/**
* Remove old indices which are not active anymore (remember, each bulk index creates a new index from scratch,
* making the "old" index a stale one).
*
* @return array<string> a list of index names which were removed
*/
public function removeOldIndices()
{
$aliasName = $this->searchClient->getIndexName();
// The alias name is the unprefixed index name
$currentlyLiveIndices = array_keys($this->searchClient->request('GET', '/*/_alias/' . $aliasName)->getTreatedContent());
$indexStatus = $this->searchClient->request('GET', '/_status')->getTreatedContent();
$allIndices = array_keys($indexStatus['indices']);
$indicesToBeRemoved = array();
foreach ($allIndices as $indexName) {
if (strpos($indexName, $aliasName . '-') !== 0) {
// filter out all indices not starting with the alias-name, as they are unrelated to our application
continue;
}
if (array_search($indexName, $currentlyLiveIndices) !== FALSE) {
// skip the currently live index names from deletion
continue;
}
$indicesToBeRemoved[] = $indexName;
}
if (count($indicesToBeRemoved) > 0) {
$this->searchClient->request('DELETE', '/' . implode(',', $indicesToBeRemoved) . '/');
}
return $indicesToBeRemoved;
}
