## What
- `pyproject.toml` — setuptools metadata with a `legacy-email-proxy` console script. Runtime dependencies are read dynamically from `requirements.txt`, so the Docker build and the package cannot drift apart.
- `proxy_server.run()` — a synchronous entry point for that console script; `main` is a coroutine and cannot be referenced by one. The `__main__` path behaves as before.
- `flake.nix` / `package.nix` — the package, `overlays.default`, a dev shell, and `checks`. The pytest suite runs as part of the build.
- `module.nix` — a NixOS module: `services.legacy-email-proxy` with freeform `settings` (environment variables) and a separate `environmentFile` for credentials, so secrets stay out of the Nix store. Runs under `DynamicUser`, takes `CAP_NET_BIND_SERVICE` only while a listener is on a privileged port, and opens no firewall ports.
- README: pip install, Nix usage, and a NixOS service example.
## Why
The proxy could only be consumed as a container. Anyone deploying it on NixOS had to vendor a package definition into their own configuration — which is exactly what happened downstream, and is now deleted there in favour of this.
## Not in scope
- The `Dockerfile` and its CI workflow are untouched.
- No Nix job in CI; the runner has no Nix. The build is reproducible locally with `nix flake check`.
- `version` is static and tracks the latest tag (`0.3.0`); bump it with the tag.
## Verification
- `nix flake check` — package builds, 14 tests pass inside the build.
- Consumed from a downstream NixOS host with `--override-input`: the unit's `ExecStart` resolves to the module's own build, and that flake's checks pass too.
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Co-authored-by: Emma Thorpe <emma.thorpe@citrix.com>
Reviewed-on: #16
Accept any POP3 `USER`/`PASS` from the client and discard them. The proxy always authenticates to the IMAP backend with the configured `BACKEND_IMAP_USER` / `BACKEND_IMAP_PASS`.
## Changes
- `handle_user` / `handle_pass`: accept client credentials unconditionally, no validation.
- `authenticate`: always use backend credentials; remove the fallback that connected with client-supplied credentials when backend credentials were unset. Raise a clear configuration error when backend credentials are missing.
- Tests: client credentials are ignored; missing backend credentials are reported.
Closes#14
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Co-authored-by: Emma Thorpe <emma.thorpe@citrix.com>
Reviewed-on: #15
Adds a Security section: the front-end POP3/SMTP listeners are unauthenticated and must be bound to a trusted internal network only. Closes#9
Reviewed-on: #13
Co-authored-by: Lyra Thorpe <iam@emmathe.dev>
Co-committed-by: Lyra Thorpe <iam@emmathe.dev>
Moves the actions/cache step ahead of the install step and uses the runner.os Actions expression in the cache key. Closes#8
Reviewed-on: #12
Co-authored-by: Lyra Thorpe <iam@emmathe.dev>
Co-committed-by: Lyra Thorpe <iam@emmathe.dev>
Adds a dedicated non-root user and switches to it before CMD. Verified the container runs as a non-root uid. Closes#7
Reviewed-on: #11
Co-authored-by: Lyra Thorpe <iam@emmathe.dev>
Co-committed-by: Lyra Thorpe <iam@emmathe.dev>