I have an Azure Web Job built using the Azure SDK whose only job is to call a web service (Web API) and then log a response based on the return value (a class). The problem is that as soon as it calls the HttpClient PostAsJsonAsync method to call the service, it exits out of the web job without executing any of the response handling. My code is:
public class Result
{
// Properties ---------------------------------------------------------
public bool Success { get; set; }
public string Error { get; set; }
}
public class Functions
{
// This function will be triggered based on the schedule you have set for this WebJob
// This function will enqueue a message on an Azure Queue called queue
[NoAutomaticTrigger]
public async static void ManualTrigger(TextWriter log, int value)
{
using (var client = new HttpClient())
{
var rootUrl = ConfigurationManager.AppSettings.Get("WebJobTargetUrl");
client.BaseAddress = new System.Uri(rootUrl);
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
Console.WriteLine("Call service");
var response = await client.PostAsJsonAsync("api/Reminder/ProcessDueReminders", new { ItemID = 1 });
Console.WriteLine("After service");
var result = await response.Content.ReadAsAsync<Result>();
Console.WriteLine("After result");
if (result.Success)
Console.WriteLine("Reminders Processed");
else
Console.WriteLine("Reminder process error: " + result.Error);
}
}
}
and the execution logs from the portal are:
I believe it has something to do with the asynchronous operation but I can't figure out a pattern that will work. Any help would be appreciated.
You must define the return value of your own async method as Task instead of void.
On a related note, you should suffix the name of your method with Async. That's not going to solve the problem, but it indicates that you're using the async/await pattern.
There is probably an exception in your PostAsJsonAsync call. Try to put a try catch around it to and log the error:
try {
var response = await client.PostAsJsonAsync("api/Reminder/ProcessDueReminders", new { ItemID = 1 });
} catch (Exception ex){
Console.WriteLine("Exception: "+ ex);
}
Console.WriteLine("After service");
Related
I'm facing a strange issue, and I ran out of the possible causes. The scenario is
Fetch incoming message from queue
Process it and then add new message to another queue
but the thing is, if I finish the long running task for the incoming message, and then try to add new message to another queue, I don't receive it. If I just add a face message to that another queue, then I am able to receive the real message after the long-running operation is finished. But why ? I don't want to put any fake messages to the queue, but without that my scenario doesn't work. Any ideas ?
public class WorkerRole : RoleEntryPoint
{
// QueueClient is thread-safe. Recommended that you cache
// rather than recreating it on every request
Microsoft.ServiceBus.Messaging.QueueClient Client;
ManualResetEvent CompletedEvent = new ManualResetEvent(false);
public override void Run()
{
MyResult result = null;
var queueClient = new Microsoft.Azure.ServiceBus.QueueClient("QueueConnectionString", "QueueName");
Client.OnMessage(async (receivedMessage) =>
{
try
{
using (Stream stream = receivedMessage.GetBody<Stream>())
{
using (StreamReader reader = new StreamReader(stream))
{
string json = reader.ReadToEnd();
OCRQueueItem_Incoming item = JsonConvert.DeserializeObject<IncomingClass>(json);
var someClass = new OCRManager();
var message = new Message(Encoding.UTF8.GetBytes("test 1"));
await queueClient.SendAsync(message);
result = new SomeManager().RunLongRunningTask(item); //it runs for 1-2min
}
}
}
catch (Exception ex) { }
finally
{
var json = JsonConvert.SerializeObject(result);
var message = new Message(Encoding.UTF8.GetBytes(json));
await queueClient.SendAsync(message);
}
});
CompletedEvent.WaitOne();
}
public override bool OnStart()
{
ServicePointManager.DefaultConnectionLimit = 12;
string connectionString = CloudConfigurationManager.GetSetting("Queue.ConnectionString");
Client = Microsoft.ServiceBus.Messaging.QueueClient.Create(connectionString);
return base.OnStart();
}
public override void OnStop()
{
Client.Close();
CompletedEvent.Set();
base.OnStop();
}
}
Good day everyone,
I'm creating a chatbot for my company and I started with the samples on github and the framework docs.
