Merge branch 'feature/event-network' into 'development'

Feature/event network

See merge request fabinfra/fabaccess/bffh!3
This commit is contained in:
Gregor Reitzenstein 2020-09-18 13:07:12 +00:00
commit 832baea07d
9 changed files with 362 additions and 96 deletions

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@ -19,9 +19,9 @@ use crate::config::Settings;
use crate::error::Result; use crate::error::Result;
// FIXME: fabinfra/fabaccess/bffh#3 // FIXME: fabinfra/fabaccess/bffh#3
type UserIdentifier = u64; pub type UserIdentifier = u64;
type RoleIdentifier = u64; pub type RoleIdentifier = u64;
type PermIdentifier = u64; pub type PermIdentifier = u64;
pub struct PermissionsProvider { pub struct PermissionsProvider {
log: Logger, log: Logger,

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@ -1,6 +1,9 @@
use std::str::FromStr;
use std::collections::HashMap; use std::collections::HashMap;
use std::fs;
use std::fs::File; use std::fs::File;
use std::io::{Read, Write}; use std::io::{Read, Write};
use std::path::{Path, PathBuf};
use slog::Logger; use slog::Logger;
@ -11,19 +14,25 @@ use smol::lock::RwLock;
use crate::error::Result; use crate::error::Result;
use crate::config::Settings; use crate::config::Settings;
use crate::access;
use capnp::Error; use capnp::Error;
use uuid::Uuid; use uuid::Uuid;
use lmdb::{Transaction, RwTransaction}; use lmdb::{Transaction, RwTransaction, Cursor};
use smol::channel::{Receiver, Sender}; use smol::channel::{Receiver, Sender};
use futures_signals::signal::*; use futures_signals::signal::*;
use crate::registries::StatusSignal;
pub type ID = Uuid;
/// Status of a Machine /// Status of a Machine
#[derive(Clone, Copy, PartialEq, Eq, Debug, Serialize, Deserialize)] #[derive(Clone, Copy, PartialEq, Eq, Debug, Serialize, Deserialize)]
#[repr(u8)]
pub enum Status { pub enum Status {
/// Not currently used by anybody /// Not currently used by anybody
Free, Free,
@ -33,17 +42,6 @@ pub enum Status {
Blocked, Blocked,
} }
pub struct MachinesProvider {
log: Logger,
mdb: MachineDB,
}
impl MachinesProvider {
pub fn new(log: Logger, mdb: MachineDB) -> Self {
Self { log, mdb }
}
}
#[derive(Clone)] #[derive(Clone)]
pub struct Machines { pub struct Machines {
inner: Arc<RwLock<MachinesProvider>>, inner: Arc<RwLock<MachinesProvider>>,
@ -98,11 +96,16 @@ impl MachineManager {
/// machine, checking that the user who wants the machine (de)activated has the required /// machine, checking that the user who wants the machine (de)activated has the required
/// permissions. /// permissions.
pub struct Machine { pub struct Machine {
/// Computer-readable identifier for this machine
// Implicit in database since it's the key.
#[serde(skip)]
id: ID,
/// The human-readable name of the machine. Does not need to be unique /// The human-readable name of the machine. Does not need to be unique
name: String, name: String,
/// The required permission to use this machine. /// The required permission to use this machine.
perm: String, perm: access::PermIdentifier,
/// The state of the machine as bffh thinks the machine *should* be in. /// The state of the machine as bffh thinks the machine *should* be in.
/// ///
@ -112,8 +115,9 @@ pub struct Machine {
} }
impl Machine { impl Machine {
pub fn new(name: String, perm: String) -> Machine { pub fn new(id: Uuid, name: String, perm: access::PermIdentifier) -> Machine {
Machine { Machine {
id: id,
name: name, name: name,
perm: perm, perm: perm,
state: Mutable::new(Status::Free), state: Mutable::new(Status::Free),
@ -128,18 +132,41 @@ impl Machine {
/// dedupe ensures that if state is changed but only changes to the value it had beforehand /// dedupe ensures that if state is changed but only changes to the value it had beforehand
/// (could for example happen if the machine changes current user but stays activated) no /// (could for example happen if the machine changes current user but stays activated) no
