Messages can be set with an optional time to live when sending them.

Apache ActiveMQ Artemis will not deliver a message to a consumer after it’s time-to-live has been exceeded. If the message hasn’t been delivered by the time that time-to-live is reached the server can discard it.

Apache ActiveMQ Artemis’s addresses can be assigned an expiry address so that, when messages are expired, they are removed from the queue and sent to the expiry address. Many different queues can be bound to an expiry address. These expired messages can later be consumed for further inspection.

1. Core API

Using Apache ActiveMQ Artemis Core API, you can set an expiration time directly on the message:

// message will expire in 5000ms from now
message.setExpiration(System.currentTimeMillis() + 5000);

JMS MessageProducer allows to set a TimeToLive for the messages it sent:

// messages sent by this producer will be retained for 5s (5000ms) before expiration
producer.setTimeToLive(5000);

Expired messages get special properties plus this additional property:

_AMQ_ACTUAL_EXPIRY

a Long property containing the actual expiration time of the expired message

2. Configuring Expiry Delay

There are multiple address-settings which you can use to modify the expiry delay for incoming messages:

  1. no-expiry

  2. expiry-delay

  3. max-expiry-delay & min-expiry-delay

These settings are applied exclusively in this order of precedence. For example, if no-expiry is set and expiry-delay is also set then expiry-delay is ignored completely and no-expiry is enforced.

If you set any of these values for the expiry-address then messages which expire will have corresponding new expiry delays potentially causing the expired messages to themselves expire and be removed completely from the broker.

Let’s look at each of these in turn.

2.1. Never Expire

If you want to force messages to never expire regardless of their existing settings then set no-expiry to true, e.g.:

<!-- messages will never expire -->
<address-setting match="exampleQueue">
   <no-expiry>true</no-expiry>
</address-setting>

For example, if no-expiry is set to true and a message which is using an expiration of 10 arrives then its expiration time of 10 will be changed to 0.

The default is false.

2.2. Modify Default Expiry

To modify the expiry delay on a message using the default expiration (i.e. 0) set expiry-delay, e.g.

<!-- expired messages in exampleQueue will be sent to the expiry address expiryQueue -->
<address-setting match="exampleQueue">
   <expiry-address>expiryQueue</expiry-address>
   <expiry-delay>10</expiry-delay>
</address-setting>

For example, if expiry-delay is set to 10 and a message which is using the default expiration time (i.e. 0) arrives then its expiration time of 0 will be changed to 10. However, if a message which is using an expiration time of 20 arrives then its expiration time will remain unchanged.

This value is measured in milliseconds. The default is -1 (i.e. disabled).

2.3. Enforce an Expiry Range

To enforce a range of expiry delay values

<address-setting match="exampleQueue">
   <min-expiry-delay>10</min-expiry-delay>
   <max-expiry-delay>100</max-expiry-delay>
</address-setting>

Semantics are as follows:

  • Messages without an expiration will be set to max-expiry-delay.

    • If max-expiry-delay is not defined then the message will be set to min-expiry-delay.

    • If min-expiry-delay is not defined then the message will not be changed.

  • Messages with an expiration above max-expiry-delay will be set to max-expiry-delay.

  • Messages with an expiration below min-expiry-delay will be set to min-expiry-delay.

  • Messages with an expiration within min-expiry-delay and max-expiry-delay range will not be changed.

These values are measured in milliseconds. The default for both is -1 (i.e. disabled).

Setting a value of 0 for max-expiry-delay will cause messages to expire immediately.

3. Configuring Expiry Addresses

Expiry address are defined in the address-setting configuration:

<!-- expired messages in exampleQueue will be sent to the expiry address expiryQueue -->
<address-setting match="exampleQueue">
   <expiry-address>expiryQueue</expiry-address>
</address-setting>

If messages are expired and no expiry address is specified, messages are simply removed from the queue and dropped. Address wildcards can be used to configure expiry address for a set of addresses.

If a wildcard is used to configure the expiry address for a set of addresses and you want to unset the expiry address for a particular addess (or set of addresses) then you can do so, e.g.:

<address-setting match="#">
   <expiry-address>expiryQueue</expiry-address>
</address-setting>
<address-setting match="exampleQueue">
   <expiry-address/> <!-- unset expiry-address so messages which expire from queues bound to matching addresses are dropped -->
</address-setting>

4. Configuring Automatic Creation of Expiry Resources

It’s common to segregate expired messages by their original address. For example, a message sent to the stocks address that expired for some reason might be ultimately routed to the EXP.stocks queue, and likewise a message sent to the orders address that expired might be routed to the EXP.orders queue.

Using this pattern can make it easy to track and administrate expired messages. However, it can pose a challenge in environments which predominantly use auto-created addresses and queues. Typically administrators in those environments don’t want to manually create an address-setting to configure the expiry-address much less the actual address and queue to hold the expired messages.

The solution to this problem is to set the auto-create-expiry-resources address-setting to true (it’s false by default) so that the broker will create the address and queue to deal with the expired messages automatically. The address created will be the one defined by the expiry-address. A MULTICAST queue will be created on that address. It will be named by the address to which the message was previously sent, and it will have a filter defined using the property _AMQ_ORIG_ADDRESS so that it will only receive messages sent to the relevant address. The queue name can be configured with a prefix and suffix. See the relevant settings in the table below:

address-setting default

expiry-queue-prefix

EXP.

expiry-queue-suffix

(empty string)

Here is an example configuration:

<address-setting match="#">
   <expiry-address>expiryAddress</expiry-address>
   <auto-create-expiry-resources>true</auto-create-expiry-resources>
   <expiry-queue-prefix></expiry-queue-prefix> <!-- override the default -->
   <expiry-queue-suffix>.EXP</expiry-queue-suffix>
</address-setting>

The queue holding the expired messages can be accessed directly either by using the queue’s name by itself (e.g. when using the core client) or by using the fully qualified queue name (e.g. when using a JMS client) just like any other queue. Also, note that the queue is auto-created which means it will be auto-deleted as per the relevant address-settings.

5. Configuring The Expiry Reaper Thread

A reaper thread will periodically inspect the queues to check if messages have expired.

The reaper thread can be configured with the following properties in broker.xml

message-expiry-scan-period

How often the queues will be scanned to detect expired messages (in milliseconds, default is 30000ms, set to -1 to disable the reaper thread)

6. Example

See the Message Expiration Example which shows how message expiry is configured and used with JMS.