core: fix NPE when picking host for transfer-image

When picking a host for transfer-image job, we filter hosts that
are UP and then process the data they reported on storage domains
without checking whether the host actually reported this data.
It can happen that hosts are UP and still have not reported data
on storage domains, in which case the data is null, resulting in
an NPE in the transfer-image flow.

This patch changes the predicate that is used to filter hosts for
transfer-image, adding a null-check to avoid that NPE.

Bug-Url: https://bugzilla.redhat.com/2203132
Signed-off-by: Arik Hadas <ahadas@redhat.com>

backend/manager/modules/bll/src/main/java/org/ovirt/engine/core/bll/storage/disk/image/TransferDiskImageCommand.java

@@ -42,7 +42,6 @@
 import org.ovirt.engine.core.common.businessentities.ActionGroup;
 import org.ovirt.engine.core.common.businessentities.StorageDomain;
 import org.ovirt.engine.core.common.businessentities.VDS;
-import org.ovirt.engine.core.common.businessentities.VDSDomainsData;
 import org.ovirt.engine.core.common.businessentities.VM;
 import org.ovirt.engine.core.common.businessentities.VmBackup;
 import org.ovirt.engine.core.common.businessentities.VmBackupPhase;
@@ -1136,12 +1135,17 @@ private static boolean proxyEnabled() {
 
     @Override
     protected VDS checkForActiveVds() {
-        Guid hostForExecution = vdsCommandsHelper.getHostForExecution(getStoragePoolId(), host ->
-                resourceManager.getVdsManager(host.getId()).getDomains()
-                        .stream()
+        Guid hostForExecution = vdsCommandsHelper.getHostForExecution(getStoragePoolId(), host -> {
+                var domainsData = resourceManager.getVdsManager(host.getId()).getDomains();
+                if (domainsData == null) {
+                    return false;
+                }
+                var domainData = domainsData.stream()
                         .filter(vdsDomainsData -> vdsDomainsData.getDomainId().equals(getStorageDomainId()))
-                        .allMatch(VDSDomainsData::isValid)
-        );
+                        .findFirst()
+                        .orElse(null);
+                return domainData != null ? domainData.isValid() : false;
+        });
 
         if (hostForExecution == null) {
             addValidationMessage(EngineMessage.ACTION_TYPE_FAILED_NO_VDS_IN_POOL);

backend/manager/modules/bll/src/main/java/org/ovirt/engine/core/bll/storage/utils/VdsCommandsHelper.java

@@ -154,7 +154,8 @@ public Guid getHostForExecution(Guid poolId, Predicate<VDS> predicate) {
         List<Guid> hostsForExecution = vdsDao
                 .getAllForStoragePoolAndStatus(poolId, VDSStatus.Up).stream()
                 .filter(predicate)
-                .map(x -> x.getId()).collect(Collectors.toList());
+                .map(VDS::getId)
+                .collect(Collectors.toList());
         if (hostsForExecution.isEmpty()) {
             return null;
         }