# Noisebell

Door status monitor for [Noisebridge](https://www.noisebridge.net). A Raspberry Pi watches a door sensor and reports open/closed state; remote services cache the data and fan it out to Discord and an Atom feed.

## Architecture

```
Pi (door sensor) ──webhook──▸ Cache Service ──webhook──▸ Discord Bot
                                   │                        │
                        polls Pi ◂──┘            Atom feed ◂──┘
                                                  RSS Service
```

The **Pi** runs a small HTTP service that reads GPIO and exposes `GET /` (status) and `GET /info`. It also pushes state changes to the cache service via webhook.

The **Cache Service** is the central hub. It polls the Pi for status and info, stores everything in SQLite, and forwards state changes to downstream webhooks (Discord, etc.). It exposes a read API for consumers.

The **Discord Bot** receives webhooks from the cache service and posts embeds to a Discord channel.

The **RSS Service** fetches history from the cache service and serves an Atom feed of door events from the last 7 days.

## Services

| Service | Crate | Default Port | Description |
|---------|-------|-------------|-------------|
| Cache | `noisebell-cache` | 3000 | Polls Pi, caches state in SQLite, forwards webhooks |
| Discord | `noisebell-discord` | 3001 | Posts door status embeds to Discord |
| RSS | `noisebell-rss` | 3002 | Serves Atom feed of recent door events |

## Cache API

| Method | Path | Auth | Description |
|--------|------|------|-------------|
| `GET` | `/status` | None | Current door status (`status`, `timestamp`, `last_seen`) |
| `GET` | `/info` | None | Pi system info (JSON blob) |
| `GET` | `/history` | None | Last 100 state changes |
| `POST` | `/webhook` | Bearer token | Inbound webhook from Pi |
| `GET` | `/health` | None | Returns `200 OK` |

## Building

All remote services live in a Cargo workspace under `remote/`.

```sh
cd remote
cargo build --release
```

Or with Nix:

```sh
cd remote
nix build .#noisebell-cache
nix build .#noisebell-discord
nix build .#noisebell-rss
```

## NixOS Configuration

The flake at `remote/flake.nix` exports NixOS modules. Example configuration:

```nix
{
  inputs.noisebell.url = "git+https://git.extremist.software/jet/noisebell?dir=remote";

  outputs = { self, nixpkgs, noisebell, ... }: {
    nixosConfigurations.myhost = nixpkgs.lib.nixosSystem {
      system = "x86_64-linux";
      modules = [
        noisebell.nixosModules.default
        ({ ... }: {
          services.noisebell-cache = {
            enable = true;
            domain = "cache.noisebell.example.com";
            piAddress = "http://noisebell-pi:80";
            piApiKeyFile = "/run/secrets/noisebell-pi-api-key";
            inboundApiKeyFile = "/run/secrets/noisebell-inbound-api-key";
            outboundWebhooks = [
              {
                url = "http://localhost:3001/webhook";
                secretFile = "/run/secrets/noisebell-discord-webhook-secret";
              }
            ];
          };

          services.noisebell-discord = {
            enable = true;
            domain = "discord.noisebell.example.com";
            discordTokenFile = "/run/secrets/noisebell-discord-token";
            channelId = "123456789012345678";
            webhookSecretFile = "/run/secrets/noisebell-discord-webhook-secret";
          };

          services.noisebell-rss = {
            enable = true;
            domain = "rss.noisebell.example.com";
            cacheUrl = "http://localhost:3000";
          };
        })
      ];
    };
  };
}
```

## Secrets

| Secret | Used by | Description |
|--------|---------|-------------|
| `piApiKeyFile` | Cache | Bearer token for authenticating to Pi GET endpoints |
| `inboundApiKeyFile` | Cache | Bearer token the Pi uses when POSTing to `/webhook` |
| `outboundWebhooks[].secretFile` | Cache | Bearer token sent with outbound webhook POSTs |
| `discordTokenFile` | Discord | Discord bot token |
| `webhookSecretFile` | Discord | Must match the cache's outbound webhook secret |