public static function getArtifactIndex(HarbormasterBuildTarget $target, $artifact_key)
 {
     $build = $target->getBuild();
     $parts = array($build->getPHID(), $target->getBuildGeneration(), $artifact_key);
     $parts = implode("", $parts);
     return PhabricatorHash::digestForIndex($parts);
 }
 protected function shouldAbort(HarbormasterBuild $build, HarbormasterBuildTarget $target)
 {
     return $build->getBuildGeneration() !== $target->getBuildGeneration();
 }