Skip to main content

Updating content of messages from Azure Queues

In the era of microservices and cloud, applications contain more and more components and sub-components that are design to do only one thing. All this components needs to communicate between each other in a fast and reliable way.
For communication purpose, different messaging solutions are used. Nowadays, a Enterprise Service Bus solution like Azure Services Bus Topic or BizTalk is normal. For more simple problems, one or more queues can be enough (Azure Storage Queue)

Almost all messaging system allow us to consume messages using Peek and Lock pattern. This allow us to take a message from the queue, lock it for a specific time, process it and at the end, if we are able to process it with success to remove it from the queue. During this time, the message is hidden from others consumers and cannot be peeked by others. After a specific time interval if we don't mark the message as consumed the message will be available in the queue for consuming.

But what should we do when we have a long running processing task, that can take 20 minutes or 1 hour. The most simple solution would be to split the task in subtasks - when is possible.
This means that we would have multiple sub-components that needs to communicate between each other. We would end up with multiple queues or with an enterprise service bus system like Azure Service Bus Topic.


But what should we do when we cannot split it? Or the complexity of splitting in subtasks is so high that it not worth it... and even if we would be able to split it in subtasks, we would end up with something similar like a 'state machine'. This state would be used to know the current status of the tasks and would allow us to be able to continue from the last step. For this case, it would be nice to be able to update the content of a message that is the queue without having to remove the original message.

For long running tasks this could be very useful. We could update the current progress/status of task in the queue, without having to use a storage for this. This can be done very simple if we are using Azure Storage Queue. This queue system allow us to update an existing message that is the queue. See below code:
CloudQueue queue = queueClient. GetQueueReference("fooqueue");

CloudQueueMessage message = queue.GetMessage(new TimeSpan(0,0,10);
String newMessageContent = message + " new message content";
message.SetMessageContent(message);

queue.UpdateMessage(message, MessageUpdateField.Content);
We can use this feature each time when we need to update the progress of a task that was triggered by a message in the queue. Beside the content we can update any other fields of the message (for example the visibility property).

In this post we saw how simple is to update the content of a message from a queue without having to remove and recreate it.

Comments

Popular posts from this blog

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 …

Entity Framework (EF) TransactionScope vs Database.BeginTransaction

In today blog post we will talk a little about a new feature that is available on EF6+ related to Transactions.
Until now, when we had to use transaction we used ‘TransactionScope’. It works great and I would say that is something that is now in our blood.
using (var scope = new TransactionScope(TransactionScopeOption.Required)) { using (SqlConnection conn = new SqlConnection("...")) { conn.Open(); SqlCommand sqlCommand = new SqlCommand(); sqlCommand.Connection = conn; sqlCommand.CommandText = ... sqlCommand.ExecuteNonQuery(); ... } scope.Complete(); } Starting with EF6.0 we have a new way to work with transactions. The new approach is based on Database.BeginTransaction(), Database.Rollback(), Database.Commit(). Yes, no more TransactionScope.
In the followi…

GET call of REST API that contains '/'-slash character in the value of a parameter

Let’s assume that we have the following scenario: I have a public HTTP endpoint and I need to post some content using GET command. One of the parameters contains special characters like “\” and “/”. If the endpoint is an ApiController than you may have problems if you encode the parameter using the http encoder.
using (var httpClient = new HttpClient()) { httpClient.BaseAddress = baseUrl; Task<HttpResponseMessage> response = httpClient.GetAsync(string.Format("api/foo/{0}", "qwert/qwerqwer"))); response.Wait(); response.Result.EnsureSuccessStatusCode(); } One possible solution would be to encode the query parameter using UrlTokenEncode method of HttpServerUtility class and GetBytes method ofUTF8. In this way you would get the array of bytes of the parameter and encode them as a url token.
The following code show to you how you could write the encode and decode methods.
publ…