Getting the oracle database host name at runtime

Question

There is a Springboot application which connects to the Oracle data. The URL for the database is configured as

spring.datasource.url=jdbc:oracle:thin:@(DESCRIPTION=\
  (LOAD_BALANCE=OFF)(FAILOVER=ON)\
  (ADDRESS=(PROTOCOL=TCP)(HOST=domainName1.com) (PORT=1521))\
  (ADDRESS=(PROTOCOL=TCP)(HOST=domainName2.com)(PORT=1521))\
  (CONNECT_DATA=(SERVICE_NAME=xyz)))

This URL is configured so that when one host is down then the application connects to second database. The URL to the database is printed in the application healthcheck as shown below

Hello 
version    : 4.0.0
build      : 2022-03-3 
datasource :    oracle.jdbc.OracleDriver
db url     :    jdbc:oracle:thin:@(DESCRIPTION=(LOAD_BALANCE=OFF)(FAILOVER=ON)(ADDRESS=(PROTOCOL=TCP)(HOST=domainName1.com) (PORT=1521))(ADDRESS=(PROTOCOL=TCP)(HOST=domainName2.com)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=xyz)))
db status  :    ok 

My question is how can I get just the host name of the database being used, that means how can I get the host currently being used (domainName1 or domainName2) by the application and display it on healthcheck? For example as shown below.

Hello 
version    : 4.0.0
build      : 2022-03-3
datasource :    oracle.jdbc.OracleDriver
db url     :    jdbc:oracle:thin:@domainName1.com: 1521/coldv1
db status  :    ok (LVZ count = 379)

The java code I used for this healthcheck is as shown below.

@GetMapping(path = "/healthcheck",
            produces = MediaType.APPLICATION_JSON_VALUE
    )
    public String getServiceStatus(){
        String[] activeProfiles = environment.getActiveProfiles();
        final BeanWrapper accessor = PropertyAccessorFactory.forBeanPropertyAccess(dataSource);
        final String driverClassName = String.valueOf(accessor.getPropertyValue("driverClassName"));
        String url = null;

        if(activeProfiles[1].equals("external_tomcat")) {
            url = String.valueOf(accessor.getPropertyValue("url"));
        }else{
            try {
                String[] dataSourceProperties = nameService.getDataSource();
                url = dataSourceProperties[0];
            } catch (SQLException ex) {
//                throwables.printStackTrace();
                log.error(ex.getMessage(), ex);
            }
        }

        String version = buildProperties.getVersion();
        String buildTimestamp = String.valueOf(buildProperties.getTime());
        BigDecimal count = nameService.getCount("Table_name_of_database");

        StringBuilder result = new StringBuilder("Hello")
                .append("\nversion    :\t")
                .append(version)
                .append("\nbuild      :\t")
                .append(buildTimestamp)
                .append("\ndatasource :\t")
                .append(driverClassName)
                .append("\ndb url     :\t")
                .append(url)
                .append("\ndb status  :\tok  ")
                .append(count.intValue())
                .append(")");
        return result.toString();
    }

NameService.java

 @Override
    public String[] getDataSource() throws SQLException {
        return getDataSourceProperties();
    }


   

    public String[] getDataSourceProperties() {
        String[] dataSourceProperties = new String[2];
        HikariDataSource dataSource = getDataSourceFromHibernateEntityManager();
        if(dataSource.getJdbcUrl() != null){
            dataSourceProperties[0] = dataSource.getJdbcUrl();
            dataSourceProperties[1] = dataSource.getDataSourceClassName();
        }
        return dataSourceProperties;
    }

Answer 1

A solution is to execute an SQL query to retrieve the server host name, for example:

SELECT host_name FROM v$instance

See this question for more details.