In the example below, I successfully fall into the end point - mandatory() - although one of two mutually exclusive #Transactional annotations must throw an exception: whether Propagation.NEVER or Propagation.MANDATORY. But the code is executed successfully.
How could that be?!
A couple (not all) of my services are affected by that and I'd like to understand what is the cause.
class NewService {
static transactional = true
boolean process() {
return never()
}
#Transactional(propagation = Propagation.NEVER)
boolean never() {
return mandatory()
}
#Transactional(propagation = Propagation.MANDATORY)
boolean mandatory() {
// successfully breakpointed here o_O
return true
}
}
Grails 2.2.0
It looks like you are bypassing the bean proxy, as Burt Beckwith (Slide 23) called it "Unintentionally bypassing the bean proxy".
You need to get proxy and execute your method on that.
#Transactional(propagation = Propagation.NEVER)
boolean never() {
def myproxy= grailsApplication.mainContext.newService
return myproxy.mandatory()
}
#Transactional(propagation = Propagation.MANDATORY)
boolean mandatory() {
// successfully breakpointed here o_O
return true
}
Spring declarative transactions are AOP-based. And Spring AOP is proxy-based. This means that the transactional annotation is read and taken into account when a bean is called from another bean, through a proxy:
Bean A --> injected transactional proxy --> Bean B
In your case, you call another ethod of the same bean directly. The transactional proxy is thus not aware of this call, and thus can't enforce the presence of a transaction:
Bean A --> this
Related
I added a class in src/groovy that implements the DataBindingListener interface. My init/Application file registers the Spring bean in the doWithSpring method
#Override
Closure doWithSpring() {
def beans = {
applicationBindingListener(org.mkv.ApplicationBindingListener)
}
return beans
}
I confirmed the bean is registered. However it doesn't seem to be receiving any of the binding events.
I'm using grails 4.0.0
In my case, I edit config/spring/resources.groovy. It's the source.
beans = {
dataBindingListener org.mkv.ApplicationBindingListener
}
And, The code below is added as a test case method to ensure that the bean configured in the test code is used.
boolean loadExternalBeans() {
true
}
In my Spring Boot project I have implemented following service method:
#Transactional
public boolean validateBoard(Board board) {
boolean result = false;
if (inProgress(board)) {
if (!canPlayWithCurrentBoard(board)) {
update(board, new Date(), Board.AFK);
throw new InvalidStateException(ErrorMessage.BOARD_TIMEOUT_REACHED);
}
if (!canSelectCards(board)) {
update(board, new Date(), Board.COMPLETED);
throw new InvalidStateException(ErrorMessage.ALL_BOARD_CARDS_ALREADY_SELECTED);
}
result = true;
}
return result;
}
Inside this method I use another service method which is called update:
#Transactional(propagation = Propagation.REQUIRES_NEW)
public Board update(Board board, Date finishedDate, Integer status) {
board.setStatus(status);
board.setFinishedDate(finishedDate);
return boardRepository.save(board);
}
I need to commit changes to database in update method independently of the owner transaction which is started in validateBoard method. Right now any changes is rolling back in case of any exception.
Even with #Transactional(propagation = Propagation.REQUIRES_NEW) it doesn't work.
How to correctly do this with Spring and allow nested transactions ?
This documentation covers your problem - https://docs.spring.io/spring-framework/docs/current/spring-framework-reference/data-access.html#transaction-declarative-annotations
In proxy mode (which is the default), only external method calls coming in through the proxy are intercepted. This means that self-invocation, in effect, a method within the target object calling another method of the target object, will not lead to an actual transaction at runtime even if the invoked method is marked with #Transactional. Also, the proxy must be fully initialized to provide the expected behaviour so you should not rely on this feature in your initialization code, i.e. #PostConstruct.
However, there is an option to switch to AspectJ mode
Using "self" inject pattern you can resolve this issue.
sample code like below:
#Service #Transactional
public class YourService {
//... your member
#Autowired
private YourService self; //inject proxy as an instance member variable ;
#Transactional(propagation= Propagation.REQUIRES_NEW)
public void methodFoo() {
//...
}
public void methodBar() {
//call self.methodFoo() rather than this.methodFoo()
self.methodFoo();
}
}
The point is using "self" rather than "this".
The basic thumb rule in terms of nested Transactions is that they are completely dependent on the underlying database, i.e. support for Nested Transactions and their handling is database dependent and varies with it.
In some databases, changes made by the nested transaction are not seen by the 'host' transaction until the nested transaction is committed. This can be achieved using Transaction isolation in #Transactional (isolation = "")
You need to identify the place in your code from where an exception is thrown, i.e. from the parent method: "validateBoard" or from the child method: "update".
