Azure Function with RabbitMQ: output multiple messages

I have an Azure Function made in Java, which is triggered by RabbitMQ messages on a specific queue.
My problem is that I need to output two different messages, one in the middle of the function's code and one at the end. I saw that OutputBinding.setValue doesn't immediately send a message but only sets the value to be used as the output of the function.

Here's my code structure:

import com.microsoft.azure.functions.ExecutionContext;
import com.microsoft.azure.functions.OutputBinding;
import com.microsoft.azure.functions.annotation.FunctionName;
import com.microsoft.azure.functions.rabbitmq.annotation.RabbitMQOutput;
import com.microsoft.azure.functions.rabbitmq.annotation.RabbitMQTrigger;

public class MyFunction {

    @FunctionName("MyFunction")
    public void run(
            @RabbitMQTrigger(connectionStringSetting = "RABBIT_URL", queueName = "input-queue")
            InputMessage message,
            @RabbitMQOutput(connectionStringSetting = "RABBIT_URL", queueName = "output-queue")
            OutputBinding<OutputMessage> output,
            final ExecutionContext context) {
        
        // some code...
        
        output.setValue(new OutputMessage(OutputMessage.Status.PROCESSING, "some other info 1"));
        
        // other code...
        
        output.setValue(new OutputMessage(OutputMessage.Status.DONE, "some other info 2"));
    }
}

public record OutputMessage (Status status, String info) {
    
    public enum Status {
        PROCESSING,
        DONE
    }
}

The message with status "PROCESSING" needs to be fired before the function has done its thing, but if I test the function and go to the RabbitMQ management interface I see that there's only 1 message in the output queue, not 2, and it's the one with status "DONE".

Is there actually a way to send 2 messages from 1 function by using the available tools provided by the Azure Functions Java library/es? Or do I have to import the RabbitMQ library, connect to the queue and manually send a message through that?

The issue occurred because @RabbitMQOutput combined with OutputBinding.setValue() only sends a single message when the function finishes. It doesn't support sending multiple messages at different points during execution.

To fix the issue, I used the native RabbitMQ Java client (com.rabbitmq.client) inside the RabbitMQ trigger function. This allows me to manually publish messages to the output-queue exactly when needed, one during processing and another after completion.

RabbitMQTriggerJava.java :

import com.microsoft.azure.functions.*;
import com.microsoft.azure.functions.annotation.*;
import com.microsoft.azure.functions.rabbitmq.annotation.RabbitMQTrigger;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;

public class RabbitMQTriggerJava {

    private static final String RABBIT_URL = System.getenv("RABBIT_URL");
    private static final String OUTPUT_QUEUE = "output-queue";

    @FunctionName("RabbitMQTriggerJava")
    public void run(
            @RabbitMQTrigger(connectionStringSetting = "RABBIT_URL", queueName = "input-queue")
            InputMessage message,
            final ExecutionContext context) {

        context.getLogger().info("Processing message: " + message);

        try (Connection connection = createRabbitConnection();
             Channel channel = connection.createChannel()) {

            OutputMessage processingMsg = new OutputMessage(OutputMessage.Status.PROCESSING, "Processing started");
            channel.basicPublish("", OUTPUT_QUEUE, null, processingMsg.toString().getBytes());
            Thread.sleep(2000); 

            OutputMessage doneMsg = new OutputMessage(OutputMessage.Status.DONE, "Processing completed");
            channel.basicPublish("", OUTPUT_QUEUE, null, doneMsg.toString().getBytes());
            
        } catch (Exception e) {
            context.getLogger().severe("Error sending message: " + e.getMessage());
        }
    }

    private Connection createRabbitConnection() throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setUri(RABBIT_URL);
        return factory.newConnection();
    }
}

InputMessage.java :

public class InputMessage {
    private String content;

    public InputMessage() {
    }

    public InputMessage(String content) {
        this.content = content;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

    @Override
    public String toString() {
        return "InputMessage{content='" + content + "'}";
    }
}

OutputMessage.java :

public class OutputMessage {

    private Status status;
    private String info;

    public OutputMessage(Status status, String info) {
        this.status = status;
        this.info = info;
    }

    public Status getStatus() {
        return status;
    }

    public String getInfo() {
        return info;
    }

    @Override
    public String toString() {
        return "OutputMessage{" +
                "status=" + status +
                ", info='" + info + '\'' +
                '}';
    }

    public enum Status {
        PROCESSING,
        DONE
    }
}

local.settings.json :

"RABBIT_URL": "amqp://guest:guest@localhost:5672",

I sent a message to the input-queue in RabbitMQ as shown below,

The RabbitMQ trigger function ran successfully.

I successfully received two messages in the output-queue of RabbitMQ as shown below.