I am using a thread based approach to poll the status of a specific task on AWS. For this, I use a while loop to constantly check the status as shown in below code. The issue is that when the code switches from one Service to another, it runs into an error -
Could not obtain transaction-synchronised hibernate session
The function in the thread is as below:
Runnable task = new Runnable() {
#Override
public void run() {
Session session = null;
try {
session = sessionFactory.openSession();
RmlWorkspace rmlWorkspace = session.get(RmlWorkspace.class, id);
logger.info("Starting Status check for "+id);
if (rmlWorkspace.getCloudStack().getStatus() == RUNNING_STATUS.STARTING) {
while (rmlWorkspace.getCloudStack().getStatus() != RUNNING_STATUS.ON) {
logger.info("Checking Status for "+id);
rmlWorkspace = checkStatus(session, rmlWorkspace);
TimeUnit.SECONDS.sleep(5);
}
} else if (rmlWorkspace.getCloudStack().getStatus() == RUNNING_STATUS.STOPPING) {
while (rmlWorkspace.getCloudStack().getStatus() != RUNNING_STATUS.OFF) {
Transaction tx = session.beginTransaction();
rmlWorkspace = checkStatus(session, rmlWorkspace);
tx.commit();
TimeUnit.SECONDS.sleep(5);
}
}
session.close();
} catch (Exception e) {
logger.info(e.getMessage());
if (session != null)
session.close();
}
}
};
The checkStatus function tries to call a function inside another class with the annotation #Service. The code meets an error at the below code:
private AssumeRoleResult assumeRole() {
try {
BasicAWSCredentials credentials = new BasicAWSCredentials(configAttributeService.getAttribute("aws.iamkey"),
configAttributeService.getAttribute("aws.iampass"));
AWSSecurityTokenService client = AWSSecurityTokenServiceClientBuilder.standard()
.withRegion(Regions.US_WEST_2).withCredentials(new AWSStaticCredentialsProvider(credentials))
.build();
AssumeRoleRequest request = new AssumeRoleRequest()
.withRoleArn(configAttributeService.getAttribute("aws.assumerole"))
.withRoleSessionName(UUID.randomUUID().toString()).withDurationSeconds(900);
AssumeRoleResult assumeRoleResult = client.assumeRole(request);
return assumeRoleResult;
} catch (Exception e) {
throw e;
}
}
The class containing the above function has an annotation #Service("xxx")
Could someone explain the reason for this and how to get this working.
Related
What is the appropriate way to handle live events (i.e. service/component should keep on listening to events and save it to offchain db (h2/postgres))
How to close event subscription gracefully?
Implementation tried so far:
#Component
public class ERC20Listener implements Listener {
private final Logger logger = LoggerFactory.getLogger(this.getClass());
/**
* Do something useful with the state update received
*/
#Override
#PostConstruct
public void listen() throws Exception {
Web3j web3j = null;
Disposable flowableEvent = null;
try {
WebSocketService web3jService = new WebSocketService("ws://", true);
web3jService.connect();
web3j = Web3j.build(web3jService);
ERC20Token token= ... //creating contract instance
flowableEvent = token.transferEventFlowable(DefaultBlockParameterName.LATEST, DefaultBlockParameterName.LATEST)
.subscribe(event -> {
try {
System.out.printf("hash=%s from=%s to=%s amount=%s%n",
event.log.getTransactionHash(),
event.from,
event.to,
event.value);
//process event data save to offchain db ==> service call
}catch(Throwable e) {
e.printStackTrace();
}
});
} catch (Exception e) {
logger.error("Unknown Exception " + e.getMessage());
throw new Exception(e.getMessage());
} finally {
web3j.shutdown();
flowableEvent.dispose();
}
}
}
We are trying to use google cloud datastore in our project and trying to use objectify as the ORM since google recommends it. I have carefully used and tried everything i could read about and think of but somehow the transactions don't seem to work. Following is my code and setup.