We decided to host it on Azure and added LUIS and Table Storage to it. The Bot runs fine locally in Botframework Emulator, but on Azure (WebChat, Telegram) it will only run for approximatly an hour to an hour and fifteen minutes, if no one tries to communicate with the bot. After this period of time, the bot will just run into an internal server error. When you ask the bot something, you can stretch this time window (For how long I don't know and why I don't know either, sorry).
In Azure "Always On" is set to true.
I'm really frustrated at this point, because I cannot find the problem and I'm pretty sure there must be something wrong with my code, because I don't properly understand the framework. I'm still a beginner with Azure, C# and Bot Framework.
Also I have already read everything on "internal server error's" on here and github. Also tried Debugging, even with extra Debbug options in VS. We have not tried Application Insights yet.
At the moment I'm doing everything with the LUIS Dialog which calls / Forwards to other IDialogs:
[LuisIntent(Intent_Existens)]
public async Task ExistensOf(IDialogContext context, IAwaitable<IMessageActivity> message, LuisResult result)
{
var existens = new ExistensDialog();
var messageToForward = await message;
if (result.Entities.Count == 1)
{
messageToForward.Value = result.Entities[0].Entity;
await context.Forward(existens, AfterDialog, messageToForward);
}
else
{
context.Wait(this.MessageReceived);
}
}
I know that "Value" is for CardActions, but I don't know how else I could pass Entities to the child dialog.
[Serializable]
public class ExistensDialog : IDialog<object>
{
public async Task StartAsync(IDialogContext context)
{
context.Wait(MessageReceivedAsync);
}
private async Task MessageReceivedAsync(IDialogContext context, IAwaitable<IMessageActivity> result)
{
var message = await result;
if (message.Text.Contains("specificWord"))
{
await context.Forward(new ExistensHU(), AfterDialog, message);
}
else
{
await context.Forward(new ExistensBin(), AfterDialog, message);
}
}
private async Task AfterDialog(IDialogContext context, IAwaitable<object> result)
{
context.Done<object>(null);
}
}
then:
[Serializable]
internal class ExistensHU : IDialog<object>
{
private Renamer renamer = new Renamer(); // Just for renaming
private ExternalConnection ec = new ExternalConnection(); //Just a HTTP connection to a WebApp to get data from it
public async Task StartAsync(IDialogContext context)
{
context.Wait(MessageReceivedAsync);
}
private async Task MessageReceivedAsync(IDialogContext context, IAwaitable<IMessageActivity> result)
{
const string apiCallURL = "some/API/"; // ExternalConnection...
var message = await result;
string nameHU = renamer.RemoveBlanks(message.Value.ToString());
StringBuilder answerBuilder = new StringBuilder();
var name = ec.CreateSingleAPIParameter("name", nameHU);
Dictionary<string, string> wms = await ec.APIResultAsDictionary(apiCallURL, name);
foreach (var item in wms)
{
if (item.Key.Equals("none") && item.Value.Equals("none"))
{
answerBuilder.AppendLine($"Wrong Answer");
}
else
{
answerBuilder.AppendLine($"Correct Answer");
}
}
await context.PostAsync(answerBuilder.ToString());
context.Done<object>(null);
}
}
That's basically every Dialog in my project.
Also I have an IDialog which looks like this:
[Serializable]
public class VerificationDialog : IDialog<object>
{
[NonSerializedAttribute]
private readonly LuisResult _luisResult;
public VerificationDialog(LuisResult luisResult)
{
_luisResult = luisResult;
}
public async Task StartAsync(IDialogContext context)
{
var message = _luisResult.Query;
if (!message.StartsWith("Wie viele"))
{
context.Call(new ByVerificationDialog(_luisResult), AfterDialog);
}
else
{
context.Call(new CountBinsByVerification(_luisResult), AfterDialog);
}
}
private async Task AfterDialog(IDialogContext context, IAwaitable<object> result)
{
context.Done<object>(null);
}
}
I don't know if I'm allowed to pass the luisResult like this from BasicLuisDialog. This could be the issue or one of the issues.
