SyncRule: introduce purge strategies

library/Director/Import/PurgeStrategy/ImportRunBasedPurgeStrategy.php

@@ -0,0 +1,73 @@
+<?php
+
+namespace Icinga\Module\Director\Import\PurgeStrategy;
+
+use Icinga\Module\Director\Objects\ImportRun;
+use Icinga\Module\Director\Objects\ImportSource;
+
+class ImportRunBasedPurgeStrategy extends PurgeStrategy
+{
+    public function listObjectsToPurge()
+    {
+        $remove = array();
+
+        foreach ($this->getSyncRule()->fetchInvolvedImportSources() as $source) {
+            $remove += $this->checkImportSource($source);
+        }
+
+        return $remove;
+    }
+
+    protected function getLastSync()
+    {
+        return strtotime($this->getSyncRule()->getLastSyncTimestamp());
+    }
+
+    // TODO: NAMING!
+    protected function checkImportSource(ImportSource $source)
+    {
+        if (null === ($lastSync = $this->getLastSync())) {
+            // No last sync, nothing to purge
+            return array();
+        }
+
+        $runA = $source->fetchLastRunBefore($lastSync);
+        if ($runA === null) {
+            // Nothing to purge for this source
+            return array();
+        }
+
+        $runB = $source->fetchLastRun();
+        if ($runA->rowset_checksum === $runB->rowset_checksum) {
+            // Same source data, nothing to purge
+            return array();
+        }
+
+        return $this->listKeysRemovedBetween($runA, $runB);
+    }
+
+    public function listKeysRemovedBetween(ImportRun $runA, ImportRun $runB)
+    {
+        $db = $this->getSyncRule()->getDb();
+
+        $selectA = $runA->prepareImportedObjectQuery();
+        $selectB = $runB->prepareImportedObjectQuery();
+
+        $query = $db->select()->from(
+            array('a' => $selectA),
+            'a.object_name'
+        )->joinLeft(
+            array('b' => $selectB),
+            'a.object_name = b.object_name',
+            array()
+        )->where('b.object_name IS NULL');
+
+        $result = $db->fetchCol($query);
+
+        if ($result) {
+            return array_combine($result, $result);
+        } else {
+            return array();
+        }
+    }
+}

library/Director/Import/PurgeStrategy/PurgeNothingPurgeStrategy.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace Icinga\Module\Director\Import\PurgeStrategy;
+
+class PurgeNothingPurgeStrategy extends PurgeStrategy
+{
+    public function listObjectsToPurge()
+    {
+        return array();
+    }
+}

library/Director/Import/PurgeStrategy/PurgeStrategy.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace Icinga\Module\Director\Import\PurgeStrategy;
+
+use Icinga\Module\Director\Objects\SyncRule;
+
+abstract class PurgeStrategy
+{
+    private $rule;
+
+    public function __construct(SyncRule $rule)
+    {
+        $this->rule = $rule;
+    }
+
+    protected function getSyncRule()
+    {
+        return $this->rule;
+    }
+
+    abstract function listObjectsToPurge();
+
+    /**
+     * @return PurgeStrategy
+     */
+    public static function load($name, SyncRule $rule)
+    {
+        $class = __NAMESPACE__ . '\\' . $name . 'PurgeStrategy';
+        return new $class($rule);
+    }
+}

library/Director/Objects/SyncRule.php

@@ -5,6 +5,7 @@ namespace Icinga\Module\Director\Objects;
 use Icinga\Application\Benchmark;
 use Icinga\Data\Filter\Filter;
 use Icinga\Module\Director\Data\Db\DbObject;
+use Icinga\Module\Director\Import\PurgeStrategy\PurgeStrategy;
 use Icinga\Module\Director\Import\Sync;
 use Exception;
 
@@ -30,6 +31,8 @@ class SyncRule extends DbObject
 
     private $sync;
 
+    private $purgeStrategy;
+
     private $currentSyncRunId;
 
     private $filter;
@@ -52,6 +55,17 @@ class SyncRule extends DbObject
         ));
     }
 
+    public function fetchInvolvedImportSources()
+    {
+        $sources = array();
+
+        foreach ($this->listInvolvedSourceIds() as $sourceId) {
+            $sources[$sourceId] = ImportSource::load($sourceId, $this->getConnection());
+        }
+
+        return $sources;
+    }
+
     public function getLastSyncTimestamp()
     {
         if (! $this->hasBeenLoadedFromDb()) {
@@ -117,6 +131,8 @@ class SyncRule extends DbObject
 
         Benchmark::measure('Checking sync rule ' . $this->rule_name);
         try {
+            $this->last_attempt = date('Y-m-d H:i:s');
+            $this->sync_state = 'unknown';
             $sync = $this->sync();
             if ($sync->hasModifications()) {
                 Benchmark::measure('Got modifications for sync rule ' . $this->rule_name);
@@ -136,6 +152,7 @@ class SyncRule extends DbObject
 
             $this->last_error_message = null;
         } catch (Exception $e) {
+throw $e;
             $this->sync_state = 'failing';
             $this->last_error_message = $e->getMessage();
         }
@@ -175,6 +192,25 @@ class SyncRule extends DbObject
         return $this->filter;
     }
 
+    public function purgeStrategy()
+    {
+        if ($this->purgeStrategy === null) {
+            $this->purgeStrategy = $this->loadConfiguredPurgeStrategy();
+        }
+
+        return $this->purgeStrategy;
+    }
+
+    // TODO: Allow for more
+    protected function loadConfiguredPurgeStrategy()
+    {
+        if ($this->purge_existing) {
+            return PurgeStrategy::load('ImportRunBased', $this);
+        } else {
+            return PurgeStrategy::load('PurgeNothing', $this);
+        }
+    }
+
     public function fetchSyncProperties()
     {
         $db = $this->getDb();