Commit Graph

6 Commits

Author SHA1 Message Date
Daniel Nephin a2f8605c66 stream: Add forceClose and refactor subscription filtering
Move the subscription context to Next. context.Context should generally
never be stored in a struct because it makes that struct only valid
while the context is valid. This is rarely obvious from the caller.
Adds a forceClosed channel in place of the old context, and uses the new
context as a way for the caller to stop the Subscription blocking.

Remove some recursion out of bufferImte.Next. The caller is already looping so we can continue
in that loop instead of recursing. This ensures currentItem is updated immediately (which probably
does not matter in practice), and also removes the chance that we overflow the stack.

NextNoBlock and FollowAfter do not need to handle bufferItem.Err, the caller already
handles it.

Moves filter to a method to simplify Next, and more explicitly separate filtering from looping.

Also improve some godoc

Only unwrap itemBuffer.Err when necessary
2020-07-14 15:57:47 -04:00
Daniel Nephin 2595436f62 stream: Improve docstrings
Also rename ResumeStrema to EndOfEmptySnapshot to be more consistent with other framing events

Co-authored-by: Paul Banks <banks@banksco.de>
2020-07-14 15:57:47 -04:00
Daniel Nephin 16a2b3fafc stream: change Topic to an interface
Consumers of the package can decide on which type to use for the Topic. In the future we may
use a gRPC type for the topic.
2020-07-14 15:57:47 -04:00
Daniel Nephin aa571bd0ce state: Move change processing out of EventPublisher
EventPublisher was receiving TopicHandlers, which had a couple of
problems:

- ChangeProcessors were being grouped by Topic, but they completely
  ignored the topic and were performed on every change
- ChangeProcessors required EventPublisher to be aware of database
  changes

By moving ChangeProcesors out of EventPublisher, and having Publish
accept events instead of changes, EventPublisher no longer needs to
be aware of these things.

Handlers is now only SnapshotHandlers, which are still mapped by Topic.

Also allows us to remove the small 'db' package that had only two types.
They can now be unexported types in state.
2020-07-14 15:57:47 -04:00
Daniel Nephin e1305fe80c stream: unexport identifiers
Now that EventPublisher is part of stream a lot of the internals can be hidden
2020-07-14 15:57:47 -04:00
Daniel Nephin 9e37894778 stream: Move EventPublisher to stream package
The EventPublisher is the central hub of the PubSub system. It is toughly coupled with much of
stream. Some stream internals were exported exclusively for EventPublisher.

The two Subscribe cases (with or without index) were also awkwardly split between two packages. By
moving EventPublisher into stream they are now both in the same package (although still in different files).
2020-07-14 15:57:47 -04:00
Renamed from agent/consul/state/event_publisher.go (Browse further)