SagaJournal

Pluggable append-only event log for saga executions.

Each saga run appends entries in the following lifecycle order:

1. EntryPhase.Started — emitted once, seq = 0.

2. EntryPhase.Intent / EntryPhase.Effect — one pair per successful step.

3. EntryPhase.Compensation — for each step rolled back (with JournalEntry.reverses set).

4. EntryPhase.Terminal — emitted once as the final entry.

Implementation contract

Implementations MUST:

• Be thread-safe — multiple concurrent saga runs may append simultaneously.

• Preserve insertion order within a single RunId.

• Assign monotonic, gapless seq values within a RunId starting at 0.

• Treat payload bytes as opaque — never inspect or transform them.

Implementations SHOULD:

• Make append durable before returning JournalOutcome.Ok (audit-grade consumers depend on it).

• Respect coroutine cancellation in all suspend operations.

All operations return JournalOutcome instead of kotlin.Result to avoid historical compiler restrictions on kotlin.Result in suspend-interface positions (critic A2 HIGH).

Parameters

Inheritors