/// update is sent. /// update is sent.
pub fn signal(&self) -> impl Signal { pub fn signal(&self) -> StatusSignal {
self.state.signal().dedupe() Box::pin(self.state.signal().dedupe())
}
/// Requests to use a machine. Returns `true` if successful.
///
/// This will update the internal state of the machine, notifying connected actors, if any.
pub fn request_use<T: Transaction>
( &mut self
, txn: &T
, pp: &access::PermissionsProvider
, who: access::UserIdentifier
) -> Result<bool>
{
if pp.check(txn, who, self.perm)? {
self.state.set(Status::Occupied);
return Ok(true);
} else {
return Ok(false);
}
}
pub fn set_state(&mut self, state: Status) {
self.state.set(state)
} }
} }
pub struct MachineDB { pub struct MachinesProvider {
log: Logger,
db: lmdb::Database, db: lmdb::Database,
} }
impl MachineDB { impl MachinesProvider {
pub fn new(db: lmdb::Database) -> Self { pub fn new(log: Logger, db: lmdb::Database) -> Self {
Self { db } Self { log, db }
} }
pub fn get_machine<T: Transaction>(&self, txn: &T, uuid: Uuid) pub fn get_machine<T: Transaction>(&self, txn: &T, uuid: Uuid)
@ -147,7 +174,10 @@ impl MachineDB {
{ {
match txn.get(self.db, &uuid.as_bytes()) { match txn.get(self.db, &uuid.as_bytes()) {
Ok(bytes) => { Ok(bytes) => {
Ok(Some(flexbuffers::from_slice(bytes)?)) let mut machine: Machine = flexbuffers::from_slice(bytes)?;
machine.id = uuid;
Ok(Some(machine))
}, },
Err(lmdb::Error::NotFound) => { Ok(None) }, Err(lmdb::Error::NotFound) => { Ok(None) },
Err(e) => { Err(e.into()) }, Err(e) => { Err(e.into()) },
@ -162,8 +192,75 @@ impl MachineDB {
Ok(()) Ok(())
} }
pub fn load_db(&mut self, txn: &mut RwTransaction, mut path: PathBuf) -> Result<()> {
path.push("machines");
for entry in std::fs::read_dir(path)? {
let entry = entry?;
let path = entry.path();
if path.is_file() {
// will only ever be none if the path has no file name and then how is it a file?!
let machID_str = path
.file_stem().expect("Found a file with no filename?")
.to_str().expect("Found an OsStr that isn't valid Unicode. Fix your OS!");
let machID = match uuid::Uuid::from_str(machID_str) {
Ok(i) => i,
Err(e) => {
warn!(self.log, "File {} had a invalid name. Expected an u64 in [0-9a-z] hex with optional file ending: {}. Skipping!", path.display(), e);
continue;
}
};
let s = match fs::read_to_string(path.as_path()) {
Ok(s) => s,
Err(e) => {
warn!(self.log, "Failed to open file {}: {}, skipping!"
, path.display()
, e);
continue;
}
};
let mach: Machine = match toml::from_str(&s) {
Ok(r) => r,
Err(e) => {
warn!(self.log, "Failed to parse mach at path {}: {}, skipping!"
, path.display()
, e);
continue;
}
};
self.put_machine(txn, machID, mach)?;
debug!(self.log, "Loaded machine {}", machID);
} else {
warn!(self.log, "Path {} is not a file, skipping!", path.display());
}
}
Ok(())
}
pub fn dump_db<T: Transaction>(&self, txn: &T, mut path: PathBuf) -> Result<()> {
path.push("machines");
let mut mach_cursor = txn.open_ro_cursor(self.db)?;
for buf in mach_cursor.iter_start() {
let (kbuf, vbuf) = buf?;
let machID = uuid::Uuid::from_slice(kbuf).unwrap();
let mach: Machine = flexbuffers::from_slice(vbuf)?;
let filename = format!("{}.yml", machID.to_hyphenated().to_string());
path.set_file_name(filename);
let mut fp = std::fs::File::create(&path)?;
let out = toml::to_vec(&mach)?;
fp.write_all(&out)?;
}
Ok(())
}
} }
pub async fn init(log: Logger, config: &Settings) -> Result<MachinesProvider> { pub fn init(log: Logger, config: &Settings, env: &lmdb::Environment) -> Result<MachinesProvider> {
unimplemented!() let mut flags = lmdb::DatabaseFlags::empty();
flags.set(lmdb::DatabaseFlags::INTEGER_KEY, true);
let machdb = env.create_db(Some("machines"), flags)?;
debug!(&log, "Opened machine db successfully.");
Ok(MachinesProvider::new(log, machdb))
} }

