ATLAS-3315: Database initialization exception handling.

graphdb/janus/src/main/java/org/apache/atlas/repository/graphdb/janus/AtlasJanusGraphDatabase.java

@@ -18,6 +18,7 @@
 
 package org.apache.atlas.repository.graphdb.janus;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.ImmutableMap;
 import org.apache.atlas.ApplicationProperties;
 import org.apache.atlas.AtlasException;
@@ -165,25 +166,30 @@ public class AtlasJanusGraphDatabase implements GraphDatabase<AtlasJanusVertex,
                         throw new RuntimeException(e);
                     }
 
+                    graphInstance = initJanusGraph(config);
+                    atlasGraphInstance = new AtlasJanusGraph();
+                    validateIndexBackend(config);
+
+                }
+            }
+        }
+        return graphInstance;
+    }
+
+    @VisibleForTesting
+    static JanusGraph initJanusGraph(Configuration config) {
         try {
-                        graphInstance = JanusGraphFactory.open(config);
+            return JanusGraphFactory.open(config);
         } catch (JanusGraphException e) {
             LOG.warn("JanusGraphException: {}", e.getMessage());
             if (e.getMessage().startsWith(OLDER_STORAGE_EXCEPTION)) {
                 LOG.info("Newer client is being used with older janus storage version. Setting allow-upgrade=true and reattempting connection");
                 config.addProperty("graph.allow-upgrade", true);
-                            graphInstance = JanusGraphFactory.open(config);
-                        }
-                        else {
+                return JanusGraphFactory.open(config);
+            } else {
                 throw new RuntimeException(e);
             }
         }
-                    atlasGraphInstance = new AtlasJanusGraph();
-                    validateIndexBackend(config);
-                }
-            }
-        }
-        return graphInstance;
     }
 
     public static JanusGraph getBulkLoadingGraphInstance() {

graphdb/janus/src/test/java/org/apache/atlas/repository/graphdb/janus/AtlasJanusDatabaseTest.java

@@ -31,6 +31,7 @@ import org.apache.atlas.repository.graphdb.AtlasGraphQuery.ComparisionOperator;
 import org.apache.atlas.repository.graphdb.AtlasPropertyKey;
 import org.apache.atlas.repository.graphdb.AtlasVertex;
 import org.apache.atlas.typesystem.types.DataTypes.TypeCategory;
+import org.apache.commons.configuration.Configuration;
 import org.testng.annotations.AfterClass;
 import org.testng.annotations.Test;
 
@@ -39,9 +40,18 @@ import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
 
-import static org.testng.Assert.*;
+import static org.apache.atlas.repository.graphdb.janus.AtlasJanusGraphDatabase.initJanusGraph;
+import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.assertFalse;
+import static org.testng.Assert.assertNotNull;
+import static org.testng.Assert.assertNull;
+import static org.testng.Assert.assertTrue;
+import static org.testng.Assert.fail;
 
 /**
  * Sanity test of basic graph operations using the Janus graphdb
@@ -81,6 +91,30 @@ public class AtlasJanusDatabaseTest {
     }
 
     @Test
+    public void initializationFailureShouldThrowRuntimeException() throws AtlasException {
+        Configuration cfg = AtlasJanusGraphDatabase.getConfiguration();
+        Map<String, Object> cfgBackup = new HashMap<>();
+        Iterator<String> keys = cfg.getKeys();
+        while(keys.hasNext()) {
+            String key = keys.next();
+            cfgBackup.put(key, cfg.getProperty(key));
+        }
+
+        try {
+            cfg.clear();
+            initJanusGraph(cfg);
+
+            fail("Should have thrown an exception!");
+        }
+        catch (RuntimeException ex) {
+            assertTrue(true);
+            for (Map.Entry<String, Object> entry : cfgBackup.entrySet()) {
+                cfg.setProperty(entry.getKey(), entry.getValue());
+            }
+        }
+    }
+
+    @Test
     public <V, E> void testPropertyDataTypes() {
 
         // primitives