Can someone point me in the right direction on how to configure network settings within event hub so i can successfully send data via the ASP.NET MVC application while running locally (localhost) as well as when I deploy the application in azure's dev/qa/production web environment.
I have build a proof of concept console application in .NET locally and on Azure's EventHub side added my IP address within Networking/Firewall settings, and have no issue sending data and receiving data from a local machine.
But when I try the same code in the ASP.NET MVC web application, the page just hangs on CreateBatchAsync() method and does not return any exception..
var producerClient = new EventHubProducerClient(connectionString, eventHubName);
EventDataBatch eventBatch = await producerClient.CreateBatchAsync();
eventBatch.TryAdd(new EventData(Encoding.UTF8.GetBytes("Event 1z at " + DateTime.Now.ToString())));
await producerClient.SendAsync(eventBatch);
Any help would be appreciated.
Thanks
The call to CreateBatchAsync is the first point in your code to request a network operation and, consequently, will trigger creation of the connection and link to the Event Hubs service. The connection attempt has a timeout associated with it which is 60 seconds in the default configuration that you're using. Depending on the error that it is encountering, you may see retries take place, each of which would have a 60 second timeout. With the default configuration, this would look like a 3 minute hang. (60 seconds * 3 attempts)
The most common connection issue in an enterprise environment is that the ports needed for AMQP over TCP (5671/5672) are not open. Changing the transport to AMQP over WebSockets often helps, as it will use port 443 and may be routed through a proxy, if needed.
For more information, you may want to look at the sample for configuring Event Hubs clients and the Event Hubs network troubleshooting guide.
Related
There is a server application (ASP.NET Core (gRPC service)) and a client application running on another PC (WPF).
One of the functions of the gRPC service is to send screenshots to the client application, but it has to be run as a Windows service, so I can't get screenshots directly from the service to the client application.
Question: how to implement an "agent" application running on a remote computer where the service is, but in a user session to get screenshots through it and then pass them to the client?
As I understand it is possible to do it with the help of IPC, but I can't understand the details of implementation, how can I call from gRPC service to the agent to make a screenshot, return the result (as an array of bytes) to the service and it sends it to the client...
So when I run my two services locally, I can hit service A which sends a command to service B which picks it up and processes it. Pretty straight forward. However, when I publish these to my web server and I send a request to service A which sends it to service B (I can see the message in service B's queue) but it won't get picked up and processed. I created an endpoint on service B that simply returns an OK response -- if I call this endpoint, effectively "touching" the service, everything kicks on and the messages get processed from that point on.
I figured maybe this had something to do with with late compiling, so I changed the publish to precompile on publish, but I get the same result.
Is there a way to have the service start processing as soon as it is published? Also worth noting that both services are WebAPI 2
Another option (probably more “standard”) would be to move the “handlers” into a Windows Service instead of a web application.
For this Windows Service you can leverage the NServiceBus Host which will turn a standard class library into a Windows Service for you. They have a good amount of documentation about this here: https://docs.particular.net/nservicebus/hosting/nservicebus-host/?version=Host_6
I would argue that this is more stable as you can separate the processing of sending commands (Web Application / WebApi) and processing commands / publishing events (NSB Host). The host can sit on the web server itself or you can put these on a different server.
Our default architecture is to have a separate server run our NSB Hosts as you scale web applications and NSB Hosts differently. If you run the NSB Host on the web server, you can get issues where a web app gets too much traffic and takes the NSB Host processing down. You can always start simple with using 1 server for both, monitor the server and then move things around as traffic increases.
Not sure if this is the "right way" to do things, but what I ended up doing is setting up each site to be always running and auto initialize.
App pool set to "Always Running"
Website set preload enabled = true
Web.config has webServer entry for application initialization doAppInitAfterRestart="true"
Web Role added to server "Application Initialization"
With those things being set, the deployment process is basically to publish the site and iisreset. If there are better options, I'm still looking :)
Help needed please
What's is the best WebSocket client library for a .net 4.5 on windows web application hosted on windows 2008 servers to connect to a remote server web socket.
The scenario is: our web application will use a web socket to connect to a server WebSocket on a third party infrastructure. Our client WebSocket will connect and send some commands and read the responses where we can identify the information needed. So there is no interaction from the user or browser its just in the code. e.g. user clicks a button and we go and get some data, and give a message dependant on the response.
so for example our client will connect to the third party socket and pass the users car registration number and send a tell me the car details and the server socket will return the data like: make, model, year etc... so we can then display that to the user.
Has anyone used this library with some good success? http://www.nuget.org/packages/WebSocket4Net
I'm hoping someone here can provide the best approach for doing this with some tried and tested solutions. I have been thinking about a web API that handles all the socket stuff in our client so i can call it and let it handle the close connection etc.
I am learning Signal-R, and this is something that has been in my head during all time.
