contrib/storage-googlesheets/src/main/java/org/apache/drill/exec/store/googlesheets/schema/GoogleSheetsRootSchema.java

/*
 * 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.drill.exec.store.googlesheets.schema;

import com.google.api.services.sheets.v4.Sheets;
import com.google.api.services.sheets.v4.model.Sheet;
import org.apache.calcite.schema.SchemaPlus;
import org.apache.calcite.schema.Table;
import org.apache.drill.exec.planner.logical.DynamicDrillTable;
import org.apache.drill.exec.store.AbstractSchema;
import org.apache.drill.exec.store.SchemaConfig;
import org.apache.drill.exec.store.googlesheets.GoogleSheetsStoragePlugin;
import org.apache.drill.exec.store.googlesheets.GoogleSheetsStoragePluginConfig;
import org.apache.drill.exec.store.googlesheets.utils.GoogleSheetsUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class GoogleSheetsRootSchema extends AbstractSchema {
  private static final Logger logger = LoggerFactory.getLogger(GoogleSheetsRootSchema.class);

  private final Map<String, DynamicDrillTable> activeTables = new HashMap<>();
  private final Map<String, GoogleSheetsDrillSchema> schemas = new HashMap<>();

  private List<Sheet> sheetList = new ArrayList<>();
  private final GoogleSheetsStoragePlugin plugin;
  private final SchemaConfig schemaConfig;


  public GoogleSheetsRootSchema(GoogleSheetsStoragePlugin plugin, SchemaConfig schemaConfig) {
    super(Collections.emptyList(), plugin.getName());
    this.schemaConfig = schemaConfig;
    this.plugin = plugin;
  }

  void setHolder(SchemaPlus plusOfThis) {
    for (String s : getSubSchemaNames()) {
      GoogleSheetsDrillSchema inner = getSubSchema(s);
      SchemaPlus holder = plusOfThis.add(s, inner);
      inner.setHolder(holder);
    }
  }

  @Override
  public Set<String> getSubSchemaNames() {
    return schemas.keySet();
  }

  @Override
  public GoogleSheetsDrillSchema getSubSchema(String name) {
    GoogleSheetsDrillSchema schema = schemas.get(name);
    // This level here represents the actual Google document. Attempt to validate that it exists, and
    // if so, add it to the schema list.  If not, throw an exception.
    //
    // TODO In the future, we could add a check here to see whether the user has the DRIVE permission, and if so,
    // retrieve the actual "file" name to use in the query instead of the non-readable ID.
    if (schema == null) {
      Sheets service = plugin.getSheetsService(schemaConfig.getUserName());
      try {
        // This is needed for stored credentials.  In theory while we aren't impersonating the user
        // we are storing separate access tokens for each user.
        logger.debug("Accessing credentials for {}", schemaConfig.getUserName());

        sheetList = GoogleSheetsUtils.getSheetList(service, name);
      } catch (IOException e) {
        // Do nothing
      }
      // At this point we know we have a valid sheet because we obtained the Sheet list, so we need to
      // add the schema to the schemas list and return it.
      schema = new GoogleSheetsDrillSchema(this, name, plugin, sheetList, schemaConfig);
      schemas.put(name, schema);
    }
    return schema;
  }

  @Override
  public Table getTable(String tableName) {
    logger.debug("Getting table in root schema: {}", tableName);
    DynamicDrillTable table = activeTables.computeIfAbsent(tableName, this::getDrillTable);
    if (table != null) {
      logger.debug("Found table: {}", table.getJdbcTableType().jdbcName);
    } else {
      logger.debug("Oh no! {} not found and returning null!", tableName);
    }
    return table;
  }

  private DynamicDrillTable getDrillTable(String tableName) {
    logger.debug("Getting Drill Table in Root schema {}", tableName);
    return activeTables.get(tableName);
  }

  @Override
  public String getTypeName() {
    return GoogleSheetsStoragePluginConfig.NAME;
  }
}