Skip to main content

CRON job in Windows Azure - Scheduler

Yesterday I realized that I have to run a task on Windows Azure every 30 minutes. The job is pretty simple; it has to retrieve new data from an endpoint. This is a perfect task for a CRON-base job.
The only problem with the current version of Windows Azure is that it doesn't have support for CRON jobs. People might say that we can have a timer and every 30 minutes we could run the given task. This is a good solution and it will work perfectly, but I wanted something different.
I didn’t want to create my own CRON-base job. I wanted something build-in in the system. I started to look around and I found an add-on for this. So, Windows Azure offers a Store for any company that want to offer different add-ons for Windows Azure. These add-ons can be very easily installed. If they are not free, the payment method is quite simple. Each month the Azure subscription will contain the cost of these add-ons. From my perspective this is a pretty simple and clean mechanism of payment.
Under the store I discovered the “Scheduler” add-on, offered by ADITI Cloud Services. This add-on gives us the possibility to create different jobs that are called at a specific time interval. We don’t need a timer, another machine or something similar.
How it works? It is based on normal HTTP requests that will be made automatically to your machine. Their servers will call your machines when a job needs to be executed. In this moment, they support only HTTP, without any kind of authentication. I expect in the near future to have support for authentication and HTTPS.
In this moment the service is free and you can execute around 5000 jobs per month for free. This mean that you can trigger a job every ~9 minutes.
Let’s see some code now. After you install the add-on from the Windows Azure Store, the “Scheduler” will generate a tenant id and a secret key. This will be used from your application when you will need to configure the jobs.
After this step, we need to install a NuGet package called “Aditi.Scheduler”. This will contain all the components that we need to be able to configure and use this add-on.
In our application we have to create an instance of “ScheduledTasks”. Using this instance we can create, modify or delete jobs.
ScheduledTasks scheduledTasks = new ScheduledTasks([tenantId], [secretKey]);

ScheduledTasks task = new TaskModel
    {
        Name = "MyFooJob",
        JobType = JobType.Webhook,
        CronExpression = "0 0/5 * 1/1 * ? *",
        Params = new Dictionary<string, object>
        {
            {"url", "http://foo.com/service1"}
        }
    };

scheduledTasks.CreateTask(task);
Each job can be changed, deleted and so on. What we should remember is to delete a job when we stop using it. Even if our solution will not be deployed anymore, the job will still be trigged each time. Because this solution is based on HTTP request, we need to expose a REST service from where we want to trigger our job.
A cool thing that we already have is the different type of jobs. We don’t have only web jobs but also jobs that use Service Bus Queue or Azure Queue. In this way we can listen to an Azure Queue from our application and our job will be triggered when a specific message is found in the queue. This feature can be used on worker roles that don’t have a HTTP endpoint exposed.
In conclusion I could say that this is a pretty interesting add-on that has a lot of potential.

Comments

Popular posts from this blog

How to check in AngularJS if a service was register or not

There are cases when you need to check in a service or a controller was register in AngularJS.
For example a valid use case is when you have the same implementation running on multiple application. In this case, you may want to intercept the HTTP provider and add a custom step there. This step don’t needs to run on all the application, only in the one where the service exist and register.
A solution for this case would be to have a flag in the configuration that specify this. In the core you would have an IF that would check the value of this flag.
Another solution is to check if a specific service was register in AngularJS or not. If the service was register that you would execute your own logic.
To check if a service was register or not in AngularJS container you need to call the ‘has’ method of ‘inhector’. It will return TRUE if the service was register.
if ($injector.has('httpInterceptorService')) { $httpProvider.interceptors.push('httpInterceptorService&#…

ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded

Today blog post will be started with the following error when running DB tests on the CI machine:
threw exception: System.InvalidOperationException: The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer' registered in the application config file for the ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded. Make sure that the assembly-qualified name is used and that the assembly is available to the running application. See http://go.microsoft.com/fwlink/?LinkId=260882 for more information. at System.Data.Entity.Infrastructure.DependencyResolution.ProviderServicesFactory.GetInstance(String providerTypeName, String providerInvariantName) This error happened only on the Continuous Integration machine. On the devs machines, everything has fine. The classic problem – on my machine it’s working. The CI has the following configuration:

TeamCity.NET 4.51EF 6.0.2VS2013
It seems that there …

Run native .NET application in Docker (.NET Framework 4.6.2)

Scope
The main scope of this post is to see how we can run a legacy application written in .NET Framework in Docker.

Context
First of all, let’s define what is a legacy application in our context. By a legacy application we understand an application that runs .NET Framework 3.5 or higher in a production environment where we don’t have any more the people or documentation that would help us to understand what is happening behind the scene.
In this scenarios, you might want to migrate the current solution from a standard environment to Docker. There are many advantages for such a migration, like:

Continuous DeploymentTestingIsolationSecurity at container levelVersioning ControlEnvironment Standardization
Until now, we didn’t had the possibility to run a .NET application in Docker. With .NET Core, there was support for .NET Core in Docker, but migration from a full .NET framework to .NET Core can be costly and even impossible. Not only because of lack of features, but also because once you…