Add more semantic convention attributes of Apache RocketMQ

[aaron-ai]

Add more semantics convention attributes of Apache RocketMQ.

1. messaging.rocketmq.message_group: message group is essential for FIFO message. Messages that belong to the same message group are always processed one by one within the same consumer group.
2. messaging.rocketmq.delivery_timestamp: the timestamp in milliseconds that the delay message is expected to be delivered to consumer.
3. messaging.rocketmq.delay_time_level: the delay time level for delay message, which determines the message delay time.

[carlosalberto]

Overall good, although we don't have any actual semantic convention (for tracing) using a timestamp value. Also, we need actual examples or doc references for some of these values (e.g. I didn't know about delay type, but I found this: https://rocketmq.apache.org/docs/4.x/producer/07message3/)

Also, let's discuss it in tomorrow's Spec call, to double confirm we are good with this. We will post an update if you can't make it.

[aaron-ai]

Thanks for reply. We use either of delay_time_level and delivery_timestamp to determine the specified delay time for delay message, it depends on the version of RocketMQ client.

• delay_time_level: as you saw in https://rocketmq.apache.org/docs/4.x/producer/07message3
• delivery_timestamp: here is an example: https://github.com/apache/rocketmq-clients/blob/master/java/client/src/main/java/org/apache/rocketmq/client/java/example/ProducerDelayMessageExample.java

[carlosalberto]

@jsuereth I was wondering whether you have any opinion regarding adding general trace attributes (special attention to the timestamp value).