I have an Spring MVC app with an embedded database (HSQLDB) that I want to initialize after deployment. I know that I could use an xml script to define initial data for my datasource but, as long I'm using JPA + Hibernate, I would like to use Java code. Is there a way to do this?
Heavily updated answer (it was too complex before):
All you need is to add initializing bean to your context, which will insert all the necessary data into the database:
public class MockDataPopulator {
private static boolean populated = false;
#Autowired
private SessionFactory sessionFactory;
#PostConstruct
public void populateDatabase() {
// Prevent duplicate initialization as HSQL is also initialized only once. Duplicate executions
// can happen when the application context is reloaded - e.g. when running unit tests).
if (populated) {
return;
}
// Create new persistence session
Session session = sessionFactory.openSession();
session.setFlushMode(FlushMode.ALWAYS);
// Insert mock entities
session.merge(MockDataFactory.createMyFirstObject())
session.merge(MockDataFactory.createMySeconfObject())
// ...
// Flush and close
session.flush();
session.close();
// Set initialization flag
populated = true;
}
}
Related
I am developing small POC application to test .NET7 support for distributed transactions since this is pretty important aspect in our workflow.
So far I've been unable to make it work and I'm not sure why. It seems to me either some kind of bug in .NET7 or im missing something.
In short POC is pretty simple, it runs WorkerService which does two things:
Saves into "bussiness database"
Publishes a message on NServiceBus queue which uses MSSQL Transport.
Without Transaction Scope this works fine however, when adding transaction scope I'm asked to turn on support for distributed transactions using:
TransactionManager.ImplicitDistributedTransactions = true;
Executable code in Worker service is as follows:
protected override async Task ExecuteAsync(CancellationToken stoppingToken)
{
int number = 0;
try
{
while (!stoppingToken.IsCancellationRequested)
{
number = number + 1;
using var transactionScope = TransactionUtils.CreateTransactionScope();
await SaveDummyDataIntoTable2Dapper($"saved {number}").ConfigureAwait(false);
await messageSession.Publish(new MyMessage { Number = number }, stoppingToken)
.ConfigureAwait(false);
_logger.LogInformation("Publishing message {number}", number);
_logger.LogInformation("Worker running at: {time}", DateTimeOffset.Now);
transactionScope.Complete();
_logger.LogInformation("Transaction complete");
await Task.Delay(1000, stoppingToken);
}
}
catch (Exception e)
{
_logger.LogError("Exception: {ex}", e);
throw;
}
}
Transaction scope is created with the following parameters:
public class TransactionUtils
{
public static TransactionScope CreateTransactionScope()
{
var transactionOptions = new TransactionOptions();
transactionOptions.IsolationLevel = IsolationLevel.ReadCommitted;
transactionOptions.Timeout = TransactionManager.MaximumTimeout;
return new TransactionScope(TransactionScopeOption.Required, transactionOptions,TransactionScopeAsyncFlowOption.Enabled);
}
}
Code for saving into database uses simple dapper GenericRepository library:
private async Task SaveDummyDataIntoTable2Dapper(string data)
{
using var scope = ServiceProvider.CreateScope();
var mainTableRepository =
scope.ServiceProvider
.GetRequiredService<MainTableRepository>();
await mainTableRepository.InsertAsync(new MainTable()
{
Data = data,
UpdatedDate = DateTime.Now
});
}
I had to use scope here since repository is scoped and worker is singleton so It cannot be injected directly.
I've tried persistence with EF Core as well same results:
Transaction.Complete() line passes and then when trying to dispose of transaction scope it hangs(sometimes it manages to insert couple of rows then hangs).
Without transaction scope everything works fine
I'm not sure what(if anything) I'm missing here or simply this still does not work in .NET7?
Note that I have MSDTC enable on my machine and im executing this on Windows 10
We've been able to solve this by using the following code.
