Changeset 8927 for trunk/wp-includes/cron.php

Timestamp:

09/18/2008 07:09:38 AM (16 years ago)

Author:

azaozz

Message:

Cron improvement, props hailin, fixes #7068

File:

• trunk/wp-includes/cron.php (modified) (4 diffs)

trunk/wp-includes/cron.php

@@ -153 +153 @@
  * @return null Cron could not be spawned, because it is not needed to run.
  */
-function spawn_cron() {
-    $crons = _get_cron_array();
-
+function spawn_cron( $local_time ) {
+    global $current_blog;
+
+    /*
+     * do not even start the cron if local server timer has drifted
+     * such as due to power failure, or misconfiguration
+     */
+    $timer_accurate = check_server_timer( $local_time );
+    if ( !$timer_accurate )
+        return;
+
+    //sanity check
+    $crons = _get_cron_array();
     if ( !is_array($crons) )
         return;
 
     $keys = array_keys( $crons );
-    if ( array_shift( $keys ) > time() )
+    $timestamp =  $keys[0];
+    if ( $timestamp > $local_time )
         return;
 
     $cron_url = get_option( 'siteurl' ) . '/wp-cron.php?check=' . wp_hash('187425');
+    /*
+    * multiple processes on multiple web servers can run this code concurrently
+    * try to make this as atomic as possible by setting doing_cron switch
+    */
+    $flag = get_option('doing_cron');
+
+    // clean up potential invalid value resulted from various system chaos
+    if ( $flag != 0 ) {
+        if ( $flag > $local_time + 10*60 || $flag < $local_time - 10*60 ) {
+            update_option('doing_cron', 0);
+            $flag = 0;
+        }
+    }
+
+     //don't run if another process is currently running it
+    if ( $flag > $local_time )
+        return;
+
+    update_option( 'doing_cron', $local_time + 30 );
 
     wp_remote_post($cron_url, array('timeout' => 0.01, 'blocking' => false));
@@ -176 +206 @@
  */
 function wp_cron() {
+
     // Prevent infinite loops caused by lack of wp-cron.php
     if ( strpos($_SERVER['REQUEST_URI'], '/wp-cron.php') !== false )
@@ -189 +220 @@
         return;
 
+    $local_time = time();
     $schedules = wp_get_schedules();
     foreach ( $crons as $timestamp => $cronhooks ) {
-        if ( $timestamp > time() ) break;
+        if ( $timestamp > $local_time ) break;
         foreach ( (array) $cronhooks as $hook => $args ) {
             if ( isset($schedules[$hook]['callback']) && !call_user_func( $schedules[$hook]['callback'] ) )
                 continue;
-            spawn_cron();
+            spawn_cron( $local_time );
             break 2;
         }
@@ -328 +360 @@
 }
 
+// stub for checking server timer accuracy, using outside standard time sources
+function check_server_timer( $local_time ) {
+    return true;
+}
+
 ?>