#RunWith(SpringRunner.class)
#EnableAspectJAutoProxy(proxyTargetClass = true)
#ContextConfiguration(classes = { CoreTestConfiguration.class })
public class TestObjectifyTransactionAspect {
private final LocalServiceTestHelper helper = new LocalServiceTestHelper(
// Our tests assume strong consistency
new LocalDatastoreServiceTestConfig().setApplyAllHighRepJobPolicy(),
new LocalMemcacheServiceTestConfig(), new LocalTaskQueueTestConfig());
private Closeable closeableSession;
#Autowired
private DummyService dummyService;
#BeforeClass
public static void setUpBeforeClass() {
// Reset the Factory so that all translators work properly.
ObjectifyService.setFactory(new ObjectifyFactory());
}
/**
* #throws java.lang.Exception
*/
#Before
public void setUp() throws Exception {
System.setProperty("DATASTORE_EMULATOR_HOST", "localhost:8081");
ObjectifyService.register(UserEntity.class);
this.closeableSession = ObjectifyService.begin();
this.helper.setUp();
}
/**
* #throws java.lang.Exception
*/
#After
public void tearDown() throws Exception {
AsyncCacheFilter.complete();
this.closeableSession.close();
this.helper.tearDown();
}
#Test
public void testTransactionMutationRollback() {
// save initial list of users
List<UserEntity> users = new ArrayList<UserEntity>();
for (int i = 1; i <= 10; i++) {
UserEntity user = new UserEntity();
user.setAge(i);
user.setUsername("username_" + i);
users.add(user);
}
ObjectifyService.ofy().save().entities(users).now();
try {
dummyService.mutateDataWithException("username_1", 6L);
} catch (Exception e) {
e.printStackTrace();
}
List<UserEntity> users2 = this.dummyService.findAllUsers();
Assert.assertEquals("Size mismatch on rollback", users2.size(), 10);
boolean foundUserIdSix = false;
for (UserEntity userEntity : users2) {
if (userEntity.getUserId() == 1) {
Assert.assertEquals("Username update failed in transactional context rollback.", "username_1",
userEntity.getUsername());
}
if (userEntity.getUserId() == 6) {
foundUserIdSix = true;
}
}
if (!foundUserIdSix) {
Assert.fail("Deleted user with userId 6 but it is not rolledback.");
}
}
}
Since I am using spring, idea is to use an aspect with a custom annotation to weave objectify.transact around the spring service beans methods that are calling my daos.
But somehow the update due to ObjectifyService.ofy().save().entities(users).now(); is not gettign rollbacked though the exception throws causes Objectify to run its rollback code. I tried printing the ObjectifyImpl instance hashcodes and they are all same but still its not rollbacking.
Can someone help me understand what am i doing wrong? Havent tried the actual web based setup yet...if it cant pass transnational test cases there is no point in actual transaction usage in a web request scenario.
Update: Adding aspect, services, dao as well to make a complete picture. The code uses spring boot.
DAO class. Note i am not using any transactions here because as per code of com.googlecode.objectify.impl.TransactorNo.transactOnce(ObjectifyImpl<O>, Work<R>) a transnational ObjectifyImpl is flushed and committed in this method which i don't want. I want commit to happen once and rest all to join in on that transaction. Basically this is the wrong code in com.googlecode.objectify.impl.TransactorNo ..... i will try to explain my understanding a later in the question.
