVE_YES) {
$this->set_status(backup::STATUS_SETTING_UI);
} else {
$this->set_status(backup::STATUS_NEED_PRECHECK);
}
$this->progress->end_progress();
}
/**
* Do the necessary copy preparation actions.
* This method should only be called once the backup of a copy operation is completed.
*
* @throws restore_controller_exception
*/
public function prepare_copy(): void {
// Check that we are in the correct mode.
if ($this->mode != backup::MODE_COPY) {
throw new restore_controller_exception('cannot_prepare_copy_wrong_mode');
}
$this->progress->start_progress('Prepare Copy');
// If no exceptions were thrown, then we are in the proper format.
$this->format = backup::FORMAT_MOODLE;
// Load plan, apply security and set status based on interactivity.
$this->load_plan();
$this->set_status(backup::STATUS_NEED_PRECHECK);
$this->progress->end_progress();
}
/**
* Get the course copy data.
*
* @return \stdClass
*/
public function get_copy(): \stdClass {
if ($this->mode != backup::MODE_COPY) {
throw new restore_controller_exception('cannot_get_copy_wrong_mode');
}
return $this->copy;
}
// Protected API starts here
protected function calculate_restoreid() {
// Current epoch time + tempdir + courseid + interactive + mode + userid + target + operation + random bits
$this->restoreid = md5(time() . '-' . $this->tempdir . '-' . $this->courseid . '-'. $this->interactive . '-' .
$this->mode . '-' . $this->userid . '-'. $this->target . '-' . $this->operation . '-' .
random_string(20));
}
protected function load_plan() {
// First of all, we need to introspect the moodle_backup.xml file
// in order to detect all the required stuff. So, create the
// monster $info structure where everything will be defined
$this->log('loading backup info', backup::LOG_DEBUG);
$this->info = backup_general_helper::get_backup_information($this->tempdir);
// Set the controller type to the one found in the information
$this->type = $this->info->type;
// Set the controller samesite flag as needed
$this->samesite = backup_general_helper::backup_is_samesite($this->info);
// Now we load the plan that will be configured following the
// information provided by the $info
$this->log('loading controller plan', backup::LOG_DEBUG);
$this->plan = new restore_plan($this);
$this->plan->build(); // Build plan for this controller
$this->set_status(backup::STATUS_PLANNED);
}
/**
* Apply defaults from the global admin settings
*/
protected function apply_defaults() {
$this->log('applying restore defaults', backup::LOG_DEBUG);
restore_controller_dbops::apply_config_defaults($this);
$this->set_status(backup::STATUS_CONFIGURED);
}
}
/*
* Exception class used by all the @restore_controller stuff
*/
class restore_controller_exception extends backup_exception {
public function __construct($errorcode, $a=NULL, $debuginfo=null) {
parent::__construct($errorcode, $a, $debuginfo);
}
}