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@ -132,7 +132,7 @@ fn main() -> Result<(), Error> {
// Start loading the machine database, authentication system and permission system // Start loading the machine database, authentication system and permission system
// All of those get a custom logger so the source of a log message can be better traced and // All of those get a custom logger so the source of a log message can be better traced and
// filtered // filtered
let machinedb_f = machine::init(log.new(o!("system" => "machines")), &config); let mdb = machine::init(log.new(o!("system" => "machines")), &config, &env);
let pdb = access::init(log.new(o!("system" => "permissions")), &config, &env); let pdb = access::init(log.new(o!("system" => "permissions")), &config, &env);
let authentication_f = auth::init(log.new(o!("system" => "authentication")), config.clone()); let authentication_f = auth::init(log.new(o!("system" => "authentication")), config.clone());
@ -148,7 +148,8 @@ fn main() -> Result<(), Error> {
let mut txn = env.begin_rw_txn()?; let mut txn = env.begin_rw_txn()?;
let path = path.to_path_buf(); let path = path.to_path_buf();
pdb?.load_db(&mut txn, path)?; pdb?.load_db(&mut txn, path.clone())?;
mdb?.load_db(&mut txn, path)?;
txn.commit(); txn.commit();
} else { } else {
error!(log, "You must provide a directory path to load from"); error!(log, "You must provide a directory path to load from");
@ -165,9 +166,9 @@ fn main() -> Result<(), Error> {
let txn = env.begin_ro_txn()?; let txn = env.begin_ro_txn()?;
let path = path.to_path_buf(); let path = path.to_path_buf();
pdb?.dump_db(&txn, path)?; pdb?.dump_db(&txn, path.clone())?;
mdb?.dump_db(&txn, path)?;
} else { } else {
error!(log, "You must provide a directory path to dump into"); error!(log, "You must provide a directory path to dump into");
} }
@ -197,16 +198,16 @@ fn main() -> Result<(), Error> {
} }
}).collect(); }).collect();
let (mach, auth) = exec.run_until(async { //let (mach, auth) = exec.run_until(async {
// Rull all futures to completion in parallel. // // Rull all futures to completion in parallel.
// This will block until all three are done starting up. // // This will block until all three are done starting up.
join!(machinedb_f, authentication_f) // join!(machinedb_f, authentication_f)
}); //});
// Error out if any of the subsystems failed to start. // Error out if any of the subsystems failed to start.
let mach = mach?; let mdb = mdb?;
let pdb = pdb?; let pdb = pdb?;
let auth = auth?; //let auth = auth?;
// Since the below closures will happen at a much later time we need to make sure all pointers // Since the below closures will happen at a much later time we need to make sure all pointers
// are still valid. Thus, Arc. // are still valid. Thus, Arc.
@ -228,8 +229,8 @@ fn main() -> Result<(), Error> {
// FIXME: implement notification so the modules can shut down cleanly instead of being killed // FIXME: implement notification so the modules can shut down cleanly instead of being killed
// without warning. // without warning.
let modlog = log.clone(); let modlog = log.clone();
let regs = Registries::new(); let mut regs = Registries::new();
match modules::init(modlog.new(o!("system" => "modules")), &config, &local_spawn, regs) { match exec.run_until(modules::init(modlog.new(o!("system" => "modules")), config.clone(), pool.clone(), regs.clone())) {
Ok(()) => {} Ok(()) => {}
Err(e) => { Err(e) => {
error!(modlog, "Module startup failed: {}", e); error!(modlog, "Module startup failed: {}", e);

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@ -10,16 +10,15 @@ use slog::Logger;
mod shelly; mod shelly;
use futures::prelude::*; use futures::prelude::*;
use futures::task::LocalSpawn; use futures::task::Spawn;
use crate::config::Settings; use crate::config::Settings;
use crate::error::Result; use crate::error::Result;
use crate::registries::Registries; use crate::registries::Registries;
// spawner is a type that allows 'tasks' to be spawned on it, running them to completion. // spawner is a type that allows 'tasks' to be spawned on it, running them to completion.
pub fn init<S: LocalSpawn>(log: Logger, config: &Settings, spawner: &S, registries: Registries) -> Result<()> { pub async fn init<S: Spawn + Clone + Send>(log: Logger, config: Settings, spawner: S, registries: Registries) -> Result<()> {
let f = Box::new(shelly::run(log.clone(), config.clone(), registries.clone())); shelly::run(log.clone(), config.clone(), registries.clone(), spawner.clone()).await;
spawner.spawn_local_obj(f.into())?;
Ok(()) Ok(())
} }

