Moves committed-but-unrelayed rows from a model's own outbox table to a durable IActionLog, then marks them relayed in the model's own store. More...

#include <outbox.hpp>

Public Member Functions
OutboxRelayResult	relay ()
	Moves every row drainOutbox() currently reports to sink, then marks the whole batch relayed via markRelayed.

Public Attributes
std::function< std::vector< LogEntry >()>	drainOutbox
	Pulls committed-but-unrelayed rows from the model's own store. Must be non-destructive: the same rows are re-drained until markRelayed records them, including across process restarts.
std::function< void(std::span< const LogEntry >)>	markRelayed
	Marks `rows` relayed in the model's own store (by identity or LogEntry::idempotencyKey) so a later drainOutbox() call no longer returns them.
std::shared_ptr< IActionLog >	sink
	Durable audit sink rows are forwarded to.

Detailed Description

Moves committed-but-unrelayed rows from a model's own outbox table to a durable IActionLog, then marks them relayed in the model's own store.

Closes the "two independent writes" gap between a model's own transactional store and the action log: a store-backed model writes its business tables and an outbox row (shaped like LogEntry, including a stable idempotencyKey) in one local transaction — see IModelHolder::setOutboxManaged — and OutboxRelay is the separate, asynchronous step that moves that row into the real durable sink.

drainOutbox/markRelayed are injected callables against the model's own store, exactly as morph::offline::ReconnectCoordinator::Deps and morph::offline::SyncWorker::ReplayFunction inject their side effects — morph::journal never touches the model's database. Mirroring ReconnectCoordinator::Deps, a null member is logged (via morph::log::logError) at the start of every relay() call but is not rejected — invoking a null member still throws (std::bad_function_call) or crashes as usual.

Crash safety: relay() is idempotent and safe to call repeatedly: it appends every row drainOutbox() currently reports to sink, flushes sink, and only then calls markRelayed with the whole batch. A crash between the sink append and markRelayed committing simply means the next relay() call sees the same row again from drainOutbox() — appending it again is a safe no-op as long as sink dedups by LogEntry::idempotencyKey (InMemoryActionLog and FileActionLog do this out of the box — see their class docs; SessionLog deliberately does not, since its contract is full fidelity with nothing dropped). This is at-least-once-plus-dedup, not a two-phase commit: sink and the model's own store are never committed as a single distributed transaction.

Definition at line 67 of file outbox.hpp.

Member Function Documentation

◆ relay()

OutboxRelayResult morph::journal::OutboxRelay::relay ( )

inline

Moves every row drainOutbox() currently reports to sink, then marks the whole batch relayed via markRelayed.

A no-op (returns {.relayed = 0} without touching sink or calling markRelayed) if drainOutbox() returns no rows.

markRelayed runs only after sink->flush() returns normally. An IActionLog that cannot make the batch durable throws (see IActionLog::flush), which propagates out of here before the rows are marked — so they stay in the outbox and a later relay() retries them. This is what keeps the relay at-least-once instead of at-most-once: were the failure swallowed, the rows would be recorded as relayed while nothing reached the sink, and nothing would ever surface the loss.

Runs on sink's owner (see IActionLog::owner()): sink->flush() answers only there, which is what lets its failure reach this call.

Returns: The number of rows relayed in this call.

Exceptions

NullSinkError	if sink is null and drainOutbox() reports at least one row — thrown before sink is ever dereferenced, so no row is lost or marked relayed. A null sink with nothing to relay is still a no-op, exactly like an empty outbox with a real sink: nothing would touch sink either way.
std::exception	propagated from sink->append() or sink->flush(); the batch is left unmarked and therefore retryable.

Definition at line 106 of file outbox.hpp.

Member Data Documentation

◆ drainOutbox

std::function<std::vector<LogEntry>()> morph::journal::OutboxRelay::drainOutbox

Pulls committed-but-unrelayed rows from the model's own store. Must be non-destructive: the same rows are re-drained until markRelayed records them, including across process restarts.

Definition at line 71 of file outbox.hpp.

◆ markRelayed

std::function<void(std::span<const LogEntry>)> morph::journal::OutboxRelay::markRelayed

Marks rows relayed in the model's own store (by identity or LogEntry::idempotencyKey) so a later drainOutbox() call no longer returns them.

Definition at line 76 of file outbox.hpp.

◆ sink

std::shared_ptr<IActionLog> morph::journal::OutboxRelay::sink

Durable audit sink rows are forwarded to.

Definition at line 79 of file outbox.hpp.

The documentation for this struct was generated from the following file:

morph/journal/outbox.hpp

Public Member Functions