I have the following setup to test my Durable Function.
public class TestDurableFunction
{
private readonly ITestRepository _testRepository;
public TestDurableFunction(ITestRepository testRepository)
{
_testRepository = testRepository; // needed for later use
}
[FunctionName("TimerTrigger")]
public async Task Run([TimerTrigger("0 1 * * *", RunOnStartup = true)] TimerInfo myTimer, [DurableClient] IDurableClient starter, ILogger logger)
{
try
{
await starter.StartNewAsync("OrchestrateSavings", null);
}
catch (Exception exception)
{
logger.LogFunctionError(nameof(Run), nameof(TestDurableFunction), exception);
}
}
[FunctionName("OrchestrateTest")]
public async Task<int> OrchestrateTest([OrchestrationTrigger] IDurableOrchestrationContext context)
{
await Task.CompletedTask;
return 10;
}
}
When I start this function locally, then the TimerTrigger function starts with no problems. This function then calls my OrchestrateTest Durable Function.
But that immediately throws the following error in the Command Prompt window:
Microsoft.Azure.WebJobs.Script.WebHost: Unable to load metadata for
function 'OrchestrateTest'. Function 'OrchestrateTest (Orchestrator)'
was aborted. Reason: An internal error occurred while attempting to
execute this function. The execution will be aborted and retried.
Details: System.NullReferenceException: Object reference not set to an
instance of an object.
Anyone any idea what the issue could be?
As per your code the orchestrator function you are invoking is OrchestrateSavings; however there is not orchestrator function registered with that name. As per posted code the orchestrator function name is OrchestrateTest. So change the line to
await starter.StartNewAsync("OrchestrateTest", null);
in the Run method.
Related
InvalidOperationException: A second operation was started on this context before a previous operation completed. This is usually caused by different threads concurrently using the same instance of DbContext. For more information on how to avoid threading issues with DbContext, see https://go.microsoft.com/fwlink/?linkid=2097913.
public async Task<List<SiteBanner>> GetSiteAllBanners()
{
return await _siteBannerRepository.GetQuery().ToListAsync();
}
public IQueryable<TEntity> GetQuery()
{
return _DbSet.AsQueryable();
}
services.AddScoped<ISiteService, SiteService>();`
[HttpGet("show-banners")]
public async Task<IActionResult> ShowBanners()
{
ViewBag.banners = await _siteService.GetSiteAllBanners();
return View();
}
enter image description here
I have two application e.g) A, B
A has a Saga
B is just web application
A sent Command messages to B and
B sent exception for that Command to A's Saga and A's Saga received well
and B have a #ExceptionHandler which I hope to be invoked but it's not working
How can I make them be invoked?
EDIT
this is A application's Saga that sends command messages to B application
and deals with exception which B sent
#Saga
public class OrderSaga {
#Autowired
private transient CommandGateway commandGateway;
#StartSaga
#SagaEventHandler(associationProperty = "orderId")
public void handle(CreateOrderEvent evt) {
String paymentId = UUID.randomUUID().toString();
SagaLifecycle.associateWith("paymentId", paymentId);
commandGateway.send(new CreatedPaymentCommand(paymentId, evt.getUserId(),evt.getFoodPrice())).exceptionally(exp -> {
System.out.println("got it");
System.out.println(exp.getMessage());
return null;
});
}
}
this is B application that throws exception for test
#Aggregate
#NoArgsConstructor
public class PaymentAggregate {
#AggregateIdentifier
private String paymentId;
private String userId;
private PaymentStatus status;
#CommandHandler
public PaymentAggregate(CreatedPaymentCommand cmd) {
throw new IllegalStateException("this exception was came from payment aggregates");
// AggregateLifecycle.apply(new CreatedPaymentEvent(cmd.getPaymentId(),
// cmd.getUserId(),cmd.getMoney()));
}
#ExceptionHandler(resultType = IllegalStateException.class)
public void error(IllegalStateException exp) {
System.out.println(exp.getMessage());
}
// I want this #ExceptionHandler to be invoked
#EventSourcingHandler
public void on(CreatedPaymentEvent evt) {
this.paymentId = evt.getPaymentId();
this.userId = evt.getUserId();
}
}
A application catch exception well like below
2021-08-24 11:46:43.534 WARN 14244 --- [ault-executor-2] o.a.c.gateway.DefaultCommandGateway : Command 'com.common.cmd.CreatedPaymentCommand' resulted in org.axonframework.commandhandling.CommandExecutionException(this exception was came from payment aggregates)
got it
this exception was came from payment aggregates
but B is not I thought that B's #ExceptionHandler will catch that exception
in short, How can I make B's #ExceptionHandler to be invoked
It doesn't work right now because the exception is thrown from the constructor of your aggregate.
As you are using a constructor command handler, there is no instance present yet.
And without an instance, Axon Framework cannot spot the #ExceptionHandler annotated method you've set up.
This is the only missing point for the exception handlers at this stage. Honestly, the reference guide should be a bit more specific about this. I am sure this will change in the future, though.
