In broadcast mode, the instance name is too long and the message cannot be consumed. #417

BUG REPORT

1. Please describe the issue you observed:

Use broadcast mode to consume, consumers will save offset information locally.

When creating the local offset file, the file path defaults to :

/${user.home}/.rocketmq_offset/${consumer client id}/${consumer group name}/offsets.json

The consumer client id defaults to :

${client IP}@${instance name}@${unit name}

Because the instance name is too long, the offset file creation fails, the message cannot be consumed.

2. Please tell us about your environment:

rocketmq-spring 2.1.1

3. Other information (e.g. detailed explanation, logs, related issues, suggestions how to fix, etc):

I am willing to submit a PR!