With this modification DTC is actually invoked correctly and works from within .NET7.
using var transactionScope = TransactionUtils.CreateTransactionScope().EnsureDistributed();
Extension method EnsureDistributed implementation is as follows:
public static TransactionScope EnsureDistributed(this TransactionScope ts)
{
Transaction.Current?.EnlistDurable(DummyEnlistmentNotification.Id, new DummyEnlistmentNotification(),
EnlistmentOptions.None);
return ts;
}
internal class DummyEnlistmentNotification : IEnlistmentNotification
{
internal static readonly Guid Id = new("8d952615-7f67-4579-94fa-5c36f0c61478");
public void Prepare(PreparingEnlistment preparingEnlistment)
{
preparingEnlistment.Prepared();
}
public void Commit(Enlistment enlistment)
{
enlistment.Done();
}
public void Rollback(Enlistment enlistment)
{
enlistment.Done();
}
public void InDoubt(Enlistment enlistment)
{
enlistment.Done();
}
This is 10year old code snippet yet it works(im guessing because .NET Core merely copied and refactored the code from .NET for DistributedTransactions, which also copied bugs).
What it does it creates Distributed transaction right away rather than creating LTM transaction then promoting it to DTC if required.
More details explanation can be found here:
https://www.davidboike.dev/2010/04/forcibly-creating-a-distributed-net-transaction/
https://github.com/davybrion/companysite-dotnet/blob/master/content/blog/2010-03-msdtc-woes-with-nservicebus-and-nhibernate.md
Ensure you're using Microsoft.Data.SqlClient +v5.1
Replace all "usings" System.Data.SqlClient > Microsoft.Data.SqlClient
Ensure ImplicitDistributedTransactions is set True:
TransactionManager.ImplicitDistributedTransactions = true;
using (var ts = new TransactionScope(your options))
{
TransactionInterop.GetTransmitterPropagationToken(Transaction.Current);
... your code ..
ts.Complete();
}
I have one database with 3 schemas (OPS, TEST, TRAIN). All of these schemas have a completely identical table structure. Now lets say I have an endpoint /cars that accepts a query param for the schema/environment. When the user makes a GET request to this endpoint, I need the Spring Boot backend to be able to dynamically access either the OPS, TEST, or TRAIN schema based on the query param specified in the client request.
The idea is something like this where the environment is passed as a request param to the endpoint and then is somehow used in the code to set the schema/datasource that the repository will use.
#Autowired
private CarsRepository carsRepository;
#GetMapping("/cars")
public List<Car> getCars(#RequestParam String env) {
setSchema(env);
return carsRepository.findAll();
}
private setSchema(String env) {
// Do something here to set the schema that the CarsRepository
// will use when it runs the .findAll() method.
}
So, if a client made a GET request to the /cars endpoint with the env request param set to "OPS" then the response would be a list of all the cars in the OPS schema. If a client made the same request but with the env request param set to "TEST", then the response would be all the cars in the TEST schema.
An example of my datasource configuration is below. This one is for the OPS schema. The other schemas are done in the same fashion, but without the #Primary annotation above the beans.
#Configuration
#EnableTransactionManagement
#EnableJpaRepositories(
entityManagerFactoryRef = "opsEntityManagerFactory",
transactionManagerRef = "opsTransactionManager",
basePackages = { "com.example.repo" }
)
public class OpsDbConfig {
#Autowired
private Environment env;
#Primary
#Bean(name = "opsDataSource")
#ConfigurationProperties(prefix = "db-ops.datasource")
public DataSource dataSource() {
return DataSourceBuilder
.create()
.url(env.getProperty("db-ops.datasource.url"))
.driverClassName(env.getProperty("db-ops.database.driverClassName"))
.username(env.getProperty("db-ops.database.username"))
.password(env.getProperty("db-ops.database.password"))
.build();
}
#Primary
#Bean(name = "opsEntityManagerFactory")
public LocalContainerEntityManagerFactoryBean opsEntityManagerFactory(
EntityManagerFactoryBuilder builder,
#Qualifier("opsDataSource") DataSource dataSource
) {
return builder
.dataSource(dataSource)
.packages("com.example.domain")
.persistenceUnit("ops")
.build();
}
#Primary
#Bean(name = "opsTransactionManager")
public PlatformTransactionManager opsTransactionManager(
#Qualifier("opsEntityManagerFactory") EntityManagerFactory opsEntityManagerFactory
) {
return new JpaTransactionManager(opsEntityManagerFactory);
}
}
Personally, I don't feel its right to pass environment as Request Param and toggle the repository based on the value passed.