Your code snippet shows that you are explicitly throwing the exceptions.
YOU MUST KNOW::
In its default configuration, Spring Frameworkâs transaction
infrastructure code only marks a transaction for rollback in the case
of runtime, unchecked exceptions; that is when the thrown exception is
an instance or subclass of RuntimeException.
But #Transactional never rolls back a transaction for any checked exception.
Thus, Spring allows you to define
Exception for which transaction should be rollbacked
Exception for which transaction shouldn't be rollbacked
Try annotating your child method: update with #Transactional(no-rollback-for="ExceptionName") or your parent method.
Your transaction annotation in update method will not be regarded by Spring transaction infrastructure if called from some method of same class. For more understanding on how Spring transaction infrastructure works please refer to this.
Your problem is a method's call from another method inside the same proxy.It's self-invocation.
In your case, you can easily fix it without moving a method inside another service (why do you need to create another service just for moving some method from one service to another just for avoid self-invocation?), just to call the second method not directly from current class, but from spring container. In this case you call proxy second method with transaction not with self-invocatio.
This principle is useful for any proxy-object when you need self-invocation, not only a transactional proxy.
#Service
class SomeService ..... {
-->> #Autorired
-->> private ApplicationContext context;
-->> //or with implementing ApplicationContextAware
#Transactional(any propagation , it's not important in this case)
public boolean methodOne(SomeObject object) {
.......
-->> here you get a proxy from context and call a method from this proxy
-->>context.getBean(SomeService.class).
methodTwo(object);
......
}
#Transactional(any propagation , it's not important in this case)public boolean
methodTwo(SomeObject object) {
.......
}
}
when you do call context.getBean(SomeService.class).methodTwo(object); container returns proxy object and on this proxy you can call methodTwo(...) with transaction.
You could create a new service (CustomTransactionalService) that will run your code in a new transaction :
#Service
public class CustomTransactionalService {
#Transactional(propagation= Propagation.REQUIRES_NEW)
public <U> U runInNewTransaction(final Supplier<U> supplier) {
return supplier.get();
}
#Transactional(propagation= Propagation.REQUIRES_NEW)
public void runInNewTransaction(final Runnable runnable) {
runnable.run();
}
}
And then :
#Service
public class YourService {
#Autowired
private CustomTransactionalService customTransactionalService;
#Transactional
public boolean validateBoard(Board board) {
// ...
}
public Board update(Board board, Date finishedDate, Integer status) {
this.customTransactionalService.runInNewTransaction(() -> {
// ...
});
}
}
I want to know what actually happens when you annotate a method with #Transactional with ScheduledExecutorService?
Assume that the methodA is called externally. Am I correct in assuming that when methodA is called, someDao.methodDao() joins in a transaction and scheduleMethodB() returns immediately.
Later after 2 seconds, the scheduler calls the methodB(). What would this hold in this case? Would it hold the TransactionProxy and execute methodB in a separate transaction? If not, then how would we able to achieve this.
I am aware that #Transactional is based on proxies so is methodB call a self invocation under scheduler.
Note: Since this mechanism is based on proxies, only 'external' method
calls coming in through the proxy will be intercepted. This means that
'self-invocation', i.e. a method within the target object calling some
other method of the target object, won't lead to an actual transaction
at runtime even if the invoked method is marked with #Transactional!
public class ServiceABImpl implements ServiceAB {
#Autowired
private ScheduledExecutorService scheduledExecutorService;
#Transactional
public void methodA() {
//do some work in a transaction.
someDao.methodDao();
//schedule a methodB
scheduleMethodB();
}
public void scheduleMethodB() {
scheduledExecutorService.schedule(() -> {
this.methodB();
return "";
},
2,
TimeUnit.SECONDS);
}
#Transactional
public void methodB() {
}
}
Since the class is not annotated with #Transactional, the decision of whether an invoked method participates in the transaction of the parent invokee method depends on whether you annotate the invoked methods also with #Transactional and what propagation level you configure it with I think. So for example
#Transactional(propagation=Propagation.REQUIRED)
I am new with spring/grails transaction and i am still not clear after reading so i am posting it in here,
I have a service class which is annotated as #Transactional
and i have methods some of them are annotated as
#Transactional(propagation = Propagation.REQUIRES_NEW)
and some of them are not.
