avoid NPE, fix mock compute driver

bubble-server/src/main/java/bubble/cloud/compute/ComputeServiceDriverBase.java

@@ -59,15 +59,17 @@ public abstract class ComputeServiceDriverBase
     @Getter(lazy=true) private final List<CloudRegion> regions = initRegions();
     private List<CloudRegion> initRegions() {
         final ArrayList<CloudRegion> cloudRegions = new ArrayList<>();
-        for (CloudRegion configRegion : config.getRegions()) {
-            final CloudRegion cloudRegion = getCloudRegions().stream()
-                    .filter(s -> s.getInternalName().equalsIgnoreCase(configRegion.getInternalName()))
-                    .findFirst()
-                    .orElse(null);
-            if (cloudRegion == null) {
-                log.warn("initRegions: config region not found: "+configRegion.getInternalName());
-            } else {
-                cloudRegions.add(configRegion.setId(cloudRegion.getId()));
+        if (config != null && config.getRegions() != null) {
+            for (CloudRegion configRegion : config.getRegions()) {
+                final CloudRegion cloudRegion = getCloudRegions().stream()
+                        .filter(s -> s.getInternalName().equalsIgnoreCase(configRegion.getInternalName()))
+                        .findFirst()
+                        .orElse(null);
+                if (cloudRegion == null) {
+                    log.warn("initRegions: config region not found: " + configRegion.getInternalName());
+                } else {
+                    cloudRegions.add(configRegion.setId(cloudRegion.getId()));
+                }
             }
         }
         return cloudRegions;

bubble-server/src/main/java/bubble/cloud/compute/mock/MockComputeDriver.java

@@ -29,12 +29,18 @@ public class MockComputeDriver extends ComputeServiceDriverBase {
             .setName("nyc_mock")
             .setLocation(MockGeoLocationDriver.MOCK_LOCAION));
 
+    @Override public List<CloudRegion> getRegions() { return getCloudRegions(); }
+
     @Getter private final List<ComputeNodeSize> cloudSizes = singletonList(new ComputeNodeSize()
             .setName("standard")
             .setType(ComputeNodeSizeType.small));
 
+    @Override public List<ComputeNodeSize> getSizes() { return getCloudSizes(); }
+
     @Getter private final List<OsImage> cloudOsImages = singletonList(new OsImage().setName("dummy operating system"));
 
+    @Getter(lazy=true) private final OsImage os = new OsImage().setName("Ubuntu 20.04 x84").setId("ubuntu20.04x84");
+
     @Override public BubbleNode start(BubbleNode node) throws Exception {
         node.setIp4("127.0.0.1");
         node.setIp6("::1");