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FAQ: Anypoint MQ

This document lists frequently asked questions about Anypoint MQ.

Why is Anypoint MQ not shown in Anypoint Platform?

Anypoint MQ requires a separate Enterprise subscription and is not included in the Anypoint Platform trial version. Contact MuleSoft Support for more information. If you don’t have an Enterprise subscription, you can use Apache Active MQ or Rabbit MQ.

In which regions is Anypoint MQ available?

Anypoint MQ standard and FIFO queues are available in these regions:

  • North America:

    • Northern Virginia (us-east-1)

    • Oregon (us-west-2)

    • Central Canada (ca-central-1)

  • Europe:

    • Ireland (eu-west-1)

    • London (eu-west-2)

  • APAC:

    • Singapore (ap-southeast-1)

    • Sydney (ap-southeast-2)

How do I create and send messages into Anypoint MQ from Mule runtime?

After you obtain an Enterprise subscription and contacted your MuleSoft representative to activate Anypoint MQ, you can use Anypoint Platform to create a queue or message exchange, and send messages to it. For more information, see the Configure Queues and Configure Message Exchanges.

How does Anypoint MQ encrypt messages?

Anypoint MQ messages are always transported using in-flight HTTPS encryption with the latest Transport Layer Security (TLS) protocols. If you configure Anypoint MQ queues for encryption at rest, the payloads are encrypted with the AES-256 GCM algorithm on the server side.

If your app requires an additional layer of encryption security, then you can encrypt the payloads yourself before publishing messages to Anypoint MQ. You must manage your encryption keys for both the message publishers and the consumers.

Why do I see the message decrypted in the UI for my encrypted queues?

When you have a queue encrypted, the messages are stored encrypted but they are decrypted when they are read. Encryption and decryption are automatic and transparent to the final user. There’s no option to disable the automatic decryption. If you need to encrypt the message so that the payload remains encrypted, manually encrypt the content.

How can I send a Java Object as a message?

The body of an Anypoint MQ message is sent as a string as part of a JSON message, thus any content that needs to be published should be serializable in a string format from which you can later deserialize. One way to do this is to serialize the Java object to its JSON representation using DataWeave, which can be serialized and deserialized from a string. Sending Java objects that don’t have a proper string serialization causes the message to be unreadable on the receiving end.

Can I share messages or queues between regions?

No, queues and message exchanges are unique to the region in which they were created and cannot share messages or queues between regions. Developers can manually create custom programs that load balance between regions, but Anypoint MQ itself does not provide multi-region support.

The queues in each region are separate from those in other regions. You can name queues the same in each region, but queues can’t share messages across regions.

How many messages can I fetch using the Anypoint MQ user interface?

In Anypoint Platform > MQ > Message Browser, you can fetch up to 50 messages from a standard (non-FIFO) queue. For a FIFO queue, you can fetch up to 10 messages. The FIFO restriction exists because the FIFO queues are limited to 10 in-flight messages per message group. For more information on in-flight messages, see How many in-flight messages can I have per queue?

Why do I receive fewer messages than my batch size when retrieving messages with the Anypoint MQ REST API?

Anypoint MQ is a highly distributed messaging system, so the results of an API call to receive messages are not guaranteed to be entirely representative of what is fully in the queue. Anypoint MQ operates in a best-effort case. For example, if there are 5 messages in a queue, the system returns anywhere from 0-5 messages in a single API call depending on what distributed subsystems are accessed by that request. Subsequent API calls retrieve more messages and if you keep making API requests to receive messages, then you get all of them. Normally in high throughput cases, repeated API calls happen extremely fast. The Anypoint MQ connector, for example, continuously polls the Anypoint MQ backend for new messages and from the user perspective, the messages are processed nearly instantly even though many API calls were used.

In what order are messages in a standard (non-FIFO) queue?

Standard queues attempt to preserve the order of messages, but strict order is not guaranteed. Because standard queues are designed to be scalable and distributed, they can’t guarantee that messages are received in the same order that they are sent. If message order is important, use a FIFO queue or set the Anypoint MQ connector to the Consume operation.

Can messages be larger than 10 MB?

Anypoint MQ limits messages to 10 MB.

If a larger size is required, you can split the payload into multiple messages, or implement a claim check style service in which you store the payload in a file system or blob storage, and then put a pointer to the payload in the message so it can be downloaded later. However, you must manage access control to the blob storage for both the sender and receiver. You also need to consider that messages can be received unordered unless you use a FIFO queue.

Are message exchanges and queues unique and accessible only in their created environment?

