[SAMZA-147] Add a generic stream metadata API to SystemAdmin

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.6.0
• Component/s: container
• Assignee: Chris Riccomini
• Reporter: Chris Riccomini
• Created: 18/Feb/14 18:24
• Updated: 24/Feb/14 18:33
• Resolved: 24/Feb/14 18:33

Description

While investigating SAMZA-142, it became clear that the getLastOffsets and getPartitions APIs in SystemAdmin are insufficient.

Samza currently wants to know four things:

1. Partition count for each stream it's reading from.
2. Offset of the oldest message in the stream. This is useful to fully read a changelog.
3. Offset of the newest message in the stream. This is useful when checking of we've finished bootstrapping a stream in the DefaultChooser.
4. Offset of the "future" message in the stream. This is useful when a job wishes to start reading from "realtime", and skip all older messages.

In addition, (2) is useful in cases where a job wishes to start reading input topics from the oldest message in the stream (the opposite (4)).