[KAFKA-2648] Coordinator should not allow empty groupIds

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.9.0.0
• Fix Version/s: 0.9.0.0
• Assignee: Jason Gustafson
• Reporter: Jason Gustafson
• Created: 14/Oct/15 04:56
• Updated: 15/Nov/23 20:18
• Resolved: 28/Oct/15 21:09

Description

The coordinator currently allows consumer groups with empty groupIds, but there probably aren't any cases where this is actually a good idea and it tends to mask problems where different groups have simply not configured a groupId. To address this, we can add a new error code, say INVALID_GROUP_ID, which the coordinator can return when it encounters an empty groupID. We should also make groupId a required property in consumer configuration and enforce that it is non-empty.

It's a little unclear whether this change would have compatibility concerns. The old consumer will fail with an empty groupId (because it cannot create the zookeeper paths), but other clients may allow it.

Issue Links

• relates to: KAFKA-14438 Throw error when consumer configured with empty/whitespace-only group.id for AsyncKafkaConsumer