From 267ba1e25d0e1139dca7284e26449f403804f3d3 Mon Sep 17 00:00:00 2001
From: Florian Brandes <florian.brandes@posteo.de>
Date: Tue, 28 Oct 2025 21:26:28 +0100
Subject: [PATCH] add Dockerfile

Signed-off-by: Florian Brandes <florian.brandes@posteo.de>
---
 Dockerfile | 41 +++++++++++++++++++++++++++++++++++++++++
 README.md  | 13 +++++++++++++
 2 files changed, 54 insertions(+)
 create mode 100644 Dockerfile

diff --git a/Dockerfile b/Dockerfile
new file mode 100644
index 0000000..1c01965
--- /dev/null
+++ b/Dockerfile
@@ -0,0 +1,41 @@
+# syntax=docker/dockerfile:1
+
+FROM python:3.13.8-slim as base
+# Prevents Python from writing pyc files.
+ENV PYTHONDONTWRITEBYTECODE=1
+# Keeps Python from buffering stdout and stderr to avoid situations where
+# the application crashes without emitting any logs due to buffering.
+ENV PYTHONUNBUFFERED=1
+
+WORKDIR /app
+
+# Create a non-privileged user that the app will run under.
+# See https://docs.docker.com/go/dockerfile-user-best-practices/
+ARG UID=10001
+RUN adduser \
+    --disabled-password \
+    --gecos "" \
+    --home "/nonexistent" \
+    --shell "/sbin/nologin" \
+    --no-create-home \
+    --uid "${UID}" \
+    appuser
+
+RUN apt-get update
+RUN apt-get install -y build-essential libssl-dev python3-dev swig
+
+# Download dependencies as a separate step to take advantage of Docker's caching.
+# Leverage a cache mount to /root/.cache/pip to speed up subsequent builds.
+# Leverage a bind mount to requirements.txt to avoid having to copy them into
+# into this layer.
+RUN --mount=type=cache,target=/root/.cache/pip \
+    --mount=type=bind,source=requirements.txt,target=requirements.txt \
+    python -m pip install -r requirements.txt
+
+# Switch to the non-privileged user to run the application.
+USER appuser
+
+ADD smtprd_ng /app/smtprd_ng
+
+EXPOSE 8025
+CMD python smtprd_ng/smtprd.py --config /app/config.ini
diff --git a/README.md b/README.md
index d9b3646..9194971 100644
--- a/README.md
+++ b/README.md
@@ -11,6 +11,8 @@ This can also for example use `msmtp`. This way scripts can use `sendmail` which
 
 Additionally, we can sign and encrypt the emails with S/MIME certificates, which adds a layer of authentification and security for automated information delivery (think security notifications, logs, etc.)
 
+Please note: This will only forward emails to email addresses specified in `config.ini`, so it is not useful as a general SMTP-relay (like `msmtp`) but only for a predefined email set. This is by design.
+
 For now, this is a proof-of-concept.
 
 
@@ -49,6 +51,17 @@ Note: `build` must be installed. You should use a `venv` for this.
 
 Clone this repo and run `devenv shell`
 
+### docker
+
+
+
+1. Clone this repo
+2. `cp config.example config.ini`
+3. edit `config.ini` as you need it. I'd suggest using `/app/pw` as password file and bild-mounting it.
+4. `docker build -t smtprd-ng:latest .`
+5. `docker run  -p 8025:8025 -v ./config.ini:/app/config.ini -v ./pw:/app/pw --rm -it smtprd-ng:latest`
+
+
 ## Contributing
 
 Contributions are always welcome!