Files
clean-architecture-backend-…/docs/notification/adr/NOTIF-ADR-002-event-ledger-projection.md
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DongHyeonkaandClaude Opus 5 701ba67456 feat(notification): implement the notification delivery platform
Maps the 31-module plan onto the registry's 19 leaves as packages; the two
edges the registry forbids (provider->httpclient, inbox->messaging) are
replaced by application-owned ports. See docs/notification/module-mapping.md.

Acceptance is not delivery: ProviderSubmissionResult refuses to carry a
delivery outcome, and AMBIGUOUS is a first-class terminal state that blocks
automatic retry and fallback until reconciliation resolves it.

Providers: SES (SigV4 + SNS callback), Twilio (X-Twilio-Signature +
reconciliation), FCM (FID-primary batch), APNs, Web Push (RFC 8030/8291/8292),
SMTP and webhook. Contact points are AES-256-GCM encrypted with a separate
HMAC lookup fingerprint; nothing raw reaches a log, metric tag or exception.

Dispatch commits the attempt row, calls the provider with no transaction open,
then records the outcome; the durable queue uses FOR UPDATE SKIP LOCKED.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-14 13:57:27 +09:00

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# NOTIF-ADR-002 — append-only event ledger with channel projectors
## Status
Accepted.
## Context
A single linear delivery status has to be updated in place, which forces a rule for deciding whether
a new event outranks the stored one. The natural rule — compare ordinals — is wrong for real provider
traffic. Twilio does not guarantee callback ordering, so `sent` arrives after `delivered`. Email
generates complaints after deliveries. Both cases lose information under an ordinal rule.
## Decision
Provider events are appended to an immutable ledger before any projection runs. Channel-specific
projectors merge events into `SubmissionOutcome`, `DeliveryOutcome`, `EvidenceLevel`,
`EngagementFacts` and `SuppressionFacts` using explicit transition tables. Projection is idempotent
and can be replayed from the ledger.
## Consequences
Duplicate, out-of-order and late events are normal inputs rather than defects. A projector bug is
recoverable, because the events it mis-projected are still stored. Projector versions can be migrated
by replay. The cost is a second write per event and a projection that can lag its ledger.