Semantic logging (SLAB) for MVC Azure Webapp - azure

Am trying to implement SLAB for my Azure Web app (In Process) and my listner is Azure table Storage (table conection string) ,
the problem am facing is -“EventSource.IsEnabled() = always returns false”
(Am running the application from VS2013 with IIS express)
my code
————global.asax
var listener2 = new ObservableEventListener();
listener2.EnableEvents(SBEvents.Log, EventLevel.Verbose,Keywords.All);
listener2.LogToWindowsAzureTable(“sdf”, “DefaultEndpointsProtocol=https;AccountName=********;AccountKey=****************);
———-Event Source
Public class SBEvents :EventSource {
public class keywords{...}
public class Tasks {..}
private static readonly Lazy Instance = new Lazy(() => new SBEvents());
public static SBEvents Log { get { return Instance.Value; } }
[Event(102, Message = “Bike started with Bike ID :{0}”, Keywords = Keywords.Application, Level = EventLevel.Informational)]
public void BikeStarted(String BikeID){
if (this.IsEnabled()) //// = always returns false
this.WriteEvent(102,BikeID);

It looks like 'Azure Web Apps' cannot listen to ETW events.
https://azure.microsoft.com/en-in/documentation/articles/choose-web-site-cloud-service-vm/
Areas of diagnostics logging and tracing that aren't available to web applications on Azure are Windows ETW events, and common Windows event logs (e.g. System, Application and Security event logs). Since ETW trace information can potentially be viewable machine-wide (with the right ACLs), read and write access to ETW events are blocked. Developers might notice that API calls to read and write ETW events and common Windows event logs appear to work, but that is because WEb Apps is "faking" the calls so that they appear to succeed. In reality, the web app code has no access to this event data
Thanks

Related

Application Insights skipping events

I am using this code to send events to application insights in a console application
TelemetryConfiguration.Active.InstrumentationKey = "XXXXXXXXX";
TelemetryClient telemetryClient = new TelemetryClient();
for (int i = 0; i < 100; i++)
{
telemetryClient.TrackEvent("Hello World!");
telemetryClient.TrackException(new OutOfMemoryException());
}
telemetryClient.Flush();
Task.Delay(60000).Wait();
Now the problem i am having is that it is not seeming to log all my events , sometimes the visual studio toolbar says 44 , sometimes it is 68 and never 100 .
The type of information i am going to send is important cause i will be monitoring several console applications from this service .
Is there any way to have application insights send every thing to azure and not skip events ? I think i am giving it enough time to send every thing before exiting .
Without full code, its hard to say the configuration used.Couple of things to look for:
Have you enabled sampling? If you really want accurate count of events, then disable sampling (https://learn.microsoft.com/en-us/azure/azure-monitor/app/sampling)
Have you configured channel explicitly? If not, the default will be InMemoryChannel, which does not do any retries for transient issues. Its best to use ServerTelemetryChannel, to protect data loss in the even of network issue or application insights backend transient issues.
var config = new TelemetryConfiguration(); // or active or create default...
var channel = new ServerTelemetryChannel();
channel.initialize(config)
// create client from the config.
TelemetryClient tc= new TelemetryClient(config);

Polling storage queue for messages using console app webjob

I wanted to create a console app as a WebJob using .NET Core but the WebJobs SDK is not yet available in .NET Core.
I've been advised to handle the scenario of reading messages from Azure Storage Queue manually. Looks like all the WebJobs SDK does is to keep polling the queue anyway.
Is the following code the basic idea in doing this? It doesn't look very sophisticated but not sure how it can be more sophisticated.
static void Main(string[] args)
{
var runContinuously = true;
while (runContinuously)
{
ReadAndProcessMessage();
System.Threading.Thread.Sleep(1000);
};
}
private static void ReadAndProcessMessage()
{
// Read message
ReadMessage();
// Process message and handle the work
HandleWork();
}
That will work. And I like simplicity.
The QueueTriggerAttribute makes use of a random exponential back-off algorithm to help minimize your transaction costs. If you'd like to trace through the logic of how this is accomplished, starting with the QueueListener class is a good way to go. Clone the project and then hop over to the RandomizedExponentialBackoffStrategy class.

Azure Socket Leaks?

