Spring boot multiple data sources - Connectivity Error Handling - spring-boot

Question

I'm working with multiple data sources (Oracle and SQL-Server) in spring boot rest application. In this application, I have more than 25+ end-points exist to process client requests. But when one of the databases is down like Oracle or SQL-server is not available for some reason, my application is unable to start the server.
Looked couple examples on google and stack overflow but they're different what I'm looking for...
package com.foobar;
#Configuration
#EnableTransactionManagement
#EnableJpaRepositories
(
entityManagerFactoryRef = "entityManagerFactory",
basePackages = { "com.foobar.foo.repo" }
)
public class FooDbConfig
{
#Primary
#Bean(name = "dataSource")
#ConfigurationProperties(prefix = "spring.datasource")
public DataSource dataSource() {
return DataSourceBuilder.create().build();
}
#Primary
#Bean(name = "entityManagerFactory")
public LocalContainerEntityManagerFactoryBean
entityManagerFactory(
EntityManagerFactoryBuilder builder,
#Qualifier("dataSource") DataSource dataSource
) {
return builder
.dataSource(dataSource)
.packages("com.foobar.foo.domain")
.persistenceUnit("foo")
.build();
}
#Primary
#Bean(name = "transactionManager")
public PlatformTransactionManager transactionManager(
#Qualifier("entityManagerFactory") EntityManagerFactory
entityManagerFactory)
{
return new JpaTransactionManager(entityManagerFactory);
}
}
same configuration for 2nd data-source but with different properties.
I'm using below example as a base code reference to implement my requirements
Example link
I'm looking for a solution if one DB server is available out of N application should start and process client requests and whenever 2nd DB server is available then it connects automatically and processes other endpoints requests

Answer 1

I've created a solution recently for multitenancy with datasources and using liquibase, but if not use the liquibase, just remove that works too!
Example of application.yml
spring:
dataSources:
- tenantId: db1
url: jdbc:postgresql://localhost:5432/db1
username: postgres
password: 123456
driver-class-name: org.postgresql.Driver
liquibase:
enabled: true
default-schema: public
change-log: classpath:db/master/changelog/db.changelog-master.yaml
- tenantId: db2
url: jdbc:postgresql://localhost:5432/db2
username: postgres
password: 123456
driver-class-name: org.postgresql.Driver
- tenantId: db3
url: jdbc:postgresql://localhost:5432/db3
username: postgres
password: 123456
driver-class-name: org.postgresql.Driver
DataSourceConfiguration
#Configuration
#EnableTransactionManagement
#EntityScan(basePackages = { "br.com.dijalmasilva.springbootmultitenancyliquibase" })
#EnableJpaRepositories(basePackages = { "br.com.dijalmasilva.springbootmultitenancyliquibase" })
public class DataSourceConfiguration {
#Bean(name = "dataSources")
#Primary
public Map<Object, Object> getDataSources(DataSourceProperties dataSourceProperties) {
return dataSourceProperties.getDataSources().stream().map(dataSourceProperty -> {
DataSource dataSource = DataSourceBuilder.create()
.url(dataSourceProperty.getUrl())
.username(dataSourceProperty.getUsername())
.password(dataSourceProperty.getPassword())
.driverClassName(dataSourceProperty.getDriverClassName())
.build();
return new TenantIdDataSource(dataSourceProperty.getTenantId(), dataSource);
}).collect(Collectors.toMap(TenantIdDataSource::getTenantId, TenantIdDataSource::getDataSource));
}
#Bean(name = "tenantRoutingDataSource")
#DependsOn("dataSources")
public DataSource dataSource(Map<Object, Object> dataSources) {
AbstractRoutingDataSource tenantRoutingDataSource = new TenantRoutingDataSource();
tenantRoutingDataSource.setTargetDataSources(dataSources);
tenantRoutingDataSource.setDefaultTargetDataSource(dataSources.get("db1"));
tenantRoutingDataSource.afterPropertiesSet();
return tenantRoutingDataSource;
}
#Data
#AllArgsConstructor
private class TenantIdDataSource {
private Object tenantId;
private Object dataSource;
}
}
TenantRoutingDataSource
public class TenantRoutingDataSource extends AbstractRoutingDataSource {
#Override
protected Object determineCurrentLookupKey() {
return TenantContext.getCurrentTenant();
}
}
DataSourceProperties
#Data
#Component
#ConfigurationProperties(prefix = "spring")
public class DataSourceProperties {
private List<DataSourceProperty> dataSources = new ArrayList<>();
}
DataSourceProperty
#Data
public class DataSourceProperty {
private String tenantId;
private String url;
private String username;
private String password;
private String driverClassName;
private LiquibaseProperties liquibase;
}
See the complete code, maybe help you!
Link of project: https://github.com/dijalmasilva/spring-boot-multitenancy-datasource-liquibase