# Alert-Me

[Alertswiss](https://www.alert.swiss/) is _an information hub collecting all
relevant information pertaining to precautions and behaviour during disasters
and emergencies in Switzerland._

The usual way of getting that information (the _alerts_) is via a proprietary
smartphone app and push notifications. While this works very well and is
perfectly fine for most, I think that such data is a nice stepping stone to
build upon.

Fortunately, the data is not hidden and easily accessible through a JSON
endpoint. In order to prepare this for consumption, the service in [app](./app/)
periodically polls the JSON data and persists alerts that changed or have not
been seen yet. Additionally it publishes all changes to an MQTT broker where
other clients can use that data as they see fit.

An example client is implemented for an
[nRF52840](https://www.nordicsemi.com/Products/nRF52840) microcontroller in
[display](./display/).

# Workspace Organization

## [app](./app/)

Backend service to poll alerts and publish new ones to an MQTT broker.

## [display](./display/)

Microcontroller ([nRF52840](https://www.nordicsemi.com/Products/nRF52840))
application to show basic alert information on an LCD. Because cargo has trouble
with different target architectures (see
[issue 9406](https://github.com/rust-lang/cargo/issues/9406)) this can not be
part of the workspace. Go into the directory to run build commands. There is a
separate [readme](./display/README.md) in its project directory.

## [entity](./entity/)

Entity definitions (_tables_) for [SeaORM](https://www.sea-ql.org/SeaORM/). This
translates the RDBMS entities to rust structs.

## [migration](./migration/)

Database migrations that get run at the start of the [alert-me app](./app/).

# Building

The recommended way is to use [nix](https://nixos.org/download/) with
[nix flakes](https://nixos.wiki/wiki/Flakes). It still is not for the faint of
heart but worth the investment.

Otherwise, [rustup](https://rustup.rs/) and other tools can be installed
manually.

## Nix

Install [nix](https://nixos.org/download/) and enable
[nix flakes](https://nixos.wiki/wiki/Flakes).

Enter the dev environment with `nix develop`. From there on the usual rust
commands work.

To build for different architectures use `nix-build .#cross-<architecture>` with
the desired architecture.

The following architectures are supported so far (different operating systems
would be nice but makes it more complicated):

- x86_64-linux
- i686-linux
- aarch64-linux
- armv6l-linux

The resulting binary (statically linked with [musl](https://musl.libc.org/)) is
written to `result/bin`.

## Manual Way

Install [rustup](https://rustup.rs/) and an MQTT broker (such as
[mosquitto](https://mosquitto.org/)). When running rust commands (such as
`cargo build`), rustup should pull in the specified toolchain. However, I can
not test this.

# Usage

During development the typical way is to run `cargo run -p alert-me --`,
followed by the cli arguments. Nothing changes if instead one runs an already
built binary directly (such as `result/bin/alert-me`) apart from that first
part.

```
Usage: alert-me [OPTIONS] --mqtt-broker <MQTT_BROKER> --mqtt-user <MQTT_USER> --mqtt-password <MQTT_PASSWORD>

Options:
  -i, --interval <INTERVAL>            Update interval in seconds [default: 10]
  -c, --connection <CONNECTION>        Database connection string where timestamps are stored (SQLite, Postgres or MySql) [default: sqlite::memory:]
  -m, --mqtt-broker <MQTT_BROKER>      MQTT broker where alerts get published
  -p, --mqtt-port <MQTT_PORT>          MQTT port [default: 1883]
  -u, --mqtt-user <MQTT_USER>          MQTT user
  -P, --mqtt-password <MQTT_PASSWORD>  MQTT password
  -h, --help                           Print help
  -V, --version                        Print version
```

## MQTT Broker

The alert-me app needs to connect to an MQTT broker to publish alerts. The
following is an example of running your own with
[mosquitto](https://mosquitto.org/)).

Create a file `mosquitto.conf` with a content of:

```
```

A password for publishing is set, so not everyone can just publish alerts. This
is not mandatory though.

Run the broker with `mosquitto -v -c mosquitto.conf`. With
`mosquitto_sub -v -h localhost -p 1883 -t 'alerts'` new alerts will be shown as
they arrive.