I have an ASP.NET Core a website with a lot of simultaneous users which crashes many times during the day and I scaled up and out but no luck.
I have been told my numerous Azure support staff that the issue is that I'm sending out a lot of database calls although database utilization improved after creating indexes. Can you kindly advise what you think the problem is as I have done my best...
I was told that I have "socket leaks".
Please note:
I don't have any external service calls except to sendgrid
I have not used ConfigureAwait(false)
I'm not using "using" statements or explicitly disposing contexts
This is my connection string If it may help...
Server=tcp:sarahah.database.windows.net,1433;Initial Catalog=SarahahDb;Persist Security Info=False;User ID=********;Password=******;MultipleActiveResultSets=True;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;Max Pool Size=400;
These are some code examples:
In Startup.CS:
services.AddDbContext<ApplicationDbContext>(options =>
options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
Main class:
private readonly ApplicationDbContext _context;
public MessagesController(ApplicationDbContext context, IEmailSender emailSender, UserManager<ApplicationUser> userManager)
{
_context = context;
_emailSender = emailSender;
_userManager = userManager;
}
This an important method code for example:
string UserId = _userManager.GetUserId(User);
var user = await _context.Users.Where(u => u.Id.Equals(UserId)).Include(u => u.Messages).FirstOrDefaultAsync();
// some other code
return View(user.Messages);
Please advise as I have tried my best but this is very embarrassing to me in font of my customers.
Without the error messages that you're seeing, here's a few ideas that you can check.
I'd start with going to your Web App's Overview blade in the Azure Portal. Update the monitoring graph to a time period when you're experiencing problems. Are you CPU bound? Have you exhausted memory? Also, check the HTTP Queue length. If your HTTP queue is really long, it's because your server is choking trying to service the requests and users are experiencing timeout issues.
Next, jump over to your SQL Server's Overview blade in the Azure Portal, and look at the resource utilization chart. Set the time period on the chart to when you're experiencing problems. Have you pegged out your DTUs for your database? If so, it's a sign of poor indexing, poor schema design, or you're just undersized and need to scale up.
Turn on ApplicationInsights if you haven't already. You can use the ApplicationInsights API to insert your own trace statements into your code. Or, you might be able to see exceptions causing the issue without having to do your own tracing.
Check the Kudu logs for your Web Apps.
I agree with Tseng - your usage of EF and .NET Core's DI framework looks correct.
Let us know how the troubleshooting goes and provide additional information on exactly what kind of errors you're seeing. Best of luck!
It looks like a DI issue to me. You are injecting ApplicationDbContext context. Which means the ApplicationDbContext will be resolved from the DI container meaning it will stay open the entire request (transient) as Tseng pointed out. It should be a scoped.
You can inject IServiceScopeFactory scopeFactory in your controller and do something like:
using (var scope = _scopeFactory.CreateScope())
{
var context = scope.ServiceProvider.GetRequiredService<ApplicationDbContext>();
}
Note that if you are using ASP.NET Core 1.1 and want to be sure that all your services are being resolved correctly change your ConfigureService method in the Startup to:
public IServiceProvider ConfigureServices(IServiceCollection services)
{
// Register services
return services.BuildServiceProvider(validateScopes: true);
}

No job functions found in Azure Webjobs

Trying to get Azure Webjobs to react to incoming Service Bus event, Im running this by hitting F5. Im getting the error at startup.
No job functions found. Try making your job classes and methods
public. If you're using binding extensions (e.g. ServiceBus, Timers,
etc.) make sure you've called the registration method for the
extension(s) in your startup code (e.g. config.UseServiceBus(),
config.UseTimers(), etc.).
My functions-class look like this:
public class Functions
{
// This function will get triggered/executed when a new message is written
// on an Azure Queue called queue.
public static void ProcessQueueMessage([ServiceBusTrigger("test-from-dynamics-queue")] BrokeredMessage message, TextWriter log)
{
log.WriteLine(message);
}
}
I have every class and method set to public
I am calling config.UseServiceBus(); in my program.cs file
Im using Microsoft.Azure.WebJobs v 1.1.2
((Im not entirely sure I have written the correct AzureWebJobsDashboard- and AzureWebJobsStorage-connectionstrings, I took them from my only Azure storage-settings in Azure portal. If that might be the problem, where should I get them ))
According to your mentioned error, it seems that you miss parameter config for ininitializing JobHost. If it is that case, please use the following code.
JobHost host = new JobHost(config)
More detail info about how to use Azure Service Bus with the WebJobs SDK please refer to the document.The following is the sample code from document.
public class Program
{
public static void Main()
{
JobHostConfiguration config = new JobHostConfiguration();
config.UseServiceBus();
JobHost host = new JobHost(config);
host.RunAndBlock();
}
}

ServiceStack RedisMqServer not always handling messages published from separate application

Context
I have a RedisMqServer configured to handle a single message on my ServiceStack web service. The messages on that MQ originate from another application and show up in the .inq with all the correct properties. Everything is on 4.0.38.
My configuration in MyAppHost.cs:
public override void Configure(Container container)
{
var redisFactory = new PooledRedisClientManager(0, "etc:etc");
redisFactory.ConnectTimeout = 5;
redisFactory.IdleTimeOutSecs = 30;
redisFactory.PoolTimeout = 3;
container.Register<IRedisClientsManager>(redisFactory);
//Plugins, Filters, other Registrations omitted
var mqHost = new RedisMqServer(redisFactory, retryCount: 2);
mqHost.DisablePublishingResponses = true;
mqHost.RegisterHandler<CreateVisitor>(ServiceController.ExecuteMessage);
mqHost.Start();
}
And then in Global.asax.cs:
void Application_Start(object sender, EventArgs e)
{
new MyAppHost().Init();
}
Problem
The messages are not consistently handled when I deploy this elsewhere. They wait in the .inq until whenever. Nothing is lost, just delayed for an indeterminate duration.
As of this moment, the only things that come to mind are:
I'm using IIS Express locally, and the server is using IIS.
Application_Start needs to happen before it can handle messages.
I've tried initializing the service by making other API calls over HTTP, before and after queuing messages, with more failure than success. Sometimes the service starts to handle them, but I am unable to identify and thus influence when this happens.
Note
I do have several other console applications and windows services that listen on other MQs and handle messages placed by other applications, and those have always worked flawlessly. This is the first time I've tried this from within an existing web service, however.
Hard to know what the issue from this description (are messages getting lost or just delayed?) but this sounds like it's due to ASP.NET AppDomain recycling in which case you can disable AppDomain recycling or setup up a continuous ping route to hit your ASP.NET Web Application to keep the AppDomain alive.
If the ASP.NET Service is available on the Internet you can use services like https://uptimerobot.com or https://www.pingdom.com to configure it to ping your Service at different intervals (e.g. 5-10 minutes) otherwise if this is an internal Service you can use a Scheduled Task.

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