Basically that's it and I'm still getting used to the framework. I'm not expecting an absolute answer. Just hints/tips and advice how to make everything better.
Thanks in advance!
If you are using the .NET SDK version 3.14.0.7. There is currently a bug we are tracking in this version. There has been a number of reports and we are actively investigating. Please try downgrading to 3.13.1. This should fix the issue for you until we can release a new version.
for reference we are tracking the issue on these GitHub issues:
https://github.com/Microsoft/BotBuilder/issues/4322
https://github.com/Microsoft/BotBuilder/issues/4321
Update 3/21/2018:
We have pushed a new version of the SDK which includes a fix for this issue https://www.nuget.org/packages/Microsoft.Bot.Builder/3.14.1.1
Internal error usually means exceptions in .NET application.
Use AppDomain.CurrentDomain.UnhandledException to receive all unhandled exceptions and log them somewhere (consider using Application Insights).
After you investigate logged information fix that.
I've tried to come up with something from the example in the WebJobsSDK gitHub
var eventHubConfig = new EventHubConfiguration();
string eventHubName = "MyHubName";
eventHubConfig.AddSender(eventHubName,"Endpoint=sb://test.servicebus.windows.net/;SharedAccessKeyName=SendRule;SharedAccessKey=xxxxxxxx");
eventHubConfig.AddReceiver(eventHubName, "Endpoint=sb://test.servicebus.windows.net/;SharedAccessKeyName=ReceiveRule;SharedAccessKey=yyyyyyy");
config.UseEventHub(eventHubConfig);
JobHost host = new JobHost(config);
But I'm afraid that's not far enough for someone of my limited "skillset"!
I can find no instance of JobHostConfiguration that has a UseEventHub property (using the v1.2.0-alpha-10291 version of the Microsoft.AzureWebJobs package), so I can't pass the EventHubConfiguration to the JobHost.
I've used EventHub before, not within the WebJob context. I don't see if the EventHostProcessor is still required if using the WebJob triggering...or does the WebJob trigger essentially act as the EventHostProcessor?
Anyway, if anyone has a more complete example for a simpleton like me that would be really sweet! Thanks
From the documentation here, you should have all the information you need.
What you are missing is a reference of the Microsoft.Azure.WebJobs.ServiceBus.1.2.0-alpha-10291 nuget package.
The UseEventHub is an extension method that is declared in this package.
Otherwise your configuration seems ok.
Here is an example on how to receive or send messages from/to an EventHub:
public class BasicTest
{
public class Payload
{
public int Counter { get; set; }
}
public static void SendEvents([EventHub("MyHubName")] out Payload x)
{
x = new Payload { Counter = 100 };
}
public static void Trigger(
[EventHubTrigger("MyHubName")] Payload x,
[EventHub("MyHubName")] out Payload y)
{
x.Counter++;
y = x;
}
}
EventProcessorHost is still required, as the WebJob just provides the hosting environment for running it. As far as I know, EventProcessorHost is not integrated so deeply into WebJob, so its triggering mechanism cannot be used for processing EventHub messages. I use WebJob for running EventProcessorHost continuously:
public static void Main()
{
RunAsync().Wait();
}
private static async Task RunAsync()
{
try
{
using (var shutdownWatcher = new WebJobsShutdownWatcher())
{
await Console.Out.WriteLineAsync("Initializing...");
var eventProcessorHostName = "eventProcessorHostName";
var eventHubName = ConfigurationManager.AppSettings["eventHubName"];
var consumerGroupName = ConfigurationManager.AppSettings["eventHubConsumerGroupName"];
var eventHubConnectionString = ConfigurationManager.ConnectionStrings["EventHub"].ConnectionString;
var storageConnectionString = ConfigurationManager.ConnectionStrings["EventHubStorage"].ConnectionString;
var eventProcessorHost = new EventProcessorHost(eventProcessorHostName, eventHubName, consumerGroupName, eventHubConnectionString, storageConnectionString);