How does Signal-R fits in the IIS/ASP.NET life cycle?
How long does the Hubs live (I see they have re-connection semantics)?
Does IIS does prevent the shutdown of an AppDomain that has a persistent connection?
It is my understanding that IIS is designed to handle request-response scenarios. A request hits IIS, this finds the AppDomain, activate it, and then pass the request to it. And after an idle time, shutdown the AppDomain. If the request takes too long, a timeout exception is thrown.
Now let´s imagine that I have another application that broadcast information through a TCP socket. I want my javascript clients to get that information in real time, so I create a Signal-R web application. I can create a TCP client on application start, but what does guarantee that IIS is not going to shutdown the whole thing after some time with inactivity?
I could self host the Signal-R app in a window service, but then I would have to use a different port, enable cross domain, etc... Many problems for deployment. But, I am concerned about using an ASP.NET MVC application for this, since it looks to me like fitting a driving wheel in a motorbike.
Cheers.
SignalR in IIS/ASP.NET Lifecycle
SignalR uses Owin: http://owin.org/
A good article on Owin here: http://msdn.microsoft.com/en-us/magazine/dn451439.aspx
Hub object lifetime
From the SignalR docs: http://www.asp.net/signalr/overview/signalr-20/hubs-api/hubs-api-guide-server#transience:
You don't instantiate the Hub class or call its methods from your own code on the server; all that is done for you by the SignalR Hubs pipeline. SignalR creates a new instance of your Hub class each time it needs to handle a Hub operation such as when a client connects, disconnects, or makes a method call to the server.
Because instances of the Hub class are transient, you can't use them to maintain state from one method call to the next. Each time the server receives a method call from a client, a new instance of your Hub class processes the message. To maintain state through multiple connections and method calls, use some other method such as a database, or a static variable on the Hub class, or a different class that does not derive from Hub. If you persist data in memory, using a method such as a static variable on the Hub class, the data will be lost when the app domain recycles.
Your long running TCP client
This is not a problem with SignalR. Your TCP client can be shutdown by IIS: http://haacked.com/archive/2011/10/16/the-dangers-of-implementing-recurring-background-tasks-in-asp-net.aspx/
I would rather make the TCP client run in a windows service. The TCP client receives TCP broadcast messages and forwards the messages to the Hub using the SignalR .NET client.
Hubs are recreated on each SignalR request, so if you need a persistent connection you may have to look into using static vars or dictionary to hold state. But as you point ASP.NET can restart for a variety of reasons.
It depends on what persistancy you really need. If you have a connection that MUST stay alive at all times and cannot be torn down and reestablished then hosting in IIS is not the right choice. However, if you can re-establish the same connection after a shutdown, then maybe this can still work.
You can do quite a bit in making sure that ASP.NET apps don't shut down in recent versions of IIS:
http://weblog.west-wind.com/posts/2013/Oct/02/Use-IIS-Application-Initialization-for-keeping-ASPNET-Apps-alive
If that's not enough for you running as a separate service is an option. If you run as a service on the same IP address there are no cross domain concerns. Here's more info on running SignalR using a Windows Service:
http://weblog.west-wind.com/posts/2013/Sep/04/SelfHosting-SignalR-in-a-Windows-Service
I have created a sweet ASP.NET 4.0 UDP listener via WCF that starts on Application_Start. As usual, everything is hunky dory on my local machine. On my local machine using the VS Dev Environment and setting it to not open any page upon debug, the listener starts without browsing to anything yet. However, whenever I deploy to my shared host, I must access the site via a web browser before the listener will start. I do not have access to the IIS control panel but I do have some limited setting changes I can make to IIS via "Website Panel" software. I believe the shared host uses IIS 7.5.
Is there a better way to solve this rather than creating a polling service from my home PC to send an HTTP request to the shared host every so often to kick off the listener?
Requirements
The client sends UDP packets over a configurable port. I cannot change anything other than the IP and port that the client uses to connect
The solution must work with my shared host since I cannot afford a VPS at this time - otherwise I would've created a Windows Service. I got around creating a window service before by creating a polling service via WCF Application_Start but that only works because the info the users would see have to be on a webpage therefore application_start would always be called. In this case, the users/clients are not necessarily accessing the webpage.
Ideas:
Somehow pull this into a .svc. That way when the .svc is accessed by the client, it kicks off the listener for everyone else. But how can a .svc running on port 80 accept UDP calls? I'm also not sure if the client will be able to connect to more than an IP:PORT (I don't think it'd accept a .svc path like URL.com/awesomeListener.svc).
Any suggestions? Thank you so much.
If you are running ASP.NET 4.0 you can set it to auto-start for you which will fire Application_Start:
http://weblogs.asp.net/scottgu/archive/2009/09/15/auto-start-asp-net-applications-vs-2010-and-net-4-0-series.aspx