[HDFS-11918] Ozone: Encapsulate KSM metadata key for better (de)serialization

• Type: Sub-task
• Status: Resolved
• Priority: Critical
• Resolution: Later
• Component/s: ozone
• Target Version/s: HDFS-7240
• Assignee: Weiwei Yang
• Reporter: Weiwei Yang
• Created: 02/Jun/17 09:56
• Updated: 23/Jun/17 08:59
• Resolved: 23/Jun/17 08:59

Description

There are multiple type of keys stored in KSM database

1. Volume Key
2. Bucket Key
3. Object Key
4. User Key

Currently they are represented as plain string with some conventions, such as

1. /volume
2. /volume/bucket
3. /volume/bucket/key
4. $user

this approach makes it so difficult to parse volume/bucket/keys from KSM database. Propose to encapsulate these types of keys into protobuf messages, and take advantage of protobuf to serialize(deserialize) classes to byte arrays (and vice versa).