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wiggleverse-ecomm/backend/app/platform/mailer.py
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Python

"""platform/mailer — the outbound email port (SD-0001 §6.2).
A one-method port `send(to, subject, body)` with two adapters: `LogMailer` (dev/tests —
the message lands in the app log and an in-memory outbox tests read back, §6.8) and the
deployed `SmtpMailer` (relay coordinates from configuration, INV-8). The adapter is chosen
by configuration at startup, so no deployment shape lives in the domain. LogMailer logs the
full body on purpose: that is PUC-10's "local dev channel" — the one-time code reaches the
developer in the terminal. SmtpMailer never logs the body or the recipient (INV-3 / §6.6
log hygiene) and raises MailerError on delivery failure (INV-9 → the §6.4 502).
"""
from __future__ import annotations
import hashlib
import logging
import smtplib
from dataclasses import dataclass
from email.message import EmailMessage
from typing import Protocol
from app.platform import config
logger = logging.getLogger("ecomm.mailer")
class MailerError(Exception):
"""Delivery failed — the relay refused or was unreachable (INV-9)."""
@dataclass(frozen=True)
class SentMessage:
to: str
subject: str
body: str
class Mailer(Protocol):
"""The outbound-message port. Raises on delivery failure (INV-9 → §6.4 502)."""
def send(self, to: str, subject: str, body: str) -> None: ...
class LogMailer:
"""Dev/test adapter: records to an in-memory outbox and logs the message (PUC-10)."""
def __init__(self) -> None:
self.outbox: list[SentMessage] = []
def send(self, to: str, subject: str, body: str) -> None:
self.outbox.append(SentMessage(to=to, subject=subject, body=body))
# Full body incl. the code — the local dev channel. Dev/test only (never deployed).
logger.info("LogMailer -> %s | %s\n%s", to, subject, body)
class SmtpMailer:
"""Deployed adapter: real mail over an SMTP relay (STARTTLS + login by default).
Logs only a hashed recipient — never the address, subject, or body (§6.6).
"""
def __init__(self, host: str, port: int, user: str, password: str, sender: str, starttls: bool) -> None:
self._host, self._port = host, port
self._user, self._password = user, password
self._sender, self._starttls = sender, starttls
def send(self, to: str, subject: str, body: str) -> None:
msg = EmailMessage()
msg["To"] = to
msg["From"] = self._sender
msg["Subject"] = subject
msg.set_content(body)
to_hash = hashlib.sha256(to.encode("utf-8")).hexdigest()[:8]
try:
with smtplib.SMTP(self._host, self._port, timeout=10) as smtp:
if self._starttls:
smtp.starttls()
if self._user:
smtp.login(self._user, self._password)
smtp.send_message(msg)
except Exception as exc:
logger.warning("smtp send FAILED to=%s: %s", to_hash, type(exc).__name__)
raise MailerError(str(exc)) from exc
logger.info("smtp sent to=%s", to_hash)
def build_mailer(kind: str) -> Mailer:
"""Select the mailer adapter by configured kind (config.mailer_kind(), INV-8)."""
if kind == "log":
return LogMailer()
if kind == "smtp":
return SmtpMailer(
host=config.smtp_host(),
port=config.smtp_port(),
user=config.smtp_user(),
password=config.smtp_password(),
sender=config.smtp_from(),
starttls=config.smtp_starttls(),
)
raise ValueError(f"unknown mailer kind: {kind!r}")