Static Table Operations

core/src/main/java/org/apache/iceberg/StaticTableOperations.java

@@ -0,0 +1,72 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ *
+ */
+
+package org.apache.iceberg;
+
+import org.apache.iceberg.io.FileIO;
+import org.apache.iceberg.io.LocationProvider;
+
+/**
+ * TableOperations implementation that provides access to metadata for a Table at some point in time, using a
+ * table metadata location. It will never refer to a different Metadata object than the one it was created with
+ * and cannot be used to create or delete files.
+ */
+public class StaticTableOperations implements TableOperations {
+  private final TableMetadata staticMetadata;
+  private final FileIO io;
+
+  /**
+   * Creates a StaticTableOperations tied to a specific static version of the TableMetadata
+   */
+  public StaticTableOperations(String metadataFileLocation, FileIO io) {
+    this.io = io;
+    this.staticMetadata = TableMetadataParser.read(io, metadataFileLocation);
+  }
+
+  @Override
+  public TableMetadata current() {
+    return staticMetadata;
+  }
+
+  @Override
+  public TableMetadata refresh() {
+    return staticMetadata;
+  }
+
+  @Override
+  public void commit(TableMetadata base, TableMetadata metadata) {
+    throw new UnsupportedOperationException("Cannot modify a static table");
+  }
+
+  @Override
+  public FileIO io() {
+    return this.io;
+  }
+
+  @Override
+  public String metadataFileLocation(String fileName) {
+    throw new UnsupportedOperationException("Cannot modify a static table");
+  }
+
+  @Override
+  public LocationProvider locationProvider() {
+    throw new UnsupportedOperationException("Cannot modify a static table");
+  }
+}

core/src/main/java/org/apache/iceberg/hadoop/HadoopTables.java

@@ -36,6 +36,7 @@
 import org.apache.iceberg.PartitionsTable;
 import org.apache.iceberg.Schema;
 import org.apache.iceberg.SnapshotsTable;
+import org.apache.iceberg.StaticTableOperations;
 import org.apache.iceberg.Table;
 import org.apache.iceberg.TableMetadata;
 import org.apache.iceberg.TableOperations;
@@ -44,12 +45,14 @@
 import org.apache.iceberg.exceptions.NoSuchTableException;
 import org.apache.iceberg.relocated.com.google.common.base.Preconditions;
 import org.apache.iceberg.relocated.com.google.common.collect.ImmutableMap;
+import org.apache.iceberg.util.Pair;
 
 /**
  * Implementation of Iceberg tables that uses the Hadoop FileSystem
  * to store metadata and manifests.
  */
 public class HadoopTables implements Tables, Configurable {
+  private static final String METADATA_JSON = "metadata.json";
   private Configuration conf;
 
   public HadoopTables() {
@@ -68,27 +71,38 @@ public HadoopTables(Configuration conf) {
    */
   @Override
   public Table load(String location) {
-    TableOperations ops = newTableOps(location);
-    if (ops.current() == null) {
-      // try to resolve a metadata table, which we encode as URI fragments
-      // e.g. hdfs:///warehouse/my_table#snapshots
-      int hashIndex = location.lastIndexOf('#');
-      if (hashIndex != -1 && location.length() - 1 != hashIndex) {
-        // we found char '#', and it is not the last char of location
-        String baseTable = location.substring(0, hashIndex);
-        String metaTable = location.substring(hashIndex + 1);
-        MetadataTableType type = MetadataTableType.from(metaTable);
-        if (type != null) {
-          return loadMetadataTable(baseTable, type);
-        } else {
-          throw new NoSuchTableException("Table does not exist at location: " + location);
-        }
+    Pair<String, MetadataTableType> parsedMetadataType = parseMetadataType(location);
+
+    if (parsedMetadataType != null) {
+      // Load a metadata table
+      return loadMetadataTable(parsedMetadataType.first(), parsedMetadataType.second());
+    } else {
+      // Load a normal table
+      TableOperations ops = newTableOps(location);
+      if (ops.current() != null) {
+        return new BaseTable(ops, location);
       } else {
         throw new NoSuchTableException("Table does not exist at location: " + location);
       }
     }
+  }
 
