Merge branch 'MDL-59594-SIGINT' of https://github.com/brendanheywood/…

…moodle
moodle · Jan 20, 2020 · c282319 · c282319
2 parents d29c986 + b15c53f
commit c282319
Show file tree

Hide file tree

Showing 7 changed files with 142 additions and 20 deletions.
diff --git a/admin/cli/cron.php b/admin/cli/cron.php
@@ -74,4 +74,6 @@
     die;
 }
 
+\core\local\cli\shutdown::script_supports_graceful_exit();
+
 cron_run();
diff --git a/admin/tool/task/cli/adhoc_task.php b/admin/tool/task/cli/adhoc_task.php
@@ -115,5 +115,7 @@
 $humantimenow = date('r', time());
 $keepalive = (int)$options['keep-alive'];
 
+\core\local\cli\shutdown::script_supports_graceful_exit();
+
 mtrace("Server Time: {$humantimenow}\n");
 cron_run_adhoc_tasks(time(), $keepalive, $checklimits);
diff --git a/lang/en/admin.php b/lang/en/admin.php
@@ -120,6 +120,8 @@
 $string['cleanup'] = 'Cleanup';
 $string['clianswerno'] = 'n';
 $string['cliansweryes'] = 'y';
+$string['cliexitgraceful'] = 'Exiting gracefully, please wait ...';
+$string['cliexitnow'] = 'Exiting right NOW';
 $string['cliincorrectvalueerror'] = 'Error, incorrect value "{$a->value}" for "{$a->option}"';
 $string['cliincorrectvalueretry'] = 'Incorrect value, please retry';
 $string['clistatusdisabled'] = 'Status: disabled';

diff --git a/lib/classes/local/cli/shutdown.php b/lib/classes/local/cli/shutdown.php
@@ -0,0 +1,81 @@
+<?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/>.
+
+/**
+ * CLI script shutdown helper class.
+ *
+ * @package    core
+ * @copyright  2019 Brendan Heywood <brendan@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core\local\cli;
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * CLI script shutdown helper class.
+ *
+ * @package    core
+ * @copyright  2019 Brendan Heywood <brendan@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class shutdown {
+
+    /** @var bool Should we exit gracefully at the next opportunity? */
+    protected static $cligracefulexit = false;
+
+    /**
+     * Declares that this CLI script can gracefully handle signals
+     *
+     * @return void
+     */
+    public static function script_supports_graceful_exit(): void {
+        \core_shutdown_manager::register_signal_handler('\core\local\cli\shutdown::signal_handler');
+    }
+
+    /**
+     * Should we gracefully exit?
+     *
+     * @return bool true if we should gracefully exit
+     */
+    public static function should_gracefully_exit(): bool {
+        return self::$cligracefulexit;
+    }
+
+    /**
+     * Handle the signal
+     *
+     * The first signal flags a graceful exit. If a second signal is received
+     * then it immediately exits.
+     *
+     * @param int $signo The signal number
+     * @return bool true if we should exit
+     */
+    public static function signal_handler(int $signo): bool {
+
+        if (self::$cligracefulexit) {
+            cli_heading(get_string('cliexitnow', 'admin'));
+            return true;
+        }
+
+        cli_heading(get_string('cliexitgraceful', 'admin'));
+        self::$cligracefulexit = true;
+        return false;
+    }
+
+}
+
diff --git a/lib/classes/shutdown_manager.php b/lib/classes/shutdown_manager.php
@@ -33,7 +33,9 @@
  */
 class core_shutdown_manager {
     /** @var array list of custom callbacks */
-    protected static $callbacks = array();
+    protected static $callbacks = [];
+    /** @var array list of custom signal callbacks */
+    protected static $signalcallbacks = [];
     /** @var bool is this manager already registered? */
     protected static $registered = false;
 
@@ -66,7 +68,7 @@ public static function initialize() {
      *
      * @param   int     $signo The signal being handled
      */
-    public static function signal_handler($signo) {
+    public static function signal_handler(int $signo) {
         // Note: There is no need to manually call the shutdown handler.
         // The fact that we are calling exit() in this script means that the standard shutdown handling is performed
         // anyway.
@@ -92,17 +94,57 @@ public static function signal_handler($signo) {
                 $exitcode = 1;
         }
 
