with-mq.md

Using Lambda with Amazon MQ

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.

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

• 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 AWSaccount.
• Authentication – For ActiveMQ, only the ActiveMQ SimpleAuthenticationPlugin is supported. For RabbitMQ, only the PLAIN authentication mechanism is supported. Users must use AWS 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 Event source mapping API 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 https://activemq.apache.org/maven/apidocs/org/apache/activemq/command/ActiveMQTextMessage.html and https://activemq.apache.org/maven/apidocs/org/apache/activemq/command/ActiveMQBytesMessage.html are supported. 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

• Lambda consumer group
• Execution role permissions
• Configuring a broker as an event source
• Event source mapping API
• Event source mapping errors
• Amazon MQ and RabbitMQ configuration parameters

Lambda consumer group

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, 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 Managing Lambda reserved concurrency.

Example Amazon MQ record events

{
   "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 
      },
      { 
        "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 
      }
   ]
}

{
  "eventSource": "aws:rmq",
  "eventSourceArn": "arn:aws: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=="
      }
    ]
  }
}

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::/.

Execution role permissions

To read records from an Amazon MQ broker, your Lambda function needs the following permissions added to its execution role:

• mq:DescribeBroker
• secretsmanager:GetSecretValue
• ec2:CreateNetworkInterface
• ec2:DeleteNetworkInterface
• ec2:DescribeNetworkInterfaces
• ec2:DescribeSecurityGroups
• ec2:DescribeSubnets
• ec2:DescribeVpcs
• logs:CreateLogGroup
• logs:CreateLogStream
• logs:PutLogEvents

Note
When using an encrypted customer managed key, add the [kms:Decrypt](https://docs.aws.amazon.com/msk/1.0/apireference/clusters-clusterarn-bootstrap-brokers.html#clusters-clusterarn-bootstrap-brokersget) permission as well.

Configuring a broker as an event source

Create an event source mapping to tell Lambda to send records from an Amazon MQ broker to a Lambda function. You can create multiple event source mappings to process the same data with multiple functions, or to process items from multiple sources with a single function.

To configure your function to read from Amazon MQ, create an MQ trigger in the Lambda console.

To create a trigger

1. Open the Functions page of the Lambda console.

2. Choose the name of a function.

3. Under Function overview, choose Add trigger.

4. Choose a trigger type.

5. Configure the required options, and then choose Add.

Lambda supports the following options for Amazon MQ event sources:

• MQ broker – Select an Amazon MQ broker.
• Batch size – Set the maximum number of messages to retrieve in a single batch.
• Queue name – Enter the Amazon MQ queue to consume.
• Source access configuration – Enter virtual host information and the Secrets Manager secret that stores your broker credentials.
• Enable trigger – Disable the trigger to stop processing records.

To enable or disable the trigger (or delete it), choose the MQ trigger in the designer. To reconfigure the trigger, use the event source mapping API operations.

Event source mapping API

To manage an event source with the AWS Command Line Interface (AWS CLI) or an AWS SDK, you can use the following API operations:

• CreateEventSourceMapping
• ListEventSourceMappings
• GetEventSourceMapping
• UpdateEventSourceMapping
• DeleteEventSourceMapping

To create the event source mapping with the AWS Command Line Interface (AWS CLI), use the https://docs.aws.amazon.com/cli/latest/reference/lambda/create-event-source-mapping.html command.

By default, Amazon MQ brokers are created with the PubliclyAccessible flag set to false. It is only when PubliclyAccessible is set to true that the broker receives a public IP address.

For full access with your event source mapping, your broker must either use a public endpoint or provide access to the VPC. Note that when you add Amazon MQ as a trigger, Lambda assumes the VPC settings of the Amazon MQ broker, not the Lambda function's VPC settings. To meet the Amazon Virtual Private Cloud (Amazon VPC) access requirements, you can do one of the following:

• Configure one NAT gateway per public subnet. For more information, see Internet and service access for VPC-connected functions.
• Create a connection between your Amazon VPC and Lambda. Your Amazon VPC must also connect to AWS Security Token Service (AWS STS) and Secrets Manager endpoints. For more information, see Configuring interface VPC endpoints for Lambda.

The Amazon VPC security group rules that you configure should have the following settings at minimum:

• Inbound rules – For a broker without public accessibility, allow all traffic on all ports for the security group that's specified as your source. For a broker with public accessibility, allow all traffic on all ports for all destinations.
• Outbound rules – Allow all traffic on all ports for all destinations.

The Amazon VPC configuration is discoverable through the Amazon MQ API and does not need to be configured in the create-event-source-mapping setup.