-    return new BaseTable(ops, location);
+  /**
+   * Try to resolve a metadata table, which we encode as URI fragments
+   * e.g. hdfs:///warehouse/my_table#snapshots
+   * @param location Path to parse
+   * @return A base table name and MetadataTableType if a type is found, null if not
+   */
+  private Pair<String, MetadataTableType> parseMetadataType(String location) {
+    int hashIndex = location.lastIndexOf('#');
+    if (hashIndex != -1 & !location.endsWith("#")) {
+      String baseTable = location.substring(0, hashIndex);
+      String metaTable = location.substring(hashIndex + 1);
+      MetadataTableType type = MetadataTableType.from(metaTable);
+      return (type == null) ? null : Pair.of(baseTable, type);
+    } else {
+      return null;
+    }
   }
 
   private Table loadMetadataTable(String location, MetadataTableType type) {
@@ -152,7 +166,11 @@ public Table create(Schema schema, PartitionSpec spec, Map<String, String> prope
   }
 
   private TableOperations newTableOps(String location) {
-    return new HadoopTableOperations(new Path(location), conf);
+    if (location.contains(METADATA_JSON)) {
+      return new StaticTableOperations(location, new HadoopFileIO(conf));
+    } else {
+      return new HadoopTableOperations(new Path(location), conf);
+    }
   }
 
   @Override

core/src/test/java/org/apache/iceberg/hadoop/TestStaticTable.java

@@ -0,0 +1,101 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.iceberg.hadoop;
+
+import org.apache.iceberg.AssertHelpers;
+import org.apache.iceberg.HasTableOperations;
+import org.apache.iceberg.MetadataTableType;
+import org.apache.iceberg.StaticTableOperations;
+import org.apache.iceberg.Table;
+import org.apache.iceberg.relocated.com.google.common.collect.Maps;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class TestStaticTable extends HadoopTableTestBase {
+
+  private Table getStaticTable() {
+    return TABLES.load(((HasTableOperations) table).operations().current().metadataFileLocation());
+  }
+
+  private Table getStaticTable(MetadataTableType type) {
+    return TABLES.load(((HasTableOperations) table).operations().current().metadataFileLocation() + "#" + type);
+  }
+
+  @Test
+  public void testLoadFromMetadata() {
+    Table staticTable = getStaticTable();
+    Assert.assertTrue("Loading a metadata file based table should return StaticTableOperations",
+        ((HasTableOperations) staticTable).operations() instanceof StaticTableOperations);
+  }
+
+  @Test
+  public void testCannotBeAddedTo() {
+    Table staticTable = getStaticTable();
+    AssertHelpers.assertThrows("Cannot modify a static table", UnsupportedOperationException.class,
+        () -> staticTable.newOverwrite().addFile(FILE_A).commit());
+  }
+
+  @Test
+  public void testCannotBeDeletedFrom() {
+    table.newAppend().appendFile(FILE_A).commit();
+    Table staticTable = getStaticTable();
+    AssertHelpers.assertThrows("Cannot modify a static table", UnsupportedOperationException.class,
+        () -> staticTable.newDelete().deleteFile(FILE_A).commit());
+  }
+
+  @Test
+  public void testHasSameProperties() {
+    table.newAppend().appendFile(FILE_A).commit();
+    table.newAppend().appendFile(FILE_B).commit();
+    table.newOverwrite().deleteFile(FILE_B).addFile(FILE_C).commit();
+    Table staticTable = getStaticTable();
+    Assert.assertTrue("Same history?",
+        table.history().containsAll(staticTable.history()));
+    Assert.assertTrue("Same snapshot?",
+        table.currentSnapshot().snapshotId() ==  staticTable.currentSnapshot().snapshotId());
+    Assert.assertTrue("Same properties?",
+        Maps.difference(table.properties(), staticTable.properties()).areEqual());
+  }
+
+  @Test
+  public void testImmutable() {
+    table.newAppend().appendFile(FILE_A).commit();
+    Table staticTable = getStaticTable();
+    long originalSnapshot = table.currentSnapshot().snapshotId();
+
+    table.newAppend().appendFile(FILE_B).commit();
+    table.newOverwrite().deleteFile(FILE_B).addFile(FILE_C).commit();
+    staticTable.refresh();
+
+    Assert.assertEquals("Snapshot unchanged after table modified",
+        staticTable.currentSnapshot().snapshotId(), originalSnapshot);
+  }
+
+  @Test
+  public void testMetadataTables() {
+    for (MetadataTableType type : MetadataTableType.values()) {
+      String enumName = type.name().replace("_", "").toLowerCase();
+      Assert.assertTrue("Should be able to get MetadataTable of type : " + type,
+          getStaticTable(type).getClass().getName().toLowerCase().contains(enumName));
+    }
+  }
+
+
+}