Closes the documentation gaps from the freshly-audited diplomail
implementation. FUNCTIONAL.md gains a §11 "Diplomatic mail" with
the full user-facing story across all five stages, mirrored into
FUNCTIONAL_ru.md as the project conventions require. A new
backend/docs/diplomail-translator-setup.md captures the
LibreTranslate operational recipe (Docker image, env wiring,
manual smoke test, troubleshooting). The package README gains a
"Multi-instance posture" note documenting the deliberate absence
of FOR UPDATE in the worker pickup query — single-instance is
safe today; multi-instance scaling will revisit the claim
mechanism.
Two small edge-case tests round things out: malformed
LibreTranslate response bodies (single string, short array,
empty array, missing field) must surface as errors so the worker
falls back instead of crashing; and an empty translation queue
must produce zero events on three consecutive Worker.Tick calls.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Synchronous translation on read (Stage D) blocks the HTTP handler on
translator I/O. Stage E switches to "send moments-fast, deliver
when translated": recipients whose preferred_language differs from
the detected body_lang are inserted with available_at=NULL, and an
async worker turns them on once a LibreTranslate call materialises
the cache row (or fails terminally after 5 retries).
Schema delta on diplomail_recipients: available_at,
translation_attempts, next_translation_attempt_at, plus a snapshot
recipient_preferred_language so the worker queries do not need a
join. Read paths (ListInbox, GetMessage, UnreadCount) filter on
available_at IS NOT NULL. Push fan-out is moved from Service to the
worker so the recipient only sees the toast when the inbox row is
actually visible.
Translator backend is now a configurable choice: empty
BACKEND_DIPLOMAIL_TRANSLATOR_URL → noop (deliver original);
populated → LibreTranslate HTTP client. Per-attempt timeout, max
attempts, and worker interval all live in DiplomailConfig. The HTTP
client itself is unit-tested via httptest (happy path, BCP47
normalisation, unsupported pair, 5xx, identical src/dst, missing
URL); worker delivery + fallback paths are covered by the
testcontainers-backed e2e tests in diplomail_e2e_test.go.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Ilia Denisov