Spring Integration - JdbcPollingChannelAdapter commit instead of rollback on handled Exceptions - spring

Question

I am using Spring 4.1.x APIs, Spring Integration 4.1.x APIs and Spring Integration Java DSL 1.0.x APIs for an EIP flow where we consume messages from an Oracle database table using a JdbcPollingChannelAdpater as the entry point into the flow.
Even though we have an ErrorHandler configured on the JdbcPollingChannelAdapter's Poller, we are seeing that a session's Transaction is still rolled back and not committed when a RuntimeException is thrown and correctly handled by the ErrorHandler.
After reading through this thread: Spring Transactions - Prevent rollback after unchecked exceptions (RuntimeException), I get the feeling that it is not possible to prevent a rollback and instead force a commit. Is this correct? And, if there is a way, what is the cleanest way to force a commit instead of a rollback when an error is safely handled?
Current Configuration:
IntegrationConfig.java:
#Bean
public MessageSource<Object> jdbcMessageSource() {
JdbcPollingChannelAdapter adapter = new JdbcPollingChannelAdapter(
dataSource,
"select * from SERVICE_TABLE where rownum <= 10 for update skip locked");
adapter.setUpdateSql("delete from SERVICE_TABLE where SERVICE_MESSAGE_ID in (:id)");
adapter.setRowMapper(serviceMessageRowMapper);
adapter.setMaxRowsPerPoll(1);
adapter.setUpdatePerRow(true);
return adapter;
}
#SuppressWarnings("unchecked")
#Bean
public IntegrationFlow inFlow() {
return IntegrationFlows
.from(jdbcMessageSource(),
c -> {
c.poller(Pollers.fixedRate(100)
.maxMessagesPerPoll(10)
.transactional(transactionManager)
.errorHandler(errorHandler));
})
.channel(inProcessCh()).get();
}
ErrorHandler.java
#Component
public class ErrorHandler implements org.springframework.util.ErrorHandler {
#Autowired
private PlatformTransactionManager transactionManager;
private static final Logger logger = LogManager.getLogger();
#Override
public void handleError(Throwable t) {
logger.trace("handling error:{}", t.getMessage(), t);
// handle error code here...
// we want to force commit the transaction here?
TransactionStatus txStatus = transactionManager.getTransaction(null);
transactionManager.commit(txStatus);
}
}
--- EDITED to include ExpressionEvaluatingRequestHandlerAdvice Bean ---
#Bean
public Advice expressionEvaluatingRequestHandlerAdvice() {
ExpressionEvaluatingRequestHandlerAdvice expressionEvaluatingRequestHandlerAdvice = new ExpressionEvaluatingRequestHandlerAdvice();
expressionEvaluatingRequestHandlerAdvice.setTrapException(true);
expressionEvaluatingRequestHandlerAdvice.setOnSuccessExpression("payload");
expressionEvaluatingRequestHandlerAdvice
.setOnFailureExpression("payload");
expressionEvaluatingRequestHandlerAdvice.setFailureChannel(errorCh());
return expressionEvaluatingRequestHandlerAdvice;
}
--- EDITED to show Dummy Test Message handler ---
.handle(Message.class,
(m, h) -> {
boolean forceTestError = m.getHeaders().get("forceTestError");
if (forceTestError) {
logger.trace("simulated forced TestException");
TestException testException = new TestException(
"forced test exception");
throw testException;
}
logger.trace("simulated successful process");
return m;
}, e-> e.advice(expressionEvaluatingRequestHandlerAdvice())
--- EDITED to show ExecutorChannelInterceptor method ---
#Bean
public IntegrationFlow inFlow() {
return IntegrationFlows
.from(jdbcMessageSource(), c -> {
c.poller(Pollers.fixedRate(100).maxMessagesPerPoll(10)
.transactional(transactionManager));
})
.enrichHeaders(h -> h.header("errorChannel", errorCh(), true))
.channel(
MessageChannels.executor("testSyncTaskExecutor",
syncTaskExecutor()).interceptor(
testExecutorChannelInterceptor()))
.handle(Message.class, (m, h) -> {
boolean forceTestError = m.getHeaders().get("forceTestError");
if (forceTestError) {
logger.trace("simulated forced TestException");
TestException testException = new TestException(
"forced test exception");
throw testException;
}
logger.trace("simulated successful process");
}).channel("nullChannel").get();
}

Answer 1

It won't work just because your ErrorHandler works already after the finish of TX.
Here is a couple lines of source code (AbstractPollingEndpoint.Poller):
#Override
public void run() {
taskExecutor.execute(new Runnable() {
#Override
public void run() {
.............
try {
if (!pollingTask.call()) {
break;
}
count++;
}
catch (Exception e) {
....
}
}
}
});
}
Where:
The ErrorHandler is applied for the taskExecutor (SyncTaskExecutor) by default.
TransactionInterceptor being as Aspect is applied for the Proxy around that pollingTask.
Therefore TX is done around the pollingTask.call() and goes out. And only after that your ErrorHandler starts to work inside taskExecutor.execute().
To fix your issue, you need to figure out which downstream flow part isn't so critical for TX rallback and make there some try...catch or use ExpressionEvaluatingRequestHandlerAdvice to "burke" that RuntimeException.
But as you have noticed by my reasoning that must be done within TX.