The following example AWS CLI command creates an event source which maps a Lambda function named MQ-Example-Function to an Amazon MQ RabbitMQ-based broker named ExampleMQBroker. The command also provides the virtual host name and a Secrets Manager secret ARN that stores the broker credentials.

aws lambda create-event-source-mapping \
--event-source-arn arn:aws:mq:us-east-1:123456789012:broker:ExampleMQBroker:b-24cacbb4-b295-49b7-8543-7ce7ce9dfb98 \
--function-name arn:aws:lambda:us-east-1:123456789012:function:MQ-Example-Function \
--queues ExampleQueue \
--source-access-configuration Type=VIRTUAL_HOST,URI="/" Type=BASIC_AUTH,URI=arn:aws:secretsmanager:us-east-1:123456789012:secret:ExampleMQBrokerUserPassword-xPBMTt \

You should see the following output:

{
    "UUID": "91eaeb7e-c976-1234-9451-8709db01f137",
    "BatchSize": 100,
    "EventSourceArn": "arn:aws:mq:us-east-1:123456789012:broker:ExampleMQBroker:b-b4d492ef-bdc3-45e3-a781-cd1a3102ecca",
    "FunctionArn": "arn:aws:lambda:us-east-1:123456789012:function:MQ-Example-Function",
    "LastModified": 1601927898.741,
    "LastProcessingResult": "No records processed",
    "State": "Creating",
    "StateTransitionReason": "USER_INITIATED",
    "Queues": [
        "ExampleQueue"
    ],
    "SourceAccessConfigurations": [
        {
            "Type": "BASIC_AUTH",
            "URI": "arn:aws:secretsmanager:us-east-1:123456789012:secret:ExampleMQBrokerUserPassword-xPBMTt"
        }
    ]
}

Using the [update\-event\-source\-mapping](https://docs.aws.amazon.com/cli/latest/reference/lambda/update-event-source-mapping.html) command, you can configure additional options such as how Lambda processes batches and to specify when to discard records that cannot be processed. The following example command updates an event source mapping to have a batch size of 2.

aws lambda update-event-source-mapping \
--uuid 91eaeb7e-c976-1234-9451-8709db01f137 \
--batch-size 2

You should see the following output:

{
    "UUID": "91eaeb7e-c976-1234-9451-8709db01f137",
    "BatchSize": 2,
    "EventSourceArn": "arn:aws:mq:us-east-1:123456789012:broker:ExampleMQBroker:b-b4d492ef-bdc3-45e3-a781-cd1a3102ecca",
    "FunctionArn": "arn:aws:lambda:us-east-1:123456789012:function:MQ-Example-Function",
    "LastModified": 1601928393.531,
    "LastProcessingResult": "No records processed",
    "State": "Updating",
    "StateTransitionReason": "USER_INITIATED"
}

Lambda updates these settings asynchronously. The output will not reflect changes until this process completes. To view the current status of your resource, use the https://docs.aws.amazon.com/cli/latest/reference/lambda/get-event-source-mapping.html command.

aws lambda get-event-source-mapping \
--uuid 91eaeb7e-c976-4939-9451-8709db01f137

You should see the following output:

{
    "UUID": "91eaeb7e-c976-4939-9451-8709db01f137",
    "BatchSize": 2,
    "EventSourceArn": "arn:aws:mq:us-east-1:123456789012:broker:ExampleMQBroker:b-b4d492ef-bdc3-45e3-a781-cd1a3102ecca",
    "FunctionArn": "arn:aws:lambda:us-east-1:123456789012:function:MQ-Example-Function",
    "LastModified": 1601928393.531,
    "LastProcessingResult": "No records processed",
    "State": "Enabled",
    "StateTransitionReason": "USER_INITIATED"
}

Event source mapping errors

When a Lambda function encounters an unrecoverable error, your Amazon MQ consumer stops processing records. Any other consumers can continue processing, provided that they do not encounter the same error. To determine the potential cause of a stopped consumer, check the StateTransitionReason field in the return details of your EventSourceMapping for one of the following codes:

ESM_CONFIG_NOT_VALID
The event source mapping configuration is not valid.

EVENT_SOURCE_AUTHN_ERROR
Lambda failed to authenticate the event source.

EVENT_SOURCE_AUTHZ_ERROR
Lambda does not have the required permissions to access the event source.

FUNCTION_CONFIG_NOT_VALID
The function's configuration is not valid.

Records also go unprocessed if Lambda drops them due to their size. The size limit for Lambda records is 6 MB. To redeliver messages upon function error, you can use a dead-letter queue (DLQ). For more information, see Message Redelivery and DLQ Handling on the Apache ActiveMQ website and Reliability Guide on the RabbitMQ website.

Note
Lambda does not support custom redelivery policies. Instead, Lambda uses a policy with the default values from the Redelivery Policy page on the Apache ActiveMQ website, with maximumRedeliveries set to 5.

Amazon MQ and RabbitMQ configuration 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		Lambda event filtering
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.