RabbitMQ trigger for Azure Functions overview

A C# function can be created by using one of the following C# modes:

• In-process class library: Compiled C# function that runs in the same process as the Functions runtime.
• Isolated worker process class library: Compiled C# function that runs in a worker process that's isolated from the runtime. Isolated worker process is required to support C# functions running on LTS and non-LTS versions .NET and the .NET Framework.
• C# script: Used primarily when you create C# functions in the Azure portal.

        [Function(nameof(RabbitMQFunction))]
        [RabbitMQOutput(QueueName = "destinationQueue", ConnectionStringSetting = "RabbitMQConnection")]
        public static string Run([RabbitMQTrigger("queue", ConnectionStringSetting = "RabbitMQConnection")] string item,
            FunctionContext context)
        {
            var logger = context.GetLogger(nameof(RabbitMQFunction));

            logger.LogInformation(item);

            var message = $"Output message created at {DateTime.Now}";
            return message;
        }

[FunctionName("RabbitMQTriggerCSharp")]
public static void RabbitMQTrigger_BasicDeliverEventArgs(
    [RabbitMQTrigger("queue", ConnectionStringSetting = "rabbitMQConnectionAppSetting")] BasicDeliverEventArgs args,
    ILogger logger
    )
{
    logger.LogInformation($"C# RabbitMQ queue trigger function processed message: {Encoding.UTF8.GetString(args.Body)}");
}

namespace Company.Function
{
    public class TestClass
    {
        public string x { get; set; }
    }

    public class RabbitMQTriggerCSharp{
        [FunctionName("RabbitMQTriggerCSharp")]
        public static void RabbitMQTrigger_BasicDeliverEventArgs(
            [RabbitMQTrigger("queue", ConnectionStringSetting = "rabbitMQConnectionAppSetting")] TestClass pocObj,
            ILogger logger
            )
        {
            logger.LogInformation($"C# RabbitMQ queue trigger function processed message: {pocObj}");
        }
    }
}

The following Java function uses the @RabbitMQTrigger annotation from the Java RabbitMQ types to describe the configuration for a RabbitMQ queue trigger. The function grabs the message placed on the queue and adds it to the logs.

@FunctionName("RabbitMQTriggerExample")
public void run(
    @RabbitMQTrigger(connectionStringSetting = "rabbitMQConnectionAppSetting", queueName = "queue") String input,
    final ExecutionContext context)
{
    context.getLogger().info("Java HTTP trigger processed a request." + input);
}

The following example shows a RabbitMQ trigger binding in a function.json file and a JavaScript function that uses the binding. The function reads and logs a RabbitMQ message.

Here's the binding data in the function.json file:

{​​
    "bindings": [
        {​​
            "name": "myQueueItem",
            "type": "rabbitMQTrigger",
            "direction": "in",
            "queueName": "queue",
            "connectionStringSetting": "rabbitMQConnectionAppSetting"
        }​​
    ]
}​​

Here's the JavaScript script code:

module.exports = async function (context, myQueueItem) {​​
    context.log('JavaScript RabbitMQ trigger function processed work item', myQueueItem);
}​​;

The following example demonstrates how to read a RabbitMQ queue message via a trigger.

A RabbitMQ binding is defined in function.json where type is set to RabbitMQTrigger.

{​​
    "scriptFile": "__init__.py",
    "bindings": [
        {​​
            "name": "myQueueItem",
            "type": "rabbitMQTrigger",
            "direction": "in",
            "queueName": "queue",
            "connectionStringSetting": "rabbitMQConnectionAppSetting"
        }​​
    ]
}​​

import logging
import azure.functions as func

def main(myQueueItem) -> None:
    logging.info('Python RabbitMQ trigger function processed a queue item: %s', myQueueItem)

Attributes

Both in-process and isolated worker process C# libraries use the attribute to define the function. C# script instead uses a function.json configuration file.

The attribute's constructor takes the following parameters:

        [Function(nameof(RabbitMQFunction))]
        [RabbitMQOutput(QueueName = "destinationQueue", ConnectionStringSetting = "RabbitMQConnection")]
        public static string Run([RabbitMQTrigger("queue", ConnectionStringSetting = "RabbitMQConnection")] string item,
            FunctionContext context)
        {

[FunctionName("RabbitMQTest")]
public static void RabbitMQTest([RabbitMQTrigger("queue")] string message, ILogger log)
{
    ...
}

Annotations

The RabbitMQTrigger annotation allows you to create a function that runs when a RabbitMQ message is created.

The annotation supports the following configuration options:

Configuration

The following table explains the binding configuration properties that you set in the function.json file.

When you're developing locally, add your application settings in the local.settings.json file in the Values collection.

The parameter type supported by the RabbitMQ trigger depends on the C# modality used.

For a complete example, see C# example.

Refer to Java annotations.

The queue message is available via context.bindings.<NAME> where <NAME> matches the name defined in function.json. If the payload is JSON, the value is deserialized into an object.

Refer to the Python example.