ryu-email-send 0.1.3

BYOK SMTP email sink for Ryu self-host: a swappable outbound-email transport (the SES agent-inbox path in `packages/mail` is the other) delivering policy/monitor alerts and, later, agent-inbox send. A rich multi-recipient / cc-bcc / text+html multipart / threaded / attachment builder plus a one-line alert helper, over a BYO relay resolved prefs-first then `RYU_SMTP_*` env — no default provider, no-op when unconfigured. An extracted Core capability crate; secret custody stays kernel-side via an injected password resolver, so this crate has ZERO dependency on apps/core.
Documentation

ryu-email-send

BYOK SMTP email sink for Ryu self-host — the outbound-email delivery leg for policy/monitor alerts (budget/firewall alerts, monitor notifications) and, later, agent-inbox send.

Role in the decomposition

An extracted Core capability crate, compiled into apps/core as the in-process default. Delivery is what runs → Core, not policy: the Gateway decides an alert fires; the node opens the socket and sends.

Zero dependency on apps/core. Secret custody stays kernel-side: the SMTP password is never held here — Core injects a resolver via set_password_resolver (backed by its smtp_auth BYO-key store, prefs-first + RYU_SMTP_PASSWORD env). That resolver is the seam.

Nothing hardcoded — the swappable transport

There is no default provider. The transport is a BYO SMTP relay resolved prefs-first (the desktop Settings SMTP card writes non-secret TransportPrefs under smtp-transport) then RYU_SMTP_* env for headless setups. With no relay configured the sink is a fail-safe no-op (resolve_transport returns None) and callers skip email — never a plaintext leak. SMTP is one swappable sink; the SES agent-inbox path (packages/mail) is another.

Key surface

  • set_password_resolver / set_transport / apply_transport_prefs_json / current_transport_prefs — wiring from Core prefs.
  • resolve_transport → EmailTransportConfig — effective config (prefs, else env).
  • OutboundEmail — the rich builder: multi-recipient, cc/bcc/reply-to, text+html multipart, RFC 5322 threading headers, and attachments. Shared by the agent-inbox send path and the one-line alert helper.
  • send_email — sends over a transport, returns the generated Message-ID; bounded by a 30s SEND_TIMEOUT (lettre has no built-in timeout).
  • send_email_alert — thin single-recipient plain-text helper.
  • EmailError — NotConfigured / InvalidAddress / Build / Transport / Send / Timeout.

Consumed as

Compiled-into-Core crate; called by Core's alert + inbox-send paths.

Deps: lettre (tokio1-native-tls, smtp-transport, builder), tokio (time), serde/serde_json.