There's a different approach for having a command handler that constructs the aggregate and that can use the #ExceptionHandler: with the #CreationPolicy annotation. The reference guide has this to say about it, by the way.
Thus, instead of having a constructor command handler, you would set up a regular command handler using the AggregateCreationPolicy.ALWAYS.
That would adjust your sample like so:
#Aggregate
#NoArgsConstructor
public class PaymentAggregate {
#AggregateIdentifier
private String paymentId;
private String userId;
private PaymentStatus status;
#CommandHandler
#CreationPolicy(AggregateCreationPolicy.ALWAYS)
public void handle(CreatedPaymentCommand cmd) {
throw new IllegalStateException("this exception was came from payment aggregates");
// AggregateLifecycle.apply(new CreatedPaymentEvent(cmd.getPaymentId(),
// cmd.getUserId(),cmd.getMoney()));
}
#ExceptionHandler(resultType = IllegalStateException.class)
public void error(IllegalStateException exp) {
System.out.println(exp.getMessage());
}
// I want this #ExceptionHandler to be invoked
#EventSourcingHandler
public void on(CreatedPaymentEvent evt) {
this.paymentId = evt.getPaymentId();
this.userId = evt.getUserId();
}
}
Please give this a try in your application, #YongD.
Im trying to use olingo with Flutter on Android. I set up my channel and I can call the library but I keep getting this message:
E/AndroidRuntime(28391): FATAL EXCEPTION: main
E/AndroidRuntime(28391): Process: com.example.odata, PID: 28391
E/AndroidRuntime(28391): org.apache.olingo.client.api.http.HttpClientException: android.os.NetworkOnMainThreadException
E/AndroidRuntime(28391): at org.apache.olingo.client.core.communication.request.AbstractODataRequest.doExecute(AbstractODataRequest.java:312)
So it looks like it is running on the main thread - which is a no go as this would block. I tried the looper to ask Java to run on the UI Thread:
public void onMethodCall(MethodCall call, Result result) {
// Note: this method is invoked on the main thread.
Log.i("test", "using " + call.method);
String serviceUrl = "http://services.odata.org/OData/OData.svc/";
new Handler(Looper.getMainLooper()).post(new Runnable() {
#Override
public void run() {
if (call.method.equals("getMetaData")) {
String metadata;
final Edm edm = ODataClientFactory.getClient().getRetrieveRequestFactory().getMetadataRequest(serviceUrl).execute().getBody();
metadata = edm.toString();
if (metadata != "") {
result.success(metadata);
} else {
result.error("UNAVAILABLE", "Metadata cannot read.", null);
}
} else {
result.notImplemented();
}
}
});
But Im still getting the same error.
So how exactly can I deal with external JAR Library which are doing blocking operations ? To my understanding an external call is a Future anyway so it will not block my Flutter thread anyway - but Android Java does not think so ...
This is my method call in flutter
Future<void> _getMetaData() async {
String metadata;
try {
final String result = await platform.invokeMethod('getMetaData');
metadata = result;
} on PlatformException catch (e) {
metadata = e.message;
}
setState(() {
_metadata = metadata;
});
}
Thanks for the answer, this is the solution for anyone that may be interested:
public void onMethodCall(MethodCall call, Result result) {
if (call.method.equals("getMetaData")) {
class MetadataLoader extends AsyncTask<String , Integer, String> {
#Override
protected String doInBackground(String... urls) {
// call your Java library method here, including blocking methods
return your_return_value;
}
protected void onPostExecute(String _result) {
// your_return_value is now passed in _result
result.success(_result);
}
}
new MetadataLoader().execute(); // Start the Async
}
On the flutter side,
Future<void> _getMetaData() async {
String metadata;
try {
final String result = await platform.invokeMethod('getMetaData');
// do something with the result
// the Flutter thread will stop at the await and resume when the Java
// will call result.success
}
}
You will need to create a new Java thread or Worker. (Note that the "main" thread and the "UI" thread are the same thing - so by posting to the main looper you've ended up in the same place - trying to do network i/o on the main thread.)
Yes, the Flutter engine is running in different threads, but you still need to leave the main native thread unblocked as it is responsible for detecting user input, etc.
Also note that when your blocking activity completes - on its non-main thread - it will likely want to deliver the response to Dart. To do this it will need to use part of your code above - to post the results back to the main thread, which can then invoke method channel operations.
You'll probably want to use your method channel bi-directionally. From flutter to native to request an operation (returning, say, a sequence number), and from native to flutter to deliver the results (quoting the sequence number so that the result can be tied back to the request).
