DatMail

DatMail is the SMTP mailing-list forwarder for @fredagscafeen.dk.

The current master branch is a hybrid SMTP + HTTP + object-storage system:

• Postfix receives inbound mail and relays outbound mail.
• DatMail applies mailing-list policy, spam checks, header rewriting, and resend handling.
• Mailing-list membership and spam-filter rules come from a Django API.
• Raw inbound .eml files are archived to S3-compatible storage.
• Processed and dropped mail is reported back to the Django backend.

Documentation

Location	Purpose
GitHub wiki	Published developer docs, architecture, message flows, and API reference
Architecture	Docs for architecture, flows, and code map
Message Flows	Docs for message flows
API Reference	Docs for API reference

Recommended reading order:

1. Wiki Home
2. Architecture
3. Message Flows
4. API Reference
5. Code Map

Update the wiki

The wiki is a separate Git repository:

git clone git@github.com:fredagscafeen/mail.wiki.git
cd mail.wiki
git pull --rebase origin master

After editing the wiki pages:

git add .
git commit -m "docs: update wiki"
git push origin master

If the push is rejected, rebase on the latest wiki changes and push again:

git pull --rebase origin master
git push origin master

Running with Docker

cp datmail/config.local.py datmail/config.py
docker-compose up --build

DatMail listens on port 9000 and relays outbound mail to host.docker.internal:25.

The resend control endpoint listens on port 9001 inside the container by default.

Useful commands:

docker-compose up -d --build
docker-compose logs -f app
docker-compose down

Running locally

Python 3.8.10 is the expected runtime version.

python3 -m venv ~/.cache/venvs/fredagscafeen-mail
source ~/.cache/venvs/fredagscafeen-mail/bin/activate
pip install pip-tools
pip-sync requirements.txt dev-requirements.txt
pre-commit install

Then start DatMail with:

python3 -m datmail

Configuration

Create datmail/config.py from the checked-in sample:

cp datmail/config.local.py datmail/config.py

At minimum, configure:

• SRS_SECRET
• S3_ENDPOINT_URL, S3_ACCESS_KEY_ID, S3_SECRET_ACCESS_KEY
• DATMAIL_CONTROL_HOST, DATMAIL_CONTROL_PORT, DATMAIL_CONTROL_TOKEN
• the Django API base URL and token used by datmail/django_api_client.py

For the detailed API contracts and payload shapes, use the GitHub wiki API Reference.

Monitoring

The legacy monitoring job is still used for local error digests:

python3 -m datmail.monitor

It reads error/, emails an admin digest when the threshold is reached, and archives handled reports into errorarchive/.