Merge pull request #613 in ZP/z-push from...

Merge pull request #613 in ZP/z-push from feature/ZP-1122-sync-loop-failsafe-check-for-out-of-memory to develop

* commit '704e0c93':
  ZP-1122 Read configured memory limit once, check memory limit after each message export and stop when limit is reached.

src/lib/request/request.php

@@ -25,6 +25,7 @@
 ************************************************/
 
 class Request {
+    const MAXMEMORYUSAGE = 0.9;     // use max. 90% of allowed memory when synching
     const UNKNOWN = "unknown";
 
     /**
@@ -83,6 +84,7 @@ class Request {
     static private $koeBuildDate;
     static private $koeCapabilites;
     static private $expectedConnectionTimeout;
+    static private $memoryLimit;
 
     /**
      * Initializes request data
@@ -183,6 +185,11 @@ class Request {
         if(defined('USE_FULLEMAIL_FOR_LOGIN') && ! USE_FULLEMAIL_FOR_LOGIN) {
             self::$authUser = Utils::GetLocalPartFromEmail(self::$authUser);
         }
+
+        // get & convert configured memory limit
+        (int)preg_replace_callback('/(\-?\d+)(.?)/', function ($m) {
+            self::$memoryLimit = $m[1] * pow(1024, strpos('BKMG', $m[2])) * self::MAXMEMORYUSAGE;
+        }, strtoupper(ini_get('memory_limit')));
     }
 
     /**
@@ -632,6 +639,18 @@ class Request {
         return (time() - $_SERVER["REQUEST_TIME"]) >= self::GetExpectedConnectionTimeout();
     }
 
+    /**
+     * Indicates if the memory usage limit is almost reached.
+     * Processing should stop then to prevent hard out-of-memory issues.
+     * The threshold is hardcoded at 90% in Request::MAXMEMORYUSAGE.
+     *
+     * @access public
+     * @return boolean
+     */
+    static public function IsRequestMemoryLimitReached() {
+        return memory_get_peak_usage(true) >= self::$memoryLimit;
+    }
+
     /**----------------------------------------------------------------------------------------------------------
      * Private stuff
      */

src/lib/request/sync.php

@@ -826,6 +826,12 @@ class Sync extends RequestProcessor {
                     $setupExporter = false;
                 }
 
+                // if max memory allocation is reached, stop processing other collections
+                if (Request::IsRequestMemoryLimitReached()) {
+                    ZLog::Write(LOGLEVEL_DEBUG, sprintf("Sync(): no exporter setup for '%s' as max memory allocatation reached, omitting output for collection.", $spa->GetFolderId()));
+                    $setupExporter = false;
+                }
+
                 // ZP-907: never send changes of UNKNOWN folders to an Outlook client
                 if (Request::IsOutlook() && self::$deviceManager->GetFolderTypeFromCacheById($spa->GetFolderId()) == SYNC_FOLDER_TYPE_UNKNOWN && $spa->HasSyncKey()) {
                     ZLog::Write(LOGLEVEL_DEBUG, sprintf("Sync(): no exporter setup for '%s' as type is UNKNOWN.", $spa->GetFolderId()));
@@ -1214,7 +1220,7 @@ class Sync extends RequestProcessor {
                     }
                 }
 
-                if($n >= $windowSize || Request::IsRequestTimeoutReached()) {
+                if($n >= $windowSize || Request::IsRequestTimeoutReached() || Request::IsRequestMemoryLimitReached()) {
                     ZLog::Write(LOGLEVEL_DEBUG, sprintf("HandleSync(): Exported maxItems of messages: %d / %d", $n, $changecount));
                     break;
                 }
@@ -1229,9 +1235,9 @@ class Sync extends RequestProcessor {
             self::$encoder->endTag();
 
             // log the request timeout
-            if (Request::IsRequestTimeoutReached()) {
-                ZLog::Write(LOGLEVEL_DEBUG, "HandleSync(): Stopping export as maximum request timeout is almost reached!");
-                // Send a <MoreAvailable/> tag if we reached the request timeout, there are more changes and a moreavailable was not already send
+            if (Request::IsRequestTimeoutReached() || Request::IsRequestMemoryLimitReached()) {
+                ZLog::Write(LOGLEVEL_DEBUG, "HandleSync(): Stopping export as limits of request timeout or available memory are almost reached!");
+                // Send a <MoreAvailable/> tag if we reached the request timeout or max memory, there are more changes and a moreavailable was not already send
                 if (!$moreAvailableSent && ($n > $windowSize)) {
                     self::$encoder->startTag(SYNC_MOREAVAILABLE, false, true);
                     $spa->DelFolderStat();