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@ -1,30 +1,32 @@
use slog::Logger; use slog::Logger;
use crate::config::Settings; use crate::config::Settings;
use crate::registries::{Registries, Actuator, ActBox}; use crate::registries::{Registries, Actuator, ActBox, StatusSignal};
use crate::error::Result; use crate::error::Result;
use crate::machine::Status;
use std::pin::Pin; use std::pin::Pin;
use futures::prelude::*; use futures::prelude::*;
use futures::channel::mpsc;
use futures::ready; use futures::ready;
use futures::task::{Poll, Context}; use futures::task::{Poll, Context, Waker, Spawn, FutureObj};
use futures::StreamExt;
use futures_signals::signal::Signal;
use paho_mqtt as mqtt; use paho_mqtt as mqtt;
// TODO: Late config parsing. Right now the config is validated at the very startup in its // TODO: Late config parsing. Right now the config is validated at the very startup in its
// entirety. This works reasonably enough for this static modules here but if we do dynamic loading // entirety. This works reasonably enough for this static modules here but if we do dynamic loading
// via dlopen(), lua API, python API etc it will not. // via dlopen(), lua API, python API etc it will not.
pub async fn run(log: Logger, config: Settings, registries: Registries) { pub async fn run<S: Spawn>(log: Logger, config: Settings, registries: Registries, spawner: S) {
let shelly_r = Shelly::new(config).await; let (tx, rx) = mpsc::channel(1);
if let Err(e) = shelly_r { let mut shelly = Shelly::new(log, config, rx).await;
error!(log, "Shelly module errored: {}", e);
return; let r = registries.actuators.register("shelly".to_string(), tx).await;
}
let f = shelly.for_each(|f| f);
spawner.spawn_obj(FutureObj::from(Box::pin(f)));
let r = registries.actuators.register(
"shelly".to_string(),
shelly_r.unwrap()
).await;
} }
/// An actuator for all Shellies connected listening on one MQTT broker /// An actuator for all Shellies connected listening on one MQTT broker
@ -32,31 +34,87 @@ pub async fn run(log: Logger, config: Settings, registries: Registries) {
/// This actuator can power toggle an arbitrariy named shelly on the broker it is connected to. If /// This actuator can power toggle an arbitrariy named shelly on the broker it is connected to. If
/// you need to toggle shellies on multiple brokers you need multiple instanced of this actuator. /// you need to toggle shellies on multiple brokers you need multiple instanced of this actuator.
struct Shelly { struct Shelly {
log: Logger,
sigchan: mpsc::Receiver<StatusSignal>,
signal: Option<StatusSignal>,
waker: Option<Waker>,
name: String,
client: mqtt::AsyncClient, client: mqtt::AsyncClient,
} }
impl Shelly { impl Shelly {
pub async fn new(config: Settings) -> Result<ActBox> { // Can't use Error, it's not Send. fabinfra/fabaccess/bffh#7
let client = mqtt::AsyncClient::new(config.shelly.unwrap().mqtt_url)?; pub async fn new(log: Logger, config: Settings, sigchan: mpsc::Receiver<StatusSignal>) -> Self {
let client = mqtt::AsyncClient::new(config.shelly.unwrap().mqtt_url).unwrap();
client.connect(mqtt::ConnectOptions::new()).await?; let o = client.connect(mqtt::ConnectOptions::new()).await.unwrap();
println!("{:?}", o);
Ok(Box::new(Shelly { client }) as ActBox) let name = "test".to_string();
let signal: Option<StatusSignal> = None;
let waker = None;
Shelly { log, sigchan, signal, waker, name, client }
} }
} }
#[async_trait]
impl Actuator for Shelly { impl Actuator for Shelly {
async fn power_on(&mut self, name: String) { fn subscribe(&mut self, signal: StatusSignal) {
let topic = format!("shellies/{}/relay/0/command", name); self.signal.replace(signal);
let msg = mqtt::Message::new(topic, "on", 0); if let Some(waker) = self.waker.take() {
self.client.publish(msg).map(|_| ()).await waker.wake();
} }
}
async fn power_off(&mut self, name: String) { }
let topic = format!("shellies/{}/relay/0/command", name);
let msg = mqtt::Message::new(topic, "off", 0); impl Stream for Shelly {
self.client.publish(msg).map(|_| ()).await type Item = future::BoxFuture<'static, ()>;
fn poll_next(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
let unpin = Pin::into_inner(self);
info!(unpin.log, "tick {}", unpin.signal.is_some());
if let Poll::Ready(v) = Stream::poll_next(Pin::new(&mut unpin.sigchan), cx) {
if let Some(s) = v {
// We have received a new signal to use
unpin.signal.replace(s);
// We use `if let` instead of .and_then because we want the waker to be dropped
// afterwards. It's only there to ensure the future is called when a signal is
// installed the first time
// TODO probably don't need that here because we're polling it either way directly
// afterwards, eh?
if let Some(waker) = unpin.waker.take() {
waker.wake();
}
} else {
info!(unpin.log, "bye");
// This means that the sending end was dropped, so we shut down
unpin.signal.take();
unpin.waker.take();
return Poll::Ready(None);
}
}
if let Some(ref mut s) = unpin.signal {
if let Some(status) = ready!(Signal::poll_change(Pin::new(s), cx)) {
info!(unpin.log, "Machine Status changed: {:?}", status);
let topic = format!("shellies/{}/relay/0/command", unpin.name);
let pl = match status {
Status::Free | Status::Blocked => "off",
Status::Occupied => "on",
};
let msg = mqtt::Message::new(topic, pl, 0);
let f = unpin.client.publish(msg).map(|_| ());
return Poll::Ready(Some(Box::pin(f)));
}
} else {
info!(unpin.log, "I ain't got no signal son");
unpin.waker.replace(cx.waker().clone());
}
Poll::Pending
} }
} }

