How to have a configuration based queue name for web job processing?

Question

I have a webjob app to process a ServiceBus queue, which runs fine, with the following method:

public static void ProcessQueueMessage([ServiceBusTrigger("myQueueName")] BrokeredMessage message, TextWriter log)

However, I would like to be able to change the queue name without recompiling, according for example to a configuration appsetting, can it be done?

you can not do this. but you can change which queue you are reading from as you have a key in the appSettings. — Mostafa, Nov 23 '15 at 02:50
Or you can create a new queue programmatically and add any messages to it with out the need to recompile. check this reference article: https://azure.microsoft.com/en-us/documentation/articles/storage-dotnet-how-to-use-queues/ — Mostafa, Nov 23 '15 at 02:51

mathewc · Answer 1 · 2015-11-23T05:27:33.550

6

Yes, you can do this. You can implement your own INameResolver and set it on JobHostConfiguration.NameResolver. Then, you can use a queue name like %myqueue% in our ServiceBusTrigger attribute - the runtime will call your INameResolver to resolve that %myqeuue% variable - you can use whatever custom code you want to resolve the name. You could read it from app settings, etc.

edited Nov 23 '15 at 05:27

answered Nov 23 '15 at 04:42

mathewc

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That did the trick, at first I wasn't aware that the % placeholders were required and tried to use other placeholders, like **{myqueue}** and then resolve the name with the placeholders, but then tried again as you suggested and it ran just fine :) – Alberto Silva Nov 23 '15 at 19:58

score 4 · Accepted Answer · answered Dec 08 '15 at 10:03

I've found an implementation of the INameResolver using configuration setting from the azure-webjobs-sdk-samples.

/// <summary>
/// Resolves %name% variables in attribute values from the config file.
/// </summary>
public class ConfigNameResolver : INameResolver
{
    /// <summary>
    /// Resolve a %name% to a value from the confi file. Resolution is not recursive.
    /// </summary>
    /// <param name="name">The name to resolve (without the %... %)</param>
    /// <returns>
    /// The value to which the name resolves, if the name is supported; otherwise throw an <see cref="InvalidOperationException"/>.
    /// </returns>
    /// <exception cref="InvalidOperationException"><paramref name="name"/>has not been found in the config file or its value is empty.</exception>
    public string Resolve(string name)
    {
        var resolvedName = CloudConfigurationManager.GetSetting(name);
        if (string.IsNullOrWhiteSpace(resolvedName))
        {
            throw new InvalidOperationException("Cannot resolve " + name);
        }

        return resolvedName;
    }
}

How to have a configuration based queue name for web job processing?

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