DMS for RocketMQ

Prerequisites

• You have purchased a RocketMQ instance in DMS for RocketMQ.
• When the source is DMS for RocketMQ, only FunctionGraph (function computing) can be selected for the target.

Creating a DMS for RocketMQ Event Source

1. Log in to the EG console.
2. In the navigation pane, choose Event Streams > Serverless Event Streams.
3. Click Create Serverless Event Stream, click the icon in the upper left corner, enter the event stream name and description, and click OK.
4. Click the event source.
5. Configure the event source by referring to Table 1.

   Table 1 DMS for RocketMQ parameters

   Parameter	Description
   Event Provider	Select DMS for RocketMQ.
   Instance	Select an instance.
   Group	Enter a group ID.
   Topic	Enter a topic.
   SSL	Specify whether to enable SSL.
   ACL	Specify whether to enable ACL. When ACL is enabled, you need to configure the username and secret key. Ensure that the ACL status of the created RocketMQ instance is the same as that of the RocketMQ event source.
   tag	Enter one or more tags.
   Consumption Timeout (ms)	Enter an integer ranging from 1,000 to 900,000.
   Consumption Mode	Select Concurrently or Orderly.
   Consumption Threads	Enter an integer ranging from 20 to 64.
   Max. Messages	Enter an integer ranging from 1 to 32.
   Max. Retries	Enter the maximum number of retries. –1: unlimited retry; 0: no retry. If the RocketMQ version is 4.x, each message can be retried for a maximum of 16 times by default. Table 2 describes the retry interval.
   Retry Interval (ms)	Enter an integer ranging from 1,000 to 30,000.

   Table 2 RocketMQ 4.x retry interval

   Retry	Interval	Retry	Interval
   1	10 seconds	9	7 minutes
   2	30 seconds	10	8 minutes
   3	1 minute	11	9 minutes
   4	2 minutes	12	10 minutes
   5	3 minutes	13	20 minutes
   6	4 minutes	14	30 minutes
   7	5 minutes	15	1 hour
   8	6 minutes	16	2 hours

   Table 3 Combination of production and consumption sequence

   Production Sequence	Consumption Sequence	Effect
   Orderly (message group)	Orderly	Messages preserve exact send order during consumption within a group.
   Orderly (message group)	Concurrently	Messages are processed as close to order as possible.
   Disorderly (without message group)	Orderly	Consumption follows Apache RocketMQ storage queue order which may differ from send order.
   Disorderly (without message group)	Concurrently	Messages are processed as close to order as possible.

6. Click Next. The rule configuration page is displayed. For details about how to configure rules, see Filter Rule Parameters.
7. Click Next to complete the rule configuration. You can continue to configure the event target of FunctionGraph by referring to Routing to FunctionGraph.
   

   When Event Source is set to DMS for RocketMQ and Event Target is set to FunctionGraph, Execute can be set to Synchronously or Asynchronously.

8. After the event source and target are configured, click Save in the upper right.
   

   • The MQ collection function takes effect in minutes after it is started for the first time.
   • In broadcast mode, retry upon consumption failure is not supported. That is, if a message fails to be consumed, the message will not be retried and the consumer continues to consume new messages.
   • If a message fails to be sent to the target, RocketMQ retries the message. The target must be able to process duplicate events. When the retry upper limit is reached, the source message is added to the dead letter queue of the corresponding topic in RocketMQ, and the EG event is not delivered.