That is, how do we ensure message exchanges or queues created in one environment are not confused or connected to message exchanges or queues created in a different environment if they have the same name?

You can have the same object name for queues and exchanges in different environments, but the client app ID and client secret values must be unique. You can’t access a production queue from a development environment if they don’t have the corresponding client app IDs.

How can I restrict access to a queue or message exchange?

You can use Anypoint Platform > Access Management > Business Groups or Environments. The queues and message exchanges created in a business group or environment are only visible to those with access to the business group or environment.

Can I use Anypoint MQ on-premises?

You can publish a message from an on-premises system to Anypoint MQ and have another on-premises subscriber pull messages from Anypoint MQ. Currently, Anypoint MQ cannot be deployed on-premises. If you need a messaging source on-premises, you can use Apache Active MQ instead.

How does Anypoint MQ handle disaster recovery and high availability failover?

Within each region, Anypoint MQ services deploy to multiple availability zones (AZs) to provide high availability (HA). If service in one availability zone goes down, the Anypoint MQ service operates normally in that region. If all availability zones go down in a region, the Anypoint MQ service is unavailable in that region until at least one of the availability zones comes back up. Because the storage solution for Anypoint MQ is durable, messages that were already in the Anypoint MQ system before service was interrupted are retained.

Anypoint MQ does not have built-in support for duplicating messages or queues across regions.

Can I use a retry strategy with the Anypoint MQ connector?

You cannot use reconnection strategies with the Anypoint MQ connector because it does not use a connection-based protocol. Instead, it uses REST behind the scenes.

On the inbound side, you can easily mimic a retry strategy using a max redelivery attribute set to your maximum number of retries and an exception strategy to move to a dead-letter queue (DLQ) when the limit is reached.

On the outbound side, you should use the same triggering mechanism. Otherwise, you can use the until-successful element with this connector.

You should also configure the HTTP connector so that Global Element Properties > Set Max Redelivery is set to the value of -1.

How can we replay/reprocess messages from a DLQ?

There is no built-in functionality to replay messages from a DLQ. You must implement a special flow or app to consume those messages and forward them back to the original queue for reprocessing.

How do we recover and handle failover?

The network that Anypoint MQ runs on provides high availability replications across its many datacenters.

How do we ensure a message is uniquely processed when failover occurs?

If a server fails and failover occurs, messages continue to be processed by other servers on the network in which Anypoint MQ runs. Standard Anypoint MQ queues do not guarantee only-once message delivery. Only FIFO queues support only-once message delivery. The high availability network deduplicates messages for FIFO queues automatically.

Does Anypoint MQ guarantee message delivery?

Yes, Anypoint MQ guarantees "at least once" delivery of messages to the destination.

How are API requests calculated?

Every API call to Anypoint MQ counts as one API request. Counting each call as a request includes sending, receiving, and acknowledging messages as well as all operations on queues and exchanges.

Up to 10 messages can be retrieved from a single API call, which only bills as one request. Even if the request to retrieve messages does not return a message, for example, if the queue is empty, it still bills as a single API request.

What’s the maximum TPS for Anypoint MQ?

There is no maximum number of transactions per second (TPS) for standard queues or exchanges. FIFO queues have a limit of 300 TPS. If you batch 10 messages per read and write operation (maximum) using the API, FIFO queues can support up to 3,000 TPS.

What’s the maximum number of queues and exchanges in Anypoint MQ?

There is no maximum number of queues or exchanges.

How many in-flight messages can I have per queue?

Anypoint MQ supports up to 120,000 in-flight messages per standard (non-FIFO) queue.

FIFO queues allow up to 10 in-flight messages per message group due to the extra processing required. Anypoint MQ doesn’t limit the number of message groups in FIFO queues.

A single queue can contain an unlimited number of messages. The maximum duration for any message, either in-flight or not, is two weeks, after which Anypoint MQ deletes the message.

Does the Anypoint MQ connector store the message and retry sending it?

The connector does not store the message for resending it. The connector retries 5 times after which the message is discarded and it becomes the responsibility of the app to decide what to do with a message.

Are retries synchronous or asynchronous relative to the Mule flow?

Retries for sending messages to Anypoint MQ broker are always synchronous. By contrast, the client mode specifies how to establish the connection to the backend and does not govern message-sending retries.

Are retries governed by the maxRedelivery setting?

Retries are arbitrary. The maxRedelivery parameter indicates how many times the messages were delivered but not processed (either NACK or TimeOut).

Can I consume Anypoint MQ messages in batches?

