Design plan

Components

Milestone 1

• Controller client
  • Use async gRPC calls based on Tonic.
  • Code gen from proto in main repo
• Controller command line
  • Use structopt
• Connection factory
  • Provide a fixed interface so that additional impls can be added.
• Connection pool
  • Use ownership model based on a "connectionGuard" to return connections to pool.
• Decode frames of wire commands
• Serialization
  • Use ownership to manage borrowing and non-copying.
• RawClient
  • Need layer to connect receiving bytes to reply listener.
  • Use oneshot channel to manage replies (Like a completable future)

Milestone 2

• Client Factory
  • Create other components and act as a meta service interface so they can instantiate appropriate dependencies as needed.
  • Need to manage lifetimes.
• Server command line
  • Verify wire compatibility test.
• EventSegmentReader
• EventStreamWriterImpl
  • Inflight manager - Use enum passed into mpsc on both ends to avoid mutexes and define order.

Milestone 3

• TableSegment
  • Need a read mode to receive updates.
• TableSynchronizer
  • Was delayed on server side support for tailing a table segment
  • Ownership + Functions make updates very clean.
• ReaderGroupState
  • Create MultiKeyLatestItemSequentialProcessor for the non-one-off updates.
• Segmented Readers
  • Need API to poll for segments
• 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.

Milestone 4

• Python bindings.
  • Use Py03
• TxnSegmentWriter
  • Could add support for a per-key transaction... But we need timeout.
• TxnEventStreamWriter
  • Needs to take time to pass to the controller

Milestone 5

• ByteStreamWriter
  • Can use append blocks by feeding into a channel and draining it into a single block in a loop.
• ByteStreamReader
  • Always keep a future of a task pending by pushing completed data into a non-buffered channel.
• Authentication
  • Need a client to talk to keycloak to get a token to send to the controller. (This uses a standard protocol)
• TLS support
  • Both for client -> controller and client -> server

Milestone 6

- [ ] Checkpoints

• Use reader group state similar to Java.
• Needs to call into the event reader. (Inverse dependency)

• Event pointer support.
• Membership tracker
  • Similar to example to automatically detect host failures.

Milestone 7

• Watermarking
  • EventStreamWriter noteTime
  • Reader side is similar to checkpoints, using reader group. Can call into event stream reader similar to a CP.
• Batch client API.
• [ ] Read/Ack API
  • Pull from segment and return as needed, blocking for outstanding on Checkpoint.
  • Auto manage membership with tracker.
• Jumbo event support.
  • Stream event from a non-affiliated txn segment.

Common

These may interact with many components and may have language specific functionality.

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