Deprecate max execution time

And instead, use a consistent (but filterable) 30 seconds as both
the maximum execution time, and the runner time.

Reducing the time limit to 30 seconds, from an unknown amount in many
cases, helps reduce the likelyhood of timeouts affecting batches.

This is particularly important now that Action Scheduler will loop over
batches in the available time and memory limits (with the merge of woocommerce#192)
instead of simply attempting one batch and then completing, meaning any
time there are more than the default batch size of actions sitting in
the queue, actions will be processed until we run out of actions, time
or memory..

Unifying the time limit API also fixes a few issues:

1. set_time_limit() was being called with a value that was different
   to the return value of get_maximum_execution_time() in many cases.
   This was at best ineffecient, and at worst dangerous as we could
   perceive of having two different time limits.
2. As one consequence of the above, ini_get( 'max_execution_time' ) -
   the default value when not on a known host - would presumably
   return 600, but that was intended to more of an optimistic increase
   not a reliably value for the amount of time we could consume.
3. To consistently change the amount of time allowed for a queue, the
   a callback on the 'action_scheduler_queue_runner_time_limit' filter
   was no longer enough (it would have been prior to 2.0.0), instead
   both it and 'action_scheduler_maximum_execution_time' needed to have
   a callback.

Fixes woocommerce#207.

Author: thenbrent

classes/ActionScheduler.php

@@ -59,7 +59,9 @@ public static function plugin_url( $path ) {
 
 	public static function autoload( $class ) {
 		$d = DIRECTORY_SEPARATOR;
-		if ( strpos( $class, 'ActionScheduler' ) === 0 ) {
+		if ( 'Deprecated' === substr( $class, -10 ) ) {
+			$dir = self::plugin_path('deprecated'.$d);
+		} elseif ( strpos( $class, 'ActionScheduler' ) === 0 ) {
 			$dir = self::plugin_path('classes'.$d);
 		} elseif ( strpos( $class, 'CronExpression' ) === 0 ) {
 			$dir = self::plugin_path('lib'.$d.'cron-expression'.$d);

classes/ActionScheduler_Abstract_QueueRunner.php

@@ -3,7 +3,7 @@
 /**
  * Abstract class with common Queue Cleaner functionality.
  */
-abstract class ActionScheduler_Abstract_QueueRunner {
+abstract class ActionScheduler_Abstract_QueueRunner extends ActionScheduler_Abstract_QueueRunner_Deprecated {
 
 	/** @var ActionScheduler_QueueCleaner */
 	protected $cleaner;
@@ -103,18 +103,17 @@ public function get_allowed_concurrent_batches() {
 	 *
 	 * @return int The number of seconds.
 	 */
-	protected function get_maximum_execution_time() {
+	protected function get_time_limit() {
 
-		// There are known hosts with a strict 60 second execution time.
-		if ( defined( 'WPENGINE_ACCOUNT' ) || defined( 'PANTHEON_ENVIRONMENT' ) ) {
-			$maximum_execution_time = 60;
-		} elseif ( false !== strpos( getenv( 'HOSTNAME' ), '.siteground.' ) ) {
-			$maximum_execution_time = 120;
-		} else {
-			$maximum_execution_time = ini_get( 'max_execution_time' );
+		$time_limit = 30;
+
+		// Apply deprecated filter from deprecated get_maximum_execution_time() method
+		if ( has_filter( 'action_scheduler_maximum_execution_time' ) ) {
+			_deprecated_function( 'action_scheduler_maximum_execution_time', '2.1.1', 'action_scheduler_queue_runner_time_limit' );
+			$time_limit = apply_filters( 'action_scheduler_maximum_execution_time', $time_limit );
 		}
 
-		return absint( apply_filters( 'action_scheduler_maximum_execution_time', $maximum_execution_time ) );
+		return absint( apply_filters( 'action_scheduler_queue_runner_time_limit', $time_limit ) );
 	}
 
 	/**
@@ -146,7 +145,7 @@ protected function get_execution_time() {
 	protected function time_likely_to_be_exceeded( $processed_actions ) {
 
 		$execution_time        = $this->get_execution_time();
-		$max_execution_time    = $this->get_maximum_execution_time();
+		$max_execution_time    = $this->get_time_limit();
 		$time_per_action       = $execution_time / $processed_actions;
 		$estimated_time        = $execution_time + ( $time_per_action * 3 );
 		$likely_to_be_exceeded = $estimated_time > $max_execution_time;

classes/ActionScheduler_Compatibility.php

@@ -85,7 +85,12 @@ public static function raise_memory_limit() {
 	 *
 	 * @param int The time limit in seconds.
 	 */
-	public static function increase_time_limit( $limit = 0 ) {
+	public static function raise_time_limit( $limit = 0 ) {
+
+		if ( $limit < ini_get( 'max_execution_time' ) ) {
+			return;
+		}
+
 		if ( function_exists( 'wc_set_time_limit' ) ) {
 			return wc_set_time_limit( $limit );
 		} elseif ( function_exists( 'set_time_limit' ) && false === strpos( ini_get( 'disable_functions' ), 'set_time_limit' ) && ! ini_get( 'safe_mode' ) ) {

classes/ActionScheduler_QueueRunner.php

@@ -51,7 +51,7 @@ public function init() {
 
 	public function run() {
 		ActionScheduler_Compatibility::raise_memory_limit();
-		@set_time_limit( apply_filters( 'action_scheduler_queue_runner_time_limit', 600 ) );
+		ActionScheduler_Compatibility::raise_time_limit( $this->get_time_limit() );
 		do_action( 'action_scheduler_before_process_queue' );
 		$this->run_cleanup();
 		$processed_actions = 0;

deprecated/ActionScheduler_Abstract_QueueRunner_Deprecated.php

@@ -0,0 +1,27 @@
+<?php
+
+/**
+ * Abstract class with common Queue Cleaner functionality.
+ */
+abstract class ActionScheduler_Abstract_QueueRunner_Deprecated {
+
+	/**
+	 * Get the maximum number of seconds a batch can run for.
+	 *
+	 * @deprecated 2.1.1
+	 * @return int The number of seconds.
+	 */
+	protected function get_maximum_execution_time() {
+		_deprecated_function( __METHOD__, '2.1.1', 'ActionScheduler_Abstract_QueueRunner::get_time_limit()' );
+
+		$maximum_execution_time = 30;
+
+		// Apply deprecated filter
+		if ( has_filter( 'action_scheduler_maximum_execution_time' ) ) {
+			_deprecated_function( 'action_scheduler_maximum_execution_time', '2.1.1', 'action_scheduler_queue_runner_time_limit' );
+			$maximum_execution_time = apply_filters( 'action_scheduler_maximum_execution_time', $maximum_execution_time );
+		}
+
+		return absint( $maximum_execution_time );
+	}
+}