every.channel/evolution/proposals/ECP-0064-nixos-ec-node-publisher-module.md

ECP-0064: NixOS Module For ec-node WebTransport Publisher (Tower)

Status: Draft

Decision

Ship a first-party NixOS module in this repo that runs ec-node wt-publish as one or more systemd services.

The module:

• Lives in-repo and is exported from the flake as nixosModules.ec-node.
• Builds ec-node from this repo via Nix (no mutable checkout required on the target host).
• Accepts a read-only configuration (in Nix) for:
  • HDHomeRun identity (either host IP/DNS, or deviceId with optional LAN discovery).
  • A list of broadcasts (name + channel) to publish.
  • Relay URL and a small set of wt-publish toggles (transcode/passthrough/TLS verify).

~/Projects/nix will consume this module as a flake input and enable it on the conrad-tower host, deploying with the existing deploy-flake workflow.

Motivation

Tower should run publishing continuously, reproducibly, and without "tmux as an orchestration layer".

NixOS + systemd gives:

• Immutable configuration for the HDHR/relay/channel list.
• Easy deployment/rollback via the existing host flake.
• Restart and journald logs for long-running publishers.

Scope

In scope:

• Nix packaging for ec-node sufficient to run wt-publish.
• A module that instantiates a systemd unit per broadcast.
• Optional HDHR host resolution via device-id + local network discovery (best-effort).

Out of scope (defer):

• ABR/multi-variant ladders from Nix config.
• Automatic lineup-based channel selection by callsign.
• Secrets management (publisher doesn't require secrets for Cloudflare relay preview).

Rollout / Reversibility

• Enabling the module is per-host.
• Reversible by removing the module import and disabling the service(s); roll back with the existing deployment tooling.