await Console.Out.WriteLineAsync("Registering event processors...");
var processorOptions = new EventProcessorOptions();
processorOptions.ExceptionReceived += ProcessorOptions_ExceptionReceived;
await eventProcessorHost.RegisterEventProcessorAsync<CustomEventProcessor>(processorOptions);
await Console.Out.WriteLineAsync("Processing...");
await Task.Delay(Timeout.Infinite, shutdownWatcher.Token);
await Console.Out.WriteLineAsync("Unregistering event processors...");
await eventProcessorHost.UnregisterEventProcessorAsync();
await Console.Out.WriteLineAsync("Finished.");
}
catch (Exception ex)
{
await HandleErrorAsync(ex);
}
}
}
private static async void ProcessorOptions_ExceptionReceived(object sender, ExceptionReceivedEventArgs e)
{
await HandleErrorAsync(e.Exception);
}
private static async Task HandleErrorAsync(Exception ex)
{
await Console.Error.WriteLineAsync($"Critical error occured: {ex.Message}{ex.StackTrace}");
}
I'm trying to retrieve user data from Parse (xamarin.ios using c#). I'm using an async method with await. My challenge is,each time I navigate to the tableView in the app, which should populate the user data in question,the table is always empty.
I would like to wait until the results have been returned before proceeding with the other portion of code.I have tried to use the ContinueWith() function but constantly ran into a build error -
Cannot implicitly convert type 'void' to System.Collections.Generic.IEnumerable<Parse.ParseObject>
My Questions:
Is this the best way to wait for the result?
How do I solve the build error?
Here is my current implementation:
public async void retrieveData(string username)
{
try
{
this.requests.ClearRequests();
refreshed = false;
var query = ParseObject.GetQuery("Requests").WhereEqualTo("username", username);
IEnumerable<ParseObject> results = await query.FindAsync().ContinueWith(t =>{
if(results != null)
{
foreach(ParseObject parseObject in results)
{
UserRequest request = new UserRequest();
request.objectId = parseObject.ObjectId;
request.make = parseObject.Get<string> ("item1");
request.model = parseObject.Get<string> ("item2");
request.year = parseObject.Get<string> ("item3");
request.userName = parseObject.Get<string> ("username");
this.requests.addRequest (request);
}
refreshed = true;
}
});
}
catch(ParseException e) {
Console.WriteLine (e.Message + e.StackTrace);
}
}
You shouldn't need a ContinueWith...that's what the await should handle.
await waits on a Task and then brings back the result with the proper return type. ContinueWith returns a Task, so you would have to grab the Result from the task to make it usable.
For more on this type of thing, you may want to check out Difference between await and ContinueWith
You can try something like this.
public async void retrieveData(string username, )
{
try
{
this.requests.ClearRequests();
refreshed = false;
var query = ParseObject.GetQuery("Requests").WhereEqualTo("username", username);
IEnumerable<ParseObject> results = await query.FindAsync();
if(results != null)
{
foreach(ParseObject parseObject in results)
{
UserRequest request = new UserRequest();
request.objectId = parseObject.ObjectId;
request.make = parseObject.Get<string> ("item1");
request.model = parseObject.Get<string> ("item2");
request.year = parseObject.Get<string> ("item3");
request.userName = parseObject.Get<string> ("username");
this.requests.addRequest (request);
}
refreshed = true;
}
//This is your refresh method for your TableView
this.RefreshTableView();
//or, if in iOS
NSNotificationCenter.DefaultCenter.PostNotificationName("resultsRetrieved", null);
}
catch(ParseException e) {
Console.WriteLine (e.Message + e.StackTrace);
}
}
To show the results in the tableView, I would recommend moving the refreshing of the tableView to a separate method that gets triggered synchronously after the results have been retrieved and parsed. This is shown with the this.RefreshTableView() call above.