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@ -1,5 +1,8 @@
use futures_signals::signal::Signal; use futures_signals::signal::Signal;
use crate::machine;
use crate::access;
struct Network { struct Network {
} }
@ -24,10 +27,12 @@ impl Network {
} }
} }
/// The internal bffh event type
///
/// Everything that BFFH considers an event is contained in an instance of this.
#[derive(PartialEq, Eq, Clone, PartialOrd, Ord, Debug)]
enum Event { enum Event {
/// An user wants to use a machine
} // TODO: Define /what/ an user wants to do with said machine?
MachineRequest(machine::ID, access::UserIdentifier),
trait Filter<S> {
fn filter(&self, f: Fn(&S) -> bool);
} }

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@ -1,6 +1,8 @@
mod actuators; mod actuators;
mod sensors;
pub use actuators::{Actuator, ActBox}; pub use actuators::{Actuator, ActBox, StatusSignal};
pub use sensors::{Sensor, SensBox};
#[derive(Clone)] #[derive(Clone)]
/// BFFH registries /// BFFH registries
@ -9,12 +11,14 @@ pub use actuators::{Actuator, ActBox};
/// reference, not clone the registries /// reference, not clone the registries
pub struct Registries { pub struct Registries {
pub actuators: actuators::Actuators, pub actuators: actuators::Actuators,
pub sensors: sensors::Sensors,
} }
impl Registries { impl Registries {
pub fn new() -> Self { pub fn new() -> Self {
Registries { Registries {
actuators: actuators::Actuators::new() actuators: actuators::Actuators::new(),
sensors: sensors::Sensors::new(),
} }
} }
} }