Instead you can deploy multiple instance of the service pointing to different data source and have a gate keeper(router) to route to the respective service.
By this way clients will be exposed to one gateway service which in turn routes to respective service based on input to gate keeper.
You typically don't want TEST/ACPT instances running on the very same machines because it typically gets harder to [keep under] control the extent to which load on these environments will make the PROD environment slow down.
You also don't want the setup you envisage because it makes it nigh impossible to evolve the app and/or its database structure. (You're not going to switch db schema in PROD at the very same time you're doing this in DEV are you ? Not doing that simultaneous switch is wise, but it breaks your presupposition that "all three databases have exactly the same schema".
My current system has a rather aggressive data layer that creates an SqlDatabase instance for me by calling a static method. I pass in a stored procedure name (string) and the magic just happens.
I want to try and get some of this crazy system under test and so want to control what is in the database.
Having realised that this structure
[Test]
public void Should_do_some_thing()
{
using (var scope = new TransactionScope())
{
CleanUpDatabase();
SetupDatabaseData();
//Run Test
Assert.That(someResult,Is.EqualTo("ExpectedValue");
scope.Dispose();
}
}
does what I want (no database changes persist outside the test) It would clearly be nicer if I could set up the transaction within a [SetUp] method and remove without committing in the [TearDown] section.
Is this possible?
Note I cannot call any methods on a command object or whatever...
You could use TestInitialize and TestCleanup to do the set up/clean up:
private TransactionScope scope;
[TestInitialize]
public void TestInitialize()
{
scope = new TransactionScope();
CleanUpDatabase();
SetupDatabaseData();
}
[Test]
public void Should_do_some_thing()
{
//Run Test
Assert.That(someResult,Is.EqualTo("ExpectedValue");
}
[TestCleanup]
public void CleanUp()
{
scope.Dispose();
}
You may need to add error handling etc but this is the basics of it:
TestInitialize:
Identifies the method to run before the test to allocate and configure resources needed by all tests in the test class. This class cannot be inherited.
TestCleanUp:
Identifies a method that contains code that must be used after the test has run and to free resources obtained by all the tests in the test class. This class cannot be inherited.
If you are using NUNIT then you can use [SetUp] and [TearDown] instead of [TestInitialize] and [TestCleanUp] respectively.
I have implemented Specflow to reuse some steps across features as in this example -Specflow,Selenium-Share data between different Step definitions or classes .Since, in our project, we are integrating multiple features & reusing them. What is the best way to share browser session across features if its triggered in between steps as per the above approach?
My Scenario:
Once an application created, I need to launch new session, login different User-set different services and approve it.
