src/main/java/org/apache/fineract/cn/core/data/jpa/local/LocalRoutingDataSource.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.fineract.cn.core.data.jpa.local;

import org.apache.fineract.cn.core.data.jpa.core.MigrationHelper;
import org.apache.fineract.cn.core.data.jpa.local.repository.DataSourceInstance;
import org.apache.commons.dbcp2.BasicDataSource;
import org.apache.fineract.cn.lang.TenantContextHolder;
import org.slf4j.Logger;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

import javax.annotation.PostConstruct;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

public class LocalRoutingDataSource extends AbstractRoutingDataSource {

  private final Logger logger;
  private final LocalDatabaseProperties localDatabaseProperties;
  private final Map<String, DataSource> cachedDataSources = new ConcurrentHashMap<>();
  private BasicDataSource managementDataSource;

  LocalRoutingDataSource(final Logger logger,
                         final LocalDatabaseProperties localDatabaseProperties) {
    super();
    this.logger = logger;
    this.localDatabaseProperties = localDatabaseProperties;
  }

  private DataSource getManagementDataSource() {
    if (this.managementDataSource == null) {
      this.logger.debug("Creating management data source.");
      this.managementDataSource = new BasicDataSource();
      this.managementDataSource.setDriverClassName(this.localDatabaseProperties.getManagement().getDriverClass());
      this.managementDataSource.setUrl(this.localDatabaseProperties.getManagement().getUrl());

      final String username = this.localDatabaseProperties.getManagement().getUsername();
      if (username != null) {
        this.managementDataSource.setUsername(username);
      }

      final String password = this.localDatabaseProperties.getManagement().getPassword();
      if (password != null) {
        this.managementDataSource.setPassword(password);
      }

      this.managementDataSource.setInitialSize(this.localDatabaseProperties.getPool().getMinSize());
      this.managementDataSource.setMaxTotal(this.localDatabaseProperties.getPool().getMaxSize());
      this.managementDataSource.setMaxWaitMillis(this.localDatabaseProperties.getPool().getWaitTime());
    }
    this.logger.debug("Providing management data source.");
    return this.managementDataSource;
  }

  @Override
  protected Object determineCurrentLookupKey() {
    return TenantContextHolder.identifier().orElse(null);
  }

  @Override
  protected DataSource determineTargetDataSource() {
    final Object dataSourceIdentifier = this.determineCurrentLookupKey();
    if (dataSourceIdentifier == null) {
      return this.getManagementDataSource();
    }

    final String dataSourceIdentifierAsString = dataSourceIdentifier.toString();

    this.cachedDataSources.computeIfAbsent(dataSourceIdentifierAsString, s -> {
      this.logger.debug("Creating data source for '{}'.", dataSourceIdentifierAsString);
      final DataSourceInstance dataSourceInstanceDetails = this.findDataSourceInstanceDetails(s);
      final BasicDataSource basicDataSource = new BasicDataSource();
      basicDataSource.setDriverClassName(dataSourceInstanceDetails.getDriverClass());
      basicDataSource.setUrl(dataSourceInstanceDetails.getJdbcUrl());
      basicDataSource.setUsername(dataSourceInstanceDetails.getUsername());
      basicDataSource.setPassword(dataSourceInstanceDetails.getPassword());

      basicDataSource.setInitialSize(this.localDatabaseProperties.getPool().getMinSize());
      basicDataSource.setMaxTotal(this.localDatabaseProperties.getPool().getMaxSize());
      basicDataSource.setMaxWaitMillis(this.localDatabaseProperties.getPool().getWaitTime());
      return basicDataSource;
    });
    this.logger.debug("Providing data source for '{}'.", dataSourceIdentifierAsString);
    return this.cachedDataSources.get(dataSourceIdentifierAsString);
  }

  private DataSourceInstance findDataSourceInstanceDetails(final String dataSourceIdentifier) {
    this.logger.debug("Fetching data source details for '{}'.", dataSourceIdentifier);
    final String query = "SELECT driver_class, jdbc_url, username, password FROM data_source_instances WHERE identifier = ? ";
    final DataSource managementDataSource = this.getManagementDataSource();
    try (
        final Connection conn = managementDataSource.getConnection();
        final PreparedStatement pstmt = conn.prepareCall(query)) {
      pstmt.setString(1, dataSourceIdentifier);
      try (final ResultSet rset = pstmt.executeQuery()) {
        if (rset.next()) {
          final DataSourceInstance dataSourceInstance = new DataSourceInstance();
          dataSourceInstance.setDriverClass(rset.getString(1));
          dataSourceInstance.setJdbcUrl(rset.getString(2));
          dataSourceInstance.setUsername(rset.getString(3));
          dataSourceInstance.setPassword(rset.getString(4));
          return dataSourceInstance;
        }
      } catch (final SQLException sqlex) {
        throw new IllegalStateException(sqlex.getMessage());
      }
    } catch (final SQLException sqlex) {
      throw new IllegalStateException(sqlex.getMessage());
    }
    throw new IllegalStateException("No data source instance found for identifier '" + dataSourceIdentifier + "'.");
  }

  @PostConstruct
  public void init() throws Exception {
    MigrationHelper.execute(this.getManagementDataSource(), "db/changelog/db.changelog-local.yml");
  }
}