Understanding the Lambda consumer group for Amazon MQ Event source mapping parameters

Using Lambda with Amazon MQ

Note

If you want to send data to a target other than a Lambda function or enrich the data before sending it, see Amazon EventBridge Pipes.

Amazon MQ is a managed message broker service for Apache ActiveMQ and RabbitMQ. A message broker enables software applications and components to communicate using various programming languages, operating systems, and formal messaging protocols through either topic or queue event destinations.

Amazon MQ can also manage Amazon Elastic Compute Cloud (Amazon EC2) instances on your behalf by installing ActiveMQ or RabbitMQ brokers and by providing different network topologies and other infrastructure needs.

You can use a Lambda function to process records from your Amazon MQ message broker. Lambda invokes your function through an event source mapping, a Lambda resource that reads messages from your broker and invokes the function synchronously.

Warning

Lambda event source mappings process each event at least once, and duplicate processing of records can occur. To avoid potential issues related to duplicate events, we strongly recommend that you make your function code idempotent. To learn more, see How do I make my Lambda function idempotent in the Amazon Knowledge Center.

The Amazon MQ event source mapping has the following configuration restrictions:

Concurrency – Lambda functions that use an Amazon MQ event source mapping have a default maximum concurrency setting. For ActiveMQ, the Lambda service limits the number of concurrent execution environments to five. For RabbitMQ, the number of concurrent execution environments is limited to 1. Even if you change your function's reserved or provisioned concurrency settings, the Lambda service won't make more execution environments available. To request an increase in the default maximum concurrency, contact Amazon Web Services Support.
Cross account – Lambda does not support cross-account processing. You cannot use Lambda to process records from an Amazon MQ message broker that is in a different Amazon Web Services account.
Authentication – For ActiveMQ, only the ActiveMQ SimpleAuthenticationPlugin is supported. For RabbitMQ, only the PLAIN authentication mechanism is supported. Users must use Amazon Secrets Manager to manage their credentials. For more information about ActiveMQ authentication, see Integrating ActiveMQ brokers with LDAP in the Amazon MQ Developer Guide.
Connection quota – Brokers have a maximum number of allowed connections per wire-level protocol. This quota is based on the broker instance type. For more information, see the Brokers section of Quotas in Amazon MQ in the Amazon MQ Developer Guide.
Connectivity – You can create brokers in a public or private virtual private cloud (VPC). For private VPCs, your Lambda function needs access to the VPC to receive messages. For more information, see Network configuration later in this topic.
Event destinations – Only queue destinations are supported. However, you can use a virtual topic, which behaves as a topic internally while interacting with Lambda as a queue. For more information, see Virtual Destinations on the Apache ActiveMQ website, and Virtual Hosts on the RabbitMQ website.
Network topology – For ActiveMQ, only one single-instance or standby broker is supported per event source mapping. For RabbitMQ, only one single-instance broker or cluster deployment is supported per event source mapping. Single-instance brokers require a failover endpoint. For more information about these broker deployment modes, see Active MQ Broker Architecture and Rabbit MQ Broker Architecturein the Amazon MQ Developer Guide.
Protocols – Supported protocols depend on the type of Amazon MQ integration.
- For ActiveMQ integrations, Lambda consumes messages using the OpenWire/Java Message Service (JMS) protocol. No other protocols are supported for consuming messages. Within the JMS protocol, only TextMessage and BytesMessage are supported. Lambda also supports JMS custom properties. For more information about the OpenWire protocol, see OpenWire on the Apache ActiveMQ website.
- For RabbitMQ integrations, Lambda consumes messages using the AMQP 0-9-1 protocol. No other protocols are supported for consuming messages. For more information about RabbitMQ's implementation of the AMQP 0-9-1 protocol, see AMQP 0-9-1 Complete Reference Guide on the RabbitMQ website.

Lambda automatically supports the latest versions of ActiveMQ and RabbitMQ that Amazon MQ supports. For the latest supported versions, see Amazon MQ release notes in the Amazon MQ Developer Guide.

Note

By default, Amazon MQ has a weekly maintenance window for brokers. During that window of time, brokers are unavailable. For brokers without standby, Lambda cannot process any messages during that window.

Topics

Understanding the Lambda consumer group for Amazon MQ

To interact with Amazon MQ, Lambda creates a consumer group which can read from your Amazon MQ brokers. The consumer group is created with the same ID as the event source mapping UUID.

For Amazon MQ event sources, Lambda batches records together and sends them to your function in a single payload. To control behavior, you can configure the batching window and batch size. Lambda pulls messages until it processes the payload size maximum of 6 MB, the batching window expires, or the number of records reaches the full batch size. For more information, see Batching behavior.

The consumer group retrieves the messages as a BLOB of bytes, base64-encodes them into a single JSON payload, and then invokes your function. If your function returns an error for any of the messages in a batch, Lambda retries the whole batch of messages until processing succeeds or the messages expire.

