skip presto view parsing (#211)

CHANGELOG.md

@@ -1,6 +1,7 @@
 ## [3.9.1] - TBD
 ### Fixed
 * Null pointer exception when creating a metastore tunnel by adding a check for null `configuration-properties`.
+* Fixing issue where Presto views cannot be parsed resulting in errors.
 
 ## [3.9.0] - 2021-02-26
 ### Added

waggle-dance-core/src/main/java/com/hotels/bdp/waggledance/mapping/model/ASTQueryMapping.java

@@ -39,11 +39,16 @@ public enum ASTQueryMapping implements QueryMapping {
 
   INSTANCE;
 
+  private static final String PRESTO_VIEW_MARKER = "/* Presto View";
   private final static String RE_WORD_BOUNDARY = "\\b";
   private final static Comparator<CommonToken> ON_START_INDEX = Comparator.comparingInt(CommonToken::getStartIndex);
 
   @Override
   public String transformOutboundDatabaseName(MetaStoreMapping metaStoreMapping, String query) {
+    if (hasNonHiveViewMarker(query)) {
+      // skipping queries that are not "Hive" view queries. We can't parse those.
+      return query;
+    }
     ASTNode root;
     try {
       root = ParseUtils.parse(query);
@@ -56,6 +61,13 @@ public String transformOutboundDatabaseName(MetaStoreMapping metaStoreMapping, S
     return result.toString();
   }
 
+  private boolean hasNonHiveViewMarker(String query) {
+    if (query != null && query.trim().startsWith(PRESTO_VIEW_MARKER)) {
+      return true;
+    }
+    return false;
+  }
+
   private StringBuilder transformDatabaseTableTokens(MetaStoreMapping metaStoreMapping, ASTNode root, String query) {
     StringBuilder result = new StringBuilder();
     SortedSet<CommonToken> dbNameTokens = extractDbNameTokens(root);

waggle-dance-core/src/main/java/com/hotels/bdp/waggledance/mapping/model/DatabaseMappingImpl.java

@@ -88,7 +88,15 @@ public MetaStoreFilterHook getMetastoreFilter() {
 
   @Override
   public Table transformOutboundTable(Table table) {
-    table.setDbName(metaStoreMapping.transformOutboundDatabaseName(table.getDbName()));
+    String originalDatabaseName = table.getDbName();
+    String databaseName = metaStoreMapping.transformOutboundDatabaseName(originalDatabaseName);
+    table.setDbName(databaseName);
+    if (databaseName.equalsIgnoreCase(originalDatabaseName)) {
+      // Skip all the view parsing if nothing is going to change, the parsing is not without problems and we can't catch
+      // all use cases here. For instance Presto creates views that are stored in these fields and this is stored
+      // differently than Hive. There might be others.
+      return table;
+    }
     if (table.isSetViewExpandedText()) {
       try {
         log.debug("Transforming ViewExpandedText: {}", table.getViewExpandedText());

waggle-dance-core/src/test/java/com/hotels/bdp/waggledance/mapping/model/ASTQueryMappingTest.java

@@ -38,8 +38,27 @@ public class ASTQueryMappingTest {
 
   @Before
   public void setUp() {
-    metaStoreMapping = new PrefixMapping(new MetaStoreMappingImpl(PREFIX, "mapping", null,
-        null, DIRECT, LATENCY, new DefaultMetaStoreFilterHookImpl(new HiveConf())));
+    metaStoreMapping = new PrefixMapping(new MetaStoreMappingImpl(PREFIX, "mapping", null, null, DIRECT, LATENCY,
+        new DefaultMetaStoreFilterHookImpl(new HiveConf())));
+  }
+
+  @Test
+  public void transformOutboundDatabaseNamePrestoMarker() {
+    ASTQueryMapping queryMapping = ASTQueryMapping.INSTANCE;
+
+    String query = "/* Presto View */";
+
+    assertThat(queryMapping.transformOutboundDatabaseName(metaStoreMapping, query), is(query));
+  }
+
+  @Test
+  public void transformOutboundDatabaseNamePrestoExpandedTextMarker() {
+    ASTQueryMapping queryMapping = ASTQueryMapping.INSTANCE;
+
+    String query = "/* Presto View: <base64 of view sql> */";
+
+    assertThat(queryMapping.transformOutboundDatabaseName(metaStoreMapping, query),
+        is(query));
   }
 
   @Test

waggle-dance-core/src/test/java/com/hotels/bdp/waggledance/mapping/model/DatabaseMappingImplTest.java

@@ -159,6 +159,20 @@ public void transformOutboundTableView() throws Exception {
     assertThat(result.getViewOriginalText(), is(VIEW_ORIGINAL_TEXT_TRANSFORMED));
   }
 
+  @Test
+  public void transformOutboundTableViewIgnoreParsingWhenSame() throws Exception {
+    Table table = new Table();
+    table.setDbName(OUT_DB_NAME);
+    table.setViewExpandedText(VIEW_EXPANDED_TEXT);
+    table.setViewOriginalText(VIEW_ORIGINAL_TEXT);
+
+    Table result = databaseMapping.transformOutboundTable(table);
+    assertThat(result, is(sameInstance(table)));
+    assertThat(result.getDbName(), is(OUT_DB_NAME));
+    assertThat(result.getViewExpandedText(), is(VIEW_EXPANDED_TEXT));
+    assertThat(result.getViewOriginalText(), is(VIEW_ORIGINAL_TEXT));
+  }
+
   @Test
   public void transformOutboundTableViewExpandedTextErrorKeepOriginal() throws Exception {
     String viewExpandedText = "error";