Azure Functions QueueTrigger with variable name, QueueTriggerAttribute restrictions

Question

Assume the following typical Queue Trigger function:

public void Run([QueueTrigger("queue1")]object data, ILogger log)
{
    // Do something with data
}

My problem is that "queue1" has to be a constant field, so it has to be defined at compile time. Also, I'd want to have a base class for Queue Triggers, that could work like this:

public abstract class QueueBase<TModel>
{
    public void Run([QueueTrigger("queueName")]TModel data, ILogger log)
    {
        // Do something with data, log something etc.
        OnRunExecuted(data);
        // Do something with data, log something etc.
    }

    public abstract void OnRunExecuted(TModel data);
}

with this, I could write own classes which inherit from QueueBase but can even live inside a library which doesn't have Microsoft.Azure.WebJobs dependency:

public class MyQueueHandler : QueueBase<MyModel>
{
    public void OnRunExecuted(MyModel data) => ...;
}

But it's impossible to pass in a Queue name... is it?

score 2 · Answer 1 · answered Jul 07 '20 at 10:14

2

See binding expressions:

In short, you can pass in a variable queue name as "%queue-name-variable%"

[FunctionName("QueueTrigger")]
public static void Run(
    [QueueTrigger("%queue-name-variable%")]string myQueueItem, 
    ILogger log)
{
    log.LogInformation($"C# Queue trigger function processed: {myQueueItem}");
}

Where input-queue-name is defined in your configuration like

{"queue-name-variable": "queue-name-in-current-env"}

answered Jul 07 '20 at 10:14

unie

143
10

2

Thanks for your contribution, I understand there is that option. I want the classes I write to be more flexible though, and having "queue-name-variable" always map to one specific other value (per environment) isn't very helpful. And the problem with the `INameResolver` is, that it doesn't provide any context of resolution, so within method `Resolve (string name)` you don't have much to decide upon. – thmshd Oct 02 '20 at 07:17
Exactly, writing trigger function for each queue is so arcane. Several requests are made asking for dynamic handling of queue name in the trigger function. You can also upvote my request [here](https://feedback.azure.com/d365community/idea/6ec830d8-b3b9-ed11-a81b-000d3ae6a6aa) – Anand Sowmithiran Mar 03 '23 at 11:39

score 1 · Answer 2 · answered Nov 27 '19 at 16:51

1

As i remember attribute QueueTrigger accept only const string, so you can try make some tricks using environment variables like in post how to pass dynamic queue name

answered Nov 27 '19 at 16:51

Ivan Martinyuk

1,230
1
9
13

Azure Functions QueueTrigger with variable name, QueueTriggerAttribute restrictions

2 Answers2