#Component
public class DummyDaoImpl implements DummyDao {
#Override
public List<UserEntity> loadAll() {
Query<UserEntity> query = ObjectifyService.ofy().transactionless().load().type(UserEntity.class);
return query.list();
}
#Override
public List<UserEntity> findByUserId(Long userId) {
Query<UserEntity> query = ObjectifyService.ofy().transactionless().load().type(UserEntity.class);
//query = query.filterKey(Key.create(UserEntity.class, userId));
return query.list();
}
#Override
public List<UserEntity> findByUsername(String username) {
return ObjectifyService.ofy().transactionless().load().type(UserEntity.class).filter("username", username).list();
}
#Override
public void update(UserEntity userEntity) {
ObjectifyService.ofy().save().entity(userEntity);
}
#Override
public void update(Iterable<UserEntity> userEntities) {
ObjectifyService.ofy().save().entities(userEntities);
}
#Override
public void delete(Long userId) {
ObjectifyService.ofy().delete().key(Key.create(UserEntity.class, userId));
}
}
Below is the Service class
#Service
public class DummyServiceImpl implements DummyService {
private static final Logger LOGGER = LoggerFactory.getLogger(DummyServiceImpl.class);
#Autowired
private DummyDao dummyDao;
public void saveDummydata() {
List<UserEntity> users = new ArrayList<UserEntity>();
for (int i = 1; i <= 10; i++) {
UserEntity user = new UserEntity();
user.setAge(i);
user.setUsername("username_" + i);
users.add(user);
}
this.dummyDao.update(users);
}
/* (non-Javadoc)
* #see com.bbb.core.objectify.test.services.DummyService#mutateDataWithException(java.lang.String, java.lang.Long)
*/
#Override
#ObjectifyTransactional
public void mutateDataWithException(String usernameToMutate, Long userIdToDelete) throws Exception {
//update one
LOGGER.info("Attempting to update UserEntity with username={}", "username_1");
List<UserEntity> mutatedUsersList = new ArrayList<UserEntity>();
List<UserEntity> users = dummyDao.findByUsername(usernameToMutate);
for (UserEntity userEntity : users) {
userEntity.setUsername(userEntity.getUsername() + "_updated");
mutatedUsersList.add(userEntity);
}
dummyDao.update(mutatedUsersList);
//delete another
UserEntity user = dummyDao.findByUserId(userIdToDelete).get(0);
LOGGER.info("Attempting to delete UserEntity with userId={}", user.getUserId());
dummyDao.delete(user.getUserId());
throw new RuntimeException("Dummy Exception");
}
/* (non-Javadoc)
* #see com.bbb.core.objectify.test.services.DummyService#findAllUsers()
*/
#Override
public List<UserEntity> findAllUsers() {
return dummyDao.loadAll();
}
Aspect which wraps the method annoted with ObjectifyTransactional as a transact work.
#Aspect
#Component
public class ObjectifyTransactionAspect {
private static final Logger LOGGER = LoggerFactory.getLogger(ObjectifyTransactionAspect.class);
#Around(value = "execution(* *(..)) && #annotation(objectifyTransactional)")
public Object objectifyTransactAdvise(final ProceedingJoinPoint pjp, ObjectifyTransactional objectifyTransactional) throws Throwable {
try {
Object result = null;
Work<Object> work = new Work<Object>() {
#Override
public Object run() {
try {
return pjp.proceed();
} catch (Throwable throwable) {
throw new ObjectifyTransactionExceptionWrapper(throwable);
}
}
};
switch (objectifyTransactional.propagation()) {
case REQUIRES_NEW:
int limitTries = objectifyTransactional.limitTries();
if(limitTries <= 0) {
Exception illegalStateException = new IllegalStateException("limitTries must be more than 0.");
throw new ObjectifyTransactionExceptionWrapper(illegalStateException);
} else {
if(limitTries == Integer.MAX_VALUE) {
result = ObjectifyService.ofy().transactNew(work);
} else {
result = ObjectifyService.ofy().transactNew(limitTries, work);
}
}
break;
case NOT_SUPPORTED :
case NEVER :
case MANDATORY :
result = ObjectifyService.ofy().execute(objectifyTransactional.propagation(), work);
break;
case REQUIRED :
case SUPPORTS :
ObjectifyService.ofy().transact(work);
break;
default:
break;
}
return result;
} catch (ObjectifyTransactionExceptionWrapper e) {
String packageName = pjp.getSignature().getDeclaringTypeName();
String methodName = pjp.getSignature().getName();
LOGGER.error("An exception occured while executing [{}.{}] in a transactional context."
