C# Azure Function with multiple output to a service bus

Question

I saw the Microsoft documentation for Azure Service Bus output binding for Azure Functions version 3. When I want to send a message to a service bus as return of the function, I can use this code:

[FunctionName("ServiceBusOutput")]
[return: ServiceBus("myqueue", Connection = "ServiceBusConnection")]
public static string ServiceBusOutput([HttpTrigger] dynamic input, ILogger log)
{
    log.LogInformation($"C# function processed: {input.Text}");
    return input.Text;
}

My problem started when I want to have as an output 2 messages to different Service Bus. Is it possible to output binding more than one output? In the online editor you can add more than one output. How can I do that in the code?

In the documentation there is a section of Usage, it explains what I can use as output binding. They mention ICollector<T> or IAsyncCollector<T> but I'm not sure it is what I'm looking for.

Other question is what happens in an API that returns one value to the bus and another to the user?

I found here a post where it is explained step by step how to implement multiple output https://www.puresourcecode.com/dotnet/csharp/multiple-output-in-azure-functions-with-c/ — Enrico, May 05 '20 at 10:50

Chris · Accepted Answer · 2020-05-04T16:04:40.697

You could have two IAsyncCollector<T> output bindings:

[FunctionName("HttpTriggeredFunction")]
public async Task<IActionResult> Run(
    [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
    [ServiceBus("queuename1", Connection = "ServiceBusConnectionString1")] IAsyncCollector<dynamic> outputServiceBus1,
    [ServiceBus("queuename2", Connection = "ServiceBusConnectionString2")] IAsyncCollector<dynamic> outputServiceBus2,
    ILogger log)
{
    await outputServiceBus1.AddAsync("Item1");

    await outputServiceBus2.AddAsync("Item2");

    return new OkObjectResult(null);
}

local.settings.json:

{
    "IsEncrypted": false,
    "Values": {
        "AzureWebJobsStorage": "UseDevelopmentStorage=true",
        "FUNCTIONS_WORKER_RUNTIME": "dotnet",
        "ServiceBusConnectionString1": "Endpoint=sb://sb1.servicebus.windows.net/;SharedAccessKeyName=RootManageSharedAccessKey;SharedAccessKey=",
        "ServiceBusConnectionString2": "Endpoint=sb://sb2.servicebus.windows.net/;SharedAccessKeyName=RootManageSharedAccessKey;SharedAccessKey="
    }
}

Other question is what happens in an API that returns one value to the bus and another to the user?

In the above example, it is returning (adding) a message to the Service Bus and returning a IActionResult (HTTP response) to the user.

score 1 · Answer 2 · answered Sep 20 '22 at 19:14

1

You could write to a single service bus topic that has multiple subscribers

answered Sep 20 '22 at 19:14

m0r6aN

850
1
11
19

C# Azure Function with multiple output to a service bus

2 Answers2