gdo

The transmitter that sends the code through the gate so the iris opens. iris keeps bad content out of a portal site; gdo sends the mail that lets a known person in, and every other mail a site's content says to send.

Portal decides when a person hears something and renders the mail: mail: on a state in aggregates.yaml sends when a record enters that state, and an invite mails its one-time link built in. It publishes each rendered mail on portal.mail.send in the mail JetStream stream. gdo holds a durable consumer there and hands each message to the host's SMTP. Portal never talks SMTP; gdo never reads content; a message survives either of them being down, because the stream keeps it.

Run

gdo                          # the consumer; one per host
gdo probe kari@example.no    # one message through, reports delivery
gdo --version
Env Default
NATS_URL nats://127.0.0.1:4222 credentials in the URL, as portal's own
SMTP_HOST, SMTP_PORT 127.0.0.1, 25 the host's postfix; no TLS, no auth, localhost only
SMTP_HELO the host's full name what gdo says in EHLO; a strict server refuses a bare hostname
GDO_CONSUMER gdo the durable consumer's name
GDO_TYPST_THEME unset a .typ file; set, every mail carries a PDF rendered from it

Install on a host from the [uhhm] Arch registry on project.uhhm.no (the repo and its key: see uhhm/corp's README), as root:

pacman -Sy gdo
<edit /etc/gdo/env: NATS_URL with the host's credentials>
systemctl enable --now gdo

The package puts the binary in /usr/bin, the env template in /etc/gdo/env (mode 0600, the one file with a secret), and the unit gdo.service. Then gdo probe <you>, with the env loaded.

The message

One JSON object per message, v: 1:

{ "v": 1, "id": "trafikkmeldinger:<record>:ordnet", "site": "Tomter Vel",
  "from": "Tomter Vel <vel@example.no>", "reply_to": "post@example.no",
  "to": "kari@example.no", "subject": "Ordnet: Svingen ved skolen",
  "text": "…markdown as plain text…", "html": "<!doctype html>…" }

id is the JetStream message id: a transition that fires twice sends once. Sent as multipart/alternative, text first, so the plain text is what every client can read and the HTML is the courtesy. A message gdo cannot parse is acked and logged; one with a v it does not know is left in the stream for a gdo that does; one SMTP refuses is retried after a minute, for as long as the stream keeps it (a week).

Typst themes

Plain text is the default and needs nothing. With GDO_TYPST_THEME set to a .typ file and typst on the host, gdo runs typst compile with --input site=… subject=… text=… to=… and attaches the PDF as <site>.pdf. Typst's PDF is dependable; its HTML export is not yet mail-grade, so the HTML alternative stays the plain one and the theme is the attachment. A theme that fails to render costs the attachment, never the mail.

A minimal theme:

#let site = sys.inputs.at("site", default: "")
#set page(width: 148mm, height: auto, margin: 18mm)
#set text(font: "Libertinus Serif", size: 11pt)
#text(size: 9pt, fill: gray)[#site]
#v(6mm)
#heading(sys.inputs.at("subject", default: ""))
#v(3mm)
#sys.inputs.at("text", default: "")

The way back in

With a mailbox configured, every mail about a record carries a Reply-To of its own and replies come back to the case:

Env
JMAP_URL the session endpoint, e.g. https://mail.example.no/.well-known/jmap
JMAP_TOKEN a bearer token for that account
MAIL_REPLY_DOMAIN the domain the reply addresses live on
MAIL_REPLY_PREFIX the local part before the +, case by default
JMAP_EVERY seconds between looks, 60 by default

All three of the first are needed or inbound stays off: a reply address nobody reads is worse than none. The address is case+<bucket>.<record>@<domain>, and the record id in it is portal's own chain hash - the same unguessable capability a decide link carries. It is half the proof: portal also checks the sender against the address the record holds, and a reply is only ever a note, never a decision.

gdo reads what is unread, publishes each reply on portal.mail.received, and marks it seen only once portal has it - a crash in between costs a repeated note, which portal refuses by id, rather than a lost one. Mail addressed to anything but a record is left unread for a person.

S
Description
Sends the code that opens the iris: delivers portal outgoing mail from JetStream to SMTP
Readme MIT
1.6 MiB
v0.2.0
Latest
2026-09-24 19:33:41 +00:00
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