Design plan

Components

1. Controller client
   • Use async gRPC calls based on Tonic.
   • Code gen from proto in main repo
2. Controller command line
   • Use structopt
3. Connection factory
   • Provide a fixed interface so that additional impls can be added.
4. Connection pool
   • Use ownership model based on a "connectionGuard" to return connections to pool.
5. Decode frames of wire commands
6. Serialization
   • Use ownership to manage borrowing and non-copying.
7. Client Factory
   • Create other components and act as a meta service interface so they can instantiate appropriate dependencies as needed.
   • Need to manage lifetimes.
8. RawClient
   • Need layer to connect receiving bytes to reply listener.
   • Use oneshot channel to manage replies (Like a completable future)
9. Server command line
   • Verify wire compatibility test.
10. ByteStreamWriter
    • Can use append blocks by feeding into a channel and draining it into a single block in a loop.
11. ByteStreamReader
    • Always keep a future of a task pending by pushing completed data into a non-buffered channel.
12. EventSegmentReader
13. EventStreamWriterImpl
    • Inflight manager - Use enum passed into mpsc on both ends to avoid mutexes and define order.
14. Segmented Readers
    • Need API to poll for segments
15. Python bindings.
    • Use Py03
16. EventStreamReaderImpl
    • Unlike java, doesn't manage segments. These are passed in externally. So group state is independent as opposed to a managed component.
    • Pull from segments into a 'current' buffer. (because individual events are handed to calles not blocks)
    • Caller can fill buffer if room from completed futures and then read from buffer. If no completed futures and empty buffer it can select on them.
    • Read call can return an enum.
17. TableSegment
    • Need a read mode to receive updates.
18. TableSynchronizer
    • Ownership + Functions make updates very clean.
19. Authentication
    • Need a client to talk to keycloak to get a token to send to the controller. (This uses a standard protocol)
20. Membership tracker
    • Similar to example to automatically detect host failures.
21. ReaderGroupState
    • Create MultiKeyLatestItemSequentialProcessor for the non-one-off updates.
22. Checkpoints
    • Use reader group state similar to Java.
    • Needs to call into the event reader. (Inverse dependency)
23. TxnSegmentWriter
    • Could add support for a per-key transaction... But we need timeout.
24. TxnEventStreamWriter
    • Needs to take time to pass to the controller
25. Watermarking
    • EventStreamWriter noteTime
    • Reader side is similar to checkpoints, using reader group. Can call into event stream reader similar to a CP.
26. Batch client API.
27. Event pointer support.
28. Read/Ack API
    • Pull from segment and return as needed, blocking for outstanding on Checkpoint.
    • Auto manage membership with tracker.
29. Jumbo event support.
    • Stream event from a non-affiliated txn segment.

Unordered

• Metrics
• Logging
• Reactor
• Internal Serialization
• Testing tools
• Integrations with external tools