Yes. The REST API supports the batchSize query parameter, which lets you retrieve up to 10 messages in a single call (default value). The maximum number of messages that can be retrieved in a single call is 10. You can configure a lower value using the Prefetch Config parameter in the Anypoint MQ connector.

The number of messages retrieved by the connector is sometimes fewer than the number configured. A number higher than 10 is overridden.

Can non-Mule applications interface with Anypoint MQ?

If you have non-Mule applications, you can use the Anypoint MQ REST APIs to send and receive messages.

What is the throughput capacity of Anypoint MQ?

Anypoint MQ is horizontally scalable and supports higher throughputs as needed.

Can I be notified when a message arrives in a queue?

Anypoint MQ provides long polling. You can do a REST request and ask the server to keep the TCP socket open for up to 20 seconds to fulfill your request if there are not enough messages.

How can I process messages one at a time?

You can use FIFO queues to process messages in order.

If you don’t want to use FIFO queues, you can process messages one at a time by setting the Anypoint MQ connector to the consume operation. This operation retrieves a message from the queue or receives null if a message is not available.

Then, depending on your Mule version:

Mule 4

Add the maxConcurrency="1" attribute to the flow element.

Specify this attribute to set the number of simultaneous invocations that a component can receive at any given time to 1.

Mule 4 Example:

<flow name="testanypointmq1by1Flow4" maxConcurrency="1">
    <logger level="INFO" doc:name="Logger" message="Flow triggered" />
    <anypoint-mq:consume doc:name="Anypoint MQ"
       destination="queuename" />
       <logger level="INFO" doc:name="Logger" message="Processing message received. #[payload]"/>
        doc:name="Anypoint MQ"/>
    <logger doc:name="Logger" level="INFO" message="Message processed."/>

Mule 3

  1. Set processingStrategy="synchronous" on the flow.

    Specify this attribute to process messages in the same thread that initially received the message.

  2. Set a poll scope to fire the process at specified intervals.

Mule 3 Example:

<flow name="testanypointmq1by1Flow3" processingstrategy="synchronous">
    <poll doc:name="Poll">
        <logger doc:name="Logger" level="INFO" message="Polling fired"></logger>
    <anypoint-mq:consume config-ref="Anypoint_MQ_Configuration" destination="queuename" doc:name="Anypoint MQ"/>
    <logger doc:name="Logger" level="INFO" message="Processing message received. #[payload]"/>
    <anypoint-mq:ack config-ref="Anypoint_MQ_Configuration" doc:name="Anypoint MQ"/>
    <logger doc:name="Logger" level="INFO" message="Message processed."/>

More than one in-flight message can occur if the processing time between anypoint-mq:consume and anypoint-mq:ack is higher than the value of the Default Acknowledgement Timeout setting for the queue.

Can we see the Anypoint MQ headers in the browse message options?

Anypoint MQ provides direct access to the message ID and payload. You can see the message headers using the Chrome browser and its Network Inspector feature.

Add Anypoint MQ connector support to Mule shared resources?

The only officially supported connectors and transports for shared resources are HTTP/HTTPS, VM, JMS, JMS Caching Connection Factory, Database, WMQ, JBoss Transaction Manager, and Bitronix Transaction Manager.

How do I create many queues and message exchanges?

You can use a curl command with the REST Administration API in a for loop to create the number of queues and message exchanges you need. See an example curl command that you can alter to create a queue or message exchange.

Do the messages-per-month usage charges pertain to all environments?

Yes. It applies to all environments.

What happens when our usage exceeds our license limit?

If your usage exceeds your license limit, Anypoint MQ continues to work. MuleSoft notifies your account administrator and team with any billing-related information.

Why am I seeing 400 bad request errors when using prefetch to receive messages?

When using Anypoint MQ as a message processor with prefetch, use only a global prefetch configuration.

For example, the following local prefetch does not work:

<anypoint-mq:subscriber config-ref="Anypoint_MQ_Configuration"
    destination="programmatically" doc:name="Anypoint MQ" >
    <anypoint-mq:prefetch fetchSize="50" fetchTimeout="10000"/>

Use a global prefetch instead:

<anypoint-mq:prefetch name="Prefetch_Settings" fetchSize="50"
     fetchTimeout="10000" doc:name="Prefetch Settings"/>
<anypoint-mq:subscriber config-ref="Anypoint_MQ_Configuration"
     destination="programmatically" doc:name="Anypoint MQ"

How do I delete a queue?

To delete a queue, see Delete a Queue.

How do I delete a message exchange?

To delete a message exchange, see Delete a Message Exchange.

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