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@ -1,7 +1,16 @@
use slog::Logger;
use std::sync::Arc; use std::sync::Arc;
use smol::lock::RwLock; use smol::lock::RwLock;
use std::pin::Pin;
use futures::ready;
use futures::prelude::*; use futures::prelude::*;
use futures::channel::mpsc;
use futures::task::{Context, Poll, Spawn};
use futures_signals::signal::Signal;
use crate::machine::Status;
use std::collections::HashMap; use std::collections::HashMap;
@ -10,11 +19,9 @@ pub struct Actuators {
inner: Arc<RwLock<Inner>>, inner: Arc<RwLock<Inner>>,
} }
unsafe impl Send for Actuators { } pub type ActBox = Box<dyn Actuator + Sync + Send + Unpin>;
pub type ActBox = Box<dyn Actuator>; type Inner = HashMap<String, mpsc::Sender<StatusSignal>>;
type Inner = HashMap<String, ActBox>;
impl Actuators { impl Actuators {
pub fn new() -> Self { pub fn new() -> Self {
@ -23,31 +30,53 @@ impl Actuators {
} }
} }
pub async fn register(&self, name: String, act: ActBox) { pub async fn register(&self, name: String, tx: mpsc::Sender<StatusSignal>) {
let mut wlock = self.inner.write().await; let mut wlock = self.inner.write().await;
// TODO: Log an error or something if that name was already taken // TODO: Log an error or something if that name was already taken
wlock.insert(name, act); wlock.insert(name, tx);
}
pub async fn subscribe(&mut self, name: String, signal: StatusSignal) {
let mut wlock = self.inner.write().await;
if let Some(tx) = wlock.get_mut(&name) {
tx.send(signal).await;
}
} }
} }
pub type StatusSignal = Pin<Box<dyn Signal<Item = Status> + Send + Sync>>;
#[async_trait] pub trait Actuator: Stream<Item = future::BoxFuture<'static, ()>> {
pub trait Actuator { fn subscribe(&mut self, signal: StatusSignal);
// TODO: Is it smarter to pass a (reference to?) a machine instead of 'name'? Do we need to
// pass basically arbitrary parameters to the Actuator?
async fn power_on(&mut self, name: String);
async fn power_off(&mut self, name: String);
} }
// This is merely a proof that Actuator *can* be implemented on a finite, known type. Yay for type // This is merely a proof that Actuator *can* be implemented on a finite, known type. Yay for type
// systems with halting problems. // systems with halting problems.
struct Dummy; struct Dummy {
#[async_trait] log: Logger,
sigchan: mpsc::Receiver<StatusSignal>,
signal: Option<StatusSignal>,
}
impl Actuator for Dummy { impl Actuator for Dummy {
async fn power_on(&mut self, _name: String) { fn subscribe(&mut self, signal: StatusSignal) {
return self.signal.replace(signal);
} }
async fn power_off(&mut self, _name: String) { }
return
impl Stream for Dummy {
type Item = future::BoxFuture<'static, ()>;
fn poll_next(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
let unpin = Pin::into_inner(self);
if let Some(ref mut s) = unpin.signal {
let status = ready!(Signal::poll_change(Pin::new(s), cx));
info!(unpin.log, "Dummy actuator would set status to {:?}, but is a Dummy", status);
Poll::Ready(Some(Box::pin(futures::future::ready(()))))
} else {
Poll::Pending
}
} }
} }

73
src/registries/sensors.rs Normal file
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@ -0,0 +1,73 @@
use std::pin::Pin;
use futures::task::{Context, Poll};
use futures::{Future, Stream};
use futures::future::BoxFuture;
use std::sync::Arc;
use smol::lock::RwLock;
use std::collections::HashMap;
#[derive(Clone)]
pub struct Sensors {
inner: Arc<RwLock<Inner>>,
}
impl Sensors {
pub fn new() -> Self {
Sensors {
inner: Arc::new(RwLock::new(Inner::new())),
}
}
}
pub type SensBox = Box<dyn Sensor + Send + Sync>;
type Inner = HashMap<String, SensBox>;
// Implementing Sensors.
//
// Given the coroutine/task split stays as it is - Sensor input to machine update being one,
// machine update signal to actor doing thing being another, a Sensor implementation would send a
// Stream of futures - each future being an atomic Machine update.
#[async_trait]
/// BFFH Sensor
///
/// A sensor is anything that can forward an intent of an user to do something to bffh.
/// This may be a card reader connected to a machine, a website allowing users to select a machine
/// they want to use or something like QRHello
pub trait Sensor: Stream<Item = BoxFuture<'static, ()>> {
/// Setup the Sensor.
///
/// After this async function completes the Stream implementation should be able to generate
/// futures when polled.
/// Implementations can rely on this function being polled to completeion before the stream
/// is polled.
// TODO Is this sensible vs just having module-specific setup fns?
async fn setup(&mut self);
/// Shutdown the sensor gracefully
///
/// Implementations can rely on that the stream will not be polled after this function has been
/// called.
async fn shutdown(&mut self);
}
struct Dummy;
#[async_trait]
impl Sensor for Dummy {
async fn setup(&mut self) {
return;
}
async fn shutdown(&mut self) {
return;
}
}
impl Stream for Dummy {
type Item = BoxFuture<'static, ()>;
fn poll_next(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
Poll::Ready(Some(Box::pin(futures::future::ready(()))))
}
}