#Transactional
class SomeService {
def findJob() {
MyInstance myInstance = getMeAJob();
if (myInstance) {
doSomeThing(myInstance)
doTask()
}
}
#Transactional(propagation = Propagation.REQUIRES_NEW, rollbackFor = Exception)
private doSomeThing(MyInstance myInst) {
myObj = MyInstance.lock(myInst.id)
try {
differentObj = doTask(myObj)
myObj.save()
doAnotherThing()
}
} catch (Exception e) {
log("Error in doAnotherTask")
}
}
private doAnotherThing(MyInstace myInst) {
perform some update on myInst
myInstant.save(flush: true)
}
private doTask() {
}
Suppose , I have transaction t1 from the class level and t2
transaction from doSomething()- REQUIRES_NEW.
Method that will execute in t1 - findJob() and doTask()
Method that will execute in t2 - doSomeThing() - doesn't affect the
"t1" in case of exception (Rollback)
Which one will be for doAnotherThing() method? Since I am calling it from doSomething()?
When you have a class-scope annotation, any method that's not annotated uses those settings, and annotated methods override the class-level settings with the settings from that annotation.
Note however that when using Spring's annotation support (with the #org.springframework.transaction.annotation.Transactional) annotation only public methods are supported. There won't be an error, but the annotations are silently ignored.
But even if you make doSomeThing public (either implicitly by removing the private keyword or explicitly by changing it to public) it won't do what you expect when you call doSomeThing from findJob. This is because Spring's annotation triggers the creation of a proxy of your class at runtime. The Spring bean that's registered for your service in that case is a proxy instance that has a "real" instance of your class as its delegate. All transactional public methods are intercepted by the proxy, which starts/joins/etc. a transaction and then calls your service method. Once you're "underneath" the proxy in the service instance all method calls are direct and any annotation settings have no effect. To get it to work you would need to call the method on the Spring bean and go through the proxy to start a new transaction.
To avoid this proxy issue, use the Grails #grails.transaction.Transactional annotation instead. It supports the same transaction features as the Spring annotation, but instead of creating a proxy, an AST transformation rewrites your methods to wrap them within a transaction. This makes it possible to make direct method calls like you're doing and create a new transaction or run under other transaction semantics as defined by the annotation attributes.
I did a talk a while back on using transactions in Grails that might shed some light.
i want to make somethings clear about #Transactional spring annotation.
Suppose i have written my code something as under,
case-1
#Transactional(readOnly = false, propagation = Propagation.REQUIRED, rollbackFor=Throwable.class)
public void method1(){
.....method body....
}
#Transactional(readOnly = false, propagation = Propagation.REQUIRED, rollbackFor=Throwable.class)
public String method2(){
try{
method1()
}
catch(Exce...){
}
}
case 2:
#Transactional(readOnly = false, propagation = Propagation.REQUIRED, rollbackFor=Throwable.class)
public void method1(){
try{
}
catch(Excep..){
}
}
#Transactional(readOnly = false, propagation = Propagation.REQUIRED, rollbackFor=Throwable.class)
public String method2(){
method1()
}
What would happen in case-1 if some exception occurs in excecution of method1, does it rollback transaction?
and what would happen for the same in case-2.
Thanx in advance
There will be no rollback in any of your use cases regardless of the exception type or propagation as long as you catch the exception in method2.
Why?
Spring creates a proxy class for the Transactional class or members, this is not visible for you. This proxy makes it possible to Spring to execute code before and after your function, basically open transaction, commit or rollback. This proxy is injected into your classes when you autowire them.
Of course the Transactional annotations only work when you're calling them through the proxy!
Your method1 call is always a local function call, so as long as you catch the exception in method2 it won't cause any rollback.
But please read the documentation.
You are free to specify. Using annotations for instance you can write like this:
#Transactional(rollbackFor=Exception.class, timeout=10)
Default behavior is not to rollback when an exception is thrown across the transaction demarcation line.
The Spring #Transactional default configuration (as you used it here) is rolling back only for java.lang.RuntimeException s and the propagation is REQUIRED.
So in case you are calling method2():
CASE 1: no rollback as you are catching in method2() java.lang.Exception (which is the parent of java.lang.RuntimeException)
CASE 2: same - as you are catching in method1() java.lang.Exception
The meaning of the propagation here is that when you've started a transaction if you encounter another annotation of #Transaction another transaction is not started and the application uses the "outer" transaction. So do not expect that the rollback logic will get executed before the method2() finishes. Anyway, one may assume from your snippet that the methods are in the same Spring Bean so calling a method internally in a bean (method2() calls method1() here) the AOP annotation are not "active" meaning that the f/w will not even "see" the #Transactionl on method1().
EDIT
Question changed so that the rollback is for all java.lang.Throwable s. So the answer is the same except for the fact that if an java.lang.Error is thrown then there is a rollback in both cases after the method2() is finished.