Docker compose SMPT: MAIL_FROM_ADDRESS setting ignored

[itsamemarkus]

Describe the bug
I changed the SMPT server for an existing asciinema docker compose installation. Asciinema sends the email but doesn't use the value defined in MAIL_FROM_ADDRESS as sender.
The email server that only accepts one sender rejects sending the mail.

(the previous mailserver didn't have this strict check)

To Reproduce
Steps to reproduce the behavior:

1. Have an existing asciinema installation (I don't know if it affects new ones)
2. Change the smpt server settings in docker compose (addresses and credentials modified)

    environment:
      - SECRET_KEY_BASE=mysecretkey
      - URL_HOST=terminal.mydomain.tld
      # - URL_PORT=80
      - URL_SCHEME=https
      - SMTP_HOST=the-email.server.tld
      - SMTP_USERNAME=sender@mydomain.tld
      - SMTP_PASSWORD=mypassword
      - DATABASE_URL=postgresql://postgres:mypassword@asciinema_postgres/asciinema
      - SIGN_UP_DISABLED=true
      - MAIL_FROM_ADDRESS=sender@mydomain.tld
      # - MAIL_REPLY_TO_ADDRESS=sender@mydomain.tld

3. user enters his user name on the self hosted asciinema login page, triggering magic link
4. Asciinema tries to send the mail
5. Email server rejects the mail because it comes from hello@$URL_HOST (default value)

Expected behavior
MAIL_FROM_ADDRESS in docker-compose.yml is used to set the from address in the mail that gets send out.

Logs

(addresses and credentials modified)

asciinema log

21:07:29.656 [info] {"args":{"to":"recipient@mydomain.tld","type":"login","url":"https://terminal.mydomain.tld/session/new?t=sessiontoken"},"attempt":1,"duration":407779,"error":"** (ArgumentError) raise/1 and reraise/2 expect a module name, string or exception as the first argument, got: {:permanent_failure, '1.2.3.4', \"553 5.7.1 <hello@terminal.mydomain.tld>: Sender address rejected: not owned by user sender@mydomain.tld\\r\\n\"}","event":"job:exception","id":82148,"max_attempts":20,"meta":{},"queue":"emails","queue_time":8682,"source":"oban","state":"failure","tags":[],"worker":"Asciinema.Emails.Job"}

mailserver log

03/01/2025, 10:07:55 PM NOQUEUE: reject: RCPT from unknown[4.3.2.1]: 553 5.7.1 <hello@terminal.mydomain.tld>: Sender address rejected: not owned by user sender@mydomain.tld; from=<hello@terminal.mydomain.tld> to=<recipient@mydomain.tld> proto=ESMTP helo=<hex-replaced>

Versions:

• Server-OS: Ubuntu 22.04 current dist-upgrade, docker compose
• asciinema server: ghcr.io/asciinema/asciinema-server:20240428
• Edit: I also tested this later with current latest, which had the same behaviour sha256:07d4349c0f9ef259f36f39ffb9e3b571dd245d4fe459d9ee08cbdddd6ae90e82

Troubeshooting

• docker compose down and up again
• reboot docker host

[ku1ik]

This is weird... we have this address looked up here:

asciinema-server/lib/asciinema/emails/email.ex

Lines 129 to 132 in b93b45e

	defp from_address do
	System.get_env("MAIL_FROM_ADDRESS") || System.get_env("SMTP_FROM_ADDRESS") ||
	"hello@#{instance_hostname()}"
	end

It only falls back to hello@{server-domain} when neither SMTP_FROM_ADDRESS nor MAIL_FROM_ADDRESS is set, and you clearly have it set in your env... Not sure how it's possible 🤔