Note

While Lambda functions typically have a maximum timeout limit of 15 minutes, event source mappings for Amazon MSK, self-managed Apache Kafka, Amazon DocumentDB, and Amazon MQ for ActiveMQ and RabbitMQ only support functions with maximum timeout limits of 14 minutes. This constraint ensures that the event source mapping can properly handle function errors and retries.

You can monitor a given function's concurrency usage using the ConcurrentExecutions metric in Amazon CloudWatch. For more information about concurrency, see Configuring reserved concurrency for a function.

Example Amazon MQ record events

ActiveMQ


{
   "eventSource": "aws:mq",
   "eventSourceArn": "arn:aws:mq:us-west-2:111122223333:broker:test:b-9bcfa592-423a-4942-879d-eb284b418fc8",
   "messages": [
      { 
        "messageID": "ID:b-9bcfa592-423a-4942-879d-eb284b418fc8-1.mq.us-west-2.amazonaws.com-37557-1234520418293-4:1:1:1:1", 
        "messageType": "jms/text-message",
        "deliveryMode": 1,
        "replyTo": null,
        "type": null,
        "expiration": "60000",
        "priority": 1,
        "correlationId": "myJMSCoID",
        "redelivered": false,
        "destination": { 
          "physicalName": "testQueue" 
        },
        "data":"QUJDOkFBQUE=",
        "timestamp": 1598827811958,
        "brokerInTime": 1598827811958, 
        "brokerOutTime": 1598827811959, 
        "properties": {
          "index": "1",
          "doAlarm": "false",
          "myCustomProperty": "value"
        }
      },
      { 
        "messageID": "ID:b-9bcfa592-423a-4942-879d-eb284b418fc8-1.mq.us-west-2.amazonaws.com-37557-1234520418293-4:1:1:1:1",
        "messageType": "jms/bytes-message",
        "deliveryMode": 1,
        "replyTo": null,
        "type": null,
        "expiration": "60000",
        "priority": 2,
        "correlationId": "myJMSCoID1",
        "redelivered": false,
        "destination": { 
          "physicalName": "testQueue" 
        },
        "data":"LQaGQ82S48k=",
        "timestamp": 1598827811958,
        "brokerInTime": 1598827811958, 
        "brokerOutTime": 1598827811959, 
        "properties": {
          "index": "1",
          "doAlarm": "false",
          "myCustomProperty": "value"
        }
      }
   ]
}

RabbitMQ



{
  "eventSource": "aws:rmq",
  "eventSourceArn": "arn:aws-cn:mq:us-west-2:111122223333:broker:pizzaBroker:b-9bcfa592-423a-4942-879d-eb284b418fc8",
  "rmqMessagesByQueue": {
    "pizzaQueue::/": [
      {
        "basicProperties": {
          "contentType": "text/plain",
          "contentEncoding": null,
          "headers": {
            "header1": {
              "bytes": [
                118,
                97,
                108,
                117,
                101,
                49
              ]
            },
            "header2": {
              "bytes": [
                118,
                97,
                108,
                117,
                101,
                50
              ]
            },
            "numberInHeader": 10
          },
          "deliveryMode": 1,
          "priority": 34,
          "correlationId": null,
          "replyTo": null,
          "expiration": "60000",
          "messageId": null,
          "timestamp": "Jan 1, 1970, 12:33:41 AM",
          "type": null,
          "userId": "AIDACKCEVSQ6C2EXAMPLE",
          "appId": null,
          "clusterId": null,
          "bodySize": 80
        },
        "redelivered": false,
        "data": "eyJ0aW1lb3V0IjowLCJkYXRhIjoiQ1pybWYwR3c4T3Y0YnFMUXhENEUifQ=="
      }
    ]
  }
}

Note

In the RabbitMQ example, pizzaQueue is the name of the RabbitMQ queue, and / is the name of the virtual host. When receiving messages, the event source lists messages under pizzaQueue::/.

Event source mapping parameters

All Lambda event source types share the same CreateEventSourceMapping and UpdateEventSourceMapping API operations. However, only some of the parameters apply to Amazon MQ and RabbitMQ.

Event source parameters that apply to Amazon MQ and RabbitMQ
Parameter	Required	Default	Notes
BatchSize	N	100	Maximum: 10,000
Enabled	N	true
FunctionName	Y
FilterCriteria	N		Control which events Lambda sends to your function
MaximumBatchingWindowInSeconds	N	500 ms	Batching behavior
Queues	N		The name of the Amazon MQ broker destination queue to consume.
SourceAccessConfigurations	N		For ActiveMQ, BASIC_AUTH credentials. For RabbitMQ, can contain both BASIC_AUTH credentials and VIRTUAL_HOST information.

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