-        exit ($exitcode);
+        // Normally we should exit unless a callback tells us to wait.
+        $shouldexit = true;
+        foreach (self::$signalcallbacks as $data) {
+            list($callback, $params) = $data;
+            try {
+                array_unshift($params, $signo);
+                $shouldexit = call_user_func_array($callback, $params) && $shouldexit;
+            } catch (Throwable $e) {
+                // @codingStandardsIgnoreStart
+                error_log('Exception ignored in signal function ' . get_callable_name($callback) . ': ' . $e->getMessage());
+                // @codingStandardsIgnoreEnd
+            }
+        }
+
+        if ($shouldexit) {
+            exit ($exitcode);
+        }
+    }
+
+    /**
+     * Register custom signal handler function.
+     *
+     * If a handler returns false the signal will be ignored.
+     *
+     * @param callable $callback
+     * @param array $params
+     * @return void
+     */
+    public static function register_signal_handler($callback, array $params = null): void {
+        if (!is_callable($callback)) {
+            // @codingStandardsIgnoreStart
+            error_log('Invalid custom signal function detected ' . var_export($callback, true));
+            // @codingStandardsIgnoreEnd
+        }
+        self::$signalcallbacks[] = [$callback, $params ?? []];
     }
 
     /**
      * Register custom shutdown function.
      *
      * @param callable $callback
      * @param array $params
+     * @return void
      */
-    public static function register_function($callback, array $params = null) {
-        self::$callbacks[] = array($callback, $params);
+    public static function register_function($callback, array $params = null): void {
+        if (!is_callable($callback)) {
+            // @codingStandardsIgnoreStart
+            error_log('Invalid custom shutdown function detected '.var_export($callback, true));
+            // @codingStandardsIgnoreEnd
+        }
+        self::$callbacks[] = [$callback, $params ?? []];
     }
 
     /**
@@ -115,20 +157,11 @@ public static function shutdown_handler() {
         foreach (self::$callbacks as $data) {
             list($callback, $params) = $data;
             try {
-                if (!is_callable($callback)) {
-                    error_log('Invalid custom shutdown function detected '.var_export($callback, true));
-                    continue;
-                }
-                if ($params === null) {
-                    call_user_func($callback);
-                } else {
-                    call_user_func_array($callback, $params);
-                }
-            } catch (Exception $e) {
-                error_log('Exception ignored in shutdown function '.get_callable_name($callback).': '.$e->getMessage());
+                call_user_func_array($callback, $params);
             } catch (Throwable $e) {
-                // Engine errors in PHP7 throw exceptions of type Throwable (this "catch" will be ignored in PHP5).
+                // @codingStandardsIgnoreStart
                 error_log('Exception ignored in shutdown function '.get_callable_name($callback).': '.$e->getMessage());
+                // @codingStandardsIgnoreEnd
             }
         }
 

diff --git a/lib/cronlib.php b/lib/cronlib.php
@@ -114,7 +114,8 @@ function cron_run_scheduled_tasks(int $timenow) {
 
     // Run all scheduled tasks.
     try {
-        while (!\core\task\manager::static_caches_cleared_since($timenow) &&
+        while (!\core\local\cli\shutdown::should_gracefully_exit() &&
+                !\core\task\manager::static_caches_cleared_since($timenow) &&
                 $task = \core\task\manager::get_next_scheduled_task($timenow)) {
             cron_run_inner_scheduled_task($task);
             unset($task);
@@ -167,7 +168,8 @@ function cron_run_adhoc_tasks(int $timenow, $keepalive = 0, $checklimits = true)
     $taskcount = 0;
 
     // Run all adhoc tasks.
-    while (!\core\task\manager::static_caches_cleared_since($timenow)) {
+    while (!\core\local\cli\shutdown::should_gracefully_exit() &&
+            !\core\task\manager::static_caches_cleared_since($timenow)) {
 
         if ($checklimits && (time() - $timenow) >= $maxruntime) {
             if ($waiting) {

diff --git a/version.php b/version.php
@@ -29,7 +29,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$version  = 2020011700.00;              // YYYYMMDD      = weekly release date of this DEV branch.
+$version  = 2020011700.01;              // YYYYMMDD      = weekly release date of this DEV branch.
                                         //         RR    = release increments - 00 in DEV branches.
                                         //           .XX = incremental changes.
 $release  = '3.9dev (Build: 20200117)'; // Human-friendly version name