How to manually initialize a database using a datasource? - spring

Question

My current AbstractionDataSource implementation does the following:
1- Spring initializes with the default URL/Schema so the user can login.
2- After a successful login, the default schema changes to another schema based on the UserDetails class.
An example would be a user from company X being redirected to schema X and a user from company K being redirected to schema K after a successful login.
Problem:
I need to initialize the database from step 2. With
spring.jpa.hibernate.ddl-auto=create
Currently, Spring boot only initializes the default database that the user uses to login. However, I need to execute a different initialization for the other schemas that are dependent on the logged-in user.
public class UserSchemaAwareRoutingDataSource extends AbstractDataSource {
#Autowired
private UsuarioProvider usuarioProvider;
/**
* This is the data source that is dependent on the user.
*/
#Autowired
#Qualifier(value = "companyDependentDataSource")
private DataSource companyDependentDataSource;
/**
* This is the initial datasource.
*/
#Autowired
#Qualifier(value = "loginDataSource")
private DataSource loginDataSource;
/**
* Variable representing the environment in which the current application is
* running.
*/
#Autowired
Environment env;
/**
* A semi-persistent mapping from Schemas to dataSources. This exists,
* because ??? to increase performance and diminish overhead???
*/
private LoadingCache<String, DataSource> dataSources = createCache();
public UserSchemaAwareRoutingDataSource() {
}
/**
* Creates the cache. ???
*
* #return
*/
private LoadingCache<String, DataSource> createCache() {
return CacheBuilder.newBuilder()
.maximumSize(100)
.expireAfterWrite(10, TimeUnit.MINUTES)
.build(
new CacheLoader<String, DataSource>() {
public DataSource load(String key) throws Exception {
return buildDataSourceForSchema(key);
}
});
}
/**
* Builds the datasource with the schema parameter. Notice that the other
* parameters are fixed by the application.properties.
*
* #param schema
* #return
*/
private DataSource buildDataSourceForSchema(String schema) {
logger.info("building datasource with schema " + schema);
String url = env.getRequiredProperty("companydatasource.url");
String username = env.getRequiredProperty("companydatasource.username");
String password = env.getRequiredProperty("companydatasource.password");
DataSource build = DataSourceBuilder.create()
.driverClassName(env.getRequiredProperty("companydatasource.driver-class-name"))
.username(username)
.password(password)
.url(url)
.build();
return build;
}
/**
* Gets the Schema from the Cache, or build one if it doesnt exist.
*
* #return
*/
private DataSource determineTargetDataSource() {
try {
String db_schema = determineTargetSchema();
logger.info("using schema " + db_schema);
return dataSources.get(db_schema);
} catch (Exception ex) {
throw new RuntimeException(ex);
}
}
/**
* Determine the schema based on the logger-in User.
*
* #return
*/
private String determineTargetSchema() {
try {
Usuario usuario = usuarioProvider.customUserDetails(); // request scoped answer!
return usuario.getTunnel().getDb_schema();
} catch (RuntimeException e) {
// This shouldn't be necessary, since we are planning to use a pre-initialized database.
// And there should only be usages of this DataSource in a logged-in situation
logger.info("usuario not present, falling back to default schema", e);
return "default_company_schema";
}
}
#Override
public Connection getConnection() throws SQLException {
return determineTargetDataSource().getConnection();
}
#Override
public Connection getConnection(String username, String password) throws SQLException {
return determineTargetDataSource().getConnection(username, password);
}
#Override
public ConnectionBuilder createConnectionBuilder() throws SQLException {
return super.createConnectionBuilder();
}
}
//
Im expecting there is someway to call hibernate tools to initialize the database on the following method:
/**
* Builds the datasource with the schema parameter. Notice that the other
* parameters are fixed by the application.properties.
*
* #param schema
* #return
*/
private DataSource buildDataSourceForSchema(String schema) {
logger.info("building datasource with schema " + schema);
String url = env.getRequiredProperty("companydatasource.url");
String username = env.getRequiredProperty("companydatasource.username");
String password = env.getRequiredProperty("companydatasource.password");
DataSource build = DataSourceBuilder.create()
.driverClassName(env.getRequiredProperty("companydatasource.driver-class-name"))
.username(username)
.password(password)
.url(url)
.build();
//Init database or update it with hibernate
String initDatabase = env.getRequiredProperty("spring.jpa.hibernate.ddl-auto");
if(initDatabase.equalsIgnoreCase("update")){
org.hibernate.tool.hbm2ddl.SchemaUpdate schemaUpdate = new SchemaUpdate();
schemaUpdate.execute(??);
}
//
return build;
}
//
Repository: https://github.com/KenobySky/SpringSchema

Answer 1

With the initialization of the object, there's no guarantee that Spring would have assigned the Environment object to the Autowired property before the private dataSources property would be getting set.
There are a couple of options:
Add a constructor to take on the assignment of that property for you
Use the #PostConstruct annotation to make that assignment wait for the object to be constructed.