If in iOS on Xamarin, another option is to post a notification to the NSNotificationCenter (the Xamarin documentation for which is here). Use the PostNotificationName part seen above instead and then add an observer in the ViewControllers that you want to be dependent on the data. This is done as follows:
Make a notificationToken object:
NSObject notificationToken;
Then in your setup method (you could put this inside of your ViewDidLoad):
void Setup ()
{
notificationToken = NSNotificationCenter.DefaultCenter.AddObserver ("resultsRetrieved", RefreshData);
}
Make your RefeshData method:
void RefreshData (NSString notifString)
{
this.tableView.ReloadData();
}
And then, make sure you dispose of the notification observer when you tear down the class
void Teardown ()
{
NSNotificationCenter.DefaultCenter.RemoveObserver (notificationToken);
}
I had a similar issue so started using callbacks. I'm using them in Xamarin.Android, pretty sure they're available in Xamarin.iOS.
Method that starts the task method - Note I am passing in a method of this class as a parameter
private async void updatedData()
{
await Utils.DataTasks.getNewLiveTips(populateTipsList);
}
Method that calls for data from server
public class DataTasks
{
public static async Task getAllData(Action<IEnumerable<ParseObjects>> callback) {
var query = new ParseQuery<ParseObjects>().OrderByDescending("updatedAt").Limit(5);
IEnumerable<ParseObjects> parseTips = await query.FindAsync();
foreach (var tip in parseTips)
{
// Save data to DB if needed
}
callback(parseTips);
}
Method I passed as parameter in the first instance is now called
private void populateTipsList(IEnumerable<ParseObjects> results)
{
mAdapter = new TipAdapter(this.Activity, results);
mRecyclerView.SetAdapter(mAdapter);
refresher.Refreshing = false;
}
I am attempting to write a Validation attribute in MVC4.
The purpose is to check for the existence of an application reference (just a string that represents a key I wish to prevent a duplicate for).
My data is accessed via WebAPI and because I am using 4.5 I wish to make this asynchronous if possible.
I am perhaps not making the best or appropriate usage of async and await but I would like to know how to call my async method from the overridden IsValid method of the inherited Validation class.
public class UniqueApplicationReferenceAttribute : ValidationAttribute
{
public UniqueApplicationReferenceAttribute() : base(() => "The {0} already exists") { }
public int? ApplicationCount { get; set; }
public override bool IsValid(object value)
{
var myTask = GetApplicationRefCountAsync();
myTask.Wait();
this.ApplicationCount = this.ApplicationCount ?? 0;
if (ApplicationCount > 0)
{
return true;
}
else
{
return false;
}
}
public async Task GetApplicationRefCountAsync()
{
HttpClient client = new HttpClient();
client.BaseAddress = new Uri("http://localhost:11111/");
client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));
var apps = client.GetStringAsync("api/dataapplications");
await Task.WhenAll(apps);
var appList = apps.Result;
this.ApplicationCount = appList.Count();// apps.Count();
}
}
Many thanks,
Dan.
I recommend that you call your WebAPI methods synchronously. ValidationAttribute does not support asynchronous implementations natively, so any synchronous-over-asynchronous code you'll write is just going to be a hack and not actually provide any benefit as compared to the synchronous version.
I'm not able to test this in full, but you should be able to do something like this:
public bool IsValid(object value)
{
var appCount = GetApplicationRefCountAsync().Result;
return appCount > 0;
}
public async Task<int> GetApplicationRefCountAsync()
{
var client = new HttpClient();
client.BaseAddress = new Uri("http://localhost:11111/");
client.DefaultRequestHeaders.Accept.Add(
new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));
return await client.GetStringAsync("api/dataapplications")
.ContinueWith(r => Convert.ToInt32(r))
.ConfigureAwait(false);
}
Be careful about using async/await methods in an ASP.NET thread. It's easy to create deadlocks.