I have a ServiceBusClient class that creates a QueueClient which is used to listen for messages on a bus. I have looked at the following articles to set this up:
Background tasks (Microsoft)
Hosted services (Microsoft)
Async and Await
My ServiceBusClient class that handles the QueueClient looks like this:
public class ServiceBusClient : IServiceBusClient
{
public ServiceBusClient(IEventService eventService, ServiceBusClientOptions options)
{
...
queueClient = new QueueClient(options.ConnectionString, options.QueueName);
}
public void Run()
{
RegisterOnMessageHandler();
}
private void RegisterOnMessageHandler()
{
...
queueClient.RegisterMessageHandler(ProcessMessagesAsync, messageHandlerOptions);
}
private async Task ProcessMessagesAsync(Message message, CancellationToken token)
{
var eventMessage = EventMessage.FromMessage(message);
await eventService.Write(eventMessage);
if (!token.IsCancellationRequested)
{
await queueClient.CompleteAsync(message.SystemProperties.LockToken);
}
}
private Task ExceptionReceivedHandler(ExceptionReceivedEventArgs exceptionReceivedEventArgs)
{
// log errors
...
return Task.CompletedTask;
}
}
I was hoping to launch from an IHostedService or even by extending the BackgroundService. In the examples I find, work is constantly being executed in a while loop which does not fit my scenario since I am only trying to run a single command.
So I created a super simple implementation like this:
protected override async Task ExecuteAsync(CancellationToken cancellationToken)
{
serviceBusClient.Run();
while (!cancellationToken.IsCancellationRequested)
{
// empty loop to keep running for lifetime of pod
}
}
If removing the async I obviously need to return something. I tried Task.CompletedTask but that required me to change the return type to Task<Task>.
If I have the async in place, I will need to await something, but I am not sure what.
This does not feel right. I would assume I would need to change something in the ServiceBusClient, but I am unsure what, since the ProcessMessagesAsync is async and does the heavy lifting in the background from my understanding.
All I want is for my web app to start listening for messages until it dies. How can I do that?
I gave up on using BackgroundService and implemented IHostedService instead.
public class MessageListenerService : IHostedService
{
private readonly IServiceBusClient client;
private readonly ITelemetryClient applicationInsights;
public MessageListenerService(IServiceProvider serviceProvider)
{
client = serviceProvider.GetService<IServiceBusClient>();
applicationInsights = serviceProvider.GetService<ITelemetryClient>();
}
public Task StartAsync(CancellationToken cancellationToken)
{
applicationInsights.TrackTrace(new TraceTelemetry("MessageListenerService is starting"));
client.Run();
return Task.CompletedTask;
}
public Task StopAsync(CancellationToken cancellationToken)
{
applicationInsights.TrackTrace(new TraceTelemetry("MessageListenerService is stopping"));
return client.Stop();
}
}
If you find issues with this code please let me know in the comments and I'll update as appropriate.
In the end we created a console app for it anyway.
Given the following unit test, which uses the Vertx Unit testing framework:
#RunWith(VertxUnitRunner.class)
public class VertxUnitTest {
private Vertx vertx;
#Rule
public RunTestOnContext rule = new RunTestOnContext(new VertxOptions().setClustered(false)
.setClusterManager(new HazelcastClusterManager()).setMaxEventLoopExecuteTime(2000000000000L)
.setMaxWorkerExecuteTime(60000000000000L).setBlockedThreadCheckInterval(1000000)
.setEventBusOptions(new EventBusOptions().setClustered(false).setIdleTimeout(0)));
#Before
public void setup() throws Exception {
io.vertx.core.Vertx v = rule.vertx();
vertx = Vertx.newInstance(v);
}
private class MyVerticle extends AbstractVerticle {}
#Test
public void runFlow_correctMessage_stepsCalledInCorrectOrder(TestContext context) {
Async async = context.async();
vertx.getDelegate().deployVerticle(new MyVerticle(), new DeploymentOptions().setWorker(true), c -> {
c.cause();
vertx.eventBus().<Object>send("", new JsonObject(), new DeliveryOptions(), rpl -> {
async.complete();
fail();
});
});
}
}
the call to fail() is throwing an exception to the console, but it is not actually failing the test itself, which finishes successfully and is green.
The same is true when working with Mockito. I can successfully verify the behavior of the verticle and its dependencies using mocks, but even when the Mockito assertions fail, the test itself will still pass. Calling fail on the vertx TestContext object - context.fail() - will also not fail the test.
The core issue is this: any call to fail() after async.complete() will not fail the test, only the console will show the error. But without the call to async.complete(), the code in the verticle (called upon consuming from the event bus), will not have run before the test assertions are called.
Without the call to async.complete(), the test will it appears never complete.
What is the correct approach to this?
Thanks
the correct approach is to call the TestContext.fail() method, like so:
#Test
public void runFlow_correctMessage_stepsCalledInCorrectOrder(TestContext context) {
Async async = context.async();
vertx.getDelegate().deployVerticle(new MyVerticle(), new DeploymentOptions().setWorker(true), c -> {
if(c.succeeded()) {
vertx.eventBus().<Object>send("", new JsonObject(), new DeliveryOptions(), rpl -> {
if(rpl.succeeded()) {
// make assertions based on reply contents, and then...
async.complete();
} else {
context.fail(rpl.cause());
}
});
} else {
context.fail(c.cause());
}
});
}