But after logging in fails with below error on Step definition 4 in reused Whenstep of Given(Set the service to (.*)). That particular step is from different feature, hence the new session needs to be used in those steps. The LaunchURl method below is just launching the website with url, no new session created - This works fine
OpenQA.Selenium.WebDriverException : Unexpected error. System.Net.WebException: Unable to connect to the remote server ---> System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused it "IP here"
[Given(#"A New Application is added")]
public void GivenANewApplicationIsAdded()
{
Given("UK_The Service is set");
Given("User Navigated to New Application screen");
When("User fills up form as in data row 1");
Then("new SID generated");
}
[Given(#"New Browser Launched")]
public void GivenNewBrowserLaunched()
{
SeleniumContext sl = new SeleniumContext();
this.seleniumContext = sl;
}
[Given(#"Login is successful with ""(.*)"" and ""(.*)""")]
public void GivenLoginIsSuccessfulWithAnd(string userName, string password)
{
SuperTests spr = new SuperTests();
_driver = spr.LaunchURL(seleniumContext.WebDriver);
//seleniumContext.WebDriver = _driver;
LoginPage lg = new LoginPage(_driver);
lg.LoginProcess(userName, password);
}
[Given(#"Set the service to ""(.*)""")]
public void GivenSetTheServiceTo(string serviceId)
{
When("Select a Service from the option "+serviceId);
Then("The Services is changed to the one selected " + serviceId);
}
In other feature
[When(#"Select a Service from the option (.*)")]
public void WhenSelectAServiceFromTheOptionTestTeam(string p0)
{
HomePage mst = new HomePage(seleniumContext.WebDriver);
mst.SetServiceId(p0);
}
The 2 work around what we figured was
Create a new instance of binding class to call the methods or steps as shown below
[Given(#"Set the service to ""(.*)""")]
public void GivenSetTheServiceTo(string serviceId)
{
var serIdSteps = new UK_SetServiceIDSteps(seleniumContext);
serIdSteps.WhenUK_SelectAServiceFromTheOptionTest(serviceId);
serIdSteps.ThenUK_TheServicesIsChangedToTheOneSelected(serviceId);
}
or
tried this which worked as well- basically calling a new method to create a new session. for this I need not create any new instance for Binding class. Called the Step directly.
[Given(#"New Browser Launched")]
public void GivenNewBrowserLaunched()
{
SuperTests spr = new SuperTests();
_driver = spr.LaunchURL("Firefox");
seleniumContext.WebDriver = _driver;
}
public void GivenSetTheServiceTo(string serviceId)
{
When("UK_Select a Service from the option "+serviceId);
Then("UK_The Services is changed to the one selected " + serviceId);
}
Not sure, which is correct way of doing it? Trying to figure it out from Reusable steps point?The latter one is not advised as we need to change the type of browser to launch at multiple place.
I am making a project using JSF, and I know how to get data from my view. I also know how to get data with the JDBC connector. And also how to put data in the view, from some objects, but my question is:
How to put data directly from my database, for example a list of person, in JSF, for example with the tag <h:outputText value="#{}"/> ?
I have found some examples with instantiate objects, but I did not found a real example with data from a DB.
JSF is just an MVC framework to develop web applications in Java. JSF doesn't associate with any data source at all. The only data JSF will use is retrieved from:
The data already stored in the proper object as attribute: HttpServletRequest, HttpSession or ServletContext.
The request/view/session/application context in form of fields in the managed beans, recognized by classes decorated as #ManagedBeans or #Named if using CDI. The data of these fields will be stored as attributes in the objects mentioned in the section above, depending on the scope of the managed bean.
By knowing this, then the only thing you should worry about is to fill the fields in your managed beans. You can fill them with incoming data from database, from a web service or whatever data source you have in mind.
For example, if you want/need to populate your data to pre process a request, you can do the following:
#ManagedBean
#ViewScoped
public class SomeBean {
List<Entity> entityList;
#PostConstruct
public void init() {
SomeService someService = new SomeService();
entityList = someService.findEntityList();
}
//getters and setters for the list...
}
//as you can see, this class is just pure Java
//you may use other frameworks if you want/need
public class SomeService {
public List<Entity> findEntityList() {
String sql = "SELECT field1, field2... FROM table";
List<Entity> entityList = new ArrayList<>();
try (Connection con = ...; //retrieve your connection somehow
PreparedStatement pstmt = con.prepareStatement(sql)) {
ResultSet rs = pstmt.executeQuery();
while (rs.next()) {
Entity entity = new Entity();
entity.setField1(rs.getString("field1"));
entity.setField2(rs.getString("field2"));
//...
entityList.add(entity);
}
} catch (Exception e) {
//handle exception ...
e.printStackTrace();
}
return entityList;
}
}