- Journal plugin API for storage backends with asynchronous client API (default impl: in-memory journal)
- Journal plugin API for storage backends with synchronous client API (default impl: LevelDB journal)
- Snapshot store plugin API (default impl: local filesystem snapshot store)
- capture and save snapshots of processor state
- start processor recovery from saved snapshots
- snapshot storage on local filesystem
- snapshot store completely isolated from journal
- LevelDB journal modularized (and completely re-rwritten)
- In-memory journal removed
* Replace (deprecate) akka.cluster.auto-down config setting with
akka.cluster.auto-down-unreachable-after
* AutoDown actor that keeps track of unreachable members
and performs down from the leader node when they have been
unreachable for the specified duration
* Migration guide
Moves `def ack: Event` and `def wantsAck: Boolean` from the `Tcp.WriteCommand` type down to the newly introduced `Tcp.CompactWriteCommand`, which breaks existing code depending on these.
Additionally `Tcp.WriteCommand` now has a few additional methods (`+:`, `++:`, prepend) and a companion object.
- introduce around life cycle hooks for symmetry with aroundReceive
- no custom processor-specific life cycle hooks needed any more
- preStart and preRestart can be overridden with empty implementation
(interceptors ensure that super.preXxx calls are still executed)
- all around life cycle hooks can be final
- standard life cycle hooks are non-final to preserve composability with existing traits (FSM, ...)
- use overridden processor and channel ids
- no need anymore to wait for processor instances to stop
- unrelated: fix wrong artifact names in documentation
The most prominent changes compared to eventsourced are:
- No central processor and channel registry any more
- Auto-recovery of processors on start and restart (can be disabled)
- Recovery of processor networks doesn't require coordination
- Explicit channel activation not needed any more
- Message sequence numbers generated per processor (no gaps)
- Sender references are journaled along with messages
- Processors can determine their recovery status
- No custom API on extension object, only messages
- Journal created by extension from config, not by application
- Applications only interact with processors and channels via messages
- Internal design prepared for having processor-specific journal actors (for later optimization possibilities)
Further additions and changes during review:
- Allow processor implementation classes to use inherited stash
- Channel support to resolve (potentially invalid) sender references
- Logical intead of physical deletion of messages
- Pinned dispatcher for LevelDB journal
- Processor can handle failures during recovery
- Message renamed to Persistent
This prototype has the following limitations:
- Serialization of persistent messages and their payload via JavaSerializer only (will be configurable later)
- The LevelDB journal implementation based on a LevelDB Java port, not the native LevelDB (will be configurable later)
The following features will be added later using separate tickets:
- Snapshot-based recovery
- Reliable channels
- Journal plugin API
- Optimizations
- ...
* It was a regression introduced in dc9fe4f
* Two problems:
1) Gossip merge could pop back removed member (was previously
covered by the filter of unreachable)
2) Reachability merge didn't handle all cases for removed member,
i.e. when node not in allowed set
