Spring MVC, Spring Batch load multiple DataSource properties from database - spring

Question

I have the below configuration of my db-config.xml file in several applications in work. We are using Spring Batch and each app is harvesting data from several external DB's. Everything is working fine but the problem is that all apps are deployed on different servers and every time when the password expires for one of the "Data sources", we have to go on each server and change the password manually on the db-config file for each application.
Since all applications are using more or less the same Data Sources for harvesting (about 9 in total) I am currently looking at some alternatives, so rather then declaring the "Harvest Data sources" into the db-config.xml file to place all properties into a DB table and load the properties from there. When a password expire we do the change in one single place rather then x places.
I would really appreciate any pointers in the right direction just to get started...
Sample of my db-config.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:tx="http://www.springframework.org/schema/tx" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.2.xsd">
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.ibm.db2.jcc.DB2Driver"></property>
<property name="url" value="jdbc:db2://1.111.1.11:50000/EX1"></property>
<property name="username" value="xxxxx" />
<property name="password" value="xxxxx" />
</bean>
<bean class="com.mchange.v2.c3p0.ComboPooledDataSource" id="ef_DataSource">
<property name="driverClass" value="com.ibm.db2.jcc.DB2Driver"></property>
<property name="acquireIncrement" value="5"></property>
<property name="maxIdleTime" value="3600"></property>
<property name="maxPoolSize" value="15"></property>
<property name="minPoolSize" value="5"></property>
<property name="numHelperThreads" value="3"></property>
<property name="unreturnedConnectionTimeout" value="3600"></property>
<property name="idleConnectionTestPeriod" value="100"></property>
<property name="jdbcUrl" value="jdbc:db2://2.222.2.22:50000/EX2"></property>
<property name="user" value="xxxxx" />
<property name="password" value="xxxxxx" />
</bean>
<!-- Harvest Data sources -->
<bean class="org.springframework.jdbc.datasource.DriverManagerDataSource" id="rep1">
<property name="driverClassName" value="com.ibm.db2.jcc.DB2Driver"></property>
<property name="url" value="jdbc:db2://1.11.11.111:60000/REPONE"></property>
<property name="username" value="xxxxxxxx" />
<property name="password" value="xxxxxxxx" />
</bean>
<bean class="org.springframework.jdbc.datasource.DriverManagerDataSource" id="rep4">
<property name="driverClassName" value="com.ibm.db2.jcc.DB2Driver"></property>
<property name="url" value="jdbc:db2://22.444.44.44:50000/REPTWO"></property>
<property name="username" value="xxxxxxxx"></property>
<property name="password" value="xxxxxxxx"></property>
</bean>
<bean class="org.springframework.jdbc.datasource.DriverManagerDataSource" id="rep5">
<property name="driverClassName" value="com.ibm.db2.jcc.DB2Driver"></property>
<property name="url" value="jdbc:db2://555.55.55.55:50000/REPTHREE"></property>
<property name="username" value="xxxxxxxx" />
<property name="password" value="xxxxxxxx" />
</bean>
<!-- More Harvest Data sources -->
Sample of the AbstractImportTasklet java class extended by all Tasklets classes
#Component
public abstract class AbstractImportTasklet implements ResourceLoaderAware, InitializingBean, Tasklet{
private ResourceLoader resourceLoader;
private JdbcTemplate jdbcTemplate;
private NamedParameterJdbcTemplate namedParameterJdbcTemplate;
private DataSource dataSource;
#Autowired
AmDbDAO dao;
#Autowired
protected JobExplorer jobExplorer;
public AbstractImportTasklet() {
super();
}
#Override
public void setResourceLoader(ResourceLoader resourceLoader) {
this.resourceLoader = resourceLoader;
}
public JdbcTemplate getJdbcTemplate() {
return jdbcTemplate;
}
public NamedParameterJdbcTemplate getNamedParameterJdbcTemplate(){
return namedParameterJdbcTemplate;
}
public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
this.jdbcTemplate = jdbcTemplate;
}
public void setNamedParameterJdbcTemplate(NamedParameterJdbcTemplate namedParameterJdbcTemplate){
this.namedParameterJdbcTemplate = namedParameterJdbcTemplate;
}
public DataSource getDataSource() {
return dataSource;
}
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}
#Override
public void afterPropertiesSet() throws Exception {
/*TimeZone.setDefault(TimeZone.getTimeZone("UTC"));*/
if(dataSource != null){
this.jdbcTemplate = new JdbcTemplate(dataSource);
this.namedParameterJdbcTemplate = new NamedParameterJdbcTemplate(dataSource);
}
}
}

Answer 1

One of the possible approach would be to add a step at the beginning who would read the database containing the informations on the other ones (if I understood your use case correctly). This step would then load the results in the JobExecutionContext. The results would be used in the definition of the datasources.
Here's an example (step) :
public class LoadDatasources implements Tasklet {
public RepeatStatus execute(StepContribution stepContribution, ChunkContext chunkContext) throws Exception {
// Query database here
[...]
// Save results in context
chunkContext.getStepContext().getJobExecutionContext().put(key, value)
return null;
}
}
XML configuration of the datasources :
<bean class="org.springframework.jdbc.datasource.DriverManagerDataSource" step="scope">
<property name="driverClassName" value="#{jobExecutionContext['datasource1.driver']}"></property>
<property name="url" value="#{jobExecutionContext['datasource1.url']}"></property>
<property name="username" value="#{jobExecutionContext['datasource1.username']}"></property>
<property name="password" value="#{jobExecutionContext['datasource1.password']}"></property>
</bean>

Answer 2

This is the exact use case that Spring Cloud's Configuration Server solves. It allows you to configure things, like datasources, in a central repository. From there, you can refresh the configuration of the applications using it. You can read more about the Spring Cloud Configuration Server in the documentation here: https://github.com/spring-cloud-samples/configserver