emailsender - Yuneta Simplified

E-mail sending yuno. It speaks native SMTPS (implicit TLS, RFC 8314) and queues outgoing messages with TimeRanger2 persistence so they survive transient SMTP outages and yuno restarts. Builds fully static since 7.4.3.

Architecture¶

C_EMAILSENDER          <- queueing, retry, dead-letter, MIME encoding
    > C_SMTP_SESSION   <- SMTP client FSM (banner/EHLO/AUTH/MAIL/RCPT/DATA)
        > C_TCP        <- smtps://host:465 (implicit TLS from byte zero)

C_EMAILSENDER owns two persistent queues on TimeRanger2: emails_queue (pending) and emails_failed (dead-letter). It builds the full RFC 5322 / MIME message (mime_encoder.c) and drives the send/retry loop.
C_SMTP_SESSION implements the line-based SMTP client as an FSM. It uses AUTH PLAIN; STARTTLS is not implemented (the transport is TLS from the first byte via the smtps:// C_TCP bottom). EHLO advertises the local hostname. An idle session closed by the server (SMTP 421 — OVH does this aggressively) is treated as a graceful close; C_TCP reconnects on the next send.

Configuration¶

Effective config is the usual merge of main.c fixed/variable config with the external JSON; inspect it at runtime with ycommand command-yuno id=<id> service=__yuno__ command=view-config.

Attribute	Default	Purpose
`url`	(required)	SMTP server, e.g. `smtps://ssl0.ovh.net:465`
`from`	(required)	Default envelope/From address
`from_beautiful`	`""`	Optional display name for the From header
`username` / `password`	`""`	AUTH PLAIN credentials (empty → skip AUTH)
`timeout_dequeue`	`10`	ms between queue polls
`max_retries`	`4`	Max total send attempts before dead-lettering
`disable_alarm_emails`	`false`	Drop “ALERT Queuing” alarm emails
`tranger_path` / `tranger_database`		TimeRanger2 store location
`topic_emails_queue`	`emails_queue`	Pending-queue topic
`topic_emails_failed`	`emails_failed`	Dead-letter topic
`backup_queue_size`	`1000000`	Backup the queue topic at this size

C_SMTP_SESSION adds timeout_response (default 30000 ms) — the per-command watchdog while waiting for a server reply.

Commands¶

Command	Parameters	Description
`send-email`	`to`, `subject`, `body`, `reply-to`, `attachment`, `inline_file_id`, `is_html`	Enqueue an email. `to`/`cc`/`bcc` accept comma- or semicolon-separated lists; recipients are deduplicated.
`enable-alarm-emails`	—	Re-enable alarm emails
`disable-alarm-emails`	—	Suppress “ALERT Queuing” alarm emails
`help`	`cmd`, `level`	Command help

Other yunos send mail by publishing EV_SEND_EMAIL to the emailsender service (e.g. logcenter’s summary report).

Delivery semantics¶

Outgoing messages are held in the persistent emails_queue and are never dropped while waiting:

A message is only dispatched while the SMTP session is connected and authenticated. If the server is down, the URL is wrong, or credentials are rejected, the message stays in the queue. C_TCP keeps reconnecting on its own and delivery resumes once the link is back — nothing is dead-lettered just because the link is momentarily unavailable.
The body is persisted as part of the queued message (a string), so it survives both retries and a yuno restart.
A message stays at the head of the queue until it is either sent or its attempts are exhausted. A transient send failure (server NACK, connection dropped mid-send) is retried up to max_retries total attempts.
When max_retries is exhausted — or the message is permanently undeliverable (missing recipient, un-encodable body) — it is moved to emails_failed and removed from the main queue. The dead-letter queue is not retried automatically.

Every outcome is logged: a warning per retry, an error when a message is moved to the dead-letter queue, and an info line on success.

Debugging¶

Trace levels (enable with ycommand command-yuno id=<id> service=__yuno__ command=set-gclass-trace gclass=<G> set=1 level=<L>):

GClass	Level	Shows
`C_EMAILSENDER`	`messages`	The MIME message dispatched to the SMTP child
`C_SMTP_SESSION`	`smtp`	SMTP FSM phases — commands sent (`>>>`) and reply codes (`<<<`)
`C_SMTP_SESSION`	`traffic`	Raw bytes in/out (hex dump)