Prevent Null Queue Message for Azure Webjobs Output Queue

Question

According to this WebJobs documentation page, for POCO output queue messages, "A queue message is always created, even if the object is null."

In my scenario, I only want to conditionally output queue messages from my WebJob. Currently I am getting a ton of null messages to my downstream WebJob using the "out" queue:

[Queue("myoutqueue")] out myPOCO outputQueueMessage

Is the only way to do this to not use the WebJobs Queue attribute and to queue the message myself using the client library?

Answer 1

You can conditionally enqueue an output message by using the ICollector<T> binding. For example:

[Queue("myoutqueue")] ICollector<MyPoco> outMessages

Then, only messages added to the collector via outMessages.Add(message) will be sent (one or more). More on ICollector<T> and other Queue bindings can be found here.