, packageName, methodName, e);
throw e.getCause();
} catch (Throwable ex) {
String packageName = pjp.getSignature().getDeclaringTypeName();
String methodName = pjp.getSignature().getName();
String fullyQualifiedmethodName = packageName + "." + methodName;
throw new RuntimeException("Unexpected exception while executing ["
+ fullyQualifiedmethodName + "] in a transactional context.", ex);
}
}
}
Now the problem code part that i see is as follows in com.googlecode.objectify.impl.TransactorNo:
#Override
public <R> R transact(ObjectifyImpl<O> parent, Work<R> work) {
return this.transactNew(parent, Integer.MAX_VALUE, work);
}
#Override
public <R> R transactNew(ObjectifyImpl<O> parent, int limitTries, Work<R> work) {
Preconditions.checkArgument(limitTries >= 1);
while (true) {
try {
return transactOnce(parent, work);
} catch (ConcurrentModificationException ex) {
if (--limitTries > 0) {
if (log.isLoggable(Level.WARNING))
log.warning("Optimistic concurrency failure for " + work + " (retrying): " + ex);
if (log.isLoggable(Level.FINEST))
log.log(Level.FINEST, "Details of optimistic concurrency failure", ex);
} else {
throw ex;
}
}
}
}
private <R> R transactOnce(ObjectifyImpl<O> parent, Work<R> work) {
ObjectifyImpl<O> txnOfy = startTransaction(parent);
ObjectifyService.push(txnOfy);
boolean committedSuccessfully = false;
try {
R result = work.run();
txnOfy.flush();
txnOfy.getTransaction().commit();
committedSuccessfully = true;
return result;
}
finally
{
if (txnOfy.getTransaction().isActive()) {
try {
txnOfy.getTransaction().rollback();
} catch (RuntimeException ex) {
log.log(Level.SEVERE, "Rollback failed, suppressing error", ex);
}
}
ObjectifyService.pop();
if (committedSuccessfully) {
txnOfy.getTransaction().runCommitListeners();
}
}
}
transactOnce is by code / design always using a single transaction to do things. It will either commit or rollback the transaction. there is no provision to chain transactions like a normal enterprise app would want.... service -> calls multiple dao methods in a single transaction and commits or rollbacks depending on how things look.
keeping this in mind, i removed all annotations and transact method calls in my dao methods so that they don't start an explicit transaction and the aspect in service wraps the service method in transact and ultimately in transactOnce...so basically the service method is running in a transaction and no new transaction is getting fired again. This is a very basic scenario, in actual production apps services can call other service methods and they might have the annotation on them and we could still end up in a chained transaction..but anyway...that is a different problem to solve....
I know NoSQLs dont support write consistency at table or inter table levels so am I asking too much from google cloud datastore?
I'm using this library(https://github.com/rdavisau/sockets-for-pcl) to communicate with a TCP Server, that sends me when a event was generated, then, I have to verify all the time if the TCP Server sent to me a event, but if I try read anything before the TCP Server sends me, it's thrown the UnhandledException, but it only happens if I read inside a Task, in the main thread it thrown a timeout exception, the exception that I expected to happen in Task.
Someone can help me? Thanks. below is my code.
public class CentralTcpService
{
#region ConnectTcpAsync
public async void ConnectTcpAsync()
{
try
{
_sockecClient = new TcpSocketClient();
await _sockecClient.ConnectAsync(Central.Ip, Central.Port);
_writter = new ExtendedBinaryWriter(_sockecClient.WriteStream);
_reader = new ExtendedBinaryReader(_sockecClient.ReadStream);
_writter.WriteString(EvenNotProtocol.MobileReceiverCommand);
_sockecClient.ReadStream.ReadTimeout = int.MaxValue;
EnableTcpService();
}
catch (Exception e)
{
throw new Exception(e.Message);
}
}
#endregion
#region TcpService
private void EnableTcpService()
{
_cancelationTcpService = new CancellationTokenSource();
new Task(StartService, _cancelationTcpService.Token, TaskCreationOptions.LongRunning).Start();
}
private void StartService()
{
while (!_cancelationTcpService.Token.IsCancellationRequested)
{
var ev = EvenNotProtocol.DeserializeEvent(_reader);
if (ev == null) continue;
_writter.WriteString(EvenNotProtocol.MobileOkCommand);
EventReceived?.Invoke(this, new CentralTcpEventArgs(ev));
}
}
}
public class EvenNotProtocol
{
public static Event DeserializeEvent(ExtendedBinaryReader reader)
{
try
{
reader.SkipBytes(1);
.....
}
catch (IOException e)
{
return null;
}
}
}
I am using Android Async Task function to execute an api using urlconnection. this api in turn sends emails to selected users.Now the issue is I am getting spammed by these emails at first I thought of it as an server side issue or my script but I created a new api and used it on IOS version of my application and everything works fine.But when I execute it on android I start getting spams,so I think the Issue lies in my android programming.
public class submitparse extends AsyncTask<String ,String,String> {
String Url;
#Override
protected String doInBackground(String... params) {
URL phonelink;
HttpURLConnection urlConnection = null;
try {
phonelink = new URL(params[0]);
urlConnection = (HttpURLConnection) phonelink
.openConnection();
urlConnection.connect();
InputStream in = urlConnection.getInputStream();
InputStreamReader isw = new InputStreamReader(in);
BufferedReader br = new BufferedReader(isw);
String line = "";
StringBuffer buffer = new StringBuffer();
while ((line = br.readLine()) != null) {
buffer.append(line);
}
String finalresult = buffer.toString();
return finalresult;
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
urlConnection.disconnect();
} catch (Exception e) {
e.printStackTrace(); //If you want further info on failure...
}
}
return null;
}
I am using this command to call it..
submit.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String link = "";
new submitparse().execute(link);
}
});
On getting result I start another activity,where link is a string containing url.
If you don't care, you can also use just a new Thread. That should fit your needs and works fine. As far as I read, you don't need to use an AsyncTask and therefore IMO a normal Thread would be better.
// Runnable uiThreadRunnable = new Runnable.....
Handler handler = new Handler(); // import android.os.Handler
Runnable runnable = new Runnable() {
public void run() {
// do your stuff
// use 'handler.post(uiThreadRunnable);' to if you NEED to run something on main thread
}
};
Thread thread = new Thread(runnable);
thread.start();
I have a question regarding event listener. We have a event listener which listen to delete node event and perform some activity say "send email".
While code review i found this, although this code is working fine i am not convinced with the session being handled here :
#Activate
protected void activate(ComponentContext context) {
try{
final String path="/content/dam/";
Session session = repository.loginAdministrative(repository.getDefaultWorkspace());
observationManager = session.getWorkspace().getObservationManager();
observationManager.addEventListener(this, Event.PROPERTY_REMOVED, path, true, null, null, true);
checkOutProperty = OsgiUtil.toString(context.getProperties()
.get(ASSET_LOCK_PROPNAME_UPDATE), ASSET_LOCK_PROPNAME_DEFAULT);
if (session != null && session.isLive()) {
session.save();
}
} catch (RepositoryException e) {
if(LOG.isErrorEnabled()){
LOG.error("Error Occured in activate method of Property Removed Listener class:" + e.getMessage());
}
}catch (Exception e) {
if(LOG.isErrorEnabled()){
LOG.error("Error Occured in activate method of Property Removed Listener class:"+e.getMessage());
}
}
}
#Deactivate
protected void deactivate(ComponentContext componentContext) {
try {
if (observationManager != null) {
observationManager.removeEventListener(this);
}
} catch (RepositoryException e) {
if(LOG.isErrorEnabled()){
LOG.error("Error Occured " + e);
}
} catch (Exception e) {
if(LOG.isErrorEnabled()){
LOG.error(e.getMessage());
}
}
}
Questions:
Best practice would be to create session object private to this class and should be logout in deactivate method?
Once an event is added in Observation Manager, do we really need session object? I was expecting if we should logout from session there.
EventListener are a bit cumbersome here. I fought many battles with JCR Sessions and Sling ResourceResolvers within them. The problem is, you need to keep the Session active as long as the Event Listener is active. So the only thing missing in your code is a logout on deactivate.
I created an AbstractEventListener which takes care of this and provides the following two methods and has two private members:
private Session session;
private ObservationManager observationManager;
protected void addEventListener(final EventListener eventListener,
final int eventTypes, final String path, final String[] nodeTypes) {
try {
session = getRepositorySession();
observationManager = session.getWorkspace().getObservationManager();
observationManager.addEventListener(eventListener, eventTypes,
path, true, null, nodeTypes, true);
} catch (RepositoryException e) {
LOGGER.error("Repository error while registering observation: ", e);
}
}
protected void removeEventListener(final EventListener eventListener) {
if (observationManager != null) {
try {
observationManager.removeEventListener(eventListener);
} catch (RepositoryException e) {
LOGGER.error(
"Repository error while unregistering observation: ", e);
} finally {
logoutSession(session);
}
}
}
And then in the actual EventListener I just call them:
protected void activate(ComponentContext context) {
addEventListener(this, Event.PROPERTY_ADDED| Event.PROPERTY_CHANGED, "/content/mysite", null);
}
}
protected void deactivate(ComponentContext componentContext) {
removeEventListener(this);
}