feat!: Improve lua module registration

Instead of having to call all the module registration functions in one
place it is possible for each module to register itself in a global registry.
During startup all the all the modules will be registered
automatically.

This does currently have one weakness, to need to ensure that the crate
is linked.

Cargo.lock

@@ -100,6 +100,7 @@ dependencies = [
  "git-version",
  "google_home",
  "hostname",
+ "inventory",
  "mlua",
  "reqwest",
  "rumqttc",
@@ -128,6 +129,7 @@ dependencies = [
  "dyn-clone",
  "eui48",
  "google_home",
+ "inventory",
  "mlua",
  "reqwest",
  "rumqttc",
@@ -151,6 +153,7 @@ dependencies = [
  "futures",
  "google_home",
  "indexmap",
+ "inventory",
  "mlua",
  "rumqttc",
  "serde",
@@ -967,6 +970,15 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "inventory"
+version = "0.3.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bc61209c082fbeb19919bee74b176221b27223e27b65d781eb91af24eb1fb46e"
+dependencies = [
+ "rustversion",
+]
+
 [[package]]
 name = "io-uring"
 version = "0.7.10"

Cargo.toml

@@ -34,6 +34,7 @@ google_home = { path = "./google_home/google_home" }
 google_home_macro = { path = "./google_home/google_home_macro" }
 hostname = "0.4.1"
 indexmap = { version = "2.11.0", features = ["serde"] }
+inventory = "0.3.21"
 itertools = "0.14.0"
 json_value_merge = "2.0.1"
 mlua = { version = "0.11.3", features = [
@@ -77,6 +78,7 @@ dotenvy = { workspace = true }
 git-version = "0.3.9"
 google_home = { workspace = true }
 hostname = { workspace = true }
+inventory = { workspace = true }
 mlua = { workspace = true }
 reqwest = { workspace = true }
 rumqttc = { workspace = true }

automation_devices/Cargo.toml

@@ -13,6 +13,7 @@ bytes = { workspace = true }
 dyn-clone = { workspace = true }
 eui48 = { workspace = true }
 google_home = { workspace = true }
+inventory = { workspace = true }
 mlua = { workspace = true }
 reqwest = { workspace = true }
 rumqttc = { workspace = true }

automation_devices/src/lib.rs

@@ -12,6 +12,7 @@ mod wake_on_lan;
 mod washer;
 mod zigbee;
 
+use automation_lib::Module;
 use automation_lib::device::{Device, LuaDeviceCreate};
 use zigbee::light::{LightBrightness, LightColorTemperature, LightOnOff};
 use zigbee::outlet::{OutletOnOff, OutletPower};
@@ -36,7 +37,7 @@ macro_rules! register_device {
     };
 }
 
-pub fn register_with_lua(lua: &mlua::Lua) -> mlua::Result<()> {
+pub fn create_module(lua: &mlua::Lua) -> mlua::Result<mlua::Table> {
     register_device!(lua, AirFilter);
     register_device!(lua, ContactSensor);
     register_device!(lua, HueBridge);
@@ -55,5 +56,8 @@ pub fn register_with_lua(lua: &mlua::Lua) -> mlua::Result<()> {
     register_device!(lua, WakeOnLAN);
     register_device!(lua, Washer);
 
-    Ok(())
+    // For now return an empty table and keep the devices in the global table
+    lua.create_table()
 }
+
+inventory::submit! {Module::new("devices", create_module)}

automation_lib/Cargo.toml

@@ -11,6 +11,7 @@ dyn-clone = { workspace = true }
 futures = { workspace = true }
 google_home = { workspace = true }
 indexmap = { workspace = true }
+inventory = { workspace = true }
 mlua = { workspace = true }
 rumqttc = { workspace = true }
 serde = { workspace = true }

automation_lib/src/lib.rs

@@ -12,3 +12,26 @@ pub mod lua;
 pub mod messages;
 pub mod mqtt;
 pub mod schedule;
+
+type RegisterFn = fn(lua: &mlua::Lua) -> mlua::Result<mlua::Table>;
+
+pub struct Module {
+    name: &'static str,
+    register_fn: RegisterFn,
+}
+
+impl Module {
+    pub const fn new(name: &'static str, register_fn: RegisterFn) -> Self {
+        Self { name, register_fn }
+    }
+
+    pub const fn get_name(&self) -> &'static str {
+        self.name
+    }
+
+    pub fn register(&self, lua: &mlua::Lua) -> mlua::Result<mlua::Table> {
+        (self.register_fn)(lua)
+    }
+}
+
+inventory::collect!(Module);

src/main.rs

@@ -12,8 +12,8 @@ use std::time::{SystemTime, UNIX_EPOCH};
 use ::config::{Environment, File};
 use automation_lib::config::{FulfillmentConfig, MqttConfig};
 use automation_lib::device_manager::DeviceManager;
-use automation_lib::helpers;
 use automation_lib::mqtt::{self, WrappedAsyncClient};
+use automation_lib::{Module, helpers};
 use axum::extract::{FromRef, State};
 use axum::http::StatusCode;
 use axum::routing::post;
@@ -30,6 +30,9 @@ use web::{ApiError, User};
 use crate::secret::EnvironmentSecretFile;
 use crate::version::VERSION;
 
+// Force automation_devices to link so that it gets registered as a module
+extern crate automation_devices;
+
 #[derive(Clone)]
 struct AppState {
     pub openid_url: String,
@@ -138,6 +141,13 @@ async fn app() -> anyhow::Result<()> {
     })?;
     lua.globals().set("print", print)?;
 
+    debug!("Loading modules...");
+    for module in inventory::iter::<Module> {
+        debug!(name = module.get_name(), "Registering");
+        let table = module.register(&lua)?;
+        lua.register_module(module.get_name(), table)?;
+    }
+
     let mqtt = lua.create_table()?;
     let event_channel = device_manager.event_channel();
     let mqtt_new = lua.create_function(move |lua, config: mlua::Value| {
@@ -174,7 +184,6 @@ async fn app() -> anyhow::Result<()> {
     utils.set("get_epoch", get_epoch)?;
     lua.register_module("utils", utils)?;
 
-    automation_devices::register_with_lua(&lua)?;
     helpers::register_with_lua(&lua)?;
 
     